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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
5 */
6#include <linux/list.h>
7#include <linux/init.h>
8#include <linux/mm.h>
9#include <linux/seq_file.h>
10#include <linux/sysctl.h>
11#include <linux/highmem.h>
12#include <linux/mmu_notifier.h>
13#include <linux/nodemask.h>
14#include <linux/pagemap.h>
15#include <linux/mempolicy.h>
16#include <linux/compiler.h>
17#include <linux/cpuset.h>
18#include <linux/mutex.h>
19#include <linux/memblock.h>
20#include <linux/sysfs.h>
21#include <linux/slab.h>
22#include <linux/sched/mm.h>
23#include <linux/mmdebug.h>
24#include <linux/sched/signal.h>
25#include <linux/rmap.h>
26#include <linux/string_helpers.h>
27#include <linux/swap.h>
28#include <linux/swapops.h>
29#include <linux/jhash.h>
30#include <linux/numa.h>
31#include <linux/llist.h>
32#include <linux/cma.h>
33#include <linux/migrate.h>
34#include <linux/nospec.h>
35#include <linux/delayacct.h>
36#include <linux/memory.h>
37#include <linux/mm_inline.h>
38
39#include <asm/page.h>
40#include <asm/pgalloc.h>
41#include <asm/tlb.h>
42
43#include <linux/io.h>
44#include <linux/hugetlb.h>
45#include <linux/hugetlb_cgroup.h>
46#include <linux/node.h>
47#include <linux/page_owner.h>
48#include "internal.h"
49#include "hugetlb_vmemmap.h"
50
51int hugetlb_max_hstate __read_mostly;
52unsigned int default_hstate_idx;
53struct hstate hstates[HUGE_MAX_HSTATE];
54
55#ifdef CONFIG_CMA
56static struct cma *hugetlb_cma[MAX_NUMNODES];
57static unsigned long hugetlb_cma_size_in_node[MAX_NUMNODES] __initdata;
58static bool hugetlb_cma_folio(struct folio *folio, unsigned int order)
59{
60 return cma_pages_valid(hugetlb_cma[folio_nid(folio)], &folio->page,
61 1 << order);
62}
63#else
64static bool hugetlb_cma_folio(struct folio *folio, unsigned int order)
65{
66 return false;
67}
68#endif
69static unsigned long hugetlb_cma_size __initdata;
70
71__initdata LIST_HEAD(huge_boot_pages);
72
73/* for command line parsing */
74static struct hstate * __initdata parsed_hstate;
75static unsigned long __initdata default_hstate_max_huge_pages;
76static bool __initdata parsed_valid_hugepagesz = true;
77static bool __initdata parsed_default_hugepagesz;
78static unsigned int default_hugepages_in_node[MAX_NUMNODES] __initdata;
79
80/*
81 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
82 * free_huge_pages, and surplus_huge_pages.
83 */
84DEFINE_SPINLOCK(hugetlb_lock);
85
86/*
87 * Serializes faults on the same logical page. This is used to
88 * prevent spurious OOMs when the hugepage pool is fully utilized.
89 */
90static int num_fault_mutexes;
91struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
92
93/* Forward declaration */
94static int hugetlb_acct_memory(struct hstate *h, long delta);
95static void hugetlb_vma_lock_free(struct vm_area_struct *vma);
96static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma);
97static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma);
98static void hugetlb_unshare_pmds(struct vm_area_struct *vma,
99 unsigned long start, unsigned long end);
100static struct resv_map *vma_resv_map(struct vm_area_struct *vma);
101
102static inline bool subpool_is_free(struct hugepage_subpool *spool)
103{
104 if (spool->count)
105 return false;
106 if (spool->max_hpages != -1)
107 return spool->used_hpages == 0;
108 if (spool->min_hpages != -1)
109 return spool->rsv_hpages == spool->min_hpages;
110
111 return true;
112}
113
114static inline void unlock_or_release_subpool(struct hugepage_subpool *spool,
115 unsigned long irq_flags)
116{
117 spin_unlock_irqrestore(&spool->lock, irq_flags);
118
119 /* If no pages are used, and no other handles to the subpool
120 * remain, give up any reservations based on minimum size and
121 * free the subpool */
122 if (subpool_is_free(spool)) {
123 if (spool->min_hpages != -1)
124 hugetlb_acct_memory(spool->hstate,
125 -spool->min_hpages);
126 kfree(spool);
127 }
128}
129
130struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
131 long min_hpages)
132{
133 struct hugepage_subpool *spool;
134
135 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
136 if (!spool)
137 return NULL;
138
139 spin_lock_init(&spool->lock);
140 spool->count = 1;
141 spool->max_hpages = max_hpages;
142 spool->hstate = h;
143 spool->min_hpages = min_hpages;
144
145 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
146 kfree(spool);
147 return NULL;
148 }
149 spool->rsv_hpages = min_hpages;
150
151 return spool;
152}
153
154void hugepage_put_subpool(struct hugepage_subpool *spool)
155{
156 unsigned long flags;
157
158 spin_lock_irqsave(&spool->lock, flags);
159 BUG_ON(!spool->count);
160 spool->count--;
161 unlock_or_release_subpool(spool, flags);
162}
163
164/*
165 * Subpool accounting for allocating and reserving pages.
166 * Return -ENOMEM if there are not enough resources to satisfy the
167 * request. Otherwise, return the number of pages by which the
168 * global pools must be adjusted (upward). The returned value may
169 * only be different than the passed value (delta) in the case where
170 * a subpool minimum size must be maintained.
171 */
172static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
173 long delta)
174{
175 long ret = delta;
176
177 if (!spool)
178 return ret;
179
180 spin_lock_irq(&spool->lock);
181
182 if (spool->max_hpages != -1) { /* maximum size accounting */
183 if ((spool->used_hpages + delta) <= spool->max_hpages)
184 spool->used_hpages += delta;
185 else {
186 ret = -ENOMEM;
187 goto unlock_ret;
188 }
189 }
190
191 /* minimum size accounting */
192 if (spool->min_hpages != -1 && spool->rsv_hpages) {
193 if (delta > spool->rsv_hpages) {
194 /*
195 * Asking for more reserves than those already taken on
196 * behalf of subpool. Return difference.
197 */
198 ret = delta - spool->rsv_hpages;
199 spool->rsv_hpages = 0;
200 } else {
201 ret = 0; /* reserves already accounted for */
202 spool->rsv_hpages -= delta;
203 }
204 }
205
206unlock_ret:
207 spin_unlock_irq(&spool->lock);
208 return ret;
209}
210
211/*
212 * Subpool accounting for freeing and unreserving pages.
213 * Return the number of global page reservations that must be dropped.
214 * The return value may only be different than the passed value (delta)
215 * in the case where a subpool minimum size must be maintained.
216 */
217static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
218 long delta)
219{
220 long ret = delta;
221 unsigned long flags;
222
223 if (!spool)
224 return delta;
225
226 spin_lock_irqsave(&spool->lock, flags);
227
228 if (spool->max_hpages != -1) /* maximum size accounting */
229 spool->used_hpages -= delta;
230
231 /* minimum size accounting */
232 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
233 if (spool->rsv_hpages + delta <= spool->min_hpages)
234 ret = 0;
235 else
236 ret = spool->rsv_hpages + delta - spool->min_hpages;
237
238 spool->rsv_hpages += delta;
239 if (spool->rsv_hpages > spool->min_hpages)
240 spool->rsv_hpages = spool->min_hpages;
241 }
242
243 /*
244 * If hugetlbfs_put_super couldn't free spool due to an outstanding
245 * quota reference, free it now.
246 */
247 unlock_or_release_subpool(spool, flags);
248
249 return ret;
250}
251
252static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
253{
254 return HUGETLBFS_SB(inode->i_sb)->spool;
255}
256
257static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
258{
259 return subpool_inode(file_inode(vma->vm_file));
260}
261
262/*
263 * hugetlb vma_lock helper routines
264 */
265void hugetlb_vma_lock_read(struct vm_area_struct *vma)
266{
267 if (__vma_shareable_lock(vma)) {
268 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
269
270 down_read(&vma_lock->rw_sema);
271 } else if (__vma_private_lock(vma)) {
272 struct resv_map *resv_map = vma_resv_map(vma);
273
274 down_read(&resv_map->rw_sema);
275 }
276}
277
278void hugetlb_vma_unlock_read(struct vm_area_struct *vma)
279{
280 if (__vma_shareable_lock(vma)) {
281 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
282
283 up_read(&vma_lock->rw_sema);
284 } else if (__vma_private_lock(vma)) {
285 struct resv_map *resv_map = vma_resv_map(vma);
286
287 up_read(&resv_map->rw_sema);
288 }
289}
290
291void hugetlb_vma_lock_write(struct vm_area_struct *vma)
292{
293 if (__vma_shareable_lock(vma)) {
294 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
295
296 down_write(&vma_lock->rw_sema);
297 } else if (__vma_private_lock(vma)) {
298 struct resv_map *resv_map = vma_resv_map(vma);
299
300 down_write(&resv_map->rw_sema);
301 }
302}
303
304void hugetlb_vma_unlock_write(struct vm_area_struct *vma)
305{
306 if (__vma_shareable_lock(vma)) {
307 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
308
309 up_write(&vma_lock->rw_sema);
310 } else if (__vma_private_lock(vma)) {
311 struct resv_map *resv_map = vma_resv_map(vma);
312
313 up_write(&resv_map->rw_sema);
314 }
315}
316
317int hugetlb_vma_trylock_write(struct vm_area_struct *vma)
318{
319
320 if (__vma_shareable_lock(vma)) {
321 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
322
323 return down_write_trylock(&vma_lock->rw_sema);
324 } else if (__vma_private_lock(vma)) {
325 struct resv_map *resv_map = vma_resv_map(vma);
326
327 return down_write_trylock(&resv_map->rw_sema);
328 }
329
330 return 1;
331}
332
333void hugetlb_vma_assert_locked(struct vm_area_struct *vma)
334{
335 if (__vma_shareable_lock(vma)) {
336 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
337
338 lockdep_assert_held(&vma_lock->rw_sema);
339 } else if (__vma_private_lock(vma)) {
340 struct resv_map *resv_map = vma_resv_map(vma);
341
342 lockdep_assert_held(&resv_map->rw_sema);
343 }
344}
345
346void hugetlb_vma_lock_release(struct kref *kref)
347{
348 struct hugetlb_vma_lock *vma_lock = container_of(kref,
349 struct hugetlb_vma_lock, refs);
350
351 kfree(vma_lock);
352}
353
354static void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock)
355{
356 struct vm_area_struct *vma = vma_lock->vma;
357
358 /*
359 * vma_lock structure may or not be released as a result of put,
360 * it certainly will no longer be attached to vma so clear pointer.
361 * Semaphore synchronizes access to vma_lock->vma field.
362 */
363 vma_lock->vma = NULL;
364 vma->vm_private_data = NULL;
365 up_write(&vma_lock->rw_sema);
366 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
367}
368
369static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma)
370{
371 if (__vma_shareable_lock(vma)) {
372 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
373
374 __hugetlb_vma_unlock_write_put(vma_lock);
375 } else if (__vma_private_lock(vma)) {
376 struct resv_map *resv_map = vma_resv_map(vma);
377
378 /* no free for anon vmas, but still need to unlock */
379 up_write(&resv_map->rw_sema);
380 }
381}
382
383static void hugetlb_vma_lock_free(struct vm_area_struct *vma)
384{
385 /*
386 * Only present in sharable vmas.
387 */
388 if (!vma || !__vma_shareable_lock(vma))
389 return;
390
391 if (vma->vm_private_data) {
392 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
393
394 down_write(&vma_lock->rw_sema);
395 __hugetlb_vma_unlock_write_put(vma_lock);
396 }
397}
398
399static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma)
400{
401 struct hugetlb_vma_lock *vma_lock;
402
403 /* Only establish in (flags) sharable vmas */
404 if (!vma || !(vma->vm_flags & VM_MAYSHARE))
405 return;
406
407 /* Should never get here with non-NULL vm_private_data */
408 if (vma->vm_private_data)
409 return;
410
411 vma_lock = kmalloc(sizeof(*vma_lock), GFP_KERNEL);
412 if (!vma_lock) {
413 /*
414 * If we can not allocate structure, then vma can not
415 * participate in pmd sharing. This is only a possible
416 * performance enhancement and memory saving issue.
417 * However, the lock is also used to synchronize page
418 * faults with truncation. If the lock is not present,
419 * unlikely races could leave pages in a file past i_size
420 * until the file is removed. Warn in the unlikely case of
421 * allocation failure.
422 */
423 pr_warn_once("HugeTLB: unable to allocate vma specific lock\n");
424 return;
425 }
426
427 kref_init(&vma_lock->refs);
428 init_rwsem(&vma_lock->rw_sema);
429 vma_lock->vma = vma;
430 vma->vm_private_data = vma_lock;
431}
432
433/* Helper that removes a struct file_region from the resv_map cache and returns
434 * it for use.
435 */
436static struct file_region *
437get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
438{
439 struct file_region *nrg;
440
441 VM_BUG_ON(resv->region_cache_count <= 0);
442
443 resv->region_cache_count--;
444 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
445 list_del(&nrg->link);
446
447 nrg->from = from;
448 nrg->to = to;
449
450 return nrg;
451}
452
453static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
454 struct file_region *rg)
455{
456#ifdef CONFIG_CGROUP_HUGETLB
457 nrg->reservation_counter = rg->reservation_counter;
458 nrg->css = rg->css;
459 if (rg->css)
460 css_get(rg->css);
461#endif
462}
463
464/* Helper that records hugetlb_cgroup uncharge info. */
465static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
466 struct hstate *h,
467 struct resv_map *resv,
468 struct file_region *nrg)
469{
470#ifdef CONFIG_CGROUP_HUGETLB
471 if (h_cg) {
472 nrg->reservation_counter =
473 &h_cg->rsvd_hugepage[hstate_index(h)];
474 nrg->css = &h_cg->css;
475 /*
476 * The caller will hold exactly one h_cg->css reference for the
477 * whole contiguous reservation region. But this area might be
478 * scattered when there are already some file_regions reside in
479 * it. As a result, many file_regions may share only one css
480 * reference. In order to ensure that one file_region must hold
481 * exactly one h_cg->css reference, we should do css_get for
482 * each file_region and leave the reference held by caller
483 * untouched.
484 */
485 css_get(&h_cg->css);
486 if (!resv->pages_per_hpage)
487 resv->pages_per_hpage = pages_per_huge_page(h);
488 /* pages_per_hpage should be the same for all entries in
489 * a resv_map.
490 */
491 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
492 } else {
493 nrg->reservation_counter = NULL;
494 nrg->css = NULL;
495 }
496#endif
497}
498
499static void put_uncharge_info(struct file_region *rg)
500{
501#ifdef CONFIG_CGROUP_HUGETLB
502 if (rg->css)
503 css_put(rg->css);
504#endif
505}
506
507static bool has_same_uncharge_info(struct file_region *rg,
508 struct file_region *org)
509{
510#ifdef CONFIG_CGROUP_HUGETLB
511 return rg->reservation_counter == org->reservation_counter &&
512 rg->css == org->css;
513
514#else
515 return true;
516#endif
517}
518
519static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
520{
521 struct file_region *nrg, *prg;
522
523 prg = list_prev_entry(rg, link);
524 if (&prg->link != &resv->regions && prg->to == rg->from &&
525 has_same_uncharge_info(prg, rg)) {
526 prg->to = rg->to;
527
528 list_del(&rg->link);
529 put_uncharge_info(rg);
530 kfree(rg);
531
532 rg = prg;
533 }
534
535 nrg = list_next_entry(rg, link);
536 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
537 has_same_uncharge_info(nrg, rg)) {
538 nrg->from = rg->from;
539
540 list_del(&rg->link);
541 put_uncharge_info(rg);
542 kfree(rg);
543 }
544}
545
546static inline long
547hugetlb_resv_map_add(struct resv_map *map, struct list_head *rg, long from,
548 long to, struct hstate *h, struct hugetlb_cgroup *cg,
549 long *regions_needed)
550{
551 struct file_region *nrg;
552
553 if (!regions_needed) {
554 nrg = get_file_region_entry_from_cache(map, from, to);
555 record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
556 list_add(&nrg->link, rg);
557 coalesce_file_region(map, nrg);
558 } else
559 *regions_needed += 1;
560
561 return to - from;
562}
563
564/*
565 * Must be called with resv->lock held.
566 *
567 * Calling this with regions_needed != NULL will count the number of pages
568 * to be added but will not modify the linked list. And regions_needed will
569 * indicate the number of file_regions needed in the cache to carry out to add
570 * the regions for this range.
571 */
572static long add_reservation_in_range(struct resv_map *resv, long f, long t,
573 struct hugetlb_cgroup *h_cg,
574 struct hstate *h, long *regions_needed)
575{
576 long add = 0;
577 struct list_head *head = &resv->regions;
578 long last_accounted_offset = f;
579 struct file_region *iter, *trg = NULL;
580 struct list_head *rg = NULL;
581
582 if (regions_needed)
583 *regions_needed = 0;
584
585 /* In this loop, we essentially handle an entry for the range
586 * [last_accounted_offset, iter->from), at every iteration, with some
587 * bounds checking.
588 */
589 list_for_each_entry_safe(iter, trg, head, link) {
590 /* Skip irrelevant regions that start before our range. */
591 if (iter->from < f) {
592 /* If this region ends after the last accounted offset,
593 * then we need to update last_accounted_offset.
594 */
595 if (iter->to > last_accounted_offset)
596 last_accounted_offset = iter->to;
597 continue;
598 }
599
600 /* When we find a region that starts beyond our range, we've
601 * finished.
602 */
603 if (iter->from >= t) {
604 rg = iter->link.prev;
605 break;
606 }
607
608 /* Add an entry for last_accounted_offset -> iter->from, and
609 * update last_accounted_offset.
610 */
611 if (iter->from > last_accounted_offset)
612 add += hugetlb_resv_map_add(resv, iter->link.prev,
613 last_accounted_offset,
614 iter->from, h, h_cg,
615 regions_needed);
616
617 last_accounted_offset = iter->to;
618 }
619
620 /* Handle the case where our range extends beyond
621 * last_accounted_offset.
622 */
623 if (!rg)
624 rg = head->prev;
625 if (last_accounted_offset < t)
626 add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
627 t, h, h_cg, regions_needed);
628
629 return add;
630}
631
632/* Must be called with resv->lock acquired. Will drop lock to allocate entries.
633 */
634static int allocate_file_region_entries(struct resv_map *resv,
635 int regions_needed)
636 __must_hold(&resv->lock)
637{
638 LIST_HEAD(allocated_regions);
639 int to_allocate = 0, i = 0;
640 struct file_region *trg = NULL, *rg = NULL;
641
642 VM_BUG_ON(regions_needed < 0);
643
644 /*
645 * Check for sufficient descriptors in the cache to accommodate
646 * the number of in progress add operations plus regions_needed.
647 *
648 * This is a while loop because when we drop the lock, some other call
649 * to region_add or region_del may have consumed some region_entries,
650 * so we keep looping here until we finally have enough entries for
651 * (adds_in_progress + regions_needed).
652 */
653 while (resv->region_cache_count <
654 (resv->adds_in_progress + regions_needed)) {
655 to_allocate = resv->adds_in_progress + regions_needed -
656 resv->region_cache_count;
657
658 /* At this point, we should have enough entries in the cache
659 * for all the existing adds_in_progress. We should only be
660 * needing to allocate for regions_needed.
661 */
662 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
663
664 spin_unlock(&resv->lock);
665 for (i = 0; i < to_allocate; i++) {
666 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
667 if (!trg)
668 goto out_of_memory;
669 list_add(&trg->link, &allocated_regions);
670 }
671
672 spin_lock(&resv->lock);
673
674 list_splice(&allocated_regions, &resv->region_cache);
675 resv->region_cache_count += to_allocate;
676 }
677
678 return 0;
679
680out_of_memory:
681 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
682 list_del(&rg->link);
683 kfree(rg);
684 }
685 return -ENOMEM;
686}
687
688/*
689 * Add the huge page range represented by [f, t) to the reserve
690 * map. Regions will be taken from the cache to fill in this range.
691 * Sufficient regions should exist in the cache due to the previous
692 * call to region_chg with the same range, but in some cases the cache will not
693 * have sufficient entries due to races with other code doing region_add or
694 * region_del. The extra needed entries will be allocated.
695 *
696 * regions_needed is the out value provided by a previous call to region_chg.
697 *
698 * Return the number of new huge pages added to the map. This number is greater
699 * than or equal to zero. If file_region entries needed to be allocated for
700 * this operation and we were not able to allocate, it returns -ENOMEM.
701 * region_add of regions of length 1 never allocate file_regions and cannot
702 * fail; region_chg will always allocate at least 1 entry and a region_add for
703 * 1 page will only require at most 1 entry.
704 */
705static long region_add(struct resv_map *resv, long f, long t,
706 long in_regions_needed, struct hstate *h,
707 struct hugetlb_cgroup *h_cg)
708{
709 long add = 0, actual_regions_needed = 0;
710
711 spin_lock(&resv->lock);
712retry:
713
714 /* Count how many regions are actually needed to execute this add. */
715 add_reservation_in_range(resv, f, t, NULL, NULL,
716 &actual_regions_needed);
717
718 /*
719 * Check for sufficient descriptors in the cache to accommodate
720 * this add operation. Note that actual_regions_needed may be greater
721 * than in_regions_needed, as the resv_map may have been modified since
722 * the region_chg call. In this case, we need to make sure that we
723 * allocate extra entries, such that we have enough for all the
724 * existing adds_in_progress, plus the excess needed for this
725 * operation.
726 */
727 if (actual_regions_needed > in_regions_needed &&
728 resv->region_cache_count <
729 resv->adds_in_progress +
730 (actual_regions_needed - in_regions_needed)) {
731 /* region_add operation of range 1 should never need to
732 * allocate file_region entries.
733 */
734 VM_BUG_ON(t - f <= 1);
735
736 if (allocate_file_region_entries(
737 resv, actual_regions_needed - in_regions_needed)) {
738 return -ENOMEM;
739 }
740
741 goto retry;
742 }
743
744 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
745
746 resv->adds_in_progress -= in_regions_needed;
747
748 spin_unlock(&resv->lock);
749 return add;
750}
751
752/*
753 * Examine the existing reserve map and determine how many
754 * huge pages in the specified range [f, t) are NOT currently
755 * represented. This routine is called before a subsequent
756 * call to region_add that will actually modify the reserve
757 * map to add the specified range [f, t). region_chg does
758 * not change the number of huge pages represented by the
759 * map. A number of new file_region structures is added to the cache as a
760 * placeholder, for the subsequent region_add call to use. At least 1
761 * file_region structure is added.
762 *
763 * out_regions_needed is the number of regions added to the
764 * resv->adds_in_progress. This value needs to be provided to a follow up call
765 * to region_add or region_abort for proper accounting.
766 *
767 * Returns the number of huge pages that need to be added to the existing
768 * reservation map for the range [f, t). This number is greater or equal to
769 * zero. -ENOMEM is returned if a new file_region structure or cache entry
770 * is needed and can not be allocated.
771 */
772static long region_chg(struct resv_map *resv, long f, long t,
773 long *out_regions_needed)
774{
775 long chg = 0;
776
777 spin_lock(&resv->lock);
778
779 /* Count how many hugepages in this range are NOT represented. */
780 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
781 out_regions_needed);
782
783 if (*out_regions_needed == 0)
784 *out_regions_needed = 1;
785
786 if (allocate_file_region_entries(resv, *out_regions_needed))
787 return -ENOMEM;
788
789 resv->adds_in_progress += *out_regions_needed;
790
791 spin_unlock(&resv->lock);
792 return chg;
793}
794
795/*
796 * Abort the in progress add operation. The adds_in_progress field
797 * of the resv_map keeps track of the operations in progress between
798 * calls to region_chg and region_add. Operations are sometimes
799 * aborted after the call to region_chg. In such cases, region_abort
800 * is called to decrement the adds_in_progress counter. regions_needed
801 * is the value returned by the region_chg call, it is used to decrement
802 * the adds_in_progress counter.
803 *
804 * NOTE: The range arguments [f, t) are not needed or used in this
805 * routine. They are kept to make reading the calling code easier as
806 * arguments will match the associated region_chg call.
807 */
808static void region_abort(struct resv_map *resv, long f, long t,
809 long regions_needed)
810{
811 spin_lock(&resv->lock);
812 VM_BUG_ON(!resv->region_cache_count);
813 resv->adds_in_progress -= regions_needed;
814 spin_unlock(&resv->lock);
815}
816
817/*
818 * Delete the specified range [f, t) from the reserve map. If the
819 * t parameter is LONG_MAX, this indicates that ALL regions after f
820 * should be deleted. Locate the regions which intersect [f, t)
821 * and either trim, delete or split the existing regions.
822 *
823 * Returns the number of huge pages deleted from the reserve map.
824 * In the normal case, the return value is zero or more. In the
825 * case where a region must be split, a new region descriptor must
826 * be allocated. If the allocation fails, -ENOMEM will be returned.
827 * NOTE: If the parameter t == LONG_MAX, then we will never split
828 * a region and possibly return -ENOMEM. Callers specifying
829 * t == LONG_MAX do not need to check for -ENOMEM error.
830 */
831static long region_del(struct resv_map *resv, long f, long t)
832{
833 struct list_head *head = &resv->regions;
834 struct file_region *rg, *trg;
835 struct file_region *nrg = NULL;
836 long del = 0;
837
838retry:
839 spin_lock(&resv->lock);
840 list_for_each_entry_safe(rg, trg, head, link) {
841 /*
842 * Skip regions before the range to be deleted. file_region
843 * ranges are normally of the form [from, to). However, there
844 * may be a "placeholder" entry in the map which is of the form
845 * (from, to) with from == to. Check for placeholder entries
846 * at the beginning of the range to be deleted.
847 */
848 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
849 continue;
850
851 if (rg->from >= t)
852 break;
853
854 if (f > rg->from && t < rg->to) { /* Must split region */
855 /*
856 * Check for an entry in the cache before dropping
857 * lock and attempting allocation.
858 */
859 if (!nrg &&
860 resv->region_cache_count > resv->adds_in_progress) {
861 nrg = list_first_entry(&resv->region_cache,
862 struct file_region,
863 link);
864 list_del(&nrg->link);
865 resv->region_cache_count--;
866 }
867
868 if (!nrg) {
869 spin_unlock(&resv->lock);
870 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
871 if (!nrg)
872 return -ENOMEM;
873 goto retry;
874 }
875
876 del += t - f;
877 hugetlb_cgroup_uncharge_file_region(
878 resv, rg, t - f, false);
879
880 /* New entry for end of split region */
881 nrg->from = t;
882 nrg->to = rg->to;
883
884 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
885
886 INIT_LIST_HEAD(&nrg->link);
887
888 /* Original entry is trimmed */
889 rg->to = f;
890
891 list_add(&nrg->link, &rg->link);
892 nrg = NULL;
893 break;
894 }
895
896 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
897 del += rg->to - rg->from;
898 hugetlb_cgroup_uncharge_file_region(resv, rg,
899 rg->to - rg->from, true);
900 list_del(&rg->link);
901 kfree(rg);
902 continue;
903 }
904
905 if (f <= rg->from) { /* Trim beginning of region */
906 hugetlb_cgroup_uncharge_file_region(resv, rg,
907 t - rg->from, false);
908
909 del += t - rg->from;
910 rg->from = t;
911 } else { /* Trim end of region */
912 hugetlb_cgroup_uncharge_file_region(resv, rg,
913 rg->to - f, false);
914
915 del += rg->to - f;
916 rg->to = f;
917 }
918 }
919
920 spin_unlock(&resv->lock);
921 kfree(nrg);
922 return del;
923}
924
925/*
926 * A rare out of memory error was encountered which prevented removal of
927 * the reserve map region for a page. The huge page itself was free'ed
928 * and removed from the page cache. This routine will adjust the subpool
929 * usage count, and the global reserve count if needed. By incrementing
930 * these counts, the reserve map entry which could not be deleted will
931 * appear as a "reserved" entry instead of simply dangling with incorrect
932 * counts.
933 */
934void hugetlb_fix_reserve_counts(struct inode *inode)
935{
936 struct hugepage_subpool *spool = subpool_inode(inode);
937 long rsv_adjust;
938 bool reserved = false;
939
940 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
941 if (rsv_adjust > 0) {
942 struct hstate *h = hstate_inode(inode);
943
944 if (!hugetlb_acct_memory(h, 1))
945 reserved = true;
946 } else if (!rsv_adjust) {
947 reserved = true;
948 }
949
950 if (!reserved)
951 pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
952}
953
954/*
955 * Count and return the number of huge pages in the reserve map
956 * that intersect with the range [f, t).
957 */
958static long region_count(struct resv_map *resv, long f, long t)
959{
960 struct list_head *head = &resv->regions;
961 struct file_region *rg;
962 long chg = 0;
963
964 spin_lock(&resv->lock);
965 /* Locate each segment we overlap with, and count that overlap. */
966 list_for_each_entry(rg, head, link) {
967 long seg_from;
968 long seg_to;
969
970 if (rg->to <= f)
971 continue;
972 if (rg->from >= t)
973 break;
974
975 seg_from = max(rg->from, f);
976 seg_to = min(rg->to, t);
977
978 chg += seg_to - seg_from;
979 }
980 spin_unlock(&resv->lock);
981
982 return chg;
983}
984
985/*
986 * Convert the address within this vma to the page offset within
987 * the mapping, huge page units here.
988 */
989static pgoff_t vma_hugecache_offset(struct hstate *h,
990 struct vm_area_struct *vma, unsigned long address)
991{
992 return ((address - vma->vm_start) >> huge_page_shift(h)) +
993 (vma->vm_pgoff >> huge_page_order(h));
994}
995
996/**
997 * vma_kernel_pagesize - Page size granularity for this VMA.
998 * @vma: The user mapping.
999 *
1000 * Folios in this VMA will be aligned to, and at least the size of the
1001 * number of bytes returned by this function.
1002 *
1003 * Return: The default size of the folios allocated when backing a VMA.
1004 */
1005unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
1006{
1007 if (vma->vm_ops && vma->vm_ops->pagesize)
1008 return vma->vm_ops->pagesize(vma);
1009 return PAGE_SIZE;
1010}
1011EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
1012
1013/*
1014 * Return the page size being used by the MMU to back a VMA. In the majority
1015 * of cases, the page size used by the kernel matches the MMU size. On
1016 * architectures where it differs, an architecture-specific 'strong'
1017 * version of this symbol is required.
1018 */
1019__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
1020{
1021 return vma_kernel_pagesize(vma);
1022}
1023
1024/*
1025 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
1026 * bits of the reservation map pointer, which are always clear due to
1027 * alignment.
1028 */
1029#define HPAGE_RESV_OWNER (1UL << 0)
1030#define HPAGE_RESV_UNMAPPED (1UL << 1)
1031#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
1032
1033/*
1034 * These helpers are used to track how many pages are reserved for
1035 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
1036 * is guaranteed to have their future faults succeed.
1037 *
1038 * With the exception of hugetlb_dup_vma_private() which is called at fork(),
1039 * the reserve counters are updated with the hugetlb_lock held. It is safe
1040 * to reset the VMA at fork() time as it is not in use yet and there is no
1041 * chance of the global counters getting corrupted as a result of the values.
1042 *
1043 * The private mapping reservation is represented in a subtly different
1044 * manner to a shared mapping. A shared mapping has a region map associated
1045 * with the underlying file, this region map represents the backing file
1046 * pages which have ever had a reservation assigned which this persists even
1047 * after the page is instantiated. A private mapping has a region map
1048 * associated with the original mmap which is attached to all VMAs which
1049 * reference it, this region map represents those offsets which have consumed
1050 * reservation ie. where pages have been instantiated.
1051 */
1052static unsigned long get_vma_private_data(struct vm_area_struct *vma)
1053{
1054 return (unsigned long)vma->vm_private_data;
1055}
1056
1057static void set_vma_private_data(struct vm_area_struct *vma,
1058 unsigned long value)
1059{
1060 vma->vm_private_data = (void *)value;
1061}
1062
1063static void
1064resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
1065 struct hugetlb_cgroup *h_cg,
1066 struct hstate *h)
1067{
1068#ifdef CONFIG_CGROUP_HUGETLB
1069 if (!h_cg || !h) {
1070 resv_map->reservation_counter = NULL;
1071 resv_map->pages_per_hpage = 0;
1072 resv_map->css = NULL;
1073 } else {
1074 resv_map->reservation_counter =
1075 &h_cg->rsvd_hugepage[hstate_index(h)];
1076 resv_map->pages_per_hpage = pages_per_huge_page(h);
1077 resv_map->css = &h_cg->css;
1078 }
1079#endif
1080}
1081
1082struct resv_map *resv_map_alloc(void)
1083{
1084 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
1085 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
1086
1087 if (!resv_map || !rg) {
1088 kfree(resv_map);
1089 kfree(rg);
1090 return NULL;
1091 }
1092
1093 kref_init(&resv_map->refs);
1094 spin_lock_init(&resv_map->lock);
1095 INIT_LIST_HEAD(&resv_map->regions);
1096 init_rwsem(&resv_map->rw_sema);
1097
1098 resv_map->adds_in_progress = 0;
1099 /*
1100 * Initialize these to 0. On shared mappings, 0's here indicate these
1101 * fields don't do cgroup accounting. On private mappings, these will be
1102 * re-initialized to the proper values, to indicate that hugetlb cgroup
1103 * reservations are to be un-charged from here.
1104 */
1105 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
1106
1107 INIT_LIST_HEAD(&resv_map->region_cache);
1108 list_add(&rg->link, &resv_map->region_cache);
1109 resv_map->region_cache_count = 1;
1110
1111 return resv_map;
1112}
1113
1114void resv_map_release(struct kref *ref)
1115{
1116 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
1117 struct list_head *head = &resv_map->region_cache;
1118 struct file_region *rg, *trg;
1119
1120 /* Clear out any active regions before we release the map. */
1121 region_del(resv_map, 0, LONG_MAX);
1122
1123 /* ... and any entries left in the cache */
1124 list_for_each_entry_safe(rg, trg, head, link) {
1125 list_del(&rg->link);
1126 kfree(rg);
1127 }
1128
1129 VM_BUG_ON(resv_map->adds_in_progress);
1130
1131 kfree(resv_map);
1132}
1133
1134static inline struct resv_map *inode_resv_map(struct inode *inode)
1135{
1136 /*
1137 * At inode evict time, i_mapping may not point to the original
1138 * address space within the inode. This original address space
1139 * contains the pointer to the resv_map. So, always use the
1140 * address space embedded within the inode.
1141 * The VERY common case is inode->mapping == &inode->i_data but,
1142 * this may not be true for device special inodes.
1143 */
1144 return (struct resv_map *)(&inode->i_data)->i_private_data;
1145}
1146
1147static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
1148{
1149 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1150 if (vma->vm_flags & VM_MAYSHARE) {
1151 struct address_space *mapping = vma->vm_file->f_mapping;
1152 struct inode *inode = mapping->host;
1153
1154 return inode_resv_map(inode);
1155
1156 } else {
1157 return (struct resv_map *)(get_vma_private_data(vma) &
1158 ~HPAGE_RESV_MASK);
1159 }
1160}
1161
1162static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
1163{
1164 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1165 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
1166
1167 set_vma_private_data(vma, (unsigned long)map);
1168}
1169
1170static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
1171{
1172 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1173 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
1174
1175 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
1176}
1177
1178static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
1179{
1180 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1181
1182 return (get_vma_private_data(vma) & flag) != 0;
1183}
1184
1185bool __vma_private_lock(struct vm_area_struct *vma)
1186{
1187 return !(vma->vm_flags & VM_MAYSHARE) &&
1188 get_vma_private_data(vma) & ~HPAGE_RESV_MASK &&
1189 is_vma_resv_set(vma, HPAGE_RESV_OWNER);
1190}
1191
1192void hugetlb_dup_vma_private(struct vm_area_struct *vma)
1193{
1194 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1195 /*
1196 * Clear vm_private_data
1197 * - For shared mappings this is a per-vma semaphore that may be
1198 * allocated in a subsequent call to hugetlb_vm_op_open.
1199 * Before clearing, make sure pointer is not associated with vma
1200 * as this will leak the structure. This is the case when called
1201 * via clear_vma_resv_huge_pages() and hugetlb_vm_op_open has already
1202 * been called to allocate a new structure.
1203 * - For MAP_PRIVATE mappings, this is the reserve map which does
1204 * not apply to children. Faults generated by the children are
1205 * not guaranteed to succeed, even if read-only.
1206 */
1207 if (vma->vm_flags & VM_MAYSHARE) {
1208 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
1209
1210 if (vma_lock && vma_lock->vma != vma)
1211 vma->vm_private_data = NULL;
1212 } else
1213 vma->vm_private_data = NULL;
1214}
1215
1216/*
1217 * Reset and decrement one ref on hugepage private reservation.
1218 * Called with mm->mmap_lock writer semaphore held.
1219 * This function should be only used by move_vma() and operate on
1220 * same sized vma. It should never come here with last ref on the
1221 * reservation.
1222 */
1223void clear_vma_resv_huge_pages(struct vm_area_struct *vma)
1224{
1225 /*
1226 * Clear the old hugetlb private page reservation.
1227 * It has already been transferred to new_vma.
1228 *
1229 * During a mremap() operation of a hugetlb vma we call move_vma()
1230 * which copies vma into new_vma and unmaps vma. After the copy
1231 * operation both new_vma and vma share a reference to the resv_map
1232 * struct, and at that point vma is about to be unmapped. We don't
1233 * want to return the reservation to the pool at unmap of vma because
1234 * the reservation still lives on in new_vma, so simply decrement the
1235 * ref here and remove the resv_map reference from this vma.
1236 */
1237 struct resv_map *reservations = vma_resv_map(vma);
1238
1239 if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1240 resv_map_put_hugetlb_cgroup_uncharge_info(reservations);
1241 kref_put(&reservations->refs, resv_map_release);
1242 }
1243
1244 hugetlb_dup_vma_private(vma);
1245}
1246
1247/* Returns true if the VMA has associated reserve pages */
1248static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
1249{
1250 if (vma->vm_flags & VM_NORESERVE) {
1251 /*
1252 * This address is already reserved by other process(chg == 0),
1253 * so, we should decrement reserved count. Without decrementing,
1254 * reserve count remains after releasing inode, because this
1255 * allocated page will go into page cache and is regarded as
1256 * coming from reserved pool in releasing step. Currently, we
1257 * don't have any other solution to deal with this situation
1258 * properly, so add work-around here.
1259 */
1260 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
1261 return true;
1262 else
1263 return false;
1264 }
1265
1266 /* Shared mappings always use reserves */
1267 if (vma->vm_flags & VM_MAYSHARE) {
1268 /*
1269 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1270 * be a region map for all pages. The only situation where
1271 * there is no region map is if a hole was punched via
1272 * fallocate. In this case, there really are no reserves to
1273 * use. This situation is indicated if chg != 0.
1274 */
1275 if (chg)
1276 return false;
1277 else
1278 return true;
1279 }
1280
1281 /*
1282 * Only the process that called mmap() has reserves for
1283 * private mappings.
1284 */
1285 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1286 /*
1287 * Like the shared case above, a hole punch or truncate
1288 * could have been performed on the private mapping.
1289 * Examine the value of chg to determine if reserves
1290 * actually exist or were previously consumed.
1291 * Very Subtle - The value of chg comes from a previous
1292 * call to vma_needs_reserves(). The reserve map for
1293 * private mappings has different (opposite) semantics
1294 * than that of shared mappings. vma_needs_reserves()
1295 * has already taken this difference in semantics into
1296 * account. Therefore, the meaning of chg is the same
1297 * as in the shared case above. Code could easily be
1298 * combined, but keeping it separate draws attention to
1299 * subtle differences.
1300 */
1301 if (chg)
1302 return false;
1303 else
1304 return true;
1305 }
1306
1307 return false;
1308}
1309
1310static void enqueue_hugetlb_folio(struct hstate *h, struct folio *folio)
1311{
1312 int nid = folio_nid(folio);
1313
1314 lockdep_assert_held(&hugetlb_lock);
1315 VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
1316
1317 list_move(&folio->lru, &h->hugepage_freelists[nid]);
1318 h->free_huge_pages++;
1319 h->free_huge_pages_node[nid]++;
1320 folio_set_hugetlb_freed(folio);
1321}
1322
1323static struct folio *dequeue_hugetlb_folio_node_exact(struct hstate *h,
1324 int nid)
1325{
1326 struct folio *folio;
1327 bool pin = !!(current->flags & PF_MEMALLOC_PIN);
1328
1329 lockdep_assert_held(&hugetlb_lock);
1330 list_for_each_entry(folio, &h->hugepage_freelists[nid], lru) {
1331 if (pin && !folio_is_longterm_pinnable(folio))
1332 continue;
1333
1334 if (folio_test_hwpoison(folio))
1335 continue;
1336
1337 list_move(&folio->lru, &h->hugepage_activelist);
1338 folio_ref_unfreeze(folio, 1);
1339 folio_clear_hugetlb_freed(folio);
1340 h->free_huge_pages--;
1341 h->free_huge_pages_node[nid]--;
1342 return folio;
1343 }
1344
1345 return NULL;
1346}
1347
1348static struct folio *dequeue_hugetlb_folio_nodemask(struct hstate *h, gfp_t gfp_mask,
1349 int nid, nodemask_t *nmask)
1350{
1351 unsigned int cpuset_mems_cookie;
1352 struct zonelist *zonelist;
1353 struct zone *zone;
1354 struct zoneref *z;
1355 int node = NUMA_NO_NODE;
1356
1357 zonelist = node_zonelist(nid, gfp_mask);
1358
1359retry_cpuset:
1360 cpuset_mems_cookie = read_mems_allowed_begin();
1361 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1362 struct folio *folio;
1363
1364 if (!cpuset_zone_allowed(zone, gfp_mask))
1365 continue;
1366 /*
1367 * no need to ask again on the same node. Pool is node rather than
1368 * zone aware
1369 */
1370 if (zone_to_nid(zone) == node)
1371 continue;
1372 node = zone_to_nid(zone);
1373
1374 folio = dequeue_hugetlb_folio_node_exact(h, node);
1375 if (folio)
1376 return folio;
1377 }
1378 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1379 goto retry_cpuset;
1380
1381 return NULL;
1382}
1383
1384static unsigned long available_huge_pages(struct hstate *h)
1385{
1386 return h->free_huge_pages - h->resv_huge_pages;
1387}
1388
1389static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h,
1390 struct vm_area_struct *vma,
1391 unsigned long address, int avoid_reserve,
1392 long chg)
1393{
1394 struct folio *folio = NULL;
1395 struct mempolicy *mpol;
1396 gfp_t gfp_mask;
1397 nodemask_t *nodemask;
1398 int nid;
1399
1400 /*
1401 * A child process with MAP_PRIVATE mappings created by their parent
1402 * have no page reserves. This check ensures that reservations are
1403 * not "stolen". The child may still get SIGKILLed
1404 */
1405 if (!vma_has_reserves(vma, chg) && !available_huge_pages(h))
1406 goto err;
1407
1408 /* If reserves cannot be used, ensure enough pages are in the pool */
1409 if (avoid_reserve && !available_huge_pages(h))
1410 goto err;
1411
1412 gfp_mask = htlb_alloc_mask(h);
1413 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1414
1415 if (mpol_is_preferred_many(mpol)) {
1416 folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
1417 nid, nodemask);
1418
1419 /* Fallback to all nodes if page==NULL */
1420 nodemask = NULL;
1421 }
1422
1423 if (!folio)
1424 folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
1425 nid, nodemask);
1426
1427 if (folio && !avoid_reserve && vma_has_reserves(vma, chg)) {
1428 folio_set_hugetlb_restore_reserve(folio);
1429 h->resv_huge_pages--;
1430 }
1431
1432 mpol_cond_put(mpol);
1433 return folio;
1434
1435err:
1436 return NULL;
1437}
1438
1439/*
1440 * common helper functions for hstate_next_node_to_{alloc|free}.
1441 * We may have allocated or freed a huge page based on a different
1442 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1443 * be outside of *nodes_allowed. Ensure that we use an allowed
1444 * node for alloc or free.
1445 */
1446static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1447{
1448 nid = next_node_in(nid, *nodes_allowed);
1449 VM_BUG_ON(nid >= MAX_NUMNODES);
1450
1451 return nid;
1452}
1453
1454static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1455{
1456 if (!node_isset(nid, *nodes_allowed))
1457 nid = next_node_allowed(nid, nodes_allowed);
1458 return nid;
1459}
1460
1461/*
1462 * returns the previously saved node ["this node"] from which to
1463 * allocate a persistent huge page for the pool and advance the
1464 * next node from which to allocate, handling wrap at end of node
1465 * mask.
1466 */
1467static int hstate_next_node_to_alloc(struct hstate *h,
1468 nodemask_t *nodes_allowed)
1469{
1470 int nid;
1471
1472 VM_BUG_ON(!nodes_allowed);
1473
1474 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
1475 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
1476
1477 return nid;
1478}
1479
1480/*
1481 * helper for remove_pool_hugetlb_folio() - return the previously saved
1482 * node ["this node"] from which to free a huge page. Advance the
1483 * next node id whether or not we find a free huge page to free so
1484 * that the next attempt to free addresses the next node.
1485 */
1486static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1487{
1488 int nid;
1489
1490 VM_BUG_ON(!nodes_allowed);
1491
1492 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1493 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1494
1495 return nid;
1496}
1497
1498#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
1499 for (nr_nodes = nodes_weight(*mask); \
1500 nr_nodes > 0 && \
1501 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
1502 nr_nodes--)
1503
1504#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1505 for (nr_nodes = nodes_weight(*mask); \
1506 nr_nodes > 0 && \
1507 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1508 nr_nodes--)
1509
1510/* used to demote non-gigantic_huge pages as well */
1511static void __destroy_compound_gigantic_folio(struct folio *folio,
1512 unsigned int order, bool demote)
1513{
1514 int i;
1515 int nr_pages = 1 << order;
1516 struct page *p;
1517
1518 atomic_set(&folio->_entire_mapcount, 0);
1519 atomic_set(&folio->_nr_pages_mapped, 0);
1520 atomic_set(&folio->_pincount, 0);
1521
1522 for (i = 1; i < nr_pages; i++) {
1523 p = folio_page(folio, i);
1524 p->flags &= ~PAGE_FLAGS_CHECK_AT_FREE;
1525 p->mapping = NULL;
1526 clear_compound_head(p);
1527 if (!demote)
1528 set_page_refcounted(p);
1529 }
1530
1531 __folio_clear_head(folio);
1532}
1533
1534static void destroy_compound_hugetlb_folio_for_demote(struct folio *folio,
1535 unsigned int order)
1536{
1537 __destroy_compound_gigantic_folio(folio, order, true);
1538}
1539
1540#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1541static void destroy_compound_gigantic_folio(struct folio *folio,
1542 unsigned int order)
1543{
1544 __destroy_compound_gigantic_folio(folio, order, false);
1545}
1546
1547static void free_gigantic_folio(struct folio *folio, unsigned int order)
1548{
1549 /*
1550 * If the page isn't allocated using the cma allocator,
1551 * cma_release() returns false.
1552 */
1553#ifdef CONFIG_CMA
1554 int nid = folio_nid(folio);
1555
1556 if (cma_release(hugetlb_cma[nid], &folio->page, 1 << order))
1557 return;
1558#endif
1559
1560 free_contig_range(folio_pfn(folio), 1 << order);
1561}
1562
1563#ifdef CONFIG_CONTIG_ALLOC
1564static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask,
1565 int nid, nodemask_t *nodemask)
1566{
1567 struct page *page;
1568 unsigned long nr_pages = pages_per_huge_page(h);
1569 if (nid == NUMA_NO_NODE)
1570 nid = numa_mem_id();
1571
1572#ifdef CONFIG_CMA
1573 {
1574 int node;
1575
1576 if (hugetlb_cma[nid]) {
1577 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1578 huge_page_order(h), true);
1579 if (page)
1580 return page_folio(page);
1581 }
1582
1583 if (!(gfp_mask & __GFP_THISNODE)) {
1584 for_each_node_mask(node, *nodemask) {
1585 if (node == nid || !hugetlb_cma[node])
1586 continue;
1587
1588 page = cma_alloc(hugetlb_cma[node], nr_pages,
1589 huge_page_order(h), true);
1590 if (page)
1591 return page_folio(page);
1592 }
1593 }
1594 }
1595#endif
1596
1597 page = alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1598 return page ? page_folio(page) : NULL;
1599}
1600
1601#else /* !CONFIG_CONTIG_ALLOC */
1602static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask,
1603 int nid, nodemask_t *nodemask)
1604{
1605 return NULL;
1606}
1607#endif /* CONFIG_CONTIG_ALLOC */
1608
1609#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1610static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask,
1611 int nid, nodemask_t *nodemask)
1612{
1613 return NULL;
1614}
1615static inline void free_gigantic_folio(struct folio *folio,
1616 unsigned int order) { }
1617static inline void destroy_compound_gigantic_folio(struct folio *folio,
1618 unsigned int order) { }
1619#endif
1620
1621static inline void __clear_hugetlb_destructor(struct hstate *h,
1622 struct folio *folio)
1623{
1624 lockdep_assert_held(&hugetlb_lock);
1625
1626 folio_clear_hugetlb(folio);
1627}
1628
1629/*
1630 * Remove hugetlb folio from lists.
1631 * If vmemmap exists for the folio, update dtor so that the folio appears
1632 * as just a compound page. Otherwise, wait until after allocating vmemmap
1633 * to update dtor.
1634 *
1635 * A reference is held on the folio, except in the case of demote.
1636 *
1637 * Must be called with hugetlb lock held.
1638 */
1639static void __remove_hugetlb_folio(struct hstate *h, struct folio *folio,
1640 bool adjust_surplus,
1641 bool demote)
1642{
1643 int nid = folio_nid(folio);
1644
1645 VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio(folio), folio);
1646 VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio_rsvd(folio), folio);
1647
1648 lockdep_assert_held(&hugetlb_lock);
1649 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1650 return;
1651
1652 list_del(&folio->lru);
1653
1654 if (folio_test_hugetlb_freed(folio)) {
1655 h->free_huge_pages--;
1656 h->free_huge_pages_node[nid]--;
1657 }
1658 if (adjust_surplus) {
1659 h->surplus_huge_pages--;
1660 h->surplus_huge_pages_node[nid]--;
1661 }
1662
1663 /*
1664 * We can only clear the hugetlb destructor after allocating vmemmap
1665 * pages. Otherwise, someone (memory error handling) may try to write
1666 * to tail struct pages.
1667 */
1668 if (!folio_test_hugetlb_vmemmap_optimized(folio))
1669 __clear_hugetlb_destructor(h, folio);
1670
1671 /*
1672 * In the case of demote we do not ref count the page as it will soon
1673 * be turned into a page of smaller size.
1674 */
1675 if (!demote)
1676 folio_ref_unfreeze(folio, 1);
1677
1678 h->nr_huge_pages--;
1679 h->nr_huge_pages_node[nid]--;
1680}
1681
1682static void remove_hugetlb_folio(struct hstate *h, struct folio *folio,
1683 bool adjust_surplus)
1684{
1685 __remove_hugetlb_folio(h, folio, adjust_surplus, false);
1686}
1687
1688static void remove_hugetlb_folio_for_demote(struct hstate *h, struct folio *folio,
1689 bool adjust_surplus)
1690{
1691 __remove_hugetlb_folio(h, folio, adjust_surplus, true);
1692}
1693
1694static void add_hugetlb_folio(struct hstate *h, struct folio *folio,
1695 bool adjust_surplus)
1696{
1697 int zeroed;
1698 int nid = folio_nid(folio);
1699
1700 VM_BUG_ON_FOLIO(!folio_test_hugetlb_vmemmap_optimized(folio), folio);
1701
1702 lockdep_assert_held(&hugetlb_lock);
1703
1704 INIT_LIST_HEAD(&folio->lru);
1705 h->nr_huge_pages++;
1706 h->nr_huge_pages_node[nid]++;
1707
1708 if (adjust_surplus) {
1709 h->surplus_huge_pages++;
1710 h->surplus_huge_pages_node[nid]++;
1711 }
1712
1713 folio_set_hugetlb(folio);
1714 folio_change_private(folio, NULL);
1715 /*
1716 * We have to set hugetlb_vmemmap_optimized again as above
1717 * folio_change_private(folio, NULL) cleared it.
1718 */
1719 folio_set_hugetlb_vmemmap_optimized(folio);
1720
1721 /*
1722 * This folio is about to be managed by the hugetlb allocator and
1723 * should have no users. Drop our reference, and check for others
1724 * just in case.
1725 */
1726 zeroed = folio_put_testzero(folio);
1727 if (unlikely(!zeroed))
1728 /*
1729 * It is VERY unlikely soneone else has taken a ref
1730 * on the folio. In this case, we simply return as
1731 * free_huge_folio() will be called when this other ref
1732 * is dropped.
1733 */
1734 return;
1735
1736 arch_clear_hugepage_flags(&folio->page);
1737 enqueue_hugetlb_folio(h, folio);
1738}
1739
1740static void __update_and_free_hugetlb_folio(struct hstate *h,
1741 struct folio *folio)
1742{
1743 bool clear_dtor = folio_test_hugetlb_vmemmap_optimized(folio);
1744
1745 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1746 return;
1747
1748 /*
1749 * If we don't know which subpages are hwpoisoned, we can't free
1750 * the hugepage, so it's leaked intentionally.
1751 */
1752 if (folio_test_hugetlb_raw_hwp_unreliable(folio))
1753 return;
1754
1755 /*
1756 * If folio is not vmemmap optimized (!clear_dtor), then the folio
1757 * is no longer identified as a hugetlb page. hugetlb_vmemmap_restore_folio
1758 * can only be passed hugetlb pages and will BUG otherwise.
1759 */
1760 if (clear_dtor && hugetlb_vmemmap_restore_folio(h, folio)) {
1761 spin_lock_irq(&hugetlb_lock);
1762 /*
1763 * If we cannot allocate vmemmap pages, just refuse to free the
1764 * page and put the page back on the hugetlb free list and treat
1765 * as a surplus page.
1766 */
1767 add_hugetlb_folio(h, folio, true);
1768 spin_unlock_irq(&hugetlb_lock);
1769 return;
1770 }
1771
1772 /*
1773 * Move PageHWPoison flag from head page to the raw error pages,
1774 * which makes any healthy subpages reusable.
1775 */
1776 if (unlikely(folio_test_hwpoison(folio)))
1777 folio_clear_hugetlb_hwpoison(folio);
1778
1779 /*
1780 * If vmemmap pages were allocated above, then we need to clear the
1781 * hugetlb destructor under the hugetlb lock.
1782 */
1783 if (clear_dtor) {
1784 spin_lock_irq(&hugetlb_lock);
1785 __clear_hugetlb_destructor(h, folio);
1786 spin_unlock_irq(&hugetlb_lock);
1787 }
1788
1789 /*
1790 * Non-gigantic pages demoted from CMA allocated gigantic pages
1791 * need to be given back to CMA in free_gigantic_folio.
1792 */
1793 if (hstate_is_gigantic(h) ||
1794 hugetlb_cma_folio(folio, huge_page_order(h))) {
1795 destroy_compound_gigantic_folio(folio, huge_page_order(h));
1796 free_gigantic_folio(folio, huge_page_order(h));
1797 } else {
1798 __free_pages(&folio->page, huge_page_order(h));
1799 }
1800}
1801
1802/*
1803 * As update_and_free_hugetlb_folio() can be called under any context, so we cannot
1804 * use GFP_KERNEL to allocate vmemmap pages. However, we can defer the
1805 * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate
1806 * the vmemmap pages.
1807 *
1808 * free_hpage_workfn() locklessly retrieves the linked list of pages to be
1809 * freed and frees them one-by-one. As the page->mapping pointer is going
1810 * to be cleared in free_hpage_workfn() anyway, it is reused as the llist_node
1811 * structure of a lockless linked list of huge pages to be freed.
1812 */
1813static LLIST_HEAD(hpage_freelist);
1814
1815static void free_hpage_workfn(struct work_struct *work)
1816{
1817 struct llist_node *node;
1818
1819 node = llist_del_all(&hpage_freelist);
1820
1821 while (node) {
1822 struct folio *folio;
1823 struct hstate *h;
1824
1825 folio = container_of((struct address_space **)node,
1826 struct folio, mapping);
1827 node = node->next;
1828 folio->mapping = NULL;
1829 /*
1830 * The VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio) in
1831 * folio_hstate() is going to trigger because a previous call to
1832 * remove_hugetlb_folio() will clear the hugetlb bit, so do
1833 * not use folio_hstate() directly.
1834 */
1835 h = size_to_hstate(folio_size(folio));
1836
1837 __update_and_free_hugetlb_folio(h, folio);
1838
1839 cond_resched();
1840 }
1841}
1842static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1843
1844static inline void flush_free_hpage_work(struct hstate *h)
1845{
1846 if (hugetlb_vmemmap_optimizable(h))
1847 flush_work(&free_hpage_work);
1848}
1849
1850static void update_and_free_hugetlb_folio(struct hstate *h, struct folio *folio,
1851 bool atomic)
1852{
1853 if (!folio_test_hugetlb_vmemmap_optimized(folio) || !atomic) {
1854 __update_and_free_hugetlb_folio(h, folio);
1855 return;
1856 }
1857
1858 /*
1859 * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap pages.
1860 *
1861 * Only call schedule_work() if hpage_freelist is previously
1862 * empty. Otherwise, schedule_work() had been called but the workfn
1863 * hasn't retrieved the list yet.
1864 */
1865 if (llist_add((struct llist_node *)&folio->mapping, &hpage_freelist))
1866 schedule_work(&free_hpage_work);
1867}
1868
1869static void bulk_vmemmap_restore_error(struct hstate *h,
1870 struct list_head *folio_list,
1871 struct list_head *non_hvo_folios)
1872{
1873 struct folio *folio, *t_folio;
1874
1875 if (!list_empty(non_hvo_folios)) {
1876 /*
1877 * Free any restored hugetlb pages so that restore of the
1878 * entire list can be retried.
1879 * The idea is that in the common case of ENOMEM errors freeing
1880 * hugetlb pages with vmemmap we will free up memory so that we
1881 * can allocate vmemmap for more hugetlb pages.
1882 */
1883 list_for_each_entry_safe(folio, t_folio, non_hvo_folios, lru) {
1884 list_del(&folio->lru);
1885 spin_lock_irq(&hugetlb_lock);
1886 __clear_hugetlb_destructor(h, folio);
1887 spin_unlock_irq(&hugetlb_lock);
1888 update_and_free_hugetlb_folio(h, folio, false);
1889 cond_resched();
1890 }
1891 } else {
1892 /*
1893 * In the case where there are no folios which can be
1894 * immediately freed, we loop through the list trying to restore
1895 * vmemmap individually in the hope that someone elsewhere may
1896 * have done something to cause success (such as freeing some
1897 * memory). If unable to restore a hugetlb page, the hugetlb
1898 * page is made a surplus page and removed from the list.
1899 * If are able to restore vmemmap and free one hugetlb page, we
1900 * quit processing the list to retry the bulk operation.
1901 */
1902 list_for_each_entry_safe(folio, t_folio, folio_list, lru)
1903 if (hugetlb_vmemmap_restore_folio(h, folio)) {
1904 list_del(&folio->lru);
1905 spin_lock_irq(&hugetlb_lock);
1906 add_hugetlb_folio(h, folio, true);
1907 spin_unlock_irq(&hugetlb_lock);
1908 } else {
1909 list_del(&folio->lru);
1910 spin_lock_irq(&hugetlb_lock);
1911 __clear_hugetlb_destructor(h, folio);
1912 spin_unlock_irq(&hugetlb_lock);
1913 update_and_free_hugetlb_folio(h, folio, false);
1914 cond_resched();
1915 break;
1916 }
1917 }
1918}
1919
1920static void update_and_free_pages_bulk(struct hstate *h,
1921 struct list_head *folio_list)
1922{
1923 long ret;
1924 struct folio *folio, *t_folio;
1925 LIST_HEAD(non_hvo_folios);
1926
1927 /*
1928 * First allocate required vmemmmap (if necessary) for all folios.
1929 * Carefully handle errors and free up any available hugetlb pages
1930 * in an effort to make forward progress.
1931 */
1932retry:
1933 ret = hugetlb_vmemmap_restore_folios(h, folio_list, &non_hvo_folios);
1934 if (ret < 0) {
1935 bulk_vmemmap_restore_error(h, folio_list, &non_hvo_folios);
1936 goto retry;
1937 }
1938
1939 /*
1940 * At this point, list should be empty, ret should be >= 0 and there
1941 * should only be pages on the non_hvo_folios list.
1942 * Do note that the non_hvo_folios list could be empty.
1943 * Without HVO enabled, ret will be 0 and there is no need to call
1944 * __clear_hugetlb_destructor as this was done previously.
1945 */
1946 VM_WARN_ON(!list_empty(folio_list));
1947 VM_WARN_ON(ret < 0);
1948 if (!list_empty(&non_hvo_folios) && ret) {
1949 spin_lock_irq(&hugetlb_lock);
1950 list_for_each_entry(folio, &non_hvo_folios, lru)
1951 __clear_hugetlb_destructor(h, folio);
1952 spin_unlock_irq(&hugetlb_lock);
1953 }
1954
1955 list_for_each_entry_safe(folio, t_folio, &non_hvo_folios, lru) {
1956 update_and_free_hugetlb_folio(h, folio, false);
1957 cond_resched();
1958 }
1959}
1960
1961struct hstate *size_to_hstate(unsigned long size)
1962{
1963 struct hstate *h;
1964
1965 for_each_hstate(h) {
1966 if (huge_page_size(h) == size)
1967 return h;
1968 }
1969 return NULL;
1970}
1971
1972void free_huge_folio(struct folio *folio)
1973{
1974 /*
1975 * Can't pass hstate in here because it is called from the
1976 * compound page destructor.
1977 */
1978 struct hstate *h = folio_hstate(folio);
1979 int nid = folio_nid(folio);
1980 struct hugepage_subpool *spool = hugetlb_folio_subpool(folio);
1981 bool restore_reserve;
1982 unsigned long flags;
1983
1984 VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
1985 VM_BUG_ON_FOLIO(folio_mapcount(folio), folio);
1986
1987 hugetlb_set_folio_subpool(folio, NULL);
1988 if (folio_test_anon(folio))
1989 __ClearPageAnonExclusive(&folio->page);
1990 folio->mapping = NULL;
1991 restore_reserve = folio_test_hugetlb_restore_reserve(folio);
1992 folio_clear_hugetlb_restore_reserve(folio);
1993
1994 /*
1995 * If HPageRestoreReserve was set on page, page allocation consumed a
1996 * reservation. If the page was associated with a subpool, there
1997 * would have been a page reserved in the subpool before allocation
1998 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
1999 * reservation, do not call hugepage_subpool_put_pages() as this will
2000 * remove the reserved page from the subpool.
2001 */
2002 if (!restore_reserve) {
2003 /*
2004 * A return code of zero implies that the subpool will be
2005 * under its minimum size if the reservation is not restored
2006 * after page is free. Therefore, force restore_reserve
2007 * operation.
2008 */
2009 if (hugepage_subpool_put_pages(spool, 1) == 0)
2010 restore_reserve = true;
2011 }
2012
2013 spin_lock_irqsave(&hugetlb_lock, flags);
2014 folio_clear_hugetlb_migratable(folio);
2015 hugetlb_cgroup_uncharge_folio(hstate_index(h),
2016 pages_per_huge_page(h), folio);
2017 hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h),
2018 pages_per_huge_page(h), folio);
2019 mem_cgroup_uncharge(folio);
2020 if (restore_reserve)
2021 h->resv_huge_pages++;
2022
2023 if (folio_test_hugetlb_temporary(folio)) {
2024 remove_hugetlb_folio(h, folio, false);
2025 spin_unlock_irqrestore(&hugetlb_lock, flags);
2026 update_and_free_hugetlb_folio(h, folio, true);
2027 } else if (h->surplus_huge_pages_node[nid]) {
2028 /* remove the page from active list */
2029 remove_hugetlb_folio(h, folio, true);
2030 spin_unlock_irqrestore(&hugetlb_lock, flags);
2031 update_and_free_hugetlb_folio(h, folio, true);
2032 } else {
2033 arch_clear_hugepage_flags(&folio->page);
2034 enqueue_hugetlb_folio(h, folio);
2035 spin_unlock_irqrestore(&hugetlb_lock, flags);
2036 }
2037}
2038
2039/*
2040 * Must be called with the hugetlb lock held
2041 */
2042static void __prep_account_new_huge_page(struct hstate *h, int nid)
2043{
2044 lockdep_assert_held(&hugetlb_lock);
2045 h->nr_huge_pages++;
2046 h->nr_huge_pages_node[nid]++;
2047}
2048
2049static void init_new_hugetlb_folio(struct hstate *h, struct folio *folio)
2050{
2051 folio_set_hugetlb(folio);
2052 INIT_LIST_HEAD(&folio->lru);
2053 hugetlb_set_folio_subpool(folio, NULL);
2054 set_hugetlb_cgroup(folio, NULL);
2055 set_hugetlb_cgroup_rsvd(folio, NULL);
2056}
2057
2058static void __prep_new_hugetlb_folio(struct hstate *h, struct folio *folio)
2059{
2060 init_new_hugetlb_folio(h, folio);
2061 hugetlb_vmemmap_optimize_folio(h, folio);
2062}
2063
2064static void prep_new_hugetlb_folio(struct hstate *h, struct folio *folio, int nid)
2065{
2066 __prep_new_hugetlb_folio(h, folio);
2067 spin_lock_irq(&hugetlb_lock);
2068 __prep_account_new_huge_page(h, nid);
2069 spin_unlock_irq(&hugetlb_lock);
2070}
2071
2072static bool __prep_compound_gigantic_folio(struct folio *folio,
2073 unsigned int order, bool demote)
2074{
2075 int i, j;
2076 int nr_pages = 1 << order;
2077 struct page *p;
2078
2079 __folio_clear_reserved(folio);
2080 for (i = 0; i < nr_pages; i++) {
2081 p = folio_page(folio, i);
2082
2083 /*
2084 * For gigantic hugepages allocated through bootmem at
2085 * boot, it's safer to be consistent with the not-gigantic
2086 * hugepages and clear the PG_reserved bit from all tail pages
2087 * too. Otherwise drivers using get_user_pages() to access tail
2088 * pages may get the reference counting wrong if they see
2089 * PG_reserved set on a tail page (despite the head page not
2090 * having PG_reserved set). Enforcing this consistency between
2091 * head and tail pages allows drivers to optimize away a check
2092 * on the head page when they need know if put_page() is needed
2093 * after get_user_pages().
2094 */
2095 if (i != 0) /* head page cleared above */
2096 __ClearPageReserved(p);
2097 /*
2098 * Subtle and very unlikely
2099 *
2100 * Gigantic 'page allocators' such as memblock or cma will
2101 * return a set of pages with each page ref counted. We need
2102 * to turn this set of pages into a compound page with tail
2103 * page ref counts set to zero. Code such as speculative page
2104 * cache adding could take a ref on a 'to be' tail page.
2105 * We need to respect any increased ref count, and only set
2106 * the ref count to zero if count is currently 1. If count
2107 * is not 1, we return an error. An error return indicates
2108 * the set of pages can not be converted to a gigantic page.
2109 * The caller who allocated the pages should then discard the
2110 * pages using the appropriate free interface.
2111 *
2112 * In the case of demote, the ref count will be zero.
2113 */
2114 if (!demote) {
2115 if (!page_ref_freeze(p, 1)) {
2116 pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
2117 goto out_error;
2118 }
2119 } else {
2120 VM_BUG_ON_PAGE(page_count(p), p);
2121 }
2122 if (i != 0)
2123 set_compound_head(p, &folio->page);
2124 }
2125 __folio_set_head(folio);
2126 /* we rely on prep_new_hugetlb_folio to set the destructor */
2127 folio_set_order(folio, order);
2128 atomic_set(&folio->_entire_mapcount, -1);
2129 atomic_set(&folio->_nr_pages_mapped, 0);
2130 atomic_set(&folio->_pincount, 0);
2131 return true;
2132
2133out_error:
2134 /* undo page modifications made above */
2135 for (j = 0; j < i; j++) {
2136 p = folio_page(folio, j);
2137 if (j != 0)
2138 clear_compound_head(p);
2139 set_page_refcounted(p);
2140 }
2141 /* need to clear PG_reserved on remaining tail pages */
2142 for (; j < nr_pages; j++) {
2143 p = folio_page(folio, j);
2144 __ClearPageReserved(p);
2145 }
2146 return false;
2147}
2148
2149static bool prep_compound_gigantic_folio(struct folio *folio,
2150 unsigned int order)
2151{
2152 return __prep_compound_gigantic_folio(folio, order, false);
2153}
2154
2155static bool prep_compound_gigantic_folio_for_demote(struct folio *folio,
2156 unsigned int order)
2157{
2158 return __prep_compound_gigantic_folio(folio, order, true);
2159}
2160
2161/*
2162 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
2163 * transparent huge pages. See the PageTransHuge() documentation for more
2164 * details.
2165 */
2166int PageHuge(struct page *page)
2167{
2168 struct folio *folio;
2169
2170 if (!PageCompound(page))
2171 return 0;
2172 folio = page_folio(page);
2173 return folio_test_hugetlb(folio);
2174}
2175EXPORT_SYMBOL_GPL(PageHuge);
2176
2177/*
2178 * Find and lock address space (mapping) in write mode.
2179 *
2180 * Upon entry, the page is locked which means that page_mapping() is
2181 * stable. Due to locking order, we can only trylock_write. If we can
2182 * not get the lock, simply return NULL to caller.
2183 */
2184struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
2185{
2186 struct address_space *mapping = page_mapping(hpage);
2187
2188 if (!mapping)
2189 return mapping;
2190
2191 if (i_mmap_trylock_write(mapping))
2192 return mapping;
2193
2194 return NULL;
2195}
2196
2197static struct folio *alloc_buddy_hugetlb_folio(struct hstate *h,
2198 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2199 nodemask_t *node_alloc_noretry)
2200{
2201 int order = huge_page_order(h);
2202 struct page *page;
2203 bool alloc_try_hard = true;
2204 bool retry = true;
2205
2206 /*
2207 * By default we always try hard to allocate the page with
2208 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
2209 * a loop (to adjust global huge page counts) and previous allocation
2210 * failed, do not continue to try hard on the same node. Use the
2211 * node_alloc_noretry bitmap to manage this state information.
2212 */
2213 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
2214 alloc_try_hard = false;
2215 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
2216 if (alloc_try_hard)
2217 gfp_mask |= __GFP_RETRY_MAYFAIL;
2218 if (nid == NUMA_NO_NODE)
2219 nid = numa_mem_id();
2220retry:
2221 page = __alloc_pages(gfp_mask, order, nid, nmask);
2222
2223 /* Freeze head page */
2224 if (page && !page_ref_freeze(page, 1)) {
2225 __free_pages(page, order);
2226 if (retry) { /* retry once */
2227 retry = false;
2228 goto retry;
2229 }
2230 /* WOW! twice in a row. */
2231 pr_warn("HugeTLB head page unexpected inflated ref count\n");
2232 page = NULL;
2233 }
2234
2235 /*
2236 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
2237 * indicates an overall state change. Clear bit so that we resume
2238 * normal 'try hard' allocations.
2239 */
2240 if (node_alloc_noretry && page && !alloc_try_hard)
2241 node_clear(nid, *node_alloc_noretry);
2242
2243 /*
2244 * If we tried hard to get a page but failed, set bit so that
2245 * subsequent attempts will not try as hard until there is an
2246 * overall state change.
2247 */
2248 if (node_alloc_noretry && !page && alloc_try_hard)
2249 node_set(nid, *node_alloc_noretry);
2250
2251 if (!page) {
2252 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
2253 return NULL;
2254 }
2255
2256 __count_vm_event(HTLB_BUDDY_PGALLOC);
2257 return page_folio(page);
2258}
2259
2260static struct folio *__alloc_fresh_hugetlb_folio(struct hstate *h,
2261 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2262 nodemask_t *node_alloc_noretry)
2263{
2264 struct folio *folio;
2265 bool retry = false;
2266
2267retry:
2268 if (hstate_is_gigantic(h))
2269 folio = alloc_gigantic_folio(h, gfp_mask, nid, nmask);
2270 else
2271 folio = alloc_buddy_hugetlb_folio(h, gfp_mask,
2272 nid, nmask, node_alloc_noretry);
2273 if (!folio)
2274 return NULL;
2275
2276 if (hstate_is_gigantic(h)) {
2277 if (!prep_compound_gigantic_folio(folio, huge_page_order(h))) {
2278 /*
2279 * Rare failure to convert pages to compound page.
2280 * Free pages and try again - ONCE!
2281 */
2282 free_gigantic_folio(folio, huge_page_order(h));
2283 if (!retry) {
2284 retry = true;
2285 goto retry;
2286 }
2287 return NULL;
2288 }
2289 }
2290
2291 return folio;
2292}
2293
2294static struct folio *only_alloc_fresh_hugetlb_folio(struct hstate *h,
2295 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2296 nodemask_t *node_alloc_noretry)
2297{
2298 struct folio *folio;
2299
2300 folio = __alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask,
2301 node_alloc_noretry);
2302 if (folio)
2303 init_new_hugetlb_folio(h, folio);
2304 return folio;
2305}
2306
2307/*
2308 * Common helper to allocate a fresh hugetlb page. All specific allocators
2309 * should use this function to get new hugetlb pages
2310 *
2311 * Note that returned page is 'frozen': ref count of head page and all tail
2312 * pages is zero.
2313 */
2314static struct folio *alloc_fresh_hugetlb_folio(struct hstate *h,
2315 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2316 nodemask_t *node_alloc_noretry)
2317{
2318 struct folio *folio;
2319
2320 folio = __alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask,
2321 node_alloc_noretry);
2322 if (!folio)
2323 return NULL;
2324
2325 prep_new_hugetlb_folio(h, folio, folio_nid(folio));
2326 return folio;
2327}
2328
2329static void prep_and_add_allocated_folios(struct hstate *h,
2330 struct list_head *folio_list)
2331{
2332 unsigned long flags;
2333 struct folio *folio, *tmp_f;
2334
2335 /* Send list for bulk vmemmap optimization processing */
2336 hugetlb_vmemmap_optimize_folios(h, folio_list);
2337
2338 /* Add all new pool pages to free lists in one lock cycle */
2339 spin_lock_irqsave(&hugetlb_lock, flags);
2340 list_for_each_entry_safe(folio, tmp_f, folio_list, lru) {
2341 __prep_account_new_huge_page(h, folio_nid(folio));
2342 enqueue_hugetlb_folio(h, folio);
2343 }
2344 spin_unlock_irqrestore(&hugetlb_lock, flags);
2345}
2346
2347/*
2348 * Allocates a fresh hugetlb page in a node interleaved manner. The page
2349 * will later be added to the appropriate hugetlb pool.
2350 */
2351static struct folio *alloc_pool_huge_folio(struct hstate *h,
2352 nodemask_t *nodes_allowed,
2353 nodemask_t *node_alloc_noretry)
2354{
2355 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
2356 int nr_nodes, node;
2357
2358 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
2359 struct folio *folio;
2360
2361 folio = only_alloc_fresh_hugetlb_folio(h, gfp_mask, node,
2362 nodes_allowed, node_alloc_noretry);
2363 if (folio)
2364 return folio;
2365 }
2366
2367 return NULL;
2368}
2369
2370/*
2371 * Remove huge page from pool from next node to free. Attempt to keep
2372 * persistent huge pages more or less balanced over allowed nodes.
2373 * This routine only 'removes' the hugetlb page. The caller must make
2374 * an additional call to free the page to low level allocators.
2375 * Called with hugetlb_lock locked.
2376 */
2377static struct folio *remove_pool_hugetlb_folio(struct hstate *h,
2378 nodemask_t *nodes_allowed, bool acct_surplus)
2379{
2380 int nr_nodes, node;
2381 struct folio *folio = NULL;
2382
2383 lockdep_assert_held(&hugetlb_lock);
2384 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2385 /*
2386 * If we're returning unused surplus pages, only examine
2387 * nodes with surplus pages.
2388 */
2389 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
2390 !list_empty(&h->hugepage_freelists[node])) {
2391 folio = list_entry(h->hugepage_freelists[node].next,
2392 struct folio, lru);
2393 remove_hugetlb_folio(h, folio, acct_surplus);
2394 break;
2395 }
2396 }
2397
2398 return folio;
2399}
2400
2401/*
2402 * Dissolve a given free hugepage into free buddy pages. This function does
2403 * nothing for in-use hugepages and non-hugepages.
2404 * This function returns values like below:
2405 *
2406 * -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages
2407 * when the system is under memory pressure and the feature of
2408 * freeing unused vmemmap pages associated with each hugetlb page
2409 * is enabled.
2410 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
2411 * (allocated or reserved.)
2412 * 0: successfully dissolved free hugepages or the page is not a
2413 * hugepage (considered as already dissolved)
2414 */
2415int dissolve_free_huge_page(struct page *page)
2416{
2417 int rc = -EBUSY;
2418 struct folio *folio = page_folio(page);
2419
2420retry:
2421 /* Not to disrupt normal path by vainly holding hugetlb_lock */
2422 if (!folio_test_hugetlb(folio))
2423 return 0;
2424
2425 spin_lock_irq(&hugetlb_lock);
2426 if (!folio_test_hugetlb(folio)) {
2427 rc = 0;
2428 goto out;
2429 }
2430
2431 if (!folio_ref_count(folio)) {
2432 struct hstate *h = folio_hstate(folio);
2433 if (!available_huge_pages(h))
2434 goto out;
2435
2436 /*
2437 * We should make sure that the page is already on the free list
2438 * when it is dissolved.
2439 */
2440 if (unlikely(!folio_test_hugetlb_freed(folio))) {
2441 spin_unlock_irq(&hugetlb_lock);
2442 cond_resched();
2443
2444 /*
2445 * Theoretically, we should return -EBUSY when we
2446 * encounter this race. In fact, we have a chance
2447 * to successfully dissolve the page if we do a
2448 * retry. Because the race window is quite small.
2449 * If we seize this opportunity, it is an optimization
2450 * for increasing the success rate of dissolving page.
2451 */
2452 goto retry;
2453 }
2454
2455 remove_hugetlb_folio(h, folio, false);
2456 h->max_huge_pages--;
2457 spin_unlock_irq(&hugetlb_lock);
2458
2459 /*
2460 * Normally update_and_free_hugtlb_folio will allocate required vmemmmap
2461 * before freeing the page. update_and_free_hugtlb_folio will fail to
2462 * free the page if it can not allocate required vmemmap. We
2463 * need to adjust max_huge_pages if the page is not freed.
2464 * Attempt to allocate vmemmmap here so that we can take
2465 * appropriate action on failure.
2466 *
2467 * The folio_test_hugetlb check here is because
2468 * remove_hugetlb_folio will clear hugetlb folio flag for
2469 * non-vmemmap optimized hugetlb folios.
2470 */
2471 if (folio_test_hugetlb(folio)) {
2472 rc = hugetlb_vmemmap_restore_folio(h, folio);
2473 if (rc) {
2474 spin_lock_irq(&hugetlb_lock);
2475 add_hugetlb_folio(h, folio, false);
2476 h->max_huge_pages++;
2477 goto out;
2478 }
2479 } else
2480 rc = 0;
2481
2482 update_and_free_hugetlb_folio(h, folio, false);
2483 return rc;
2484 }
2485out:
2486 spin_unlock_irq(&hugetlb_lock);
2487 return rc;
2488}
2489
2490/*
2491 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
2492 * make specified memory blocks removable from the system.
2493 * Note that this will dissolve a free gigantic hugepage completely, if any
2494 * part of it lies within the given range.
2495 * Also note that if dissolve_free_huge_page() returns with an error, all
2496 * free hugepages that were dissolved before that error are lost.
2497 */
2498int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
2499{
2500 unsigned long pfn;
2501 struct page *page;
2502 int rc = 0;
2503 unsigned int order;
2504 struct hstate *h;
2505
2506 if (!hugepages_supported())
2507 return rc;
2508
2509 order = huge_page_order(&default_hstate);
2510 for_each_hstate(h)
2511 order = min(order, huge_page_order(h));
2512
2513 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) {
2514 page = pfn_to_page(pfn);
2515 rc = dissolve_free_huge_page(page);
2516 if (rc)
2517 break;
2518 }
2519
2520 return rc;
2521}
2522
2523/*
2524 * Allocates a fresh surplus page from the page allocator.
2525 */
2526static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h,
2527 gfp_t gfp_mask, int nid, nodemask_t *nmask)
2528{
2529 struct folio *folio = NULL;
2530
2531 if (hstate_is_gigantic(h))
2532 return NULL;
2533
2534 spin_lock_irq(&hugetlb_lock);
2535 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
2536 goto out_unlock;
2537 spin_unlock_irq(&hugetlb_lock);
2538
2539 folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL);
2540 if (!folio)
2541 return NULL;
2542
2543 spin_lock_irq(&hugetlb_lock);
2544 /*
2545 * We could have raced with the pool size change.
2546 * Double check that and simply deallocate the new page
2547 * if we would end up overcommiting the surpluses. Abuse
2548 * temporary page to workaround the nasty free_huge_folio
2549 * codeflow
2550 */
2551 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
2552 folio_set_hugetlb_temporary(folio);
2553 spin_unlock_irq(&hugetlb_lock);
2554 free_huge_folio(folio);
2555 return NULL;
2556 }
2557
2558 h->surplus_huge_pages++;
2559 h->surplus_huge_pages_node[folio_nid(folio)]++;
2560
2561out_unlock:
2562 spin_unlock_irq(&hugetlb_lock);
2563
2564 return folio;
2565}
2566
2567static struct folio *alloc_migrate_hugetlb_folio(struct hstate *h, gfp_t gfp_mask,
2568 int nid, nodemask_t *nmask)
2569{
2570 struct folio *folio;
2571
2572 if (hstate_is_gigantic(h))
2573 return NULL;
2574
2575 folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL);
2576 if (!folio)
2577 return NULL;
2578
2579 /* fresh huge pages are frozen */
2580 folio_ref_unfreeze(folio, 1);
2581 /*
2582 * We do not account these pages as surplus because they are only
2583 * temporary and will be released properly on the last reference
2584 */
2585 folio_set_hugetlb_temporary(folio);
2586
2587 return folio;
2588}
2589
2590/*
2591 * Use the VMA's mpolicy to allocate a huge page from the buddy.
2592 */
2593static
2594struct folio *alloc_buddy_hugetlb_folio_with_mpol(struct hstate *h,
2595 struct vm_area_struct *vma, unsigned long addr)
2596{
2597 struct folio *folio = NULL;
2598 struct mempolicy *mpol;
2599 gfp_t gfp_mask = htlb_alloc_mask(h);
2600 int nid;
2601 nodemask_t *nodemask;
2602
2603 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
2604 if (mpol_is_preferred_many(mpol)) {
2605 gfp_t gfp = gfp_mask | __GFP_NOWARN;
2606
2607 gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
2608 folio = alloc_surplus_hugetlb_folio(h, gfp, nid, nodemask);
2609
2610 /* Fallback to all nodes if page==NULL */
2611 nodemask = NULL;
2612 }
2613
2614 if (!folio)
2615 folio = alloc_surplus_hugetlb_folio(h, gfp_mask, nid, nodemask);
2616 mpol_cond_put(mpol);
2617 return folio;
2618}
2619
2620/* folio migration callback function */
2621struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
2622 nodemask_t *nmask, gfp_t gfp_mask)
2623{
2624 spin_lock_irq(&hugetlb_lock);
2625 if (available_huge_pages(h)) {
2626 struct folio *folio;
2627
2628 folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
2629 preferred_nid, nmask);
2630 if (folio) {
2631 spin_unlock_irq(&hugetlb_lock);
2632 return folio;
2633 }
2634 }
2635 spin_unlock_irq(&hugetlb_lock);
2636
2637 return alloc_migrate_hugetlb_folio(h, gfp_mask, preferred_nid, nmask);
2638}
2639
2640/*
2641 * Increase the hugetlb pool such that it can accommodate a reservation
2642 * of size 'delta'.
2643 */
2644static int gather_surplus_pages(struct hstate *h, long delta)
2645 __must_hold(&hugetlb_lock)
2646{
2647 LIST_HEAD(surplus_list);
2648 struct folio *folio, *tmp;
2649 int ret;
2650 long i;
2651 long needed, allocated;
2652 bool alloc_ok = true;
2653
2654 lockdep_assert_held(&hugetlb_lock);
2655 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2656 if (needed <= 0) {
2657 h->resv_huge_pages += delta;
2658 return 0;
2659 }
2660
2661 allocated = 0;
2662
2663 ret = -ENOMEM;
2664retry:
2665 spin_unlock_irq(&hugetlb_lock);
2666 for (i = 0; i < needed; i++) {
2667 folio = alloc_surplus_hugetlb_folio(h, htlb_alloc_mask(h),
2668 NUMA_NO_NODE, NULL);
2669 if (!folio) {
2670 alloc_ok = false;
2671 break;
2672 }
2673 list_add(&folio->lru, &surplus_list);
2674 cond_resched();
2675 }
2676 allocated += i;
2677
2678 /*
2679 * After retaking hugetlb_lock, we need to recalculate 'needed'
2680 * because either resv_huge_pages or free_huge_pages may have changed.
2681 */
2682 spin_lock_irq(&hugetlb_lock);
2683 needed = (h->resv_huge_pages + delta) -
2684 (h->free_huge_pages + allocated);
2685 if (needed > 0) {
2686 if (alloc_ok)
2687 goto retry;
2688 /*
2689 * We were not able to allocate enough pages to
2690 * satisfy the entire reservation so we free what
2691 * we've allocated so far.
2692 */
2693 goto free;
2694 }
2695 /*
2696 * The surplus_list now contains _at_least_ the number of extra pages
2697 * needed to accommodate the reservation. Add the appropriate number
2698 * of pages to the hugetlb pool and free the extras back to the buddy
2699 * allocator. Commit the entire reservation here to prevent another
2700 * process from stealing the pages as they are added to the pool but
2701 * before they are reserved.
2702 */
2703 needed += allocated;
2704 h->resv_huge_pages += delta;
2705 ret = 0;
2706
2707 /* Free the needed pages to the hugetlb pool */
2708 list_for_each_entry_safe(folio, tmp, &surplus_list, lru) {
2709 if ((--needed) < 0)
2710 break;
2711 /* Add the page to the hugetlb allocator */
2712 enqueue_hugetlb_folio(h, folio);
2713 }
2714free:
2715 spin_unlock_irq(&hugetlb_lock);
2716
2717 /*
2718 * Free unnecessary surplus pages to the buddy allocator.
2719 * Pages have no ref count, call free_huge_folio directly.
2720 */
2721 list_for_each_entry_safe(folio, tmp, &surplus_list, lru)
2722 free_huge_folio(folio);
2723 spin_lock_irq(&hugetlb_lock);
2724
2725 return ret;
2726}
2727
2728/*
2729 * This routine has two main purposes:
2730 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2731 * in unused_resv_pages. This corresponds to the prior adjustments made
2732 * to the associated reservation map.
2733 * 2) Free any unused surplus pages that may have been allocated to satisfy
2734 * the reservation. As many as unused_resv_pages may be freed.
2735 */
2736static void return_unused_surplus_pages(struct hstate *h,
2737 unsigned long unused_resv_pages)
2738{
2739 unsigned long nr_pages;
2740 LIST_HEAD(page_list);
2741
2742 lockdep_assert_held(&hugetlb_lock);
2743 /* Uncommit the reservation */
2744 h->resv_huge_pages -= unused_resv_pages;
2745
2746 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
2747 goto out;
2748
2749 /*
2750 * Part (or even all) of the reservation could have been backed
2751 * by pre-allocated pages. Only free surplus pages.
2752 */
2753 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2754
2755 /*
2756 * We want to release as many surplus pages as possible, spread
2757 * evenly across all nodes with memory. Iterate across these nodes
2758 * until we can no longer free unreserved surplus pages. This occurs
2759 * when the nodes with surplus pages have no free pages.
2760 * remove_pool_hugetlb_folio() will balance the freed pages across the
2761 * on-line nodes with memory and will handle the hstate accounting.
2762 */
2763 while (nr_pages--) {
2764 struct folio *folio;
2765
2766 folio = remove_pool_hugetlb_folio(h, &node_states[N_MEMORY], 1);
2767 if (!folio)
2768 goto out;
2769
2770 list_add(&folio->lru, &page_list);
2771 }
2772
2773out:
2774 spin_unlock_irq(&hugetlb_lock);
2775 update_and_free_pages_bulk(h, &page_list);
2776 spin_lock_irq(&hugetlb_lock);
2777}
2778
2779
2780/*
2781 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2782 * are used by the huge page allocation routines to manage reservations.
2783 *
2784 * vma_needs_reservation is called to determine if the huge page at addr
2785 * within the vma has an associated reservation. If a reservation is
2786 * needed, the value 1 is returned. The caller is then responsible for
2787 * managing the global reservation and subpool usage counts. After
2788 * the huge page has been allocated, vma_commit_reservation is called
2789 * to add the page to the reservation map. If the page allocation fails,
2790 * the reservation must be ended instead of committed. vma_end_reservation
2791 * is called in such cases.
2792 *
2793 * In the normal case, vma_commit_reservation returns the same value
2794 * as the preceding vma_needs_reservation call. The only time this
2795 * is not the case is if a reserve map was changed between calls. It
2796 * is the responsibility of the caller to notice the difference and
2797 * take appropriate action.
2798 *
2799 * vma_add_reservation is used in error paths where a reservation must
2800 * be restored when a newly allocated huge page must be freed. It is
2801 * to be called after calling vma_needs_reservation to determine if a
2802 * reservation exists.
2803 *
2804 * vma_del_reservation is used in error paths where an entry in the reserve
2805 * map was created during huge page allocation and must be removed. It is to
2806 * be called after calling vma_needs_reservation to determine if a reservation
2807 * exists.
2808 */
2809enum vma_resv_mode {
2810 VMA_NEEDS_RESV,
2811 VMA_COMMIT_RESV,
2812 VMA_END_RESV,
2813 VMA_ADD_RESV,
2814 VMA_DEL_RESV,
2815};
2816static long __vma_reservation_common(struct hstate *h,
2817 struct vm_area_struct *vma, unsigned long addr,
2818 enum vma_resv_mode mode)
2819{
2820 struct resv_map *resv;
2821 pgoff_t idx;
2822 long ret;
2823 long dummy_out_regions_needed;
2824
2825 resv = vma_resv_map(vma);
2826 if (!resv)
2827 return 1;
2828
2829 idx = vma_hugecache_offset(h, vma, addr);
2830 switch (mode) {
2831 case VMA_NEEDS_RESV:
2832 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2833 /* We assume that vma_reservation_* routines always operate on
2834 * 1 page, and that adding to resv map a 1 page entry can only
2835 * ever require 1 region.
2836 */
2837 VM_BUG_ON(dummy_out_regions_needed != 1);
2838 break;
2839 case VMA_COMMIT_RESV:
2840 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2841 /* region_add calls of range 1 should never fail. */
2842 VM_BUG_ON(ret < 0);
2843 break;
2844 case VMA_END_RESV:
2845 region_abort(resv, idx, idx + 1, 1);
2846 ret = 0;
2847 break;
2848 case VMA_ADD_RESV:
2849 if (vma->vm_flags & VM_MAYSHARE) {
2850 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2851 /* region_add calls of range 1 should never fail. */
2852 VM_BUG_ON(ret < 0);
2853 } else {
2854 region_abort(resv, idx, idx + 1, 1);
2855 ret = region_del(resv, idx, idx + 1);
2856 }
2857 break;
2858 case VMA_DEL_RESV:
2859 if (vma->vm_flags & VM_MAYSHARE) {
2860 region_abort(resv, idx, idx + 1, 1);
2861 ret = region_del(resv, idx, idx + 1);
2862 } else {
2863 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2864 /* region_add calls of range 1 should never fail. */
2865 VM_BUG_ON(ret < 0);
2866 }
2867 break;
2868 default:
2869 BUG();
2870 }
2871
2872 if (vma->vm_flags & VM_MAYSHARE || mode == VMA_DEL_RESV)
2873 return ret;
2874 /*
2875 * We know private mapping must have HPAGE_RESV_OWNER set.
2876 *
2877 * In most cases, reserves always exist for private mappings.
2878 * However, a file associated with mapping could have been
2879 * hole punched or truncated after reserves were consumed.
2880 * As subsequent fault on such a range will not use reserves.
2881 * Subtle - The reserve map for private mappings has the
2882 * opposite meaning than that of shared mappings. If NO
2883 * entry is in the reserve map, it means a reservation exists.
2884 * If an entry exists in the reserve map, it means the
2885 * reservation has already been consumed. As a result, the
2886 * return value of this routine is the opposite of the
2887 * value returned from reserve map manipulation routines above.
2888 */
2889 if (ret > 0)
2890 return 0;
2891 if (ret == 0)
2892 return 1;
2893 return ret;
2894}
2895
2896static long vma_needs_reservation(struct hstate *h,
2897 struct vm_area_struct *vma, unsigned long addr)
2898{
2899 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2900}
2901
2902static long vma_commit_reservation(struct hstate *h,
2903 struct vm_area_struct *vma, unsigned long addr)
2904{
2905 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2906}
2907
2908static void vma_end_reservation(struct hstate *h,
2909 struct vm_area_struct *vma, unsigned long addr)
2910{
2911 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2912}
2913
2914static long vma_add_reservation(struct hstate *h,
2915 struct vm_area_struct *vma, unsigned long addr)
2916{
2917 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2918}
2919
2920static long vma_del_reservation(struct hstate *h,
2921 struct vm_area_struct *vma, unsigned long addr)
2922{
2923 return __vma_reservation_common(h, vma, addr, VMA_DEL_RESV);
2924}
2925
2926/*
2927 * This routine is called to restore reservation information on error paths.
2928 * It should ONLY be called for folios allocated via alloc_hugetlb_folio(),
2929 * and the hugetlb mutex should remain held when calling this routine.
2930 *
2931 * It handles two specific cases:
2932 * 1) A reservation was in place and the folio consumed the reservation.
2933 * hugetlb_restore_reserve is set in the folio.
2934 * 2) No reservation was in place for the page, so hugetlb_restore_reserve is
2935 * not set. However, alloc_hugetlb_folio always updates the reserve map.
2936 *
2937 * In case 1, free_huge_folio later in the error path will increment the
2938 * global reserve count. But, free_huge_folio does not have enough context
2939 * to adjust the reservation map. This case deals primarily with private
2940 * mappings. Adjust the reserve map here to be consistent with global
2941 * reserve count adjustments to be made by free_huge_folio. Make sure the
2942 * reserve map indicates there is a reservation present.
2943 *
2944 * In case 2, simply undo reserve map modifications done by alloc_hugetlb_folio.
2945 */
2946void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
2947 unsigned long address, struct folio *folio)
2948{
2949 long rc = vma_needs_reservation(h, vma, address);
2950
2951 if (folio_test_hugetlb_restore_reserve(folio)) {
2952 if (unlikely(rc < 0))
2953 /*
2954 * Rare out of memory condition in reserve map
2955 * manipulation. Clear hugetlb_restore_reserve so
2956 * that global reserve count will not be incremented
2957 * by free_huge_folio. This will make it appear
2958 * as though the reservation for this folio was
2959 * consumed. This may prevent the task from
2960 * faulting in the folio at a later time. This
2961 * is better than inconsistent global huge page
2962 * accounting of reserve counts.
2963 */
2964 folio_clear_hugetlb_restore_reserve(folio);
2965 else if (rc)
2966 (void)vma_add_reservation(h, vma, address);
2967 else
2968 vma_end_reservation(h, vma, address);
2969 } else {
2970 if (!rc) {
2971 /*
2972 * This indicates there is an entry in the reserve map
2973 * not added by alloc_hugetlb_folio. We know it was added
2974 * before the alloc_hugetlb_folio call, otherwise
2975 * hugetlb_restore_reserve would be set on the folio.
2976 * Remove the entry so that a subsequent allocation
2977 * does not consume a reservation.
2978 */
2979 rc = vma_del_reservation(h, vma, address);
2980 if (rc < 0)
2981 /*
2982 * VERY rare out of memory condition. Since
2983 * we can not delete the entry, set
2984 * hugetlb_restore_reserve so that the reserve
2985 * count will be incremented when the folio
2986 * is freed. This reserve will be consumed
2987 * on a subsequent allocation.
2988 */
2989 folio_set_hugetlb_restore_reserve(folio);
2990 } else if (rc < 0) {
2991 /*
2992 * Rare out of memory condition from
2993 * vma_needs_reservation call. Memory allocation is
2994 * only attempted if a new entry is needed. Therefore,
2995 * this implies there is not an entry in the
2996 * reserve map.
2997 *
2998 * For shared mappings, no entry in the map indicates
2999 * no reservation. We are done.
3000 */
3001 if (!(vma->vm_flags & VM_MAYSHARE))
3002 /*
3003 * For private mappings, no entry indicates
3004 * a reservation is present. Since we can
3005 * not add an entry, set hugetlb_restore_reserve
3006 * on the folio so reserve count will be
3007 * incremented when freed. This reserve will
3008 * be consumed on a subsequent allocation.
3009 */
3010 folio_set_hugetlb_restore_reserve(folio);
3011 } else
3012 /*
3013 * No reservation present, do nothing
3014 */
3015 vma_end_reservation(h, vma, address);
3016 }
3017}
3018
3019/*
3020 * alloc_and_dissolve_hugetlb_folio - Allocate a new folio and dissolve
3021 * the old one
3022 * @h: struct hstate old page belongs to
3023 * @old_folio: Old folio to dissolve
3024 * @list: List to isolate the page in case we need to
3025 * Returns 0 on success, otherwise negated error.
3026 */
3027static int alloc_and_dissolve_hugetlb_folio(struct hstate *h,
3028 struct folio *old_folio, struct list_head *list)
3029{
3030 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
3031 int nid = folio_nid(old_folio);
3032 struct folio *new_folio;
3033 int ret = 0;
3034
3035 /*
3036 * Before dissolving the folio, we need to allocate a new one for the
3037 * pool to remain stable. Here, we allocate the folio and 'prep' it
3038 * by doing everything but actually updating counters and adding to
3039 * the pool. This simplifies and let us do most of the processing
3040 * under the lock.
3041 */
3042 new_folio = alloc_buddy_hugetlb_folio(h, gfp_mask, nid, NULL, NULL);
3043 if (!new_folio)
3044 return -ENOMEM;
3045 __prep_new_hugetlb_folio(h, new_folio);
3046
3047retry:
3048 spin_lock_irq(&hugetlb_lock);
3049 if (!folio_test_hugetlb(old_folio)) {
3050 /*
3051 * Freed from under us. Drop new_folio too.
3052 */
3053 goto free_new;
3054 } else if (folio_ref_count(old_folio)) {
3055 bool isolated;
3056
3057 /*
3058 * Someone has grabbed the folio, try to isolate it here.
3059 * Fail with -EBUSY if not possible.
3060 */
3061 spin_unlock_irq(&hugetlb_lock);
3062 isolated = isolate_hugetlb(old_folio, list);
3063 ret = isolated ? 0 : -EBUSY;
3064 spin_lock_irq(&hugetlb_lock);
3065 goto free_new;
3066 } else if (!folio_test_hugetlb_freed(old_folio)) {
3067 /*
3068 * Folio's refcount is 0 but it has not been enqueued in the
3069 * freelist yet. Race window is small, so we can succeed here if
3070 * we retry.
3071 */
3072 spin_unlock_irq(&hugetlb_lock);
3073 cond_resched();
3074 goto retry;
3075 } else {
3076 /*
3077 * Ok, old_folio is still a genuine free hugepage. Remove it from
3078 * the freelist and decrease the counters. These will be
3079 * incremented again when calling __prep_account_new_huge_page()
3080 * and enqueue_hugetlb_folio() for new_folio. The counters will
3081 * remain stable since this happens under the lock.
3082 */
3083 remove_hugetlb_folio(h, old_folio, false);
3084
3085 /*
3086 * Ref count on new_folio is already zero as it was dropped
3087 * earlier. It can be directly added to the pool free list.
3088 */
3089 __prep_account_new_huge_page(h, nid);
3090 enqueue_hugetlb_folio(h, new_folio);
3091
3092 /*
3093 * Folio has been replaced, we can safely free the old one.
3094 */
3095 spin_unlock_irq(&hugetlb_lock);
3096 update_and_free_hugetlb_folio(h, old_folio, false);
3097 }
3098
3099 return ret;
3100
3101free_new:
3102 spin_unlock_irq(&hugetlb_lock);
3103 /* Folio has a zero ref count, but needs a ref to be freed */
3104 folio_ref_unfreeze(new_folio, 1);
3105 update_and_free_hugetlb_folio(h, new_folio, false);
3106
3107 return ret;
3108}
3109
3110int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
3111{
3112 struct hstate *h;
3113 struct folio *folio = page_folio(page);
3114 int ret = -EBUSY;
3115
3116 /*
3117 * The page might have been dissolved from under our feet, so make sure
3118 * to carefully check the state under the lock.
3119 * Return success when racing as if we dissolved the page ourselves.
3120 */
3121 spin_lock_irq(&hugetlb_lock);
3122 if (folio_test_hugetlb(folio)) {
3123 h = folio_hstate(folio);
3124 } else {
3125 spin_unlock_irq(&hugetlb_lock);
3126 return 0;
3127 }
3128 spin_unlock_irq(&hugetlb_lock);
3129
3130 /*
3131 * Fence off gigantic pages as there is a cyclic dependency between
3132 * alloc_contig_range and them. Return -ENOMEM as this has the effect
3133 * of bailing out right away without further retrying.
3134 */
3135 if (hstate_is_gigantic(h))
3136 return -ENOMEM;
3137
3138 if (folio_ref_count(folio) && isolate_hugetlb(folio, list))
3139 ret = 0;
3140 else if (!folio_ref_count(folio))
3141 ret = alloc_and_dissolve_hugetlb_folio(h, folio, list);
3142
3143 return ret;
3144}
3145
3146struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
3147 unsigned long addr, int avoid_reserve)
3148{
3149 struct hugepage_subpool *spool = subpool_vma(vma);
3150 struct hstate *h = hstate_vma(vma);
3151 struct folio *folio;
3152 long map_chg, map_commit, nr_pages = pages_per_huge_page(h);
3153 long gbl_chg;
3154 int memcg_charge_ret, ret, idx;
3155 struct hugetlb_cgroup *h_cg = NULL;
3156 struct mem_cgroup *memcg;
3157 bool deferred_reserve;
3158 gfp_t gfp = htlb_alloc_mask(h) | __GFP_RETRY_MAYFAIL;
3159
3160 memcg = get_mem_cgroup_from_current();
3161 memcg_charge_ret = mem_cgroup_hugetlb_try_charge(memcg, gfp, nr_pages);
3162 if (memcg_charge_ret == -ENOMEM) {
3163 mem_cgroup_put(memcg);
3164 return ERR_PTR(-ENOMEM);
3165 }
3166
3167 idx = hstate_index(h);
3168 /*
3169 * Examine the region/reserve map to determine if the process
3170 * has a reservation for the page to be allocated. A return
3171 * code of zero indicates a reservation exists (no change).
3172 */
3173 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
3174 if (map_chg < 0) {
3175 if (!memcg_charge_ret)
3176 mem_cgroup_cancel_charge(memcg, nr_pages);
3177 mem_cgroup_put(memcg);
3178 return ERR_PTR(-ENOMEM);
3179 }
3180
3181 /*
3182 * Processes that did not create the mapping will have no
3183 * reserves as indicated by the region/reserve map. Check
3184 * that the allocation will not exceed the subpool limit.
3185 * Allocations for MAP_NORESERVE mappings also need to be
3186 * checked against any subpool limit.
3187 */
3188 if (map_chg || avoid_reserve) {
3189 gbl_chg = hugepage_subpool_get_pages(spool, 1);
3190 if (gbl_chg < 0)
3191 goto out_end_reservation;
3192
3193 /*
3194 * Even though there was no reservation in the region/reserve
3195 * map, there could be reservations associated with the
3196 * subpool that can be used. This would be indicated if the
3197 * return value of hugepage_subpool_get_pages() is zero.
3198 * However, if avoid_reserve is specified we still avoid even
3199 * the subpool reservations.
3200 */
3201 if (avoid_reserve)
3202 gbl_chg = 1;
3203 }
3204
3205 /* If this allocation is not consuming a reservation, charge it now.
3206 */
3207 deferred_reserve = map_chg || avoid_reserve;
3208 if (deferred_reserve) {
3209 ret = hugetlb_cgroup_charge_cgroup_rsvd(
3210 idx, pages_per_huge_page(h), &h_cg);
3211 if (ret)
3212 goto out_subpool_put;
3213 }
3214
3215 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
3216 if (ret)
3217 goto out_uncharge_cgroup_reservation;
3218
3219 spin_lock_irq(&hugetlb_lock);
3220 /*
3221 * glb_chg is passed to indicate whether or not a page must be taken
3222 * from the global free pool (global change). gbl_chg == 0 indicates
3223 * a reservation exists for the allocation.
3224 */
3225 folio = dequeue_hugetlb_folio_vma(h, vma, addr, avoid_reserve, gbl_chg);
3226 if (!folio) {
3227 spin_unlock_irq(&hugetlb_lock);
3228 folio = alloc_buddy_hugetlb_folio_with_mpol(h, vma, addr);
3229 if (!folio)
3230 goto out_uncharge_cgroup;
3231 spin_lock_irq(&hugetlb_lock);
3232 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
3233 folio_set_hugetlb_restore_reserve(folio);
3234 h->resv_huge_pages--;
3235 }
3236 list_add(&folio->lru, &h->hugepage_activelist);
3237 folio_ref_unfreeze(folio, 1);
3238 /* Fall through */
3239 }
3240
3241 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, folio);
3242 /* If allocation is not consuming a reservation, also store the
3243 * hugetlb_cgroup pointer on the page.
3244 */
3245 if (deferred_reserve) {
3246 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
3247 h_cg, folio);
3248 }
3249
3250 spin_unlock_irq(&hugetlb_lock);
3251
3252 hugetlb_set_folio_subpool(folio, spool);
3253
3254 map_commit = vma_commit_reservation(h, vma, addr);
3255 if (unlikely(map_chg > map_commit)) {
3256 /*
3257 * The page was added to the reservation map between
3258 * vma_needs_reservation and vma_commit_reservation.
3259 * This indicates a race with hugetlb_reserve_pages.
3260 * Adjust for the subpool count incremented above AND
3261 * in hugetlb_reserve_pages for the same page. Also,
3262 * the reservation count added in hugetlb_reserve_pages
3263 * no longer applies.
3264 */
3265 long rsv_adjust;
3266
3267 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
3268 hugetlb_acct_memory(h, -rsv_adjust);
3269 if (deferred_reserve)
3270 hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h),
3271 pages_per_huge_page(h), folio);
3272 }
3273
3274 if (!memcg_charge_ret)
3275 mem_cgroup_commit_charge(folio, memcg);
3276 mem_cgroup_put(memcg);
3277
3278 return folio;
3279
3280out_uncharge_cgroup:
3281 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
3282out_uncharge_cgroup_reservation:
3283 if (deferred_reserve)
3284 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
3285 h_cg);
3286out_subpool_put:
3287 if (map_chg || avoid_reserve)
3288 hugepage_subpool_put_pages(spool, 1);
3289out_end_reservation:
3290 vma_end_reservation(h, vma, addr);
3291 if (!memcg_charge_ret)
3292 mem_cgroup_cancel_charge(memcg, nr_pages);
3293 mem_cgroup_put(memcg);
3294 return ERR_PTR(-ENOSPC);
3295}
3296
3297int alloc_bootmem_huge_page(struct hstate *h, int nid)
3298 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
3299int __alloc_bootmem_huge_page(struct hstate *h, int nid)
3300{
3301 struct huge_bootmem_page *m = NULL; /* initialize for clang */
3302 int nr_nodes, node;
3303
3304 /* do node specific alloc */
3305 if (nid != NUMA_NO_NODE) {
3306 m = memblock_alloc_try_nid_raw(huge_page_size(h), huge_page_size(h),
3307 0, MEMBLOCK_ALLOC_ACCESSIBLE, nid);
3308 if (!m)
3309 return 0;
3310 goto found;
3311 }
3312 /* allocate from next node when distributing huge pages */
3313 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
3314 m = memblock_alloc_try_nid_raw(
3315 huge_page_size(h), huge_page_size(h),
3316 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
3317 /*
3318 * Use the beginning of the huge page to store the
3319 * huge_bootmem_page struct (until gather_bootmem
3320 * puts them into the mem_map).
3321 */
3322 if (!m)
3323 return 0;
3324 goto found;
3325 }
3326
3327found:
3328
3329 /*
3330 * Only initialize the head struct page in memmap_init_reserved_pages,
3331 * rest of the struct pages will be initialized by the HugeTLB
3332 * subsystem itself.
3333 * The head struct page is used to get folio information by the HugeTLB
3334 * subsystem like zone id and node id.
3335 */
3336 memblock_reserved_mark_noinit(virt_to_phys((void *)m + PAGE_SIZE),
3337 huge_page_size(h) - PAGE_SIZE);
3338 /* Put them into a private list first because mem_map is not up yet */
3339 INIT_LIST_HEAD(&m->list);
3340 list_add(&m->list, &huge_boot_pages);
3341 m->hstate = h;
3342 return 1;
3343}
3344
3345/* Initialize [start_page:end_page_number] tail struct pages of a hugepage */
3346static void __init hugetlb_folio_init_tail_vmemmap(struct folio *folio,
3347 unsigned long start_page_number,
3348 unsigned long end_page_number)
3349{
3350 enum zone_type zone = zone_idx(folio_zone(folio));
3351 int nid = folio_nid(folio);
3352 unsigned long head_pfn = folio_pfn(folio);
3353 unsigned long pfn, end_pfn = head_pfn + end_page_number;
3354 int ret;
3355
3356 for (pfn = head_pfn + start_page_number; pfn < end_pfn; pfn++) {
3357 struct page *page = pfn_to_page(pfn);
3358
3359 __init_single_page(page, pfn, zone, nid);
3360 prep_compound_tail((struct page *)folio, pfn - head_pfn);
3361 ret = page_ref_freeze(page, 1);
3362 VM_BUG_ON(!ret);
3363 }
3364}
3365
3366static void __init hugetlb_folio_init_vmemmap(struct folio *folio,
3367 struct hstate *h,
3368 unsigned long nr_pages)
3369{
3370 int ret;
3371
3372 /* Prepare folio head */
3373 __folio_clear_reserved(folio);
3374 __folio_set_head(folio);
3375 ret = folio_ref_freeze(folio, 1);
3376 VM_BUG_ON(!ret);
3377 /* Initialize the necessary tail struct pages */
3378 hugetlb_folio_init_tail_vmemmap(folio, 1, nr_pages);
3379 prep_compound_head((struct page *)folio, huge_page_order(h));
3380}
3381
3382static void __init prep_and_add_bootmem_folios(struct hstate *h,
3383 struct list_head *folio_list)
3384{
3385 unsigned long flags;
3386 struct folio *folio, *tmp_f;
3387
3388 /* Send list for bulk vmemmap optimization processing */
3389 hugetlb_vmemmap_optimize_folios(h, folio_list);
3390
3391 /* Add all new pool pages to free lists in one lock cycle */
3392 spin_lock_irqsave(&hugetlb_lock, flags);
3393 list_for_each_entry_safe(folio, tmp_f, folio_list, lru) {
3394 if (!folio_test_hugetlb_vmemmap_optimized(folio)) {
3395 /*
3396 * If HVO fails, initialize all tail struct pages
3397 * We do not worry about potential long lock hold
3398 * time as this is early in boot and there should
3399 * be no contention.
3400 */
3401 hugetlb_folio_init_tail_vmemmap(folio,
3402 HUGETLB_VMEMMAP_RESERVE_PAGES,
3403 pages_per_huge_page(h));
3404 }
3405 __prep_account_new_huge_page(h, folio_nid(folio));
3406 enqueue_hugetlb_folio(h, folio);
3407 }
3408 spin_unlock_irqrestore(&hugetlb_lock, flags);
3409}
3410
3411/*
3412 * Put bootmem huge pages into the standard lists after mem_map is up.
3413 * Note: This only applies to gigantic (order > MAX_PAGE_ORDER) pages.
3414 */
3415static void __init gather_bootmem_prealloc(void)
3416{
3417 LIST_HEAD(folio_list);
3418 struct huge_bootmem_page *m;
3419 struct hstate *h = NULL, *prev_h = NULL;
3420
3421 list_for_each_entry(m, &huge_boot_pages, list) {
3422 struct page *page = virt_to_page(m);
3423 struct folio *folio = (void *)page;
3424
3425 h = m->hstate;
3426 /*
3427 * It is possible to have multiple huge page sizes (hstates)
3428 * in this list. If so, process each size separately.
3429 */
3430 if (h != prev_h && prev_h != NULL)
3431 prep_and_add_bootmem_folios(prev_h, &folio_list);
3432 prev_h = h;
3433
3434 VM_BUG_ON(!hstate_is_gigantic(h));
3435 WARN_ON(folio_ref_count(folio) != 1);
3436
3437 hugetlb_folio_init_vmemmap(folio, h,
3438 HUGETLB_VMEMMAP_RESERVE_PAGES);
3439 init_new_hugetlb_folio(h, folio);
3440 list_add(&folio->lru, &folio_list);
3441
3442 /*
3443 * We need to restore the 'stolen' pages to totalram_pages
3444 * in order to fix confusing memory reports from free(1) and
3445 * other side-effects, like CommitLimit going negative.
3446 */
3447 adjust_managed_page_count(page, pages_per_huge_page(h));
3448 cond_resched();
3449 }
3450
3451 prep_and_add_bootmem_folios(h, &folio_list);
3452}
3453
3454static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
3455{
3456 unsigned long i;
3457 char buf[32];
3458
3459 for (i = 0; i < h->max_huge_pages_node[nid]; ++i) {
3460 if (hstate_is_gigantic(h)) {
3461 if (!alloc_bootmem_huge_page(h, nid))
3462 break;
3463 } else {
3464 struct folio *folio;
3465 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
3466
3467 folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid,
3468 &node_states[N_MEMORY], NULL);
3469 if (!folio)
3470 break;
3471 free_huge_folio(folio); /* free it into the hugepage allocator */
3472 }
3473 cond_resched();
3474 }
3475 if (i == h->max_huge_pages_node[nid])
3476 return;
3477
3478 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
3479 pr_warn("HugeTLB: allocating %u of page size %s failed node%d. Only allocated %lu hugepages.\n",
3480 h->max_huge_pages_node[nid], buf, nid, i);
3481 h->max_huge_pages -= (h->max_huge_pages_node[nid] - i);
3482 h->max_huge_pages_node[nid] = i;
3483}
3484
3485/*
3486 * NOTE: this routine is called in different contexts for gigantic and
3487 * non-gigantic pages.
3488 * - For gigantic pages, this is called early in the boot process and
3489 * pages are allocated from memblock allocated or something similar.
3490 * Gigantic pages are actually added to pools later with the routine
3491 * gather_bootmem_prealloc.
3492 * - For non-gigantic pages, this is called later in the boot process after
3493 * all of mm is up and functional. Pages are allocated from buddy and
3494 * then added to hugetlb pools.
3495 */
3496static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
3497{
3498 unsigned long i;
3499 struct folio *folio;
3500 LIST_HEAD(folio_list);
3501 nodemask_t *node_alloc_noretry;
3502 bool node_specific_alloc = false;
3503
3504 /* skip gigantic hugepages allocation if hugetlb_cma enabled */
3505 if (hstate_is_gigantic(h) && hugetlb_cma_size) {
3506 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
3507 return;
3508 }
3509
3510 /* do node specific alloc */
3511 for_each_online_node(i) {
3512 if (h->max_huge_pages_node[i] > 0) {
3513 hugetlb_hstate_alloc_pages_onenode(h, i);
3514 node_specific_alloc = true;
3515 }
3516 }
3517
3518 if (node_specific_alloc)
3519 return;
3520
3521 /* below will do all node balanced alloc */
3522 if (!hstate_is_gigantic(h)) {
3523 /*
3524 * Bit mask controlling how hard we retry per-node allocations.
3525 * Ignore errors as lower level routines can deal with
3526 * node_alloc_noretry == NULL. If this kmalloc fails at boot
3527 * time, we are likely in bigger trouble.
3528 */
3529 node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
3530 GFP_KERNEL);
3531 } else {
3532 /* allocations done at boot time */
3533 node_alloc_noretry = NULL;
3534 }
3535
3536 /* bit mask controlling how hard we retry per-node allocations */
3537 if (node_alloc_noretry)
3538 nodes_clear(*node_alloc_noretry);
3539
3540 for (i = 0; i < h->max_huge_pages; ++i) {
3541 if (hstate_is_gigantic(h)) {
3542 /*
3543 * gigantic pages not added to list as they are not
3544 * added to pools now.
3545 */
3546 if (!alloc_bootmem_huge_page(h, NUMA_NO_NODE))
3547 break;
3548 } else {
3549 folio = alloc_pool_huge_folio(h, &node_states[N_MEMORY],
3550 node_alloc_noretry);
3551 if (!folio)
3552 break;
3553 list_add(&folio->lru, &folio_list);
3554 }
3555 cond_resched();
3556 }
3557
3558 /* list will be empty if hstate_is_gigantic */
3559 prep_and_add_allocated_folios(h, &folio_list);
3560
3561 if (i < h->max_huge_pages) {
3562 char buf[32];
3563
3564 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
3565 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
3566 h->max_huge_pages, buf, i);
3567 h->max_huge_pages = i;
3568 }
3569 kfree(node_alloc_noretry);
3570}
3571
3572static void __init hugetlb_init_hstates(void)
3573{
3574 struct hstate *h, *h2;
3575
3576 for_each_hstate(h) {
3577 /* oversize hugepages were init'ed in early boot */
3578 if (!hstate_is_gigantic(h))
3579 hugetlb_hstate_alloc_pages(h);
3580
3581 /*
3582 * Set demote order for each hstate. Note that
3583 * h->demote_order is initially 0.
3584 * - We can not demote gigantic pages if runtime freeing
3585 * is not supported, so skip this.
3586 * - If CMA allocation is possible, we can not demote
3587 * HUGETLB_PAGE_ORDER or smaller size pages.
3588 */
3589 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
3590 continue;
3591 if (hugetlb_cma_size && h->order <= HUGETLB_PAGE_ORDER)
3592 continue;
3593 for_each_hstate(h2) {
3594 if (h2 == h)
3595 continue;
3596 if (h2->order < h->order &&
3597 h2->order > h->demote_order)
3598 h->demote_order = h2->order;
3599 }
3600 }
3601}
3602
3603static void __init report_hugepages(void)
3604{
3605 struct hstate *h;
3606
3607 for_each_hstate(h) {
3608 char buf[32];
3609
3610 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
3611 pr_info("HugeTLB: registered %s page size, pre-allocated %ld pages\n",
3612 buf, h->free_huge_pages);
3613 pr_info("HugeTLB: %d KiB vmemmap can be freed for a %s page\n",
3614 hugetlb_vmemmap_optimizable_size(h) / SZ_1K, buf);
3615 }
3616}
3617
3618#ifdef CONFIG_HIGHMEM
3619static void try_to_free_low(struct hstate *h, unsigned long count,
3620 nodemask_t *nodes_allowed)
3621{
3622 int i;
3623 LIST_HEAD(page_list);
3624
3625 lockdep_assert_held(&hugetlb_lock);
3626 if (hstate_is_gigantic(h))
3627 return;
3628
3629 /*
3630 * Collect pages to be freed on a list, and free after dropping lock
3631 */
3632 for_each_node_mask(i, *nodes_allowed) {
3633 struct folio *folio, *next;
3634 struct list_head *freel = &h->hugepage_freelists[i];
3635 list_for_each_entry_safe(folio, next, freel, lru) {
3636 if (count >= h->nr_huge_pages)
3637 goto out;
3638 if (folio_test_highmem(folio))
3639 continue;
3640 remove_hugetlb_folio(h, folio, false);
3641 list_add(&folio->lru, &page_list);
3642 }
3643 }
3644
3645out:
3646 spin_unlock_irq(&hugetlb_lock);
3647 update_and_free_pages_bulk(h, &page_list);
3648 spin_lock_irq(&hugetlb_lock);
3649}
3650#else
3651static inline void try_to_free_low(struct hstate *h, unsigned long count,
3652 nodemask_t *nodes_allowed)
3653{
3654}
3655#endif
3656
3657/*
3658 * Increment or decrement surplus_huge_pages. Keep node-specific counters
3659 * balanced by operating on them in a round-robin fashion.
3660 * Returns 1 if an adjustment was made.
3661 */
3662static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
3663 int delta)
3664{
3665 int nr_nodes, node;
3666
3667 lockdep_assert_held(&hugetlb_lock);
3668 VM_BUG_ON(delta != -1 && delta != 1);
3669
3670 if (delta < 0) {
3671 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
3672 if (h->surplus_huge_pages_node[node])
3673 goto found;
3674 }
3675 } else {
3676 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
3677 if (h->surplus_huge_pages_node[node] <
3678 h->nr_huge_pages_node[node])
3679 goto found;
3680 }
3681 }
3682 return 0;
3683
3684found:
3685 h->surplus_huge_pages += delta;
3686 h->surplus_huge_pages_node[node] += delta;
3687 return 1;
3688}
3689
3690#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
3691static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
3692 nodemask_t *nodes_allowed)
3693{
3694 unsigned long min_count;
3695 unsigned long allocated;
3696 struct folio *folio;
3697 LIST_HEAD(page_list);
3698 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
3699
3700 /*
3701 * Bit mask controlling how hard we retry per-node allocations.
3702 * If we can not allocate the bit mask, do not attempt to allocate
3703 * the requested huge pages.
3704 */
3705 if (node_alloc_noretry)
3706 nodes_clear(*node_alloc_noretry);
3707 else
3708 return -ENOMEM;
3709
3710 /*
3711 * resize_lock mutex prevents concurrent adjustments to number of
3712 * pages in hstate via the proc/sysfs interfaces.
3713 */
3714 mutex_lock(&h->resize_lock);
3715 flush_free_hpage_work(h);
3716 spin_lock_irq(&hugetlb_lock);
3717
3718 /*
3719 * Check for a node specific request.
3720 * Changing node specific huge page count may require a corresponding
3721 * change to the global count. In any case, the passed node mask
3722 * (nodes_allowed) will restrict alloc/free to the specified node.
3723 */
3724 if (nid != NUMA_NO_NODE) {
3725 unsigned long old_count = count;
3726
3727 count += persistent_huge_pages(h) -
3728 (h->nr_huge_pages_node[nid] -
3729 h->surplus_huge_pages_node[nid]);
3730 /*
3731 * User may have specified a large count value which caused the
3732 * above calculation to overflow. In this case, they wanted
3733 * to allocate as many huge pages as possible. Set count to
3734 * largest possible value to align with their intention.
3735 */
3736 if (count < old_count)
3737 count = ULONG_MAX;
3738 }
3739
3740 /*
3741 * Gigantic pages runtime allocation depend on the capability for large
3742 * page range allocation.
3743 * If the system does not provide this feature, return an error when
3744 * the user tries to allocate gigantic pages but let the user free the
3745 * boottime allocated gigantic pages.
3746 */
3747 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
3748 if (count > persistent_huge_pages(h)) {
3749 spin_unlock_irq(&hugetlb_lock);
3750 mutex_unlock(&h->resize_lock);
3751 NODEMASK_FREE(node_alloc_noretry);
3752 return -EINVAL;
3753 }
3754 /* Fall through to decrease pool */
3755 }
3756
3757 /*
3758 * Increase the pool size
3759 * First take pages out of surplus state. Then make up the
3760 * remaining difference by allocating fresh huge pages.
3761 *
3762 * We might race with alloc_surplus_hugetlb_folio() here and be unable
3763 * to convert a surplus huge page to a normal huge page. That is
3764 * not critical, though, it just means the overall size of the
3765 * pool might be one hugepage larger than it needs to be, but
3766 * within all the constraints specified by the sysctls.
3767 */
3768 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
3769 if (!adjust_pool_surplus(h, nodes_allowed, -1))
3770 break;
3771 }
3772
3773 allocated = 0;
3774 while (count > (persistent_huge_pages(h) + allocated)) {
3775 /*
3776 * If this allocation races such that we no longer need the
3777 * page, free_huge_folio will handle it by freeing the page
3778 * and reducing the surplus.
3779 */
3780 spin_unlock_irq(&hugetlb_lock);
3781
3782 /* yield cpu to avoid soft lockup */
3783 cond_resched();
3784
3785 folio = alloc_pool_huge_folio(h, nodes_allowed,
3786 node_alloc_noretry);
3787 if (!folio) {
3788 prep_and_add_allocated_folios(h, &page_list);
3789 spin_lock_irq(&hugetlb_lock);
3790 goto out;
3791 }
3792
3793 list_add(&folio->lru, &page_list);
3794 allocated++;
3795
3796 /* Bail for signals. Probably ctrl-c from user */
3797 if (signal_pending(current)) {
3798 prep_and_add_allocated_folios(h, &page_list);
3799 spin_lock_irq(&hugetlb_lock);
3800 goto out;
3801 }
3802
3803 spin_lock_irq(&hugetlb_lock);
3804 }
3805
3806 /* Add allocated pages to the pool */
3807 if (!list_empty(&page_list)) {
3808 spin_unlock_irq(&hugetlb_lock);
3809 prep_and_add_allocated_folios(h, &page_list);
3810 spin_lock_irq(&hugetlb_lock);
3811 }
3812
3813 /*
3814 * Decrease the pool size
3815 * First return free pages to the buddy allocator (being careful
3816 * to keep enough around to satisfy reservations). Then place
3817 * pages into surplus state as needed so the pool will shrink
3818 * to the desired size as pages become free.
3819 *
3820 * By placing pages into the surplus state independent of the
3821 * overcommit value, we are allowing the surplus pool size to
3822 * exceed overcommit. There are few sane options here. Since
3823 * alloc_surplus_hugetlb_folio() is checking the global counter,
3824 * though, we'll note that we're not allowed to exceed surplus
3825 * and won't grow the pool anywhere else. Not until one of the
3826 * sysctls are changed, or the surplus pages go out of use.
3827 */
3828 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
3829 min_count = max(count, min_count);
3830 try_to_free_low(h, min_count, nodes_allowed);
3831
3832 /*
3833 * Collect pages to be removed on list without dropping lock
3834 */
3835 while (min_count < persistent_huge_pages(h)) {
3836 folio = remove_pool_hugetlb_folio(h, nodes_allowed, 0);
3837 if (!folio)
3838 break;
3839
3840 list_add(&folio->lru, &page_list);
3841 }
3842 /* free the pages after dropping lock */
3843 spin_unlock_irq(&hugetlb_lock);
3844 update_and_free_pages_bulk(h, &page_list);
3845 flush_free_hpage_work(h);
3846 spin_lock_irq(&hugetlb_lock);
3847
3848 while (count < persistent_huge_pages(h)) {
3849 if (!adjust_pool_surplus(h, nodes_allowed, 1))
3850 break;
3851 }
3852out:
3853 h->max_huge_pages = persistent_huge_pages(h);
3854 spin_unlock_irq(&hugetlb_lock);
3855 mutex_unlock(&h->resize_lock);
3856
3857 NODEMASK_FREE(node_alloc_noretry);
3858
3859 return 0;
3860}
3861
3862static int demote_free_hugetlb_folio(struct hstate *h, struct folio *folio)
3863{
3864 int i, nid = folio_nid(folio);
3865 struct hstate *target_hstate;
3866 struct page *subpage;
3867 struct folio *inner_folio;
3868 int rc = 0;
3869
3870 target_hstate = size_to_hstate(PAGE_SIZE << h->demote_order);
3871
3872 remove_hugetlb_folio_for_demote(h, folio, false);
3873 spin_unlock_irq(&hugetlb_lock);
3874
3875 /*
3876 * If vmemmap already existed for folio, the remove routine above would
3877 * have cleared the hugetlb folio flag. Hence the folio is technically
3878 * no longer a hugetlb folio. hugetlb_vmemmap_restore_folio can only be
3879 * passed hugetlb folios and will BUG otherwise.
3880 */
3881 if (folio_test_hugetlb(folio)) {
3882 rc = hugetlb_vmemmap_restore_folio(h, folio);
3883 if (rc) {
3884 /* Allocation of vmemmmap failed, we can not demote folio */
3885 spin_lock_irq(&hugetlb_lock);
3886 folio_ref_unfreeze(folio, 1);
3887 add_hugetlb_folio(h, folio, false);
3888 return rc;
3889 }
3890 }
3891
3892 /*
3893 * Use destroy_compound_hugetlb_folio_for_demote for all huge page
3894 * sizes as it will not ref count folios.
3895 */
3896 destroy_compound_hugetlb_folio_for_demote(folio, huge_page_order(h));
3897
3898 /*
3899 * Taking target hstate mutex synchronizes with set_max_huge_pages.
3900 * Without the mutex, pages added to target hstate could be marked
3901 * as surplus.
3902 *
3903 * Note that we already hold h->resize_lock. To prevent deadlock,
3904 * use the convention of always taking larger size hstate mutex first.
3905 */
3906 mutex_lock(&target_hstate->resize_lock);
3907 for (i = 0; i < pages_per_huge_page(h);
3908 i += pages_per_huge_page(target_hstate)) {
3909 subpage = folio_page(folio, i);
3910 inner_folio = page_folio(subpage);
3911 if (hstate_is_gigantic(target_hstate))
3912 prep_compound_gigantic_folio_for_demote(inner_folio,
3913 target_hstate->order);
3914 else
3915 prep_compound_page(subpage, target_hstate->order);
3916 folio_change_private(inner_folio, NULL);
3917 prep_new_hugetlb_folio(target_hstate, inner_folio, nid);
3918 free_huge_folio(inner_folio);
3919 }
3920 mutex_unlock(&target_hstate->resize_lock);
3921
3922 spin_lock_irq(&hugetlb_lock);
3923
3924 /*
3925 * Not absolutely necessary, but for consistency update max_huge_pages
3926 * based on pool changes for the demoted page.
3927 */
3928 h->max_huge_pages--;
3929 target_hstate->max_huge_pages +=
3930 pages_per_huge_page(h) / pages_per_huge_page(target_hstate);
3931
3932 return rc;
3933}
3934
3935static int demote_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
3936 __must_hold(&hugetlb_lock)
3937{
3938 int nr_nodes, node;
3939 struct folio *folio;
3940
3941 lockdep_assert_held(&hugetlb_lock);
3942
3943 /* We should never get here if no demote order */
3944 if (!h->demote_order) {
3945 pr_warn("HugeTLB: NULL demote order passed to demote_pool_huge_page.\n");
3946 return -EINVAL; /* internal error */
3947 }
3948
3949 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
3950 list_for_each_entry(folio, &h->hugepage_freelists[node], lru) {
3951 if (folio_test_hwpoison(folio))
3952 continue;
3953 return demote_free_hugetlb_folio(h, folio);
3954 }
3955 }
3956
3957 /*
3958 * Only way to get here is if all pages on free lists are poisoned.
3959 * Return -EBUSY so that caller will not retry.
3960 */
3961 return -EBUSY;
3962}
3963
3964#define HSTATE_ATTR_RO(_name) \
3965 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
3966
3967#define HSTATE_ATTR_WO(_name) \
3968 static struct kobj_attribute _name##_attr = __ATTR_WO(_name)
3969
3970#define HSTATE_ATTR(_name) \
3971 static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
3972
3973static struct kobject *hugepages_kobj;
3974static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
3975
3976static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
3977
3978static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
3979{
3980 int i;
3981
3982 for (i = 0; i < HUGE_MAX_HSTATE; i++)
3983 if (hstate_kobjs[i] == kobj) {
3984 if (nidp)
3985 *nidp = NUMA_NO_NODE;
3986 return &hstates[i];
3987 }
3988
3989 return kobj_to_node_hstate(kobj, nidp);
3990}
3991
3992static ssize_t nr_hugepages_show_common(struct kobject *kobj,
3993 struct kobj_attribute *attr, char *buf)
3994{
3995 struct hstate *h;
3996 unsigned long nr_huge_pages;
3997 int nid;
3998
3999 h = kobj_to_hstate(kobj, &nid);
4000 if (nid == NUMA_NO_NODE)
4001 nr_huge_pages = h->nr_huge_pages;
4002 else
4003 nr_huge_pages = h->nr_huge_pages_node[nid];
4004
4005 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
4006}
4007
4008static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
4009 struct hstate *h, int nid,
4010 unsigned long count, size_t len)
4011{
4012 int err;
4013 nodemask_t nodes_allowed, *n_mask;
4014
4015 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
4016 return -EINVAL;
4017
4018 if (nid == NUMA_NO_NODE) {
4019 /*
4020 * global hstate attribute
4021 */
4022 if (!(obey_mempolicy &&
4023 init_nodemask_of_mempolicy(&nodes_allowed)))
4024 n_mask = &node_states[N_MEMORY];
4025 else
4026 n_mask = &nodes_allowed;
4027 } else {
4028 /*
4029 * Node specific request. count adjustment happens in
4030 * set_max_huge_pages() after acquiring hugetlb_lock.
4031 */
4032 init_nodemask_of_node(&nodes_allowed, nid);
4033 n_mask = &nodes_allowed;
4034 }
4035
4036 err = set_max_huge_pages(h, count, nid, n_mask);
4037
4038 return err ? err : len;
4039}
4040
4041static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
4042 struct kobject *kobj, const char *buf,
4043 size_t len)
4044{
4045 struct hstate *h;
4046 unsigned long count;
4047 int nid;
4048 int err;
4049
4050 err = kstrtoul(buf, 10, &count);
4051 if (err)
4052 return err;
4053
4054 h = kobj_to_hstate(kobj, &nid);
4055 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
4056}
4057
4058static ssize_t nr_hugepages_show(struct kobject *kobj,
4059 struct kobj_attribute *attr, char *buf)
4060{
4061 return nr_hugepages_show_common(kobj, attr, buf);
4062}
4063
4064static ssize_t nr_hugepages_store(struct kobject *kobj,
4065 struct kobj_attribute *attr, const char *buf, size_t len)
4066{
4067 return nr_hugepages_store_common(false, kobj, buf, len);
4068}
4069HSTATE_ATTR(nr_hugepages);
4070
4071#ifdef CONFIG_NUMA
4072
4073/*
4074 * hstate attribute for optionally mempolicy-based constraint on persistent
4075 * huge page alloc/free.
4076 */
4077static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
4078 struct kobj_attribute *attr,
4079 char *buf)
4080{
4081 return nr_hugepages_show_common(kobj, attr, buf);
4082}
4083
4084static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
4085 struct kobj_attribute *attr, const char *buf, size_t len)
4086{
4087 return nr_hugepages_store_common(true, kobj, buf, len);
4088}
4089HSTATE_ATTR(nr_hugepages_mempolicy);
4090#endif
4091
4092
4093static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
4094 struct kobj_attribute *attr, char *buf)
4095{
4096 struct hstate *h = kobj_to_hstate(kobj, NULL);
4097 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
4098}
4099
4100static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
4101 struct kobj_attribute *attr, const char *buf, size_t count)
4102{
4103 int err;
4104 unsigned long input;
4105 struct hstate *h = kobj_to_hstate(kobj, NULL);
4106
4107 if (hstate_is_gigantic(h))
4108 return -EINVAL;
4109
4110 err = kstrtoul(buf, 10, &input);
4111 if (err)
4112 return err;
4113
4114 spin_lock_irq(&hugetlb_lock);
4115 h->nr_overcommit_huge_pages = input;
4116 spin_unlock_irq(&hugetlb_lock);
4117
4118 return count;
4119}
4120HSTATE_ATTR(nr_overcommit_hugepages);
4121
4122static ssize_t free_hugepages_show(struct kobject *kobj,
4123 struct kobj_attribute *attr, char *buf)
4124{
4125 struct hstate *h;
4126 unsigned long free_huge_pages;
4127 int nid;
4128
4129 h = kobj_to_hstate(kobj, &nid);
4130 if (nid == NUMA_NO_NODE)
4131 free_huge_pages = h->free_huge_pages;
4132 else
4133 free_huge_pages = h->free_huge_pages_node[nid];
4134
4135 return sysfs_emit(buf, "%lu\n", free_huge_pages);
4136}
4137HSTATE_ATTR_RO(free_hugepages);
4138
4139static ssize_t resv_hugepages_show(struct kobject *kobj,
4140 struct kobj_attribute *attr, char *buf)
4141{
4142 struct hstate *h = kobj_to_hstate(kobj, NULL);
4143 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
4144}
4145HSTATE_ATTR_RO(resv_hugepages);
4146
4147static ssize_t surplus_hugepages_show(struct kobject *kobj,
4148 struct kobj_attribute *attr, char *buf)
4149{
4150 struct hstate *h;
4151 unsigned long surplus_huge_pages;
4152 int nid;
4153
4154 h = kobj_to_hstate(kobj, &nid);
4155 if (nid == NUMA_NO_NODE)
4156 surplus_huge_pages = h->surplus_huge_pages;
4157 else
4158 surplus_huge_pages = h->surplus_huge_pages_node[nid];
4159
4160 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
4161}
4162HSTATE_ATTR_RO(surplus_hugepages);
4163
4164static ssize_t demote_store(struct kobject *kobj,
4165 struct kobj_attribute *attr, const char *buf, size_t len)
4166{
4167 unsigned long nr_demote;
4168 unsigned long nr_available;
4169 nodemask_t nodes_allowed, *n_mask;
4170 struct hstate *h;
4171 int err;
4172 int nid;
4173
4174 err = kstrtoul(buf, 10, &nr_demote);
4175 if (err)
4176 return err;
4177 h = kobj_to_hstate(kobj, &nid);
4178
4179 if (nid != NUMA_NO_NODE) {
4180 init_nodemask_of_node(&nodes_allowed, nid);
4181 n_mask = &nodes_allowed;
4182 } else {
4183 n_mask = &node_states[N_MEMORY];
4184 }
4185
4186 /* Synchronize with other sysfs operations modifying huge pages */
4187 mutex_lock(&h->resize_lock);
4188 spin_lock_irq(&hugetlb_lock);
4189
4190 while (nr_demote) {
4191 /*
4192 * Check for available pages to demote each time thorough the
4193 * loop as demote_pool_huge_page will drop hugetlb_lock.
4194 */
4195 if (nid != NUMA_NO_NODE)
4196 nr_available = h->free_huge_pages_node[nid];
4197 else
4198 nr_available = h->free_huge_pages;
4199 nr_available -= h->resv_huge_pages;
4200 if (!nr_available)
4201 break;
4202
4203 err = demote_pool_huge_page(h, n_mask);
4204 if (err)
4205 break;
4206
4207 nr_demote--;
4208 }
4209
4210 spin_unlock_irq(&hugetlb_lock);
4211 mutex_unlock(&h->resize_lock);
4212
4213 if (err)
4214 return err;
4215 return len;
4216}
4217HSTATE_ATTR_WO(demote);
4218
4219static ssize_t demote_size_show(struct kobject *kobj,
4220 struct kobj_attribute *attr, char *buf)
4221{
4222 struct hstate *h = kobj_to_hstate(kobj, NULL);
4223 unsigned long demote_size = (PAGE_SIZE << h->demote_order) / SZ_1K;
4224
4225 return sysfs_emit(buf, "%lukB\n", demote_size);
4226}
4227
4228static ssize_t demote_size_store(struct kobject *kobj,
4229 struct kobj_attribute *attr,
4230 const char *buf, size_t count)
4231{
4232 struct hstate *h, *demote_hstate;
4233 unsigned long demote_size;
4234 unsigned int demote_order;
4235
4236 demote_size = (unsigned long)memparse(buf, NULL);
4237
4238 demote_hstate = size_to_hstate(demote_size);
4239 if (!demote_hstate)
4240 return -EINVAL;
4241 demote_order = demote_hstate->order;
4242 if (demote_order < HUGETLB_PAGE_ORDER)
4243 return -EINVAL;
4244
4245 /* demote order must be smaller than hstate order */
4246 h = kobj_to_hstate(kobj, NULL);
4247 if (demote_order >= h->order)
4248 return -EINVAL;
4249
4250 /* resize_lock synchronizes access to demote size and writes */
4251 mutex_lock(&h->resize_lock);
4252 h->demote_order = demote_order;
4253 mutex_unlock(&h->resize_lock);
4254
4255 return count;
4256}
4257HSTATE_ATTR(demote_size);
4258
4259static struct attribute *hstate_attrs[] = {
4260 &nr_hugepages_attr.attr,
4261 &nr_overcommit_hugepages_attr.attr,
4262 &free_hugepages_attr.attr,
4263 &resv_hugepages_attr.attr,
4264 &surplus_hugepages_attr.attr,
4265#ifdef CONFIG_NUMA
4266 &nr_hugepages_mempolicy_attr.attr,
4267#endif
4268 NULL,
4269};
4270
4271static const struct attribute_group hstate_attr_group = {
4272 .attrs = hstate_attrs,
4273};
4274
4275static struct attribute *hstate_demote_attrs[] = {
4276 &demote_size_attr.attr,
4277 &demote_attr.attr,
4278 NULL,
4279};
4280
4281static const struct attribute_group hstate_demote_attr_group = {
4282 .attrs = hstate_demote_attrs,
4283};
4284
4285static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
4286 struct kobject **hstate_kobjs,
4287 const struct attribute_group *hstate_attr_group)
4288{
4289 int retval;
4290 int hi = hstate_index(h);
4291
4292 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
4293 if (!hstate_kobjs[hi])
4294 return -ENOMEM;
4295
4296 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
4297 if (retval) {
4298 kobject_put(hstate_kobjs[hi]);
4299 hstate_kobjs[hi] = NULL;
4300 return retval;
4301 }
4302
4303 if (h->demote_order) {
4304 retval = sysfs_create_group(hstate_kobjs[hi],
4305 &hstate_demote_attr_group);
4306 if (retval) {
4307 pr_warn("HugeTLB unable to create demote interfaces for %s\n", h->name);
4308 sysfs_remove_group(hstate_kobjs[hi], hstate_attr_group);
4309 kobject_put(hstate_kobjs[hi]);
4310 hstate_kobjs[hi] = NULL;
4311 return retval;
4312 }
4313 }
4314
4315 return 0;
4316}
4317
4318#ifdef CONFIG_NUMA
4319static bool hugetlb_sysfs_initialized __ro_after_init;
4320
4321/*
4322 * node_hstate/s - associate per node hstate attributes, via their kobjects,
4323 * with node devices in node_devices[] using a parallel array. The array
4324 * index of a node device or _hstate == node id.
4325 * This is here to avoid any static dependency of the node device driver, in
4326 * the base kernel, on the hugetlb module.
4327 */
4328struct node_hstate {
4329 struct kobject *hugepages_kobj;
4330 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
4331};
4332static struct node_hstate node_hstates[MAX_NUMNODES];
4333
4334/*
4335 * A subset of global hstate attributes for node devices
4336 */
4337static struct attribute *per_node_hstate_attrs[] = {
4338 &nr_hugepages_attr.attr,
4339 &free_hugepages_attr.attr,
4340 &surplus_hugepages_attr.attr,
4341 NULL,
4342};
4343
4344static const struct attribute_group per_node_hstate_attr_group = {
4345 .attrs = per_node_hstate_attrs,
4346};
4347
4348/*
4349 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
4350 * Returns node id via non-NULL nidp.
4351 */
4352static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
4353{
4354 int nid;
4355
4356 for (nid = 0; nid < nr_node_ids; nid++) {
4357 struct node_hstate *nhs = &node_hstates[nid];
4358 int i;
4359 for (i = 0; i < HUGE_MAX_HSTATE; i++)
4360 if (nhs->hstate_kobjs[i] == kobj) {
4361 if (nidp)
4362 *nidp = nid;
4363 return &hstates[i];
4364 }
4365 }
4366
4367 BUG();
4368 return NULL;
4369}
4370
4371/*
4372 * Unregister hstate attributes from a single node device.
4373 * No-op if no hstate attributes attached.
4374 */
4375void hugetlb_unregister_node(struct node *node)
4376{
4377 struct hstate *h;
4378 struct node_hstate *nhs = &node_hstates[node->dev.id];
4379
4380 if (!nhs->hugepages_kobj)
4381 return; /* no hstate attributes */
4382
4383 for_each_hstate(h) {
4384 int idx = hstate_index(h);
4385 struct kobject *hstate_kobj = nhs->hstate_kobjs[idx];
4386
4387 if (!hstate_kobj)
4388 continue;
4389 if (h->demote_order)
4390 sysfs_remove_group(hstate_kobj, &hstate_demote_attr_group);
4391 sysfs_remove_group(hstate_kobj, &per_node_hstate_attr_group);
4392 kobject_put(hstate_kobj);
4393 nhs->hstate_kobjs[idx] = NULL;
4394 }
4395
4396 kobject_put(nhs->hugepages_kobj);
4397 nhs->hugepages_kobj = NULL;
4398}
4399
4400
4401/*
4402 * Register hstate attributes for a single node device.
4403 * No-op if attributes already registered.
4404 */
4405void hugetlb_register_node(struct node *node)
4406{
4407 struct hstate *h;
4408 struct node_hstate *nhs = &node_hstates[node->dev.id];
4409 int err;
4410
4411 if (!hugetlb_sysfs_initialized)
4412 return;
4413
4414 if (nhs->hugepages_kobj)
4415 return; /* already allocated */
4416
4417 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
4418 &node->dev.kobj);
4419 if (!nhs->hugepages_kobj)
4420 return;
4421
4422 for_each_hstate(h) {
4423 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
4424 nhs->hstate_kobjs,
4425 &per_node_hstate_attr_group);
4426 if (err) {
4427 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
4428 h->name, node->dev.id);
4429 hugetlb_unregister_node(node);
4430 break;
4431 }
4432 }
4433}
4434
4435/*
4436 * hugetlb init time: register hstate attributes for all registered node
4437 * devices of nodes that have memory. All on-line nodes should have
4438 * registered their associated device by this time.
4439 */
4440static void __init hugetlb_register_all_nodes(void)
4441{
4442 int nid;
4443
4444 for_each_online_node(nid)
4445 hugetlb_register_node(node_devices[nid]);
4446}
4447#else /* !CONFIG_NUMA */
4448
4449static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
4450{
4451 BUG();
4452 if (nidp)
4453 *nidp = -1;
4454 return NULL;
4455}
4456
4457static void hugetlb_register_all_nodes(void) { }
4458
4459#endif
4460
4461#ifdef CONFIG_CMA
4462static void __init hugetlb_cma_check(void);
4463#else
4464static inline __init void hugetlb_cma_check(void)
4465{
4466}
4467#endif
4468
4469static void __init hugetlb_sysfs_init(void)
4470{
4471 struct hstate *h;
4472 int err;
4473
4474 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
4475 if (!hugepages_kobj)
4476 return;
4477
4478 for_each_hstate(h) {
4479 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
4480 hstate_kobjs, &hstate_attr_group);
4481 if (err)
4482 pr_err("HugeTLB: Unable to add hstate %s", h->name);
4483 }
4484
4485#ifdef CONFIG_NUMA
4486 hugetlb_sysfs_initialized = true;
4487#endif
4488 hugetlb_register_all_nodes();
4489}
4490
4491#ifdef CONFIG_SYSCTL
4492static void hugetlb_sysctl_init(void);
4493#else
4494static inline void hugetlb_sysctl_init(void) { }
4495#endif
4496
4497static int __init hugetlb_init(void)
4498{
4499 int i;
4500
4501 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
4502 __NR_HPAGEFLAGS);
4503
4504 if (!hugepages_supported()) {
4505 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
4506 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
4507 return 0;
4508 }
4509
4510 /*
4511 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
4512 * architectures depend on setup being done here.
4513 */
4514 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
4515 if (!parsed_default_hugepagesz) {
4516 /*
4517 * If we did not parse a default huge page size, set
4518 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
4519 * number of huge pages for this default size was implicitly
4520 * specified, set that here as well.
4521 * Note that the implicit setting will overwrite an explicit
4522 * setting. A warning will be printed in this case.
4523 */
4524 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
4525 if (default_hstate_max_huge_pages) {
4526 if (default_hstate.max_huge_pages) {
4527 char buf[32];
4528
4529 string_get_size(huge_page_size(&default_hstate),
4530 1, STRING_UNITS_2, buf, 32);
4531 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
4532 default_hstate.max_huge_pages, buf);
4533 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
4534 default_hstate_max_huge_pages);
4535 }
4536 default_hstate.max_huge_pages =
4537 default_hstate_max_huge_pages;
4538
4539 for_each_online_node(i)
4540 default_hstate.max_huge_pages_node[i] =
4541 default_hugepages_in_node[i];
4542 }
4543 }
4544
4545 hugetlb_cma_check();
4546 hugetlb_init_hstates();
4547 gather_bootmem_prealloc();
4548 report_hugepages();
4549
4550 hugetlb_sysfs_init();
4551 hugetlb_cgroup_file_init();
4552 hugetlb_sysctl_init();
4553
4554#ifdef CONFIG_SMP
4555 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
4556#else
4557 num_fault_mutexes = 1;
4558#endif
4559 hugetlb_fault_mutex_table =
4560 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
4561 GFP_KERNEL);
4562 BUG_ON(!hugetlb_fault_mutex_table);
4563
4564 for (i = 0; i < num_fault_mutexes; i++)
4565 mutex_init(&hugetlb_fault_mutex_table[i]);
4566 return 0;
4567}
4568subsys_initcall(hugetlb_init);
4569
4570/* Overwritten by architectures with more huge page sizes */
4571bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
4572{
4573 return size == HPAGE_SIZE;
4574}
4575
4576void __init hugetlb_add_hstate(unsigned int order)
4577{
4578 struct hstate *h;
4579 unsigned long i;
4580
4581 if (size_to_hstate(PAGE_SIZE << order)) {
4582 return;
4583 }
4584 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
4585 BUG_ON(order < order_base_2(__NR_USED_SUBPAGE));
4586 h = &hstates[hugetlb_max_hstate++];
4587 mutex_init(&h->resize_lock);
4588 h->order = order;
4589 h->mask = ~(huge_page_size(h) - 1);
4590 for (i = 0; i < MAX_NUMNODES; ++i)
4591 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
4592 INIT_LIST_HEAD(&h->hugepage_activelist);
4593 h->next_nid_to_alloc = first_memory_node;
4594 h->next_nid_to_free = first_memory_node;
4595 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
4596 huge_page_size(h)/SZ_1K);
4597
4598 parsed_hstate = h;
4599}
4600
4601bool __init __weak hugetlb_node_alloc_supported(void)
4602{
4603 return true;
4604}
4605
4606static void __init hugepages_clear_pages_in_node(void)
4607{
4608 if (!hugetlb_max_hstate) {
4609 default_hstate_max_huge_pages = 0;
4610 memset(default_hugepages_in_node, 0,
4611 sizeof(default_hugepages_in_node));
4612 } else {
4613 parsed_hstate->max_huge_pages = 0;
4614 memset(parsed_hstate->max_huge_pages_node, 0,
4615 sizeof(parsed_hstate->max_huge_pages_node));
4616 }
4617}
4618
4619/*
4620 * hugepages command line processing
4621 * hugepages normally follows a valid hugepagsz or default_hugepagsz
4622 * specification. If not, ignore the hugepages value. hugepages can also
4623 * be the first huge page command line option in which case it implicitly
4624 * specifies the number of huge pages for the default size.
4625 */
4626static int __init hugepages_setup(char *s)
4627{
4628 unsigned long *mhp;
4629 static unsigned long *last_mhp;
4630 int node = NUMA_NO_NODE;
4631 int count;
4632 unsigned long tmp;
4633 char *p = s;
4634
4635 if (!parsed_valid_hugepagesz) {
4636 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
4637 parsed_valid_hugepagesz = true;
4638 return 1;
4639 }
4640
4641 /*
4642 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
4643 * yet, so this hugepages= parameter goes to the "default hstate".
4644 * Otherwise, it goes with the previously parsed hugepagesz or
4645 * default_hugepagesz.
4646 */
4647 else if (!hugetlb_max_hstate)
4648 mhp = &default_hstate_max_huge_pages;
4649 else
4650 mhp = &parsed_hstate->max_huge_pages;
4651
4652 if (mhp == last_mhp) {
4653 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
4654 return 1;
4655 }
4656
4657 while (*p) {
4658 count = 0;
4659 if (sscanf(p, "%lu%n", &tmp, &count) != 1)
4660 goto invalid;
4661 /* Parameter is node format */
4662 if (p[count] == ':') {
4663 if (!hugetlb_node_alloc_supported()) {
4664 pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n");
4665 return 1;
4666 }
4667 if (tmp >= MAX_NUMNODES || !node_online(tmp))
4668 goto invalid;
4669 node = array_index_nospec(tmp, MAX_NUMNODES);
4670 p += count + 1;
4671 /* Parse hugepages */
4672 if (sscanf(p, "%lu%n", &tmp, &count) != 1)
4673 goto invalid;
4674 if (!hugetlb_max_hstate)
4675 default_hugepages_in_node[node] = tmp;
4676 else
4677 parsed_hstate->max_huge_pages_node[node] = tmp;
4678 *mhp += tmp;
4679 /* Go to parse next node*/
4680 if (p[count] == ',')
4681 p += count + 1;
4682 else
4683 break;
4684 } else {
4685 if (p != s)
4686 goto invalid;
4687 *mhp = tmp;
4688 break;
4689 }
4690 }
4691
4692 /*
4693 * Global state is always initialized later in hugetlb_init.
4694 * But we need to allocate gigantic hstates here early to still
4695 * use the bootmem allocator.
4696 */
4697 if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate))
4698 hugetlb_hstate_alloc_pages(parsed_hstate);
4699
4700 last_mhp = mhp;
4701
4702 return 1;
4703
4704invalid:
4705 pr_warn("HugeTLB: Invalid hugepages parameter %s\n", p);
4706 hugepages_clear_pages_in_node();
4707 return 1;
4708}
4709__setup("hugepages=", hugepages_setup);
4710
4711/*
4712 * hugepagesz command line processing
4713 * A specific huge page size can only be specified once with hugepagesz.
4714 * hugepagesz is followed by hugepages on the command line. The global
4715 * variable 'parsed_valid_hugepagesz' is used to determine if prior
4716 * hugepagesz argument was valid.
4717 */
4718static int __init hugepagesz_setup(char *s)
4719{
4720 unsigned long size;
4721 struct hstate *h;
4722
4723 parsed_valid_hugepagesz = false;
4724 size = (unsigned long)memparse(s, NULL);
4725
4726 if (!arch_hugetlb_valid_size(size)) {
4727 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
4728 return 1;
4729 }
4730
4731 h = size_to_hstate(size);
4732 if (h) {
4733 /*
4734 * hstate for this size already exists. This is normally
4735 * an error, but is allowed if the existing hstate is the
4736 * default hstate. More specifically, it is only allowed if
4737 * the number of huge pages for the default hstate was not
4738 * previously specified.
4739 */
4740 if (!parsed_default_hugepagesz || h != &default_hstate ||
4741 default_hstate.max_huge_pages) {
4742 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
4743 return 1;
4744 }
4745
4746 /*
4747 * No need to call hugetlb_add_hstate() as hstate already
4748 * exists. But, do set parsed_hstate so that a following
4749 * hugepages= parameter will be applied to this hstate.
4750 */
4751 parsed_hstate = h;
4752 parsed_valid_hugepagesz = true;
4753 return 1;
4754 }
4755
4756 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
4757 parsed_valid_hugepagesz = true;
4758 return 1;
4759}
4760__setup("hugepagesz=", hugepagesz_setup);
4761
4762/*
4763 * default_hugepagesz command line input
4764 * Only one instance of default_hugepagesz allowed on command line.
4765 */
4766static int __init default_hugepagesz_setup(char *s)
4767{
4768 unsigned long size;
4769 int i;
4770
4771 parsed_valid_hugepagesz = false;
4772 if (parsed_default_hugepagesz) {
4773 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
4774 return 1;
4775 }
4776
4777 size = (unsigned long)memparse(s, NULL);
4778
4779 if (!arch_hugetlb_valid_size(size)) {
4780 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
4781 return 1;
4782 }
4783
4784 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
4785 parsed_valid_hugepagesz = true;
4786 parsed_default_hugepagesz = true;
4787 default_hstate_idx = hstate_index(size_to_hstate(size));
4788
4789 /*
4790 * The number of default huge pages (for this size) could have been
4791 * specified as the first hugetlb parameter: hugepages=X. If so,
4792 * then default_hstate_max_huge_pages is set. If the default huge
4793 * page size is gigantic (> MAX_PAGE_ORDER), then the pages must be
4794 * allocated here from bootmem allocator.
4795 */
4796 if (default_hstate_max_huge_pages) {
4797 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
4798 for_each_online_node(i)
4799 default_hstate.max_huge_pages_node[i] =
4800 default_hugepages_in_node[i];
4801 if (hstate_is_gigantic(&default_hstate))
4802 hugetlb_hstate_alloc_pages(&default_hstate);
4803 default_hstate_max_huge_pages = 0;
4804 }
4805
4806 return 1;
4807}
4808__setup("default_hugepagesz=", default_hugepagesz_setup);
4809
4810static nodemask_t *policy_mbind_nodemask(gfp_t gfp)
4811{
4812#ifdef CONFIG_NUMA
4813 struct mempolicy *mpol = get_task_policy(current);
4814
4815 /*
4816 * Only enforce MPOL_BIND policy which overlaps with cpuset policy
4817 * (from policy_nodemask) specifically for hugetlb case
4818 */
4819 if (mpol->mode == MPOL_BIND &&
4820 (apply_policy_zone(mpol, gfp_zone(gfp)) &&
4821 cpuset_nodemask_valid_mems_allowed(&mpol->nodes)))
4822 return &mpol->nodes;
4823#endif
4824 return NULL;
4825}
4826
4827static unsigned int allowed_mems_nr(struct hstate *h)
4828{
4829 int node;
4830 unsigned int nr = 0;
4831 nodemask_t *mbind_nodemask;
4832 unsigned int *array = h->free_huge_pages_node;
4833 gfp_t gfp_mask = htlb_alloc_mask(h);
4834
4835 mbind_nodemask = policy_mbind_nodemask(gfp_mask);
4836 for_each_node_mask(node, cpuset_current_mems_allowed) {
4837 if (!mbind_nodemask || node_isset(node, *mbind_nodemask))
4838 nr += array[node];
4839 }
4840
4841 return nr;
4842}
4843
4844#ifdef CONFIG_SYSCTL
4845static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
4846 void *buffer, size_t *length,
4847 loff_t *ppos, unsigned long *out)
4848{
4849 struct ctl_table dup_table;
4850
4851 /*
4852 * In order to avoid races with __do_proc_doulongvec_minmax(), we
4853 * can duplicate the @table and alter the duplicate of it.
4854 */
4855 dup_table = *table;
4856 dup_table.data = out;
4857
4858 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
4859}
4860
4861static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
4862 struct ctl_table *table, int write,
4863 void *buffer, size_t *length, loff_t *ppos)
4864{
4865 struct hstate *h = &default_hstate;
4866 unsigned long tmp = h->max_huge_pages;
4867 int ret;
4868
4869 if (!hugepages_supported())
4870 return -EOPNOTSUPP;
4871
4872 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
4873 &tmp);
4874 if (ret)
4875 goto out;
4876
4877 if (write)
4878 ret = __nr_hugepages_store_common(obey_mempolicy, h,
4879 NUMA_NO_NODE, tmp, *length);
4880out:
4881 return ret;
4882}
4883
4884static int hugetlb_sysctl_handler(struct ctl_table *table, int write,
4885 void *buffer, size_t *length, loff_t *ppos)
4886{
4887
4888 return hugetlb_sysctl_handler_common(false, table, write,
4889 buffer, length, ppos);
4890}
4891
4892#ifdef CONFIG_NUMA
4893static int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
4894 void *buffer, size_t *length, loff_t *ppos)
4895{
4896 return hugetlb_sysctl_handler_common(true, table, write,
4897 buffer, length, ppos);
4898}
4899#endif /* CONFIG_NUMA */
4900
4901static int hugetlb_overcommit_handler(struct ctl_table *table, int write,
4902 void *buffer, size_t *length, loff_t *ppos)
4903{
4904 struct hstate *h = &default_hstate;
4905 unsigned long tmp;
4906 int ret;
4907
4908 if (!hugepages_supported())
4909 return -EOPNOTSUPP;
4910
4911 tmp = h->nr_overcommit_huge_pages;
4912
4913 if (write && hstate_is_gigantic(h))
4914 return -EINVAL;
4915
4916 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
4917 &tmp);
4918 if (ret)
4919 goto out;
4920
4921 if (write) {
4922 spin_lock_irq(&hugetlb_lock);
4923 h->nr_overcommit_huge_pages = tmp;
4924 spin_unlock_irq(&hugetlb_lock);
4925 }
4926out:
4927 return ret;
4928}
4929
4930static struct ctl_table hugetlb_table[] = {
4931 {
4932 .procname = "nr_hugepages",
4933 .data = NULL,
4934 .maxlen = sizeof(unsigned long),
4935 .mode = 0644,
4936 .proc_handler = hugetlb_sysctl_handler,
4937 },
4938#ifdef CONFIG_NUMA
4939 {
4940 .procname = "nr_hugepages_mempolicy",
4941 .data = NULL,
4942 .maxlen = sizeof(unsigned long),
4943 .mode = 0644,
4944 .proc_handler = &hugetlb_mempolicy_sysctl_handler,
4945 },
4946#endif
4947 {
4948 .procname = "hugetlb_shm_group",
4949 .data = &sysctl_hugetlb_shm_group,
4950 .maxlen = sizeof(gid_t),
4951 .mode = 0644,
4952 .proc_handler = proc_dointvec,
4953 },
4954 {
4955 .procname = "nr_overcommit_hugepages",
4956 .data = NULL,
4957 .maxlen = sizeof(unsigned long),
4958 .mode = 0644,
4959 .proc_handler = hugetlb_overcommit_handler,
4960 },
4961 { }
4962};
4963
4964static void hugetlb_sysctl_init(void)
4965{
4966 register_sysctl_init("vm", hugetlb_table);
4967}
4968#endif /* CONFIG_SYSCTL */
4969
4970void hugetlb_report_meminfo(struct seq_file *m)
4971{
4972 struct hstate *h;
4973 unsigned long total = 0;
4974
4975 if (!hugepages_supported())
4976 return;
4977
4978 for_each_hstate(h) {
4979 unsigned long count = h->nr_huge_pages;
4980
4981 total += huge_page_size(h) * count;
4982
4983 if (h == &default_hstate)
4984 seq_printf(m,
4985 "HugePages_Total: %5lu\n"
4986 "HugePages_Free: %5lu\n"
4987 "HugePages_Rsvd: %5lu\n"
4988 "HugePages_Surp: %5lu\n"
4989 "Hugepagesize: %8lu kB\n",
4990 count,
4991 h->free_huge_pages,
4992 h->resv_huge_pages,
4993 h->surplus_huge_pages,
4994 huge_page_size(h) / SZ_1K);
4995 }
4996
4997 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
4998}
4999
5000int hugetlb_report_node_meminfo(char *buf, int len, int nid)
5001{
5002 struct hstate *h = &default_hstate;
5003
5004 if (!hugepages_supported())
5005 return 0;
5006
5007 return sysfs_emit_at(buf, len,
5008 "Node %d HugePages_Total: %5u\n"
5009 "Node %d HugePages_Free: %5u\n"
5010 "Node %d HugePages_Surp: %5u\n",
5011 nid, h->nr_huge_pages_node[nid],
5012 nid, h->free_huge_pages_node[nid],
5013 nid, h->surplus_huge_pages_node[nid]);
5014}
5015
5016void hugetlb_show_meminfo_node(int nid)
5017{
5018 struct hstate *h;
5019
5020 if (!hugepages_supported())
5021 return;
5022
5023 for_each_hstate(h)
5024 printk("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
5025 nid,
5026 h->nr_huge_pages_node[nid],
5027 h->free_huge_pages_node[nid],
5028 h->surplus_huge_pages_node[nid],
5029 huge_page_size(h) / SZ_1K);
5030}
5031
5032void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
5033{
5034 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
5035 K(atomic_long_read(&mm->hugetlb_usage)));
5036}
5037
5038/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
5039unsigned long hugetlb_total_pages(void)
5040{
5041 struct hstate *h;
5042 unsigned long nr_total_pages = 0;
5043
5044 for_each_hstate(h)
5045 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
5046 return nr_total_pages;
5047}
5048
5049static int hugetlb_acct_memory(struct hstate *h, long delta)
5050{
5051 int ret = -ENOMEM;
5052
5053 if (!delta)
5054 return 0;
5055
5056 spin_lock_irq(&hugetlb_lock);
5057 /*
5058 * When cpuset is configured, it breaks the strict hugetlb page
5059 * reservation as the accounting is done on a global variable. Such
5060 * reservation is completely rubbish in the presence of cpuset because
5061 * the reservation is not checked against page availability for the
5062 * current cpuset. Application can still potentially OOM'ed by kernel
5063 * with lack of free htlb page in cpuset that the task is in.
5064 * Attempt to enforce strict accounting with cpuset is almost
5065 * impossible (or too ugly) because cpuset is too fluid that
5066 * task or memory node can be dynamically moved between cpusets.
5067 *
5068 * The change of semantics for shared hugetlb mapping with cpuset is
5069 * undesirable. However, in order to preserve some of the semantics,
5070 * we fall back to check against current free page availability as
5071 * a best attempt and hopefully to minimize the impact of changing
5072 * semantics that cpuset has.
5073 *
5074 * Apart from cpuset, we also have memory policy mechanism that
5075 * also determines from which node the kernel will allocate memory
5076 * in a NUMA system. So similar to cpuset, we also should consider
5077 * the memory policy of the current task. Similar to the description
5078 * above.
5079 */
5080 if (delta > 0) {
5081 if (gather_surplus_pages(h, delta) < 0)
5082 goto out;
5083
5084 if (delta > allowed_mems_nr(h)) {
5085 return_unused_surplus_pages(h, delta);
5086 goto out;
5087 }
5088 }
5089
5090 ret = 0;
5091 if (delta < 0)
5092 return_unused_surplus_pages(h, (unsigned long) -delta);
5093
5094out:
5095 spin_unlock_irq(&hugetlb_lock);
5096 return ret;
5097}
5098
5099static void hugetlb_vm_op_open(struct vm_area_struct *vma)
5100{
5101 struct resv_map *resv = vma_resv_map(vma);
5102
5103 /*
5104 * HPAGE_RESV_OWNER indicates a private mapping.
5105 * This new VMA should share its siblings reservation map if present.
5106 * The VMA will only ever have a valid reservation map pointer where
5107 * it is being copied for another still existing VMA. As that VMA
5108 * has a reference to the reservation map it cannot disappear until
5109 * after this open call completes. It is therefore safe to take a
5110 * new reference here without additional locking.
5111 */
5112 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
5113 resv_map_dup_hugetlb_cgroup_uncharge_info(resv);
5114 kref_get(&resv->refs);
5115 }
5116
5117 /*
5118 * vma_lock structure for sharable mappings is vma specific.
5119 * Clear old pointer (if copied via vm_area_dup) and allocate
5120 * new structure. Before clearing, make sure vma_lock is not
5121 * for this vma.
5122 */
5123 if (vma->vm_flags & VM_MAYSHARE) {
5124 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
5125
5126 if (vma_lock) {
5127 if (vma_lock->vma != vma) {
5128 vma->vm_private_data = NULL;
5129 hugetlb_vma_lock_alloc(vma);
5130 } else
5131 pr_warn("HugeTLB: vma_lock already exists in %s.\n", __func__);
5132 } else
5133 hugetlb_vma_lock_alloc(vma);
5134 }
5135}
5136
5137static void hugetlb_vm_op_close(struct vm_area_struct *vma)
5138{
5139 struct hstate *h = hstate_vma(vma);
5140 struct resv_map *resv;
5141 struct hugepage_subpool *spool = subpool_vma(vma);
5142 unsigned long reserve, start, end;
5143 long gbl_reserve;
5144
5145 hugetlb_vma_lock_free(vma);
5146
5147 resv = vma_resv_map(vma);
5148 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5149 return;
5150
5151 start = vma_hugecache_offset(h, vma, vma->vm_start);
5152 end = vma_hugecache_offset(h, vma, vma->vm_end);
5153
5154 reserve = (end - start) - region_count(resv, start, end);
5155 hugetlb_cgroup_uncharge_counter(resv, start, end);
5156 if (reserve) {
5157 /*
5158 * Decrement reserve counts. The global reserve count may be
5159 * adjusted if the subpool has a minimum size.
5160 */
5161 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
5162 hugetlb_acct_memory(h, -gbl_reserve);
5163 }
5164
5165 kref_put(&resv->refs, resv_map_release);
5166}
5167
5168static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
5169{
5170 if (addr & ~(huge_page_mask(hstate_vma(vma))))
5171 return -EINVAL;
5172
5173 /*
5174 * PMD sharing is only possible for PUD_SIZE-aligned address ranges
5175 * in HugeTLB VMAs. If we will lose PUD_SIZE alignment due to this
5176 * split, unshare PMDs in the PUD_SIZE interval surrounding addr now.
5177 */
5178 if (addr & ~PUD_MASK) {
5179 /*
5180 * hugetlb_vm_op_split is called right before we attempt to
5181 * split the VMA. We will need to unshare PMDs in the old and
5182 * new VMAs, so let's unshare before we split.
5183 */
5184 unsigned long floor = addr & PUD_MASK;
5185 unsigned long ceil = floor + PUD_SIZE;
5186
5187 if (floor >= vma->vm_start && ceil <= vma->vm_end)
5188 hugetlb_unshare_pmds(vma, floor, ceil);
5189 }
5190
5191 return 0;
5192}
5193
5194static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
5195{
5196 return huge_page_size(hstate_vma(vma));
5197}
5198
5199/*
5200 * We cannot handle pagefaults against hugetlb pages at all. They cause
5201 * handle_mm_fault() to try to instantiate regular-sized pages in the
5202 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
5203 * this far.
5204 */
5205static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
5206{
5207 BUG();
5208 return 0;
5209}
5210
5211/*
5212 * When a new function is introduced to vm_operations_struct and added
5213 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
5214 * This is because under System V memory model, mappings created via
5215 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
5216 * their original vm_ops are overwritten with shm_vm_ops.
5217 */
5218const struct vm_operations_struct hugetlb_vm_ops = {
5219 .fault = hugetlb_vm_op_fault,
5220 .open = hugetlb_vm_op_open,
5221 .close = hugetlb_vm_op_close,
5222 .may_split = hugetlb_vm_op_split,
5223 .pagesize = hugetlb_vm_op_pagesize,
5224};
5225
5226static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
5227 int writable)
5228{
5229 pte_t entry;
5230 unsigned int shift = huge_page_shift(hstate_vma(vma));
5231
5232 if (writable) {
5233 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
5234 vma->vm_page_prot)));
5235 } else {
5236 entry = huge_pte_wrprotect(mk_huge_pte(page,
5237 vma->vm_page_prot));
5238 }
5239 entry = pte_mkyoung(entry);
5240 entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
5241
5242 return entry;
5243}
5244
5245static void set_huge_ptep_writable(struct vm_area_struct *vma,
5246 unsigned long address, pte_t *ptep)
5247{
5248 pte_t entry;
5249
5250 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
5251 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
5252 update_mmu_cache(vma, address, ptep);
5253}
5254
5255bool is_hugetlb_entry_migration(pte_t pte)
5256{
5257 swp_entry_t swp;
5258
5259 if (huge_pte_none(pte) || pte_present(pte))
5260 return false;
5261 swp = pte_to_swp_entry(pte);
5262 if (is_migration_entry(swp))
5263 return true;
5264 else
5265 return false;
5266}
5267
5268bool is_hugetlb_entry_hwpoisoned(pte_t pte)
5269{
5270 swp_entry_t swp;
5271
5272 if (huge_pte_none(pte) || pte_present(pte))
5273 return false;
5274 swp = pte_to_swp_entry(pte);
5275 if (is_hwpoison_entry(swp))
5276 return true;
5277 else
5278 return false;
5279}
5280
5281static void
5282hugetlb_install_folio(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr,
5283 struct folio *new_folio, pte_t old, unsigned long sz)
5284{
5285 pte_t newpte = make_huge_pte(vma, &new_folio->page, 1);
5286
5287 __folio_mark_uptodate(new_folio);
5288 hugetlb_add_new_anon_rmap(new_folio, vma, addr);
5289 if (userfaultfd_wp(vma) && huge_pte_uffd_wp(old))
5290 newpte = huge_pte_mkuffd_wp(newpte);
5291 set_huge_pte_at(vma->vm_mm, addr, ptep, newpte, sz);
5292 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm);
5293 folio_set_hugetlb_migratable(new_folio);
5294}
5295
5296int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
5297 struct vm_area_struct *dst_vma,
5298 struct vm_area_struct *src_vma)
5299{
5300 pte_t *src_pte, *dst_pte, entry;
5301 struct folio *pte_folio;
5302 unsigned long addr;
5303 bool cow = is_cow_mapping(src_vma->vm_flags);
5304 struct hstate *h = hstate_vma(src_vma);
5305 unsigned long sz = huge_page_size(h);
5306 unsigned long npages = pages_per_huge_page(h);
5307 struct mmu_notifier_range range;
5308 unsigned long last_addr_mask;
5309 int ret = 0;
5310
5311 if (cow) {
5312 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, src,
5313 src_vma->vm_start,
5314 src_vma->vm_end);
5315 mmu_notifier_invalidate_range_start(&range);
5316 vma_assert_write_locked(src_vma);
5317 raw_write_seqcount_begin(&src->write_protect_seq);
5318 } else {
5319 /*
5320 * For shared mappings the vma lock must be held before
5321 * calling hugetlb_walk() in the src vma. Otherwise, the
5322 * returned ptep could go away if part of a shared pmd and
5323 * another thread calls huge_pmd_unshare.
5324 */
5325 hugetlb_vma_lock_read(src_vma);
5326 }
5327
5328 last_addr_mask = hugetlb_mask_last_page(h);
5329 for (addr = src_vma->vm_start; addr < src_vma->vm_end; addr += sz) {
5330 spinlock_t *src_ptl, *dst_ptl;
5331 src_pte = hugetlb_walk(src_vma, addr, sz);
5332 if (!src_pte) {
5333 addr |= last_addr_mask;
5334 continue;
5335 }
5336 dst_pte = huge_pte_alloc(dst, dst_vma, addr, sz);
5337 if (!dst_pte) {
5338 ret = -ENOMEM;
5339 break;
5340 }
5341
5342 /*
5343 * If the pagetables are shared don't copy or take references.
5344 *
5345 * dst_pte == src_pte is the common case of src/dest sharing.
5346 * However, src could have 'unshared' and dst shares with
5347 * another vma. So page_count of ptep page is checked instead
5348 * to reliably determine whether pte is shared.
5349 */
5350 if (page_count(virt_to_page(dst_pte)) > 1) {
5351 addr |= last_addr_mask;
5352 continue;
5353 }
5354
5355 dst_ptl = huge_pte_lock(h, dst, dst_pte);
5356 src_ptl = huge_pte_lockptr(h, src, src_pte);
5357 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
5358 entry = huge_ptep_get(src_pte);
5359again:
5360 if (huge_pte_none(entry)) {
5361 /*
5362 * Skip if src entry none.
5363 */
5364 ;
5365 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) {
5366 if (!userfaultfd_wp(dst_vma))
5367 entry = huge_pte_clear_uffd_wp(entry);
5368 set_huge_pte_at(dst, addr, dst_pte, entry, sz);
5369 } else if (unlikely(is_hugetlb_entry_migration(entry))) {
5370 swp_entry_t swp_entry = pte_to_swp_entry(entry);
5371 bool uffd_wp = pte_swp_uffd_wp(entry);
5372
5373 if (!is_readable_migration_entry(swp_entry) && cow) {
5374 /*
5375 * COW mappings require pages in both
5376 * parent and child to be set to read.
5377 */
5378 swp_entry = make_readable_migration_entry(
5379 swp_offset(swp_entry));
5380 entry = swp_entry_to_pte(swp_entry);
5381 if (userfaultfd_wp(src_vma) && uffd_wp)
5382 entry = pte_swp_mkuffd_wp(entry);
5383 set_huge_pte_at(src, addr, src_pte, entry, sz);
5384 }
5385 if (!userfaultfd_wp(dst_vma))
5386 entry = huge_pte_clear_uffd_wp(entry);
5387 set_huge_pte_at(dst, addr, dst_pte, entry, sz);
5388 } else if (unlikely(is_pte_marker(entry))) {
5389 pte_marker marker = copy_pte_marker(
5390 pte_to_swp_entry(entry), dst_vma);
5391
5392 if (marker)
5393 set_huge_pte_at(dst, addr, dst_pte,
5394 make_pte_marker(marker), sz);
5395 } else {
5396 entry = huge_ptep_get(src_pte);
5397 pte_folio = page_folio(pte_page(entry));
5398 folio_get(pte_folio);
5399
5400 /*
5401 * Failing to duplicate the anon rmap is a rare case
5402 * where we see pinned hugetlb pages while they're
5403 * prone to COW. We need to do the COW earlier during
5404 * fork.
5405 *
5406 * When pre-allocating the page or copying data, we
5407 * need to be without the pgtable locks since we could
5408 * sleep during the process.
5409 */
5410 if (!folio_test_anon(pte_folio)) {
5411 hugetlb_add_file_rmap(pte_folio);
5412 } else if (hugetlb_try_dup_anon_rmap(pte_folio, src_vma)) {
5413 pte_t src_pte_old = entry;
5414 struct folio *new_folio;
5415
5416 spin_unlock(src_ptl);
5417 spin_unlock(dst_ptl);
5418 /* Do not use reserve as it's private owned */
5419 new_folio = alloc_hugetlb_folio(dst_vma, addr, 1);
5420 if (IS_ERR(new_folio)) {
5421 folio_put(pte_folio);
5422 ret = PTR_ERR(new_folio);
5423 break;
5424 }
5425 ret = copy_user_large_folio(new_folio,
5426 pte_folio,
5427 addr, dst_vma);
5428 folio_put(pte_folio);
5429 if (ret) {
5430 folio_put(new_folio);
5431 break;
5432 }
5433
5434 /* Install the new hugetlb folio if src pte stable */
5435 dst_ptl = huge_pte_lock(h, dst, dst_pte);
5436 src_ptl = huge_pte_lockptr(h, src, src_pte);
5437 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
5438 entry = huge_ptep_get(src_pte);
5439 if (!pte_same(src_pte_old, entry)) {
5440 restore_reserve_on_error(h, dst_vma, addr,
5441 new_folio);
5442 folio_put(new_folio);
5443 /* huge_ptep of dst_pte won't change as in child */
5444 goto again;
5445 }
5446 hugetlb_install_folio(dst_vma, dst_pte, addr,
5447 new_folio, src_pte_old, sz);
5448 spin_unlock(src_ptl);
5449 spin_unlock(dst_ptl);
5450 continue;
5451 }
5452
5453 if (cow) {
5454 /*
5455 * No need to notify as we are downgrading page
5456 * table protection not changing it to point
5457 * to a new page.
5458 *
5459 * See Documentation/mm/mmu_notifier.rst
5460 */
5461 huge_ptep_set_wrprotect(src, addr, src_pte);
5462 entry = huge_pte_wrprotect(entry);
5463 }
5464
5465 if (!userfaultfd_wp(dst_vma))
5466 entry = huge_pte_clear_uffd_wp(entry);
5467
5468 set_huge_pte_at(dst, addr, dst_pte, entry, sz);
5469 hugetlb_count_add(npages, dst);
5470 }
5471 spin_unlock(src_ptl);
5472 spin_unlock(dst_ptl);
5473 }
5474
5475 if (cow) {
5476 raw_write_seqcount_end(&src->write_protect_seq);
5477 mmu_notifier_invalidate_range_end(&range);
5478 } else {
5479 hugetlb_vma_unlock_read(src_vma);
5480 }
5481
5482 return ret;
5483}
5484
5485static void move_huge_pte(struct vm_area_struct *vma, unsigned long old_addr,
5486 unsigned long new_addr, pte_t *src_pte, pte_t *dst_pte,
5487 unsigned long sz)
5488{
5489 struct hstate *h = hstate_vma(vma);
5490 struct mm_struct *mm = vma->vm_mm;
5491 spinlock_t *src_ptl, *dst_ptl;
5492 pte_t pte;
5493
5494 dst_ptl = huge_pte_lock(h, mm, dst_pte);
5495 src_ptl = huge_pte_lockptr(h, mm, src_pte);
5496
5497 /*
5498 * We don't have to worry about the ordering of src and dst ptlocks
5499 * because exclusive mmap_lock (or the i_mmap_lock) prevents deadlock.
5500 */
5501 if (src_ptl != dst_ptl)
5502 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
5503
5504 pte = huge_ptep_get_and_clear(mm, old_addr, src_pte);
5505 set_huge_pte_at(mm, new_addr, dst_pte, pte, sz);
5506
5507 if (src_ptl != dst_ptl)
5508 spin_unlock(src_ptl);
5509 spin_unlock(dst_ptl);
5510}
5511
5512int move_hugetlb_page_tables(struct vm_area_struct *vma,
5513 struct vm_area_struct *new_vma,
5514 unsigned long old_addr, unsigned long new_addr,
5515 unsigned long len)
5516{
5517 struct hstate *h = hstate_vma(vma);
5518 struct address_space *mapping = vma->vm_file->f_mapping;
5519 unsigned long sz = huge_page_size(h);
5520 struct mm_struct *mm = vma->vm_mm;
5521 unsigned long old_end = old_addr + len;
5522 unsigned long last_addr_mask;
5523 pte_t *src_pte, *dst_pte;
5524 struct mmu_notifier_range range;
5525 bool shared_pmd = false;
5526
5527 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, old_addr,
5528 old_end);
5529 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5530 /*
5531 * In case of shared PMDs, we should cover the maximum possible
5532 * range.
5533 */
5534 flush_cache_range(vma, range.start, range.end);
5535
5536 mmu_notifier_invalidate_range_start(&range);
5537 last_addr_mask = hugetlb_mask_last_page(h);
5538 /* Prevent race with file truncation */
5539 hugetlb_vma_lock_write(vma);
5540 i_mmap_lock_write(mapping);
5541 for (; old_addr < old_end; old_addr += sz, new_addr += sz) {
5542 src_pte = hugetlb_walk(vma, old_addr, sz);
5543 if (!src_pte) {
5544 old_addr |= last_addr_mask;
5545 new_addr |= last_addr_mask;
5546 continue;
5547 }
5548 if (huge_pte_none(huge_ptep_get(src_pte)))
5549 continue;
5550
5551 if (huge_pmd_unshare(mm, vma, old_addr, src_pte)) {
5552 shared_pmd = true;
5553 old_addr |= last_addr_mask;
5554 new_addr |= last_addr_mask;
5555 continue;
5556 }
5557
5558 dst_pte = huge_pte_alloc(mm, new_vma, new_addr, sz);
5559 if (!dst_pte)
5560 break;
5561
5562 move_huge_pte(vma, old_addr, new_addr, src_pte, dst_pte, sz);
5563 }
5564
5565 if (shared_pmd)
5566 flush_hugetlb_tlb_range(vma, range.start, range.end);
5567 else
5568 flush_hugetlb_tlb_range(vma, old_end - len, old_end);
5569 mmu_notifier_invalidate_range_end(&range);
5570 i_mmap_unlock_write(mapping);
5571 hugetlb_vma_unlock_write(vma);
5572
5573 return len + old_addr - old_end;
5574}
5575
5576void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
5577 unsigned long start, unsigned long end,
5578 struct page *ref_page, zap_flags_t zap_flags)
5579{
5580 struct mm_struct *mm = vma->vm_mm;
5581 unsigned long address;
5582 pte_t *ptep;
5583 pte_t pte;
5584 spinlock_t *ptl;
5585 struct page *page;
5586 struct hstate *h = hstate_vma(vma);
5587 unsigned long sz = huge_page_size(h);
5588 unsigned long last_addr_mask;
5589 bool force_flush = false;
5590
5591 WARN_ON(!is_vm_hugetlb_page(vma));
5592 BUG_ON(start & ~huge_page_mask(h));
5593 BUG_ON(end & ~huge_page_mask(h));
5594
5595 /*
5596 * This is a hugetlb vma, all the pte entries should point
5597 * to huge page.
5598 */
5599 tlb_change_page_size(tlb, sz);
5600 tlb_start_vma(tlb, vma);
5601
5602 last_addr_mask = hugetlb_mask_last_page(h);
5603 address = start;
5604 for (; address < end; address += sz) {
5605 ptep = hugetlb_walk(vma, address, sz);
5606 if (!ptep) {
5607 address |= last_addr_mask;
5608 continue;
5609 }
5610
5611 ptl = huge_pte_lock(h, mm, ptep);
5612 if (huge_pmd_unshare(mm, vma, address, ptep)) {
5613 spin_unlock(ptl);
5614 tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE);
5615 force_flush = true;
5616 address |= last_addr_mask;
5617 continue;
5618 }
5619
5620 pte = huge_ptep_get(ptep);
5621 if (huge_pte_none(pte)) {
5622 spin_unlock(ptl);
5623 continue;
5624 }
5625
5626 /*
5627 * Migrating hugepage or HWPoisoned hugepage is already
5628 * unmapped and its refcount is dropped, so just clear pte here.
5629 */
5630 if (unlikely(!pte_present(pte))) {
5631 /*
5632 * If the pte was wr-protected by uffd-wp in any of the
5633 * swap forms, meanwhile the caller does not want to
5634 * drop the uffd-wp bit in this zap, then replace the
5635 * pte with a marker.
5636 */
5637 if (pte_swp_uffd_wp_any(pte) &&
5638 !(zap_flags & ZAP_FLAG_DROP_MARKER))
5639 set_huge_pte_at(mm, address, ptep,
5640 make_pte_marker(PTE_MARKER_UFFD_WP),
5641 sz);
5642 else
5643 huge_pte_clear(mm, address, ptep, sz);
5644 spin_unlock(ptl);
5645 continue;
5646 }
5647
5648 page = pte_page(pte);
5649 /*
5650 * If a reference page is supplied, it is because a specific
5651 * page is being unmapped, not a range. Ensure the page we
5652 * are about to unmap is the actual page of interest.
5653 */
5654 if (ref_page) {
5655 if (page != ref_page) {
5656 spin_unlock(ptl);
5657 continue;
5658 }
5659 /*
5660 * Mark the VMA as having unmapped its page so that
5661 * future faults in this VMA will fail rather than
5662 * looking like data was lost
5663 */
5664 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
5665 }
5666
5667 pte = huge_ptep_get_and_clear(mm, address, ptep);
5668 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
5669 if (huge_pte_dirty(pte))
5670 set_page_dirty(page);
5671 /* Leave a uffd-wp pte marker if needed */
5672 if (huge_pte_uffd_wp(pte) &&
5673 !(zap_flags & ZAP_FLAG_DROP_MARKER))
5674 set_huge_pte_at(mm, address, ptep,
5675 make_pte_marker(PTE_MARKER_UFFD_WP),
5676 sz);
5677 hugetlb_count_sub(pages_per_huge_page(h), mm);
5678 hugetlb_remove_rmap(page_folio(page));
5679
5680 spin_unlock(ptl);
5681 tlb_remove_page_size(tlb, page, huge_page_size(h));
5682 /*
5683 * Bail out after unmapping reference page if supplied
5684 */
5685 if (ref_page)
5686 break;
5687 }
5688 tlb_end_vma(tlb, vma);
5689
5690 /*
5691 * If we unshared PMDs, the TLB flush was not recorded in mmu_gather. We
5692 * could defer the flush until now, since by holding i_mmap_rwsem we
5693 * guaranteed that the last refernece would not be dropped. But we must
5694 * do the flushing before we return, as otherwise i_mmap_rwsem will be
5695 * dropped and the last reference to the shared PMDs page might be
5696 * dropped as well.
5697 *
5698 * In theory we could defer the freeing of the PMD pages as well, but
5699 * huge_pmd_unshare() relies on the exact page_count for the PMD page to
5700 * detect sharing, so we cannot defer the release of the page either.
5701 * Instead, do flush now.
5702 */
5703 if (force_flush)
5704 tlb_flush_mmu_tlbonly(tlb);
5705}
5706
5707void __hugetlb_zap_begin(struct vm_area_struct *vma,
5708 unsigned long *start, unsigned long *end)
5709{
5710 if (!vma->vm_file) /* hugetlbfs_file_mmap error */
5711 return;
5712
5713 adjust_range_if_pmd_sharing_possible(vma, start, end);
5714 hugetlb_vma_lock_write(vma);
5715 if (vma->vm_file)
5716 i_mmap_lock_write(vma->vm_file->f_mapping);
5717}
5718
5719void __hugetlb_zap_end(struct vm_area_struct *vma,
5720 struct zap_details *details)
5721{
5722 zap_flags_t zap_flags = details ? details->zap_flags : 0;
5723
5724 if (!vma->vm_file) /* hugetlbfs_file_mmap error */
5725 return;
5726
5727 if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */
5728 /*
5729 * Unlock and free the vma lock before releasing i_mmap_rwsem.
5730 * When the vma_lock is freed, this makes the vma ineligible
5731 * for pmd sharing. And, i_mmap_rwsem is required to set up
5732 * pmd sharing. This is important as page tables for this
5733 * unmapped range will be asynchrously deleted. If the page
5734 * tables are shared, there will be issues when accessed by
5735 * someone else.
5736 */
5737 __hugetlb_vma_unlock_write_free(vma);
5738 } else {
5739 hugetlb_vma_unlock_write(vma);
5740 }
5741
5742 if (vma->vm_file)
5743 i_mmap_unlock_write(vma->vm_file->f_mapping);
5744}
5745
5746void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
5747 unsigned long end, struct page *ref_page,
5748 zap_flags_t zap_flags)
5749{
5750 struct mmu_notifier_range range;
5751 struct mmu_gather tlb;
5752
5753 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm,
5754 start, end);
5755 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5756 mmu_notifier_invalidate_range_start(&range);
5757 tlb_gather_mmu(&tlb, vma->vm_mm);
5758
5759 __unmap_hugepage_range(&tlb, vma, start, end, ref_page, zap_flags);
5760
5761 mmu_notifier_invalidate_range_end(&range);
5762 tlb_finish_mmu(&tlb);
5763}
5764
5765/*
5766 * This is called when the original mapper is failing to COW a MAP_PRIVATE
5767 * mapping it owns the reserve page for. The intention is to unmap the page
5768 * from other VMAs and let the children be SIGKILLed if they are faulting the
5769 * same region.
5770 */
5771static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
5772 struct page *page, unsigned long address)
5773{
5774 struct hstate *h = hstate_vma(vma);
5775 struct vm_area_struct *iter_vma;
5776 struct address_space *mapping;
5777 pgoff_t pgoff;
5778
5779 /*
5780 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
5781 * from page cache lookup which is in HPAGE_SIZE units.
5782 */
5783 address = address & huge_page_mask(h);
5784 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
5785 vma->vm_pgoff;
5786 mapping = vma->vm_file->f_mapping;
5787
5788 /*
5789 * Take the mapping lock for the duration of the table walk. As
5790 * this mapping should be shared between all the VMAs,
5791 * __unmap_hugepage_range() is called as the lock is already held
5792 */
5793 i_mmap_lock_write(mapping);
5794 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
5795 /* Do not unmap the current VMA */
5796 if (iter_vma == vma)
5797 continue;
5798
5799 /*
5800 * Shared VMAs have their own reserves and do not affect
5801 * MAP_PRIVATE accounting but it is possible that a shared
5802 * VMA is using the same page so check and skip such VMAs.
5803 */
5804 if (iter_vma->vm_flags & VM_MAYSHARE)
5805 continue;
5806
5807 /*
5808 * Unmap the page from other VMAs without their own reserves.
5809 * They get marked to be SIGKILLed if they fault in these
5810 * areas. This is because a future no-page fault on this VMA
5811 * could insert a zeroed page instead of the data existing
5812 * from the time of fork. This would look like data corruption
5813 */
5814 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
5815 unmap_hugepage_range(iter_vma, address,
5816 address + huge_page_size(h), page, 0);
5817 }
5818 i_mmap_unlock_write(mapping);
5819}
5820
5821/*
5822 * hugetlb_wp() should be called with page lock of the original hugepage held.
5823 * Called with hugetlb_fault_mutex_table held and pte_page locked so we
5824 * cannot race with other handlers or page migration.
5825 * Keep the pte_same checks anyway to make transition from the mutex easier.
5826 */
5827static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
5828 unsigned long address, pte_t *ptep, unsigned int flags,
5829 struct folio *pagecache_folio, spinlock_t *ptl)
5830{
5831 const bool unshare = flags & FAULT_FLAG_UNSHARE;
5832 pte_t pte = huge_ptep_get(ptep);
5833 struct hstate *h = hstate_vma(vma);
5834 struct folio *old_folio;
5835 struct folio *new_folio;
5836 int outside_reserve = 0;
5837 vm_fault_t ret = 0;
5838 unsigned long haddr = address & huge_page_mask(h);
5839 struct mmu_notifier_range range;
5840
5841 /*
5842 * Never handle CoW for uffd-wp protected pages. It should be only
5843 * handled when the uffd-wp protection is removed.
5844 *
5845 * Note that only the CoW optimization path (in hugetlb_no_page())
5846 * can trigger this, because hugetlb_fault() will always resolve
5847 * uffd-wp bit first.
5848 */
5849 if (!unshare && huge_pte_uffd_wp(pte))
5850 return 0;
5851
5852 /*
5853 * hugetlb does not support FOLL_FORCE-style write faults that keep the
5854 * PTE mapped R/O such as maybe_mkwrite() would do.
5855 */
5856 if (WARN_ON_ONCE(!unshare && !(vma->vm_flags & VM_WRITE)))
5857 return VM_FAULT_SIGSEGV;
5858
5859 /* Let's take out MAP_SHARED mappings first. */
5860 if (vma->vm_flags & VM_MAYSHARE) {
5861 set_huge_ptep_writable(vma, haddr, ptep);
5862 return 0;
5863 }
5864
5865 old_folio = page_folio(pte_page(pte));
5866
5867 delayacct_wpcopy_start();
5868
5869retry_avoidcopy:
5870 /*
5871 * If no-one else is actually using this page, we're the exclusive
5872 * owner and can reuse this page.
5873 */
5874 if (folio_mapcount(old_folio) == 1 && folio_test_anon(old_folio)) {
5875 if (!PageAnonExclusive(&old_folio->page)) {
5876 folio_move_anon_rmap(old_folio, vma);
5877 SetPageAnonExclusive(&old_folio->page);
5878 }
5879 if (likely(!unshare))
5880 set_huge_ptep_writable(vma, haddr, ptep);
5881
5882 delayacct_wpcopy_end();
5883 return 0;
5884 }
5885 VM_BUG_ON_PAGE(folio_test_anon(old_folio) &&
5886 PageAnonExclusive(&old_folio->page), &old_folio->page);
5887
5888 /*
5889 * If the process that created a MAP_PRIVATE mapping is about to
5890 * perform a COW due to a shared page count, attempt to satisfy
5891 * the allocation without using the existing reserves. The pagecache
5892 * page is used to determine if the reserve at this address was
5893 * consumed or not. If reserves were used, a partial faulted mapping
5894 * at the time of fork() could consume its reserves on COW instead
5895 * of the full address range.
5896 */
5897 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
5898 old_folio != pagecache_folio)
5899 outside_reserve = 1;
5900
5901 folio_get(old_folio);
5902
5903 /*
5904 * Drop page table lock as buddy allocator may be called. It will
5905 * be acquired again before returning to the caller, as expected.
5906 */
5907 spin_unlock(ptl);
5908 new_folio = alloc_hugetlb_folio(vma, haddr, outside_reserve);
5909
5910 if (IS_ERR(new_folio)) {
5911 /*
5912 * If a process owning a MAP_PRIVATE mapping fails to COW,
5913 * it is due to references held by a child and an insufficient
5914 * huge page pool. To guarantee the original mappers
5915 * reliability, unmap the page from child processes. The child
5916 * may get SIGKILLed if it later faults.
5917 */
5918 if (outside_reserve) {
5919 struct address_space *mapping = vma->vm_file->f_mapping;
5920 pgoff_t idx;
5921 u32 hash;
5922
5923 folio_put(old_folio);
5924 /*
5925 * Drop hugetlb_fault_mutex and vma_lock before
5926 * unmapping. unmapping needs to hold vma_lock
5927 * in write mode. Dropping vma_lock in read mode
5928 * here is OK as COW mappings do not interact with
5929 * PMD sharing.
5930 *
5931 * Reacquire both after unmap operation.
5932 */
5933 idx = vma_hugecache_offset(h, vma, haddr);
5934 hash = hugetlb_fault_mutex_hash(mapping, idx);
5935 hugetlb_vma_unlock_read(vma);
5936 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
5937
5938 unmap_ref_private(mm, vma, &old_folio->page, haddr);
5939
5940 mutex_lock(&hugetlb_fault_mutex_table[hash]);
5941 hugetlb_vma_lock_read(vma);
5942 spin_lock(ptl);
5943 ptep = hugetlb_walk(vma, haddr, huge_page_size(h));
5944 if (likely(ptep &&
5945 pte_same(huge_ptep_get(ptep), pte)))
5946 goto retry_avoidcopy;
5947 /*
5948 * race occurs while re-acquiring page table
5949 * lock, and our job is done.
5950 */
5951 delayacct_wpcopy_end();
5952 return 0;
5953 }
5954
5955 ret = vmf_error(PTR_ERR(new_folio));
5956 goto out_release_old;
5957 }
5958
5959 /*
5960 * When the original hugepage is shared one, it does not have
5961 * anon_vma prepared.
5962 */
5963 if (unlikely(anon_vma_prepare(vma))) {
5964 ret = VM_FAULT_OOM;
5965 goto out_release_all;
5966 }
5967
5968 if (copy_user_large_folio(new_folio, old_folio, address, vma)) {
5969 ret = VM_FAULT_HWPOISON_LARGE;
5970 goto out_release_all;
5971 }
5972 __folio_mark_uptodate(new_folio);
5973
5974 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, haddr,
5975 haddr + huge_page_size(h));
5976 mmu_notifier_invalidate_range_start(&range);
5977
5978 /*
5979 * Retake the page table lock to check for racing updates
5980 * before the page tables are altered
5981 */
5982 spin_lock(ptl);
5983 ptep = hugetlb_walk(vma, haddr, huge_page_size(h));
5984 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
5985 pte_t newpte = make_huge_pte(vma, &new_folio->page, !unshare);
5986
5987 /* Break COW or unshare */
5988 huge_ptep_clear_flush(vma, haddr, ptep);
5989 hugetlb_remove_rmap(old_folio);
5990 hugetlb_add_new_anon_rmap(new_folio, vma, haddr);
5991 if (huge_pte_uffd_wp(pte))
5992 newpte = huge_pte_mkuffd_wp(newpte);
5993 set_huge_pte_at(mm, haddr, ptep, newpte, huge_page_size(h));
5994 folio_set_hugetlb_migratable(new_folio);
5995 /* Make the old page be freed below */
5996 new_folio = old_folio;
5997 }
5998 spin_unlock(ptl);
5999 mmu_notifier_invalidate_range_end(&range);
6000out_release_all:
6001 /*
6002 * No restore in case of successful pagetable update (Break COW or
6003 * unshare)
6004 */
6005 if (new_folio != old_folio)
6006 restore_reserve_on_error(h, vma, haddr, new_folio);
6007 folio_put(new_folio);
6008out_release_old:
6009 folio_put(old_folio);
6010
6011 spin_lock(ptl); /* Caller expects lock to be held */
6012
6013 delayacct_wpcopy_end();
6014 return ret;
6015}
6016
6017/*
6018 * Return whether there is a pagecache page to back given address within VMA.
6019 */
6020static bool hugetlbfs_pagecache_present(struct hstate *h,
6021 struct vm_area_struct *vma, unsigned long address)
6022{
6023 struct address_space *mapping = vma->vm_file->f_mapping;
6024 pgoff_t idx = linear_page_index(vma, address);
6025 struct folio *folio;
6026
6027 folio = filemap_get_folio(mapping, idx);
6028 if (IS_ERR(folio))
6029 return false;
6030 folio_put(folio);
6031 return true;
6032}
6033
6034int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping,
6035 pgoff_t idx)
6036{
6037 struct inode *inode = mapping->host;
6038 struct hstate *h = hstate_inode(inode);
6039 int err;
6040
6041 idx <<= huge_page_order(h);
6042 __folio_set_locked(folio);
6043 err = __filemap_add_folio(mapping, folio, idx, GFP_KERNEL, NULL);
6044
6045 if (unlikely(err)) {
6046 __folio_clear_locked(folio);
6047 return err;
6048 }
6049 folio_clear_hugetlb_restore_reserve(folio);
6050
6051 /*
6052 * mark folio dirty so that it will not be removed from cache/file
6053 * by non-hugetlbfs specific code paths.
6054 */
6055 folio_mark_dirty(folio);
6056
6057 spin_lock(&inode->i_lock);
6058 inode->i_blocks += blocks_per_huge_page(h);
6059 spin_unlock(&inode->i_lock);
6060 return 0;
6061}
6062
6063static inline vm_fault_t hugetlb_handle_userfault(struct vm_area_struct *vma,
6064 struct address_space *mapping,
6065 pgoff_t idx,
6066 unsigned int flags,
6067 unsigned long haddr,
6068 unsigned long addr,
6069 unsigned long reason)
6070{
6071 u32 hash;
6072 struct vm_fault vmf = {
6073 .vma = vma,
6074 .address = haddr,
6075 .real_address = addr,
6076 .flags = flags,
6077
6078 /*
6079 * Hard to debug if it ends up being
6080 * used by a callee that assumes
6081 * something about the other
6082 * uninitialized fields... same as in
6083 * memory.c
6084 */
6085 };
6086
6087 /*
6088 * vma_lock and hugetlb_fault_mutex must be dropped before handling
6089 * userfault. Also mmap_lock could be dropped due to handling
6090 * userfault, any vma operation should be careful from here.
6091 */
6092 hugetlb_vma_unlock_read(vma);
6093 hash = hugetlb_fault_mutex_hash(mapping, idx);
6094 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6095 return handle_userfault(&vmf, reason);
6096}
6097
6098/*
6099 * Recheck pte with pgtable lock. Returns true if pte didn't change, or
6100 * false if pte changed or is changing.
6101 */
6102static bool hugetlb_pte_stable(struct hstate *h, struct mm_struct *mm,
6103 pte_t *ptep, pte_t old_pte)
6104{
6105 spinlock_t *ptl;
6106 bool same;
6107
6108 ptl = huge_pte_lock(h, mm, ptep);
6109 same = pte_same(huge_ptep_get(ptep), old_pte);
6110 spin_unlock(ptl);
6111
6112 return same;
6113}
6114
6115static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
6116 struct vm_area_struct *vma,
6117 struct address_space *mapping, pgoff_t idx,
6118 unsigned long address, pte_t *ptep,
6119 pte_t old_pte, unsigned int flags)
6120{
6121 struct hstate *h = hstate_vma(vma);
6122 vm_fault_t ret = VM_FAULT_SIGBUS;
6123 int anon_rmap = 0;
6124 unsigned long size;
6125 struct folio *folio;
6126 pte_t new_pte;
6127 spinlock_t *ptl;
6128 unsigned long haddr = address & huge_page_mask(h);
6129 bool new_folio, new_pagecache_folio = false;
6130 u32 hash = hugetlb_fault_mutex_hash(mapping, idx);
6131
6132 /*
6133 * Currently, we are forced to kill the process in the event the
6134 * original mapper has unmapped pages from the child due to a failed
6135 * COW/unsharing. Warn that such a situation has occurred as it may not
6136 * be obvious.
6137 */
6138 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
6139 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
6140 current->pid);
6141 goto out;
6142 }
6143
6144 /*
6145 * Use page lock to guard against racing truncation
6146 * before we get page_table_lock.
6147 */
6148 new_folio = false;
6149 folio = filemap_lock_hugetlb_folio(h, mapping, idx);
6150 if (IS_ERR(folio)) {
6151 size = i_size_read(mapping->host) >> huge_page_shift(h);
6152 if (idx >= size)
6153 goto out;
6154 /* Check for page in userfault range */
6155 if (userfaultfd_missing(vma)) {
6156 /*
6157 * Since hugetlb_no_page() was examining pte
6158 * without pgtable lock, we need to re-test under
6159 * lock because the pte may not be stable and could
6160 * have changed from under us. Try to detect
6161 * either changed or during-changing ptes and retry
6162 * properly when needed.
6163 *
6164 * Note that userfaultfd is actually fine with
6165 * false positives (e.g. caused by pte changed),
6166 * but not wrong logical events (e.g. caused by
6167 * reading a pte during changing). The latter can
6168 * confuse the userspace, so the strictness is very
6169 * much preferred. E.g., MISSING event should
6170 * never happen on the page after UFFDIO_COPY has
6171 * correctly installed the page and returned.
6172 */
6173 if (!hugetlb_pte_stable(h, mm, ptep, old_pte)) {
6174 ret = 0;
6175 goto out;
6176 }
6177
6178 return hugetlb_handle_userfault(vma, mapping, idx, flags,
6179 haddr, address,
6180 VM_UFFD_MISSING);
6181 }
6182
6183 folio = alloc_hugetlb_folio(vma, haddr, 0);
6184 if (IS_ERR(folio)) {
6185 /*
6186 * Returning error will result in faulting task being
6187 * sent SIGBUS. The hugetlb fault mutex prevents two
6188 * tasks from racing to fault in the same page which
6189 * could result in false unable to allocate errors.
6190 * Page migration does not take the fault mutex, but
6191 * does a clear then write of pte's under page table
6192 * lock. Page fault code could race with migration,
6193 * notice the clear pte and try to allocate a page
6194 * here. Before returning error, get ptl and make
6195 * sure there really is no pte entry.
6196 */
6197 if (hugetlb_pte_stable(h, mm, ptep, old_pte))
6198 ret = vmf_error(PTR_ERR(folio));
6199 else
6200 ret = 0;
6201 goto out;
6202 }
6203 clear_huge_page(&folio->page, address, pages_per_huge_page(h));
6204 __folio_mark_uptodate(folio);
6205 new_folio = true;
6206
6207 if (vma->vm_flags & VM_MAYSHARE) {
6208 int err = hugetlb_add_to_page_cache(folio, mapping, idx);
6209 if (err) {
6210 /*
6211 * err can't be -EEXIST which implies someone
6212 * else consumed the reservation since hugetlb
6213 * fault mutex is held when add a hugetlb page
6214 * to the page cache. So it's safe to call
6215 * restore_reserve_on_error() here.
6216 */
6217 restore_reserve_on_error(h, vma, haddr, folio);
6218 folio_put(folio);
6219 goto out;
6220 }
6221 new_pagecache_folio = true;
6222 } else {
6223 folio_lock(folio);
6224 if (unlikely(anon_vma_prepare(vma))) {
6225 ret = VM_FAULT_OOM;
6226 goto backout_unlocked;
6227 }
6228 anon_rmap = 1;
6229 }
6230 } else {
6231 /*
6232 * If memory error occurs between mmap() and fault, some process
6233 * don't have hwpoisoned swap entry for errored virtual address.
6234 * So we need to block hugepage fault by PG_hwpoison bit check.
6235 */
6236 if (unlikely(folio_test_hwpoison(folio))) {
6237 ret = VM_FAULT_HWPOISON_LARGE |
6238 VM_FAULT_SET_HINDEX(hstate_index(h));
6239 goto backout_unlocked;
6240 }
6241
6242 /* Check for page in userfault range. */
6243 if (userfaultfd_minor(vma)) {
6244 folio_unlock(folio);
6245 folio_put(folio);
6246 /* See comment in userfaultfd_missing() block above */
6247 if (!hugetlb_pte_stable(h, mm, ptep, old_pte)) {
6248 ret = 0;
6249 goto out;
6250 }
6251 return hugetlb_handle_userfault(vma, mapping, idx, flags,
6252 haddr, address,
6253 VM_UFFD_MINOR);
6254 }
6255 }
6256
6257 /*
6258 * If we are going to COW a private mapping later, we examine the
6259 * pending reservations for this page now. This will ensure that
6260 * any allocations necessary to record that reservation occur outside
6261 * the spinlock.
6262 */
6263 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
6264 if (vma_needs_reservation(h, vma, haddr) < 0) {
6265 ret = VM_FAULT_OOM;
6266 goto backout_unlocked;
6267 }
6268 /* Just decrements count, does not deallocate */
6269 vma_end_reservation(h, vma, haddr);
6270 }
6271
6272 ptl = huge_pte_lock(h, mm, ptep);
6273 ret = 0;
6274 /* If pte changed from under us, retry */
6275 if (!pte_same(huge_ptep_get(ptep), old_pte))
6276 goto backout;
6277
6278 if (anon_rmap)
6279 hugetlb_add_new_anon_rmap(folio, vma, haddr);
6280 else
6281 hugetlb_add_file_rmap(folio);
6282 new_pte = make_huge_pte(vma, &folio->page, ((vma->vm_flags & VM_WRITE)
6283 && (vma->vm_flags & VM_SHARED)));
6284 /*
6285 * If this pte was previously wr-protected, keep it wr-protected even
6286 * if populated.
6287 */
6288 if (unlikely(pte_marker_uffd_wp(old_pte)))
6289 new_pte = huge_pte_mkuffd_wp(new_pte);
6290 set_huge_pte_at(mm, haddr, ptep, new_pte, huge_page_size(h));
6291
6292 hugetlb_count_add(pages_per_huge_page(h), mm);
6293 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
6294 /* Optimization, do the COW without a second fault */
6295 ret = hugetlb_wp(mm, vma, address, ptep, flags, folio, ptl);
6296 }
6297
6298 spin_unlock(ptl);
6299
6300 /*
6301 * Only set hugetlb_migratable in newly allocated pages. Existing pages
6302 * found in the pagecache may not have hugetlb_migratable if they have
6303 * been isolated for migration.
6304 */
6305 if (new_folio)
6306 folio_set_hugetlb_migratable(folio);
6307
6308 folio_unlock(folio);
6309out:
6310 hugetlb_vma_unlock_read(vma);
6311 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6312 return ret;
6313
6314backout:
6315 spin_unlock(ptl);
6316backout_unlocked:
6317 if (new_folio && !new_pagecache_folio)
6318 restore_reserve_on_error(h, vma, haddr, folio);
6319
6320 folio_unlock(folio);
6321 folio_put(folio);
6322 goto out;
6323}
6324
6325#ifdef CONFIG_SMP
6326u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
6327{
6328 unsigned long key[2];
6329 u32 hash;
6330
6331 key[0] = (unsigned long) mapping;
6332 key[1] = idx;
6333
6334 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
6335
6336 return hash & (num_fault_mutexes - 1);
6337}
6338#else
6339/*
6340 * For uniprocessor systems we always use a single mutex, so just
6341 * return 0 and avoid the hashing overhead.
6342 */
6343u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
6344{
6345 return 0;
6346}
6347#endif
6348
6349vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
6350 unsigned long address, unsigned int flags)
6351{
6352 pte_t *ptep, entry;
6353 spinlock_t *ptl;
6354 vm_fault_t ret;
6355 u32 hash;
6356 pgoff_t idx;
6357 struct folio *folio = NULL;
6358 struct folio *pagecache_folio = NULL;
6359 struct hstate *h = hstate_vma(vma);
6360 struct address_space *mapping;
6361 int need_wait_lock = 0;
6362 unsigned long haddr = address & huge_page_mask(h);
6363
6364 /* TODO: Handle faults under the VMA lock */
6365 if (flags & FAULT_FLAG_VMA_LOCK) {
6366 vma_end_read(vma);
6367 return VM_FAULT_RETRY;
6368 }
6369
6370 /*
6371 * Serialize hugepage allocation and instantiation, so that we don't
6372 * get spurious allocation failures if two CPUs race to instantiate
6373 * the same page in the page cache.
6374 */
6375 mapping = vma->vm_file->f_mapping;
6376 idx = vma_hugecache_offset(h, vma, haddr);
6377 hash = hugetlb_fault_mutex_hash(mapping, idx);
6378 mutex_lock(&hugetlb_fault_mutex_table[hash]);
6379
6380 /*
6381 * Acquire vma lock before calling huge_pte_alloc and hold
6382 * until finished with ptep. This prevents huge_pmd_unshare from
6383 * being called elsewhere and making the ptep no longer valid.
6384 */
6385 hugetlb_vma_lock_read(vma);
6386 ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h));
6387 if (!ptep) {
6388 hugetlb_vma_unlock_read(vma);
6389 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6390 return VM_FAULT_OOM;
6391 }
6392
6393 entry = huge_ptep_get(ptep);
6394 if (huge_pte_none_mostly(entry)) {
6395 if (is_pte_marker(entry)) {
6396 pte_marker marker =
6397 pte_marker_get(pte_to_swp_entry(entry));
6398
6399 if (marker & PTE_MARKER_POISONED) {
6400 ret = VM_FAULT_HWPOISON_LARGE;
6401 goto out_mutex;
6402 }
6403 }
6404
6405 /*
6406 * Other PTE markers should be handled the same way as none PTE.
6407 *
6408 * hugetlb_no_page will drop vma lock and hugetlb fault
6409 * mutex internally, which make us return immediately.
6410 */
6411 return hugetlb_no_page(mm, vma, mapping, idx, address, ptep,
6412 entry, flags);
6413 }
6414
6415 ret = 0;
6416
6417 /*
6418 * entry could be a migration/hwpoison entry at this point, so this
6419 * check prevents the kernel from going below assuming that we have
6420 * an active hugepage in pagecache. This goto expects the 2nd page
6421 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
6422 * properly handle it.
6423 */
6424 if (!pte_present(entry)) {
6425 if (unlikely(is_hugetlb_entry_migration(entry))) {
6426 /*
6427 * Release the hugetlb fault lock now, but retain
6428 * the vma lock, because it is needed to guard the
6429 * huge_pte_lockptr() later in
6430 * migration_entry_wait_huge(). The vma lock will
6431 * be released there.
6432 */
6433 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6434 migration_entry_wait_huge(vma, ptep);
6435 return 0;
6436 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
6437 ret = VM_FAULT_HWPOISON_LARGE |
6438 VM_FAULT_SET_HINDEX(hstate_index(h));
6439 goto out_mutex;
6440 }
6441
6442 /*
6443 * If we are going to COW/unshare the mapping later, we examine the
6444 * pending reservations for this page now. This will ensure that any
6445 * allocations necessary to record that reservation occur outside the
6446 * spinlock. Also lookup the pagecache page now as it is used to
6447 * determine if a reservation has been consumed.
6448 */
6449 if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) &&
6450 !(vma->vm_flags & VM_MAYSHARE) && !huge_pte_write(entry)) {
6451 if (vma_needs_reservation(h, vma, haddr) < 0) {
6452 ret = VM_FAULT_OOM;
6453 goto out_mutex;
6454 }
6455 /* Just decrements count, does not deallocate */
6456 vma_end_reservation(h, vma, haddr);
6457
6458 pagecache_folio = filemap_lock_hugetlb_folio(h, mapping, idx);
6459 if (IS_ERR(pagecache_folio))
6460 pagecache_folio = NULL;
6461 }
6462
6463 ptl = huge_pte_lock(h, mm, ptep);
6464
6465 /* Check for a racing update before calling hugetlb_wp() */
6466 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
6467 goto out_ptl;
6468
6469 /* Handle userfault-wp first, before trying to lock more pages */
6470 if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) &&
6471 (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
6472 if (!userfaultfd_wp_async(vma)) {
6473 struct vm_fault vmf = {
6474 .vma = vma,
6475 .address = haddr,
6476 .real_address = address,
6477 .flags = flags,
6478 };
6479
6480 spin_unlock(ptl);
6481 if (pagecache_folio) {
6482 folio_unlock(pagecache_folio);
6483 folio_put(pagecache_folio);
6484 }
6485 hugetlb_vma_unlock_read(vma);
6486 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6487 return handle_userfault(&vmf, VM_UFFD_WP);
6488 }
6489
6490 entry = huge_pte_clear_uffd_wp(entry);
6491 set_huge_pte_at(mm, haddr, ptep, entry,
6492 huge_page_size(hstate_vma(vma)));
6493 /* Fallthrough to CoW */
6494 }
6495
6496 /*
6497 * hugetlb_wp() requires page locks of pte_page(entry) and
6498 * pagecache_folio, so here we need take the former one
6499 * when folio != pagecache_folio or !pagecache_folio.
6500 */
6501 folio = page_folio(pte_page(entry));
6502 if (folio != pagecache_folio)
6503 if (!folio_trylock(folio)) {
6504 need_wait_lock = 1;
6505 goto out_ptl;
6506 }
6507
6508 folio_get(folio);
6509
6510 if (flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) {
6511 if (!huge_pte_write(entry)) {
6512 ret = hugetlb_wp(mm, vma, address, ptep, flags,
6513 pagecache_folio, ptl);
6514 goto out_put_page;
6515 } else if (likely(flags & FAULT_FLAG_WRITE)) {
6516 entry = huge_pte_mkdirty(entry);
6517 }
6518 }
6519 entry = pte_mkyoung(entry);
6520 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
6521 flags & FAULT_FLAG_WRITE))
6522 update_mmu_cache(vma, haddr, ptep);
6523out_put_page:
6524 if (folio != pagecache_folio)
6525 folio_unlock(folio);
6526 folio_put(folio);
6527out_ptl:
6528 spin_unlock(ptl);
6529
6530 if (pagecache_folio) {
6531 folio_unlock(pagecache_folio);
6532 folio_put(pagecache_folio);
6533 }
6534out_mutex:
6535 hugetlb_vma_unlock_read(vma);
6536 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6537 /*
6538 * Generally it's safe to hold refcount during waiting page lock. But
6539 * here we just wait to defer the next page fault to avoid busy loop and
6540 * the page is not used after unlocked before returning from the current
6541 * page fault. So we are safe from accessing freed page, even if we wait
6542 * here without taking refcount.
6543 */
6544 if (need_wait_lock)
6545 folio_wait_locked(folio);
6546 return ret;
6547}
6548
6549#ifdef CONFIG_USERFAULTFD
6550/*
6551 * Can probably be eliminated, but still used by hugetlb_mfill_atomic_pte().
6552 */
6553static struct folio *alloc_hugetlb_folio_vma(struct hstate *h,
6554 struct vm_area_struct *vma, unsigned long address)
6555{
6556 struct mempolicy *mpol;
6557 nodemask_t *nodemask;
6558 struct folio *folio;
6559 gfp_t gfp_mask;
6560 int node;
6561
6562 gfp_mask = htlb_alloc_mask(h);
6563 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
6564 folio = alloc_hugetlb_folio_nodemask(h, node, nodemask, gfp_mask);
6565 mpol_cond_put(mpol);
6566
6567 return folio;
6568}
6569
6570/*
6571 * Used by userfaultfd UFFDIO_* ioctls. Based on userfaultfd's mfill_atomic_pte
6572 * with modifications for hugetlb pages.
6573 */
6574int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
6575 struct vm_area_struct *dst_vma,
6576 unsigned long dst_addr,
6577 unsigned long src_addr,
6578 uffd_flags_t flags,
6579 struct folio **foliop)
6580{
6581 struct mm_struct *dst_mm = dst_vma->vm_mm;
6582 bool is_continue = uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE);
6583 bool wp_enabled = (flags & MFILL_ATOMIC_WP);
6584 struct hstate *h = hstate_vma(dst_vma);
6585 struct address_space *mapping = dst_vma->vm_file->f_mapping;
6586 pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
6587 unsigned long size;
6588 int vm_shared = dst_vma->vm_flags & VM_SHARED;
6589 pte_t _dst_pte;
6590 spinlock_t *ptl;
6591 int ret = -ENOMEM;
6592 struct folio *folio;
6593 int writable;
6594 bool folio_in_pagecache = false;
6595
6596 if (uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) {
6597 ptl = huge_pte_lock(h, dst_mm, dst_pte);
6598
6599 /* Don't overwrite any existing PTEs (even markers) */
6600 if (!huge_pte_none(huge_ptep_get(dst_pte))) {
6601 spin_unlock(ptl);
6602 return -EEXIST;
6603 }
6604
6605 _dst_pte = make_pte_marker(PTE_MARKER_POISONED);
6606 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte,
6607 huge_page_size(h));
6608
6609 /* No need to invalidate - it was non-present before */
6610 update_mmu_cache(dst_vma, dst_addr, dst_pte);
6611
6612 spin_unlock(ptl);
6613 return 0;
6614 }
6615
6616 if (is_continue) {
6617 ret = -EFAULT;
6618 folio = filemap_lock_hugetlb_folio(h, mapping, idx);
6619 if (IS_ERR(folio))
6620 goto out;
6621 folio_in_pagecache = true;
6622 } else if (!*foliop) {
6623 /* If a folio already exists, then it's UFFDIO_COPY for
6624 * a non-missing case. Return -EEXIST.
6625 */
6626 if (vm_shared &&
6627 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
6628 ret = -EEXIST;
6629 goto out;
6630 }
6631
6632 folio = alloc_hugetlb_folio(dst_vma, dst_addr, 0);
6633 if (IS_ERR(folio)) {
6634 ret = -ENOMEM;
6635 goto out;
6636 }
6637
6638 ret = copy_folio_from_user(folio, (const void __user *) src_addr,
6639 false);
6640
6641 /* fallback to copy_from_user outside mmap_lock */
6642 if (unlikely(ret)) {
6643 ret = -ENOENT;
6644 /* Free the allocated folio which may have
6645 * consumed a reservation.
6646 */
6647 restore_reserve_on_error(h, dst_vma, dst_addr, folio);
6648 folio_put(folio);
6649
6650 /* Allocate a temporary folio to hold the copied
6651 * contents.
6652 */
6653 folio = alloc_hugetlb_folio_vma(h, dst_vma, dst_addr);
6654 if (!folio) {
6655 ret = -ENOMEM;
6656 goto out;
6657 }
6658 *foliop = folio;
6659 /* Set the outparam foliop and return to the caller to
6660 * copy the contents outside the lock. Don't free the
6661 * folio.
6662 */
6663 goto out;
6664 }
6665 } else {
6666 if (vm_shared &&
6667 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
6668 folio_put(*foliop);
6669 ret = -EEXIST;
6670 *foliop = NULL;
6671 goto out;
6672 }
6673
6674 folio = alloc_hugetlb_folio(dst_vma, dst_addr, 0);
6675 if (IS_ERR(folio)) {
6676 folio_put(*foliop);
6677 ret = -ENOMEM;
6678 *foliop = NULL;
6679 goto out;
6680 }
6681 ret = copy_user_large_folio(folio, *foliop, dst_addr, dst_vma);
6682 folio_put(*foliop);
6683 *foliop = NULL;
6684 if (ret) {
6685 folio_put(folio);
6686 goto out;
6687 }
6688 }
6689
6690 /*
6691 * The memory barrier inside __folio_mark_uptodate makes sure that
6692 * preceding stores to the page contents become visible before
6693 * the set_pte_at() write.
6694 */
6695 __folio_mark_uptodate(folio);
6696
6697 /* Add shared, newly allocated pages to the page cache. */
6698 if (vm_shared && !is_continue) {
6699 size = i_size_read(mapping->host) >> huge_page_shift(h);
6700 ret = -EFAULT;
6701 if (idx >= size)
6702 goto out_release_nounlock;
6703
6704 /*
6705 * Serialization between remove_inode_hugepages() and
6706 * hugetlb_add_to_page_cache() below happens through the
6707 * hugetlb_fault_mutex_table that here must be hold by
6708 * the caller.
6709 */
6710 ret = hugetlb_add_to_page_cache(folio, mapping, idx);
6711 if (ret)
6712 goto out_release_nounlock;
6713 folio_in_pagecache = true;
6714 }
6715
6716 ptl = huge_pte_lock(h, dst_mm, dst_pte);
6717
6718 ret = -EIO;
6719 if (folio_test_hwpoison(folio))
6720 goto out_release_unlock;
6721
6722 /*
6723 * We allow to overwrite a pte marker: consider when both MISSING|WP
6724 * registered, we firstly wr-protect a none pte which has no page cache
6725 * page backing it, then access the page.
6726 */
6727 ret = -EEXIST;
6728 if (!huge_pte_none_mostly(huge_ptep_get(dst_pte)))
6729 goto out_release_unlock;
6730
6731 if (folio_in_pagecache)
6732 hugetlb_add_file_rmap(folio);
6733 else
6734 hugetlb_add_new_anon_rmap(folio, dst_vma, dst_addr);
6735
6736 /*
6737 * For either: (1) CONTINUE on a non-shared VMA, or (2) UFFDIO_COPY
6738 * with wp flag set, don't set pte write bit.
6739 */
6740 if (wp_enabled || (is_continue && !vm_shared))
6741 writable = 0;
6742 else
6743 writable = dst_vma->vm_flags & VM_WRITE;
6744
6745 _dst_pte = make_huge_pte(dst_vma, &folio->page, writable);
6746 /*
6747 * Always mark UFFDIO_COPY page dirty; note that this may not be
6748 * extremely important for hugetlbfs for now since swapping is not
6749 * supported, but we should still be clear in that this page cannot be
6750 * thrown away at will, even if write bit not set.
6751 */
6752 _dst_pte = huge_pte_mkdirty(_dst_pte);
6753 _dst_pte = pte_mkyoung(_dst_pte);
6754
6755 if (wp_enabled)
6756 _dst_pte = huge_pte_mkuffd_wp(_dst_pte);
6757
6758 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte, huge_page_size(h));
6759
6760 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
6761
6762 /* No need to invalidate - it was non-present before */
6763 update_mmu_cache(dst_vma, dst_addr, dst_pte);
6764
6765 spin_unlock(ptl);
6766 if (!is_continue)
6767 folio_set_hugetlb_migratable(folio);
6768 if (vm_shared || is_continue)
6769 folio_unlock(folio);
6770 ret = 0;
6771out:
6772 return ret;
6773out_release_unlock:
6774 spin_unlock(ptl);
6775 if (vm_shared || is_continue)
6776 folio_unlock(folio);
6777out_release_nounlock:
6778 if (!folio_in_pagecache)
6779 restore_reserve_on_error(h, dst_vma, dst_addr, folio);
6780 folio_put(folio);
6781 goto out;
6782}
6783#endif /* CONFIG_USERFAULTFD */
6784
6785struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
6786 unsigned long address, unsigned int flags,
6787 unsigned int *page_mask)
6788{
6789 struct hstate *h = hstate_vma(vma);
6790 struct mm_struct *mm = vma->vm_mm;
6791 unsigned long haddr = address & huge_page_mask(h);
6792 struct page *page = NULL;
6793 spinlock_t *ptl;
6794 pte_t *pte, entry;
6795 int ret;
6796
6797 hugetlb_vma_lock_read(vma);
6798 pte = hugetlb_walk(vma, haddr, huge_page_size(h));
6799 if (!pte)
6800 goto out_unlock;
6801
6802 ptl = huge_pte_lock(h, mm, pte);
6803 entry = huge_ptep_get(pte);
6804 if (pte_present(entry)) {
6805 page = pte_page(entry);
6806
6807 if (!huge_pte_write(entry)) {
6808 if (flags & FOLL_WRITE) {
6809 page = NULL;
6810 goto out;
6811 }
6812
6813 if (gup_must_unshare(vma, flags, page)) {
6814 /* Tell the caller to do unsharing */
6815 page = ERR_PTR(-EMLINK);
6816 goto out;
6817 }
6818 }
6819
6820 page = nth_page(page, ((address & ~huge_page_mask(h)) >> PAGE_SHIFT));
6821
6822 /*
6823 * Note that page may be a sub-page, and with vmemmap
6824 * optimizations the page struct may be read only.
6825 * try_grab_page() will increase the ref count on the
6826 * head page, so this will be OK.
6827 *
6828 * try_grab_page() should always be able to get the page here,
6829 * because we hold the ptl lock and have verified pte_present().
6830 */
6831 ret = try_grab_page(page, flags);
6832
6833 if (WARN_ON_ONCE(ret)) {
6834 page = ERR_PTR(ret);
6835 goto out;
6836 }
6837
6838 *page_mask = (1U << huge_page_order(h)) - 1;
6839 }
6840out:
6841 spin_unlock(ptl);
6842out_unlock:
6843 hugetlb_vma_unlock_read(vma);
6844
6845 /*
6846 * Fixup retval for dump requests: if pagecache doesn't exist,
6847 * don't try to allocate a new page but just skip it.
6848 */
6849 if (!page && (flags & FOLL_DUMP) &&
6850 !hugetlbfs_pagecache_present(h, vma, address))
6851 page = ERR_PTR(-EFAULT);
6852
6853 return page;
6854}
6855
6856long hugetlb_change_protection(struct vm_area_struct *vma,
6857 unsigned long address, unsigned long end,
6858 pgprot_t newprot, unsigned long cp_flags)
6859{
6860 struct mm_struct *mm = vma->vm_mm;
6861 unsigned long start = address;
6862 pte_t *ptep;
6863 pte_t pte;
6864 struct hstate *h = hstate_vma(vma);
6865 long pages = 0, psize = huge_page_size(h);
6866 bool shared_pmd = false;
6867 struct mmu_notifier_range range;
6868 unsigned long last_addr_mask;
6869 bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
6870 bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
6871
6872 /*
6873 * In the case of shared PMDs, the area to flush could be beyond
6874 * start/end. Set range.start/range.end to cover the maximum possible
6875 * range if PMD sharing is possible.
6876 */
6877 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
6878 0, mm, start, end);
6879 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
6880
6881 BUG_ON(address >= end);
6882 flush_cache_range(vma, range.start, range.end);
6883
6884 mmu_notifier_invalidate_range_start(&range);
6885 hugetlb_vma_lock_write(vma);
6886 i_mmap_lock_write(vma->vm_file->f_mapping);
6887 last_addr_mask = hugetlb_mask_last_page(h);
6888 for (; address < end; address += psize) {
6889 spinlock_t *ptl;
6890 ptep = hugetlb_walk(vma, address, psize);
6891 if (!ptep) {
6892 if (!uffd_wp) {
6893 address |= last_addr_mask;
6894 continue;
6895 }
6896 /*
6897 * Userfaultfd wr-protect requires pgtable
6898 * pre-allocations to install pte markers.
6899 */
6900 ptep = huge_pte_alloc(mm, vma, address, psize);
6901 if (!ptep) {
6902 pages = -ENOMEM;
6903 break;
6904 }
6905 }
6906 ptl = huge_pte_lock(h, mm, ptep);
6907 if (huge_pmd_unshare(mm, vma, address, ptep)) {
6908 /*
6909 * When uffd-wp is enabled on the vma, unshare
6910 * shouldn't happen at all. Warn about it if it
6911 * happened due to some reason.
6912 */
6913 WARN_ON_ONCE(uffd_wp || uffd_wp_resolve);
6914 pages++;
6915 spin_unlock(ptl);
6916 shared_pmd = true;
6917 address |= last_addr_mask;
6918 continue;
6919 }
6920 pte = huge_ptep_get(ptep);
6921 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
6922 /* Nothing to do. */
6923 } else if (unlikely(is_hugetlb_entry_migration(pte))) {
6924 swp_entry_t entry = pte_to_swp_entry(pte);
6925 struct page *page = pfn_swap_entry_to_page(entry);
6926 pte_t newpte = pte;
6927
6928 if (is_writable_migration_entry(entry)) {
6929 if (PageAnon(page))
6930 entry = make_readable_exclusive_migration_entry(
6931 swp_offset(entry));
6932 else
6933 entry = make_readable_migration_entry(
6934 swp_offset(entry));
6935 newpte = swp_entry_to_pte(entry);
6936 pages++;
6937 }
6938
6939 if (uffd_wp)
6940 newpte = pte_swp_mkuffd_wp(newpte);
6941 else if (uffd_wp_resolve)
6942 newpte = pte_swp_clear_uffd_wp(newpte);
6943 if (!pte_same(pte, newpte))
6944 set_huge_pte_at(mm, address, ptep, newpte, psize);
6945 } else if (unlikely(is_pte_marker(pte))) {
6946 /* No other markers apply for now. */
6947 WARN_ON_ONCE(!pte_marker_uffd_wp(pte));
6948 if (uffd_wp_resolve)
6949 /* Safe to modify directly (non-present->none). */
6950 huge_pte_clear(mm, address, ptep, psize);
6951 } else if (!huge_pte_none(pte)) {
6952 pte_t old_pte;
6953 unsigned int shift = huge_page_shift(hstate_vma(vma));
6954
6955 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
6956 pte = huge_pte_modify(old_pte, newprot);
6957 pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
6958 if (uffd_wp)
6959 pte = huge_pte_mkuffd_wp(pte);
6960 else if (uffd_wp_resolve)
6961 pte = huge_pte_clear_uffd_wp(pte);
6962 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
6963 pages++;
6964 } else {
6965 /* None pte */
6966 if (unlikely(uffd_wp))
6967 /* Safe to modify directly (none->non-present). */
6968 set_huge_pte_at(mm, address, ptep,
6969 make_pte_marker(PTE_MARKER_UFFD_WP),
6970 psize);
6971 }
6972 spin_unlock(ptl);
6973 }
6974 /*
6975 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
6976 * may have cleared our pud entry and done put_page on the page table:
6977 * once we release i_mmap_rwsem, another task can do the final put_page
6978 * and that page table be reused and filled with junk. If we actually
6979 * did unshare a page of pmds, flush the range corresponding to the pud.
6980 */
6981 if (shared_pmd)
6982 flush_hugetlb_tlb_range(vma, range.start, range.end);
6983 else
6984 flush_hugetlb_tlb_range(vma, start, end);
6985 /*
6986 * No need to call mmu_notifier_arch_invalidate_secondary_tlbs() we are
6987 * downgrading page table protection not changing it to point to a new
6988 * page.
6989 *
6990 * See Documentation/mm/mmu_notifier.rst
6991 */
6992 i_mmap_unlock_write(vma->vm_file->f_mapping);
6993 hugetlb_vma_unlock_write(vma);
6994 mmu_notifier_invalidate_range_end(&range);
6995
6996 return pages > 0 ? (pages << h->order) : pages;
6997}
6998
6999/* Return true if reservation was successful, false otherwise. */
7000bool hugetlb_reserve_pages(struct inode *inode,
7001 long from, long to,
7002 struct vm_area_struct *vma,
7003 vm_flags_t vm_flags)
7004{
7005 long chg = -1, add = -1;
7006 struct hstate *h = hstate_inode(inode);
7007 struct hugepage_subpool *spool = subpool_inode(inode);
7008 struct resv_map *resv_map;
7009 struct hugetlb_cgroup *h_cg = NULL;
7010 long gbl_reserve, regions_needed = 0;
7011
7012 /* This should never happen */
7013 if (from > to) {
7014 VM_WARN(1, "%s called with a negative range\n", __func__);
7015 return false;
7016 }
7017
7018 /*
7019 * vma specific semaphore used for pmd sharing and fault/truncation
7020 * synchronization
7021 */
7022 hugetlb_vma_lock_alloc(vma);
7023
7024 /*
7025 * Only apply hugepage reservation if asked. At fault time, an
7026 * attempt will be made for VM_NORESERVE to allocate a page
7027 * without using reserves
7028 */
7029 if (vm_flags & VM_NORESERVE)
7030 return true;
7031
7032 /*
7033 * Shared mappings base their reservation on the number of pages that
7034 * are already allocated on behalf of the file. Private mappings need
7035 * to reserve the full area even if read-only as mprotect() may be
7036 * called to make the mapping read-write. Assume !vma is a shm mapping
7037 */
7038 if (!vma || vma->vm_flags & VM_MAYSHARE) {
7039 /*
7040 * resv_map can not be NULL as hugetlb_reserve_pages is only
7041 * called for inodes for which resv_maps were created (see
7042 * hugetlbfs_get_inode).
7043 */
7044 resv_map = inode_resv_map(inode);
7045
7046 chg = region_chg(resv_map, from, to, ®ions_needed);
7047 } else {
7048 /* Private mapping. */
7049 resv_map = resv_map_alloc();
7050 if (!resv_map)
7051 goto out_err;
7052
7053 chg = to - from;
7054
7055 set_vma_resv_map(vma, resv_map);
7056 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
7057 }
7058
7059 if (chg < 0)
7060 goto out_err;
7061
7062 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
7063 chg * pages_per_huge_page(h), &h_cg) < 0)
7064 goto out_err;
7065
7066 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
7067 /* For private mappings, the hugetlb_cgroup uncharge info hangs
7068 * of the resv_map.
7069 */
7070 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
7071 }
7072
7073 /*
7074 * There must be enough pages in the subpool for the mapping. If
7075 * the subpool has a minimum size, there may be some global
7076 * reservations already in place (gbl_reserve).
7077 */
7078 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
7079 if (gbl_reserve < 0)
7080 goto out_uncharge_cgroup;
7081
7082 /*
7083 * Check enough hugepages are available for the reservation.
7084 * Hand the pages back to the subpool if there are not
7085 */
7086 if (hugetlb_acct_memory(h, gbl_reserve) < 0)
7087 goto out_put_pages;
7088
7089 /*
7090 * Account for the reservations made. Shared mappings record regions
7091 * that have reservations as they are shared by multiple VMAs.
7092 * When the last VMA disappears, the region map says how much
7093 * the reservation was and the page cache tells how much of
7094 * the reservation was consumed. Private mappings are per-VMA and
7095 * only the consumed reservations are tracked. When the VMA
7096 * disappears, the original reservation is the VMA size and the
7097 * consumed reservations are stored in the map. Hence, nothing
7098 * else has to be done for private mappings here
7099 */
7100 if (!vma || vma->vm_flags & VM_MAYSHARE) {
7101 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
7102
7103 if (unlikely(add < 0)) {
7104 hugetlb_acct_memory(h, -gbl_reserve);
7105 goto out_put_pages;
7106 } else if (unlikely(chg > add)) {
7107 /*
7108 * pages in this range were added to the reserve
7109 * map between region_chg and region_add. This
7110 * indicates a race with alloc_hugetlb_folio. Adjust
7111 * the subpool and reserve counts modified above
7112 * based on the difference.
7113 */
7114 long rsv_adjust;
7115
7116 /*
7117 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
7118 * reference to h_cg->css. See comment below for detail.
7119 */
7120 hugetlb_cgroup_uncharge_cgroup_rsvd(
7121 hstate_index(h),
7122 (chg - add) * pages_per_huge_page(h), h_cg);
7123
7124 rsv_adjust = hugepage_subpool_put_pages(spool,
7125 chg - add);
7126 hugetlb_acct_memory(h, -rsv_adjust);
7127 } else if (h_cg) {
7128 /*
7129 * The file_regions will hold their own reference to
7130 * h_cg->css. So we should release the reference held
7131 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
7132 * done.
7133 */
7134 hugetlb_cgroup_put_rsvd_cgroup(h_cg);
7135 }
7136 }
7137 return true;
7138
7139out_put_pages:
7140 /* put back original number of pages, chg */
7141 (void)hugepage_subpool_put_pages(spool, chg);
7142out_uncharge_cgroup:
7143 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
7144 chg * pages_per_huge_page(h), h_cg);
7145out_err:
7146 hugetlb_vma_lock_free(vma);
7147 if (!vma || vma->vm_flags & VM_MAYSHARE)
7148 /* Only call region_abort if the region_chg succeeded but the
7149 * region_add failed or didn't run.
7150 */
7151 if (chg >= 0 && add < 0)
7152 region_abort(resv_map, from, to, regions_needed);
7153 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
7154 kref_put(&resv_map->refs, resv_map_release);
7155 set_vma_resv_map(vma, NULL);
7156 }
7157 return false;
7158}
7159
7160long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
7161 long freed)
7162{
7163 struct hstate *h = hstate_inode(inode);
7164 struct resv_map *resv_map = inode_resv_map(inode);
7165 long chg = 0;
7166 struct hugepage_subpool *spool = subpool_inode(inode);
7167 long gbl_reserve;
7168
7169 /*
7170 * Since this routine can be called in the evict inode path for all
7171 * hugetlbfs inodes, resv_map could be NULL.
7172 */
7173 if (resv_map) {
7174 chg = region_del(resv_map, start, end);
7175 /*
7176 * region_del() can fail in the rare case where a region
7177 * must be split and another region descriptor can not be
7178 * allocated. If end == LONG_MAX, it will not fail.
7179 */
7180 if (chg < 0)
7181 return chg;
7182 }
7183
7184 spin_lock(&inode->i_lock);
7185 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
7186 spin_unlock(&inode->i_lock);
7187
7188 /*
7189 * If the subpool has a minimum size, the number of global
7190 * reservations to be released may be adjusted.
7191 *
7192 * Note that !resv_map implies freed == 0. So (chg - freed)
7193 * won't go negative.
7194 */
7195 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
7196 hugetlb_acct_memory(h, -gbl_reserve);
7197
7198 return 0;
7199}
7200
7201#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
7202static unsigned long page_table_shareable(struct vm_area_struct *svma,
7203 struct vm_area_struct *vma,
7204 unsigned long addr, pgoff_t idx)
7205{
7206 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
7207 svma->vm_start;
7208 unsigned long sbase = saddr & PUD_MASK;
7209 unsigned long s_end = sbase + PUD_SIZE;
7210
7211 /* Allow segments to share if only one is marked locked */
7212 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED_MASK;
7213 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED_MASK;
7214
7215 /*
7216 * match the virtual addresses, permission and the alignment of the
7217 * page table page.
7218 *
7219 * Also, vma_lock (vm_private_data) is required for sharing.
7220 */
7221 if (pmd_index(addr) != pmd_index(saddr) ||
7222 vm_flags != svm_flags ||
7223 !range_in_vma(svma, sbase, s_end) ||
7224 !svma->vm_private_data)
7225 return 0;
7226
7227 return saddr;
7228}
7229
7230bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
7231{
7232 unsigned long start = addr & PUD_MASK;
7233 unsigned long end = start + PUD_SIZE;
7234
7235#ifdef CONFIG_USERFAULTFD
7236 if (uffd_disable_huge_pmd_share(vma))
7237 return false;
7238#endif
7239 /*
7240 * check on proper vm_flags and page table alignment
7241 */
7242 if (!(vma->vm_flags & VM_MAYSHARE))
7243 return false;
7244 if (!vma->vm_private_data) /* vma lock required for sharing */
7245 return false;
7246 if (!range_in_vma(vma, start, end))
7247 return false;
7248 return true;
7249}
7250
7251/*
7252 * Determine if start,end range within vma could be mapped by shared pmd.
7253 * If yes, adjust start and end to cover range associated with possible
7254 * shared pmd mappings.
7255 */
7256void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
7257 unsigned long *start, unsigned long *end)
7258{
7259 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
7260 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
7261
7262 /*
7263 * vma needs to span at least one aligned PUD size, and the range
7264 * must be at least partially within in.
7265 */
7266 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
7267 (*end <= v_start) || (*start >= v_end))
7268 return;
7269
7270 /* Extend the range to be PUD aligned for a worst case scenario */
7271 if (*start > v_start)
7272 *start = ALIGN_DOWN(*start, PUD_SIZE);
7273
7274 if (*end < v_end)
7275 *end = ALIGN(*end, PUD_SIZE);
7276}
7277
7278/*
7279 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
7280 * and returns the corresponding pte. While this is not necessary for the
7281 * !shared pmd case because we can allocate the pmd later as well, it makes the
7282 * code much cleaner. pmd allocation is essential for the shared case because
7283 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
7284 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
7285 * bad pmd for sharing.
7286 */
7287pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
7288 unsigned long addr, pud_t *pud)
7289{
7290 struct address_space *mapping = vma->vm_file->f_mapping;
7291 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
7292 vma->vm_pgoff;
7293 struct vm_area_struct *svma;
7294 unsigned long saddr;
7295 pte_t *spte = NULL;
7296 pte_t *pte;
7297
7298 i_mmap_lock_read(mapping);
7299 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
7300 if (svma == vma)
7301 continue;
7302
7303 saddr = page_table_shareable(svma, vma, addr, idx);
7304 if (saddr) {
7305 spte = hugetlb_walk(svma, saddr,
7306 vma_mmu_pagesize(svma));
7307 if (spte) {
7308 get_page(virt_to_page(spte));
7309 break;
7310 }
7311 }
7312 }
7313
7314 if (!spte)
7315 goto out;
7316
7317 spin_lock(&mm->page_table_lock);
7318 if (pud_none(*pud)) {
7319 pud_populate(mm, pud,
7320 (pmd_t *)((unsigned long)spte & PAGE_MASK));
7321 mm_inc_nr_pmds(mm);
7322 } else {
7323 put_page(virt_to_page(spte));
7324 }
7325 spin_unlock(&mm->page_table_lock);
7326out:
7327 pte = (pte_t *)pmd_alloc(mm, pud, addr);
7328 i_mmap_unlock_read(mapping);
7329 return pte;
7330}
7331
7332/*
7333 * unmap huge page backed by shared pte.
7334 *
7335 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
7336 * indicated by page_count > 1, unmap is achieved by clearing pud and
7337 * decrementing the ref count. If count == 1, the pte page is not shared.
7338 *
7339 * Called with page table lock held.
7340 *
7341 * returns: 1 successfully unmapped a shared pte page
7342 * 0 the underlying pte page is not shared, or it is the last user
7343 */
7344int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
7345 unsigned long addr, pte_t *ptep)
7346{
7347 pgd_t *pgd = pgd_offset(mm, addr);
7348 p4d_t *p4d = p4d_offset(pgd, addr);
7349 pud_t *pud = pud_offset(p4d, addr);
7350
7351 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
7352 hugetlb_vma_assert_locked(vma);
7353 BUG_ON(page_count(virt_to_page(ptep)) == 0);
7354 if (page_count(virt_to_page(ptep)) == 1)
7355 return 0;
7356
7357 pud_clear(pud);
7358 put_page(virt_to_page(ptep));
7359 mm_dec_nr_pmds(mm);
7360 return 1;
7361}
7362
7363#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
7364
7365pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
7366 unsigned long addr, pud_t *pud)
7367{
7368 return NULL;
7369}
7370
7371int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
7372 unsigned long addr, pte_t *ptep)
7373{
7374 return 0;
7375}
7376
7377void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
7378 unsigned long *start, unsigned long *end)
7379{
7380}
7381
7382bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
7383{
7384 return false;
7385}
7386#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
7387
7388#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
7389pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
7390 unsigned long addr, unsigned long sz)
7391{
7392 pgd_t *pgd;
7393 p4d_t *p4d;
7394 pud_t *pud;
7395 pte_t *pte = NULL;
7396
7397 pgd = pgd_offset(mm, addr);
7398 p4d = p4d_alloc(mm, pgd, addr);
7399 if (!p4d)
7400 return NULL;
7401 pud = pud_alloc(mm, p4d, addr);
7402 if (pud) {
7403 if (sz == PUD_SIZE) {
7404 pte = (pte_t *)pud;
7405 } else {
7406 BUG_ON(sz != PMD_SIZE);
7407 if (want_pmd_share(vma, addr) && pud_none(*pud))
7408 pte = huge_pmd_share(mm, vma, addr, pud);
7409 else
7410 pte = (pte_t *)pmd_alloc(mm, pud, addr);
7411 }
7412 }
7413
7414 if (pte) {
7415 pte_t pteval = ptep_get_lockless(pte);
7416
7417 BUG_ON(pte_present(pteval) && !pte_huge(pteval));
7418 }
7419
7420 return pte;
7421}
7422
7423/*
7424 * huge_pte_offset() - Walk the page table to resolve the hugepage
7425 * entry at address @addr
7426 *
7427 * Return: Pointer to page table entry (PUD or PMD) for
7428 * address @addr, or NULL if a !p*d_present() entry is encountered and the
7429 * size @sz doesn't match the hugepage size at this level of the page
7430 * table.
7431 */
7432pte_t *huge_pte_offset(struct mm_struct *mm,
7433 unsigned long addr, unsigned long sz)
7434{
7435 pgd_t *pgd;
7436 p4d_t *p4d;
7437 pud_t *pud;
7438 pmd_t *pmd;
7439
7440 pgd = pgd_offset(mm, addr);
7441 if (!pgd_present(*pgd))
7442 return NULL;
7443 p4d = p4d_offset(pgd, addr);
7444 if (!p4d_present(*p4d))
7445 return NULL;
7446
7447 pud = pud_offset(p4d, addr);
7448 if (sz == PUD_SIZE)
7449 /* must be pud huge, non-present or none */
7450 return (pte_t *)pud;
7451 if (!pud_present(*pud))
7452 return NULL;
7453 /* must have a valid entry and size to go further */
7454
7455 pmd = pmd_offset(pud, addr);
7456 /* must be pmd huge, non-present or none */
7457 return (pte_t *)pmd;
7458}
7459
7460/*
7461 * Return a mask that can be used to update an address to the last huge
7462 * page in a page table page mapping size. Used to skip non-present
7463 * page table entries when linearly scanning address ranges. Architectures
7464 * with unique huge page to page table relationships can define their own
7465 * version of this routine.
7466 */
7467unsigned long hugetlb_mask_last_page(struct hstate *h)
7468{
7469 unsigned long hp_size = huge_page_size(h);
7470
7471 if (hp_size == PUD_SIZE)
7472 return P4D_SIZE - PUD_SIZE;
7473 else if (hp_size == PMD_SIZE)
7474 return PUD_SIZE - PMD_SIZE;
7475 else
7476 return 0UL;
7477}
7478
7479#else
7480
7481/* See description above. Architectures can provide their own version. */
7482__weak unsigned long hugetlb_mask_last_page(struct hstate *h)
7483{
7484#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
7485 if (huge_page_size(h) == PMD_SIZE)
7486 return PUD_SIZE - PMD_SIZE;
7487#endif
7488 return 0UL;
7489}
7490
7491#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
7492
7493/*
7494 * These functions are overwritable if your architecture needs its own
7495 * behavior.
7496 */
7497bool isolate_hugetlb(struct folio *folio, struct list_head *list)
7498{
7499 bool ret = true;
7500
7501 spin_lock_irq(&hugetlb_lock);
7502 if (!folio_test_hugetlb(folio) ||
7503 !folio_test_hugetlb_migratable(folio) ||
7504 !folio_try_get(folio)) {
7505 ret = false;
7506 goto unlock;
7507 }
7508 folio_clear_hugetlb_migratable(folio);
7509 list_move_tail(&folio->lru, list);
7510unlock:
7511 spin_unlock_irq(&hugetlb_lock);
7512 return ret;
7513}
7514
7515int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison)
7516{
7517 int ret = 0;
7518
7519 *hugetlb = false;
7520 spin_lock_irq(&hugetlb_lock);
7521 if (folio_test_hugetlb(folio)) {
7522 *hugetlb = true;
7523 if (folio_test_hugetlb_freed(folio))
7524 ret = 0;
7525 else if (folio_test_hugetlb_migratable(folio) || unpoison)
7526 ret = folio_try_get(folio);
7527 else
7528 ret = -EBUSY;
7529 }
7530 spin_unlock_irq(&hugetlb_lock);
7531 return ret;
7532}
7533
7534int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
7535 bool *migratable_cleared)
7536{
7537 int ret;
7538
7539 spin_lock_irq(&hugetlb_lock);
7540 ret = __get_huge_page_for_hwpoison(pfn, flags, migratable_cleared);
7541 spin_unlock_irq(&hugetlb_lock);
7542 return ret;
7543}
7544
7545void folio_putback_active_hugetlb(struct folio *folio)
7546{
7547 spin_lock_irq(&hugetlb_lock);
7548 folio_set_hugetlb_migratable(folio);
7549 list_move_tail(&folio->lru, &(folio_hstate(folio))->hugepage_activelist);
7550 spin_unlock_irq(&hugetlb_lock);
7551 folio_put(folio);
7552}
7553
7554void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason)
7555{
7556 struct hstate *h = folio_hstate(old_folio);
7557
7558 hugetlb_cgroup_migrate(old_folio, new_folio);
7559 set_page_owner_migrate_reason(&new_folio->page, reason);
7560
7561 /*
7562 * transfer temporary state of the new hugetlb folio. This is
7563 * reverse to other transitions because the newpage is going to
7564 * be final while the old one will be freed so it takes over
7565 * the temporary status.
7566 *
7567 * Also note that we have to transfer the per-node surplus state
7568 * here as well otherwise the global surplus count will not match
7569 * the per-node's.
7570 */
7571 if (folio_test_hugetlb_temporary(new_folio)) {
7572 int old_nid = folio_nid(old_folio);
7573 int new_nid = folio_nid(new_folio);
7574
7575 folio_set_hugetlb_temporary(old_folio);
7576 folio_clear_hugetlb_temporary(new_folio);
7577
7578
7579 /*
7580 * There is no need to transfer the per-node surplus state
7581 * when we do not cross the node.
7582 */
7583 if (new_nid == old_nid)
7584 return;
7585 spin_lock_irq(&hugetlb_lock);
7586 if (h->surplus_huge_pages_node[old_nid]) {
7587 h->surplus_huge_pages_node[old_nid]--;
7588 h->surplus_huge_pages_node[new_nid]++;
7589 }
7590 spin_unlock_irq(&hugetlb_lock);
7591 }
7592}
7593
7594static void hugetlb_unshare_pmds(struct vm_area_struct *vma,
7595 unsigned long start,
7596 unsigned long end)
7597{
7598 struct hstate *h = hstate_vma(vma);
7599 unsigned long sz = huge_page_size(h);
7600 struct mm_struct *mm = vma->vm_mm;
7601 struct mmu_notifier_range range;
7602 unsigned long address;
7603 spinlock_t *ptl;
7604 pte_t *ptep;
7605
7606 if (!(vma->vm_flags & VM_MAYSHARE))
7607 return;
7608
7609 if (start >= end)
7610 return;
7611
7612 flush_cache_range(vma, start, end);
7613 /*
7614 * No need to call adjust_range_if_pmd_sharing_possible(), because
7615 * we have already done the PUD_SIZE alignment.
7616 */
7617 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm,
7618 start, end);
7619 mmu_notifier_invalidate_range_start(&range);
7620 hugetlb_vma_lock_write(vma);
7621 i_mmap_lock_write(vma->vm_file->f_mapping);
7622 for (address = start; address < end; address += PUD_SIZE) {
7623 ptep = hugetlb_walk(vma, address, sz);
7624 if (!ptep)
7625 continue;
7626 ptl = huge_pte_lock(h, mm, ptep);
7627 huge_pmd_unshare(mm, vma, address, ptep);
7628 spin_unlock(ptl);
7629 }
7630 flush_hugetlb_tlb_range(vma, start, end);
7631 i_mmap_unlock_write(vma->vm_file->f_mapping);
7632 hugetlb_vma_unlock_write(vma);
7633 /*
7634 * No need to call mmu_notifier_arch_invalidate_secondary_tlbs(), see
7635 * Documentation/mm/mmu_notifier.rst.
7636 */
7637 mmu_notifier_invalidate_range_end(&range);
7638}
7639
7640/*
7641 * This function will unconditionally remove all the shared pmd pgtable entries
7642 * within the specific vma for a hugetlbfs memory range.
7643 */
7644void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
7645{
7646 hugetlb_unshare_pmds(vma, ALIGN(vma->vm_start, PUD_SIZE),
7647 ALIGN_DOWN(vma->vm_end, PUD_SIZE));
7648}
7649
7650#ifdef CONFIG_CMA
7651static bool cma_reserve_called __initdata;
7652
7653static int __init cmdline_parse_hugetlb_cma(char *p)
7654{
7655 int nid, count = 0;
7656 unsigned long tmp;
7657 char *s = p;
7658
7659 while (*s) {
7660 if (sscanf(s, "%lu%n", &tmp, &count) != 1)
7661 break;
7662
7663 if (s[count] == ':') {
7664 if (tmp >= MAX_NUMNODES)
7665 break;
7666 nid = array_index_nospec(tmp, MAX_NUMNODES);
7667
7668 s += count + 1;
7669 tmp = memparse(s, &s);
7670 hugetlb_cma_size_in_node[nid] = tmp;
7671 hugetlb_cma_size += tmp;
7672
7673 /*
7674 * Skip the separator if have one, otherwise
7675 * break the parsing.
7676 */
7677 if (*s == ',')
7678 s++;
7679 else
7680 break;
7681 } else {
7682 hugetlb_cma_size = memparse(p, &p);
7683 break;
7684 }
7685 }
7686
7687 return 0;
7688}
7689
7690early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
7691
7692void __init hugetlb_cma_reserve(int order)
7693{
7694 unsigned long size, reserved, per_node;
7695 bool node_specific_cma_alloc = false;
7696 int nid;
7697
7698 cma_reserve_called = true;
7699
7700 if (!hugetlb_cma_size)
7701 return;
7702
7703 for (nid = 0; nid < MAX_NUMNODES; nid++) {
7704 if (hugetlb_cma_size_in_node[nid] == 0)
7705 continue;
7706
7707 if (!node_online(nid)) {
7708 pr_warn("hugetlb_cma: invalid node %d specified\n", nid);
7709 hugetlb_cma_size -= hugetlb_cma_size_in_node[nid];
7710 hugetlb_cma_size_in_node[nid] = 0;
7711 continue;
7712 }
7713
7714 if (hugetlb_cma_size_in_node[nid] < (PAGE_SIZE << order)) {
7715 pr_warn("hugetlb_cma: cma area of node %d should be at least %lu MiB\n",
7716 nid, (PAGE_SIZE << order) / SZ_1M);
7717 hugetlb_cma_size -= hugetlb_cma_size_in_node[nid];
7718 hugetlb_cma_size_in_node[nid] = 0;
7719 } else {
7720 node_specific_cma_alloc = true;
7721 }
7722 }
7723
7724 /* Validate the CMA size again in case some invalid nodes specified. */
7725 if (!hugetlb_cma_size)
7726 return;
7727
7728 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
7729 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
7730 (PAGE_SIZE << order) / SZ_1M);
7731 hugetlb_cma_size = 0;
7732 return;
7733 }
7734
7735 if (!node_specific_cma_alloc) {
7736 /*
7737 * If 3 GB area is requested on a machine with 4 numa nodes,
7738 * let's allocate 1 GB on first three nodes and ignore the last one.
7739 */
7740 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
7741 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
7742 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
7743 }
7744
7745 reserved = 0;
7746 for_each_online_node(nid) {
7747 int res;
7748 char name[CMA_MAX_NAME];
7749
7750 if (node_specific_cma_alloc) {
7751 if (hugetlb_cma_size_in_node[nid] == 0)
7752 continue;
7753
7754 size = hugetlb_cma_size_in_node[nid];
7755 } else {
7756 size = min(per_node, hugetlb_cma_size - reserved);
7757 }
7758
7759 size = round_up(size, PAGE_SIZE << order);
7760
7761 snprintf(name, sizeof(name), "hugetlb%d", nid);
7762 /*
7763 * Note that 'order per bit' is based on smallest size that
7764 * may be returned to CMA allocator in the case of
7765 * huge page demotion.
7766 */
7767 res = cma_declare_contiguous_nid(0, size, 0,
7768 PAGE_SIZE << HUGETLB_PAGE_ORDER,
7769 0, false, name,
7770 &hugetlb_cma[nid], nid);
7771 if (res) {
7772 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
7773 res, nid);
7774 continue;
7775 }
7776
7777 reserved += size;
7778 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
7779 size / SZ_1M, nid);
7780
7781 if (reserved >= hugetlb_cma_size)
7782 break;
7783 }
7784
7785 if (!reserved)
7786 /*
7787 * hugetlb_cma_size is used to determine if allocations from
7788 * cma are possible. Set to zero if no cma regions are set up.
7789 */
7790 hugetlb_cma_size = 0;
7791}
7792
7793static void __init hugetlb_cma_check(void)
7794{
7795 if (!hugetlb_cma_size || cma_reserve_called)
7796 return;
7797
7798 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
7799}
7800
7801#endif /* CONFIG_CMA */
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic hugetlb support.
4 * (C) Nadia Yvette Chambers, April 2004
5 */
6#include <linux/list.h>
7#include <linux/init.h>
8#include <linux/mm.h>
9#include <linux/seq_file.h>
10#include <linux/sysctl.h>
11#include <linux/highmem.h>
12#include <linux/mmu_notifier.h>
13#include <linux/nodemask.h>
14#include <linux/pagemap.h>
15#include <linux/mempolicy.h>
16#include <linux/compiler.h>
17#include <linux/cpuset.h>
18#include <linux/mutex.h>
19#include <linux/memblock.h>
20#include <linux/sysfs.h>
21#include <linux/slab.h>
22#include <linux/sched/mm.h>
23#include <linux/mmdebug.h>
24#include <linux/sched/signal.h>
25#include <linux/rmap.h>
26#include <linux/string_helpers.h>
27#include <linux/swap.h>
28#include <linux/swapops.h>
29#include <linux/jhash.h>
30#include <linux/numa.h>
31#include <linux/llist.h>
32#include <linux/cma.h>
33#include <linux/migrate.h>
34#include <linux/nospec.h>
35#include <linux/delayacct.h>
36#include <linux/memory.h>
37#include <linux/mm_inline.h>
38#include <linux/padata.h>
39
40#include <asm/page.h>
41#include <asm/pgalloc.h>
42#include <asm/tlb.h>
43
44#include <linux/io.h>
45#include <linux/hugetlb.h>
46#include <linux/hugetlb_cgroup.h>
47#include <linux/node.h>
48#include <linux/page_owner.h>
49#include "internal.h"
50#include "hugetlb_vmemmap.h"
51
52int hugetlb_max_hstate __read_mostly;
53unsigned int default_hstate_idx;
54struct hstate hstates[HUGE_MAX_HSTATE];
55
56#ifdef CONFIG_CMA
57static struct cma *hugetlb_cma[MAX_NUMNODES];
58static unsigned long hugetlb_cma_size_in_node[MAX_NUMNODES] __initdata;
59static bool hugetlb_cma_folio(struct folio *folio, unsigned int order)
60{
61 return cma_pages_valid(hugetlb_cma[folio_nid(folio)], &folio->page,
62 1 << order);
63}
64#else
65static bool hugetlb_cma_folio(struct folio *folio, unsigned int order)
66{
67 return false;
68}
69#endif
70static unsigned long hugetlb_cma_size __initdata;
71
72__initdata struct list_head huge_boot_pages[MAX_NUMNODES];
73
74/* for command line parsing */
75static struct hstate * __initdata parsed_hstate;
76static unsigned long __initdata default_hstate_max_huge_pages;
77static bool __initdata parsed_valid_hugepagesz = true;
78static bool __initdata parsed_default_hugepagesz;
79static unsigned int default_hugepages_in_node[MAX_NUMNODES] __initdata;
80
81/*
82 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
83 * free_huge_pages, and surplus_huge_pages.
84 */
85DEFINE_SPINLOCK(hugetlb_lock);
86
87/*
88 * Serializes faults on the same logical page. This is used to
89 * prevent spurious OOMs when the hugepage pool is fully utilized.
90 */
91static int num_fault_mutexes;
92struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
93
94/* Forward declaration */
95static int hugetlb_acct_memory(struct hstate *h, long delta);
96static void hugetlb_vma_lock_free(struct vm_area_struct *vma);
97static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma);
98static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma);
99static void hugetlb_unshare_pmds(struct vm_area_struct *vma,
100 unsigned long start, unsigned long end);
101static struct resv_map *vma_resv_map(struct vm_area_struct *vma);
102
103static inline bool subpool_is_free(struct hugepage_subpool *spool)
104{
105 if (spool->count)
106 return false;
107 if (spool->max_hpages != -1)
108 return spool->used_hpages == 0;
109 if (spool->min_hpages != -1)
110 return spool->rsv_hpages == spool->min_hpages;
111
112 return true;
113}
114
115static inline void unlock_or_release_subpool(struct hugepage_subpool *spool,
116 unsigned long irq_flags)
117{
118 spin_unlock_irqrestore(&spool->lock, irq_flags);
119
120 /* If no pages are used, and no other handles to the subpool
121 * remain, give up any reservations based on minimum size and
122 * free the subpool */
123 if (subpool_is_free(spool)) {
124 if (spool->min_hpages != -1)
125 hugetlb_acct_memory(spool->hstate,
126 -spool->min_hpages);
127 kfree(spool);
128 }
129}
130
131struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
132 long min_hpages)
133{
134 struct hugepage_subpool *spool;
135
136 spool = kzalloc(sizeof(*spool), GFP_KERNEL);
137 if (!spool)
138 return NULL;
139
140 spin_lock_init(&spool->lock);
141 spool->count = 1;
142 spool->max_hpages = max_hpages;
143 spool->hstate = h;
144 spool->min_hpages = min_hpages;
145
146 if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
147 kfree(spool);
148 return NULL;
149 }
150 spool->rsv_hpages = min_hpages;
151
152 return spool;
153}
154
155void hugepage_put_subpool(struct hugepage_subpool *spool)
156{
157 unsigned long flags;
158
159 spin_lock_irqsave(&spool->lock, flags);
160 BUG_ON(!spool->count);
161 spool->count--;
162 unlock_or_release_subpool(spool, flags);
163}
164
165/*
166 * Subpool accounting for allocating and reserving pages.
167 * Return -ENOMEM if there are not enough resources to satisfy the
168 * request. Otherwise, return the number of pages by which the
169 * global pools must be adjusted (upward). The returned value may
170 * only be different than the passed value (delta) in the case where
171 * a subpool minimum size must be maintained.
172 */
173static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
174 long delta)
175{
176 long ret = delta;
177
178 if (!spool)
179 return ret;
180
181 spin_lock_irq(&spool->lock);
182
183 if (spool->max_hpages != -1) { /* maximum size accounting */
184 if ((spool->used_hpages + delta) <= spool->max_hpages)
185 spool->used_hpages += delta;
186 else {
187 ret = -ENOMEM;
188 goto unlock_ret;
189 }
190 }
191
192 /* minimum size accounting */
193 if (spool->min_hpages != -1 && spool->rsv_hpages) {
194 if (delta > spool->rsv_hpages) {
195 /*
196 * Asking for more reserves than those already taken on
197 * behalf of subpool. Return difference.
198 */
199 ret = delta - spool->rsv_hpages;
200 spool->rsv_hpages = 0;
201 } else {
202 ret = 0; /* reserves already accounted for */
203 spool->rsv_hpages -= delta;
204 }
205 }
206
207unlock_ret:
208 spin_unlock_irq(&spool->lock);
209 return ret;
210}
211
212/*
213 * Subpool accounting for freeing and unreserving pages.
214 * Return the number of global page reservations that must be dropped.
215 * The return value may only be different than the passed value (delta)
216 * in the case where a subpool minimum size must be maintained.
217 */
218static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
219 long delta)
220{
221 long ret = delta;
222 unsigned long flags;
223
224 if (!spool)
225 return delta;
226
227 spin_lock_irqsave(&spool->lock, flags);
228
229 if (spool->max_hpages != -1) /* maximum size accounting */
230 spool->used_hpages -= delta;
231
232 /* minimum size accounting */
233 if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
234 if (spool->rsv_hpages + delta <= spool->min_hpages)
235 ret = 0;
236 else
237 ret = spool->rsv_hpages + delta - spool->min_hpages;
238
239 spool->rsv_hpages += delta;
240 if (spool->rsv_hpages > spool->min_hpages)
241 spool->rsv_hpages = spool->min_hpages;
242 }
243
244 /*
245 * If hugetlbfs_put_super couldn't free spool due to an outstanding
246 * quota reference, free it now.
247 */
248 unlock_or_release_subpool(spool, flags);
249
250 return ret;
251}
252
253static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
254{
255 return HUGETLBFS_SB(inode->i_sb)->spool;
256}
257
258static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
259{
260 return subpool_inode(file_inode(vma->vm_file));
261}
262
263/*
264 * hugetlb vma_lock helper routines
265 */
266void hugetlb_vma_lock_read(struct vm_area_struct *vma)
267{
268 if (__vma_shareable_lock(vma)) {
269 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
270
271 down_read(&vma_lock->rw_sema);
272 } else if (__vma_private_lock(vma)) {
273 struct resv_map *resv_map = vma_resv_map(vma);
274
275 down_read(&resv_map->rw_sema);
276 }
277}
278
279void hugetlb_vma_unlock_read(struct vm_area_struct *vma)
280{
281 if (__vma_shareable_lock(vma)) {
282 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
283
284 up_read(&vma_lock->rw_sema);
285 } else if (__vma_private_lock(vma)) {
286 struct resv_map *resv_map = vma_resv_map(vma);
287
288 up_read(&resv_map->rw_sema);
289 }
290}
291
292void hugetlb_vma_lock_write(struct vm_area_struct *vma)
293{
294 if (__vma_shareable_lock(vma)) {
295 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
296
297 down_write(&vma_lock->rw_sema);
298 } else if (__vma_private_lock(vma)) {
299 struct resv_map *resv_map = vma_resv_map(vma);
300
301 down_write(&resv_map->rw_sema);
302 }
303}
304
305void hugetlb_vma_unlock_write(struct vm_area_struct *vma)
306{
307 if (__vma_shareable_lock(vma)) {
308 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
309
310 up_write(&vma_lock->rw_sema);
311 } else if (__vma_private_lock(vma)) {
312 struct resv_map *resv_map = vma_resv_map(vma);
313
314 up_write(&resv_map->rw_sema);
315 }
316}
317
318int hugetlb_vma_trylock_write(struct vm_area_struct *vma)
319{
320
321 if (__vma_shareable_lock(vma)) {
322 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
323
324 return down_write_trylock(&vma_lock->rw_sema);
325 } else if (__vma_private_lock(vma)) {
326 struct resv_map *resv_map = vma_resv_map(vma);
327
328 return down_write_trylock(&resv_map->rw_sema);
329 }
330
331 return 1;
332}
333
334void hugetlb_vma_assert_locked(struct vm_area_struct *vma)
335{
336 if (__vma_shareable_lock(vma)) {
337 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
338
339 lockdep_assert_held(&vma_lock->rw_sema);
340 } else if (__vma_private_lock(vma)) {
341 struct resv_map *resv_map = vma_resv_map(vma);
342
343 lockdep_assert_held(&resv_map->rw_sema);
344 }
345}
346
347void hugetlb_vma_lock_release(struct kref *kref)
348{
349 struct hugetlb_vma_lock *vma_lock = container_of(kref,
350 struct hugetlb_vma_lock, refs);
351
352 kfree(vma_lock);
353}
354
355static void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock)
356{
357 struct vm_area_struct *vma = vma_lock->vma;
358
359 /*
360 * vma_lock structure may or not be released as a result of put,
361 * it certainly will no longer be attached to vma so clear pointer.
362 * Semaphore synchronizes access to vma_lock->vma field.
363 */
364 vma_lock->vma = NULL;
365 vma->vm_private_data = NULL;
366 up_write(&vma_lock->rw_sema);
367 kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
368}
369
370static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma)
371{
372 if (__vma_shareable_lock(vma)) {
373 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
374
375 __hugetlb_vma_unlock_write_put(vma_lock);
376 } else if (__vma_private_lock(vma)) {
377 struct resv_map *resv_map = vma_resv_map(vma);
378
379 /* no free for anon vmas, but still need to unlock */
380 up_write(&resv_map->rw_sema);
381 }
382}
383
384static void hugetlb_vma_lock_free(struct vm_area_struct *vma)
385{
386 /*
387 * Only present in sharable vmas.
388 */
389 if (!vma || !__vma_shareable_lock(vma))
390 return;
391
392 if (vma->vm_private_data) {
393 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
394
395 down_write(&vma_lock->rw_sema);
396 __hugetlb_vma_unlock_write_put(vma_lock);
397 }
398}
399
400static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma)
401{
402 struct hugetlb_vma_lock *vma_lock;
403
404 /* Only establish in (flags) sharable vmas */
405 if (!vma || !(vma->vm_flags & VM_MAYSHARE))
406 return;
407
408 /* Should never get here with non-NULL vm_private_data */
409 if (vma->vm_private_data)
410 return;
411
412 vma_lock = kmalloc(sizeof(*vma_lock), GFP_KERNEL);
413 if (!vma_lock) {
414 /*
415 * If we can not allocate structure, then vma can not
416 * participate in pmd sharing. This is only a possible
417 * performance enhancement and memory saving issue.
418 * However, the lock is also used to synchronize page
419 * faults with truncation. If the lock is not present,
420 * unlikely races could leave pages in a file past i_size
421 * until the file is removed. Warn in the unlikely case of
422 * allocation failure.
423 */
424 pr_warn_once("HugeTLB: unable to allocate vma specific lock\n");
425 return;
426 }
427
428 kref_init(&vma_lock->refs);
429 init_rwsem(&vma_lock->rw_sema);
430 vma_lock->vma = vma;
431 vma->vm_private_data = vma_lock;
432}
433
434/* Helper that removes a struct file_region from the resv_map cache and returns
435 * it for use.
436 */
437static struct file_region *
438get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
439{
440 struct file_region *nrg;
441
442 VM_BUG_ON(resv->region_cache_count <= 0);
443
444 resv->region_cache_count--;
445 nrg = list_first_entry(&resv->region_cache, struct file_region, link);
446 list_del(&nrg->link);
447
448 nrg->from = from;
449 nrg->to = to;
450
451 return nrg;
452}
453
454static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
455 struct file_region *rg)
456{
457#ifdef CONFIG_CGROUP_HUGETLB
458 nrg->reservation_counter = rg->reservation_counter;
459 nrg->css = rg->css;
460 if (rg->css)
461 css_get(rg->css);
462#endif
463}
464
465/* Helper that records hugetlb_cgroup uncharge info. */
466static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
467 struct hstate *h,
468 struct resv_map *resv,
469 struct file_region *nrg)
470{
471#ifdef CONFIG_CGROUP_HUGETLB
472 if (h_cg) {
473 nrg->reservation_counter =
474 &h_cg->rsvd_hugepage[hstate_index(h)];
475 nrg->css = &h_cg->css;
476 /*
477 * The caller will hold exactly one h_cg->css reference for the
478 * whole contiguous reservation region. But this area might be
479 * scattered when there are already some file_regions reside in
480 * it. As a result, many file_regions may share only one css
481 * reference. In order to ensure that one file_region must hold
482 * exactly one h_cg->css reference, we should do css_get for
483 * each file_region and leave the reference held by caller
484 * untouched.
485 */
486 css_get(&h_cg->css);
487 if (!resv->pages_per_hpage)
488 resv->pages_per_hpage = pages_per_huge_page(h);
489 /* pages_per_hpage should be the same for all entries in
490 * a resv_map.
491 */
492 VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
493 } else {
494 nrg->reservation_counter = NULL;
495 nrg->css = NULL;
496 }
497#endif
498}
499
500static void put_uncharge_info(struct file_region *rg)
501{
502#ifdef CONFIG_CGROUP_HUGETLB
503 if (rg->css)
504 css_put(rg->css);
505#endif
506}
507
508static bool has_same_uncharge_info(struct file_region *rg,
509 struct file_region *org)
510{
511#ifdef CONFIG_CGROUP_HUGETLB
512 return rg->reservation_counter == org->reservation_counter &&
513 rg->css == org->css;
514
515#else
516 return true;
517#endif
518}
519
520static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
521{
522 struct file_region *nrg, *prg;
523
524 prg = list_prev_entry(rg, link);
525 if (&prg->link != &resv->regions && prg->to == rg->from &&
526 has_same_uncharge_info(prg, rg)) {
527 prg->to = rg->to;
528
529 list_del(&rg->link);
530 put_uncharge_info(rg);
531 kfree(rg);
532
533 rg = prg;
534 }
535
536 nrg = list_next_entry(rg, link);
537 if (&nrg->link != &resv->regions && nrg->from == rg->to &&
538 has_same_uncharge_info(nrg, rg)) {
539 nrg->from = rg->from;
540
541 list_del(&rg->link);
542 put_uncharge_info(rg);
543 kfree(rg);
544 }
545}
546
547static inline long
548hugetlb_resv_map_add(struct resv_map *map, struct list_head *rg, long from,
549 long to, struct hstate *h, struct hugetlb_cgroup *cg,
550 long *regions_needed)
551{
552 struct file_region *nrg;
553
554 if (!regions_needed) {
555 nrg = get_file_region_entry_from_cache(map, from, to);
556 record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg);
557 list_add(&nrg->link, rg);
558 coalesce_file_region(map, nrg);
559 } else
560 *regions_needed += 1;
561
562 return to - from;
563}
564
565/*
566 * Must be called with resv->lock held.
567 *
568 * Calling this with regions_needed != NULL will count the number of pages
569 * to be added but will not modify the linked list. And regions_needed will
570 * indicate the number of file_regions needed in the cache to carry out to add
571 * the regions for this range.
572 */
573static long add_reservation_in_range(struct resv_map *resv, long f, long t,
574 struct hugetlb_cgroup *h_cg,
575 struct hstate *h, long *regions_needed)
576{
577 long add = 0;
578 struct list_head *head = &resv->regions;
579 long last_accounted_offset = f;
580 struct file_region *iter, *trg = NULL;
581 struct list_head *rg = NULL;
582
583 if (regions_needed)
584 *regions_needed = 0;
585
586 /* In this loop, we essentially handle an entry for the range
587 * [last_accounted_offset, iter->from), at every iteration, with some
588 * bounds checking.
589 */
590 list_for_each_entry_safe(iter, trg, head, link) {
591 /* Skip irrelevant regions that start before our range. */
592 if (iter->from < f) {
593 /* If this region ends after the last accounted offset,
594 * then we need to update last_accounted_offset.
595 */
596 if (iter->to > last_accounted_offset)
597 last_accounted_offset = iter->to;
598 continue;
599 }
600
601 /* When we find a region that starts beyond our range, we've
602 * finished.
603 */
604 if (iter->from >= t) {
605 rg = iter->link.prev;
606 break;
607 }
608
609 /* Add an entry for last_accounted_offset -> iter->from, and
610 * update last_accounted_offset.
611 */
612 if (iter->from > last_accounted_offset)
613 add += hugetlb_resv_map_add(resv, iter->link.prev,
614 last_accounted_offset,
615 iter->from, h, h_cg,
616 regions_needed);
617
618 last_accounted_offset = iter->to;
619 }
620
621 /* Handle the case where our range extends beyond
622 * last_accounted_offset.
623 */
624 if (!rg)
625 rg = head->prev;
626 if (last_accounted_offset < t)
627 add += hugetlb_resv_map_add(resv, rg, last_accounted_offset,
628 t, h, h_cg, regions_needed);
629
630 return add;
631}
632
633/* Must be called with resv->lock acquired. Will drop lock to allocate entries.
634 */
635static int allocate_file_region_entries(struct resv_map *resv,
636 int regions_needed)
637 __must_hold(&resv->lock)
638{
639 LIST_HEAD(allocated_regions);
640 int to_allocate = 0, i = 0;
641 struct file_region *trg = NULL, *rg = NULL;
642
643 VM_BUG_ON(regions_needed < 0);
644
645 /*
646 * Check for sufficient descriptors in the cache to accommodate
647 * the number of in progress add operations plus regions_needed.
648 *
649 * This is a while loop because when we drop the lock, some other call
650 * to region_add or region_del may have consumed some region_entries,
651 * so we keep looping here until we finally have enough entries for
652 * (adds_in_progress + regions_needed).
653 */
654 while (resv->region_cache_count <
655 (resv->adds_in_progress + regions_needed)) {
656 to_allocate = resv->adds_in_progress + regions_needed -
657 resv->region_cache_count;
658
659 /* At this point, we should have enough entries in the cache
660 * for all the existing adds_in_progress. We should only be
661 * needing to allocate for regions_needed.
662 */
663 VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
664
665 spin_unlock(&resv->lock);
666 for (i = 0; i < to_allocate; i++) {
667 trg = kmalloc(sizeof(*trg), GFP_KERNEL);
668 if (!trg)
669 goto out_of_memory;
670 list_add(&trg->link, &allocated_regions);
671 }
672
673 spin_lock(&resv->lock);
674
675 list_splice(&allocated_regions, &resv->region_cache);
676 resv->region_cache_count += to_allocate;
677 }
678
679 return 0;
680
681out_of_memory:
682 list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
683 list_del(&rg->link);
684 kfree(rg);
685 }
686 return -ENOMEM;
687}
688
689/*
690 * Add the huge page range represented by [f, t) to the reserve
691 * map. Regions will be taken from the cache to fill in this range.
692 * Sufficient regions should exist in the cache due to the previous
693 * call to region_chg with the same range, but in some cases the cache will not
694 * have sufficient entries due to races with other code doing region_add or
695 * region_del. The extra needed entries will be allocated.
696 *
697 * regions_needed is the out value provided by a previous call to region_chg.
698 *
699 * Return the number of new huge pages added to the map. This number is greater
700 * than or equal to zero. If file_region entries needed to be allocated for
701 * this operation and we were not able to allocate, it returns -ENOMEM.
702 * region_add of regions of length 1 never allocate file_regions and cannot
703 * fail; region_chg will always allocate at least 1 entry and a region_add for
704 * 1 page will only require at most 1 entry.
705 */
706static long region_add(struct resv_map *resv, long f, long t,
707 long in_regions_needed, struct hstate *h,
708 struct hugetlb_cgroup *h_cg)
709{
710 long add = 0, actual_regions_needed = 0;
711
712 spin_lock(&resv->lock);
713retry:
714
715 /* Count how many regions are actually needed to execute this add. */
716 add_reservation_in_range(resv, f, t, NULL, NULL,
717 &actual_regions_needed);
718
719 /*
720 * Check for sufficient descriptors in the cache to accommodate
721 * this add operation. Note that actual_regions_needed may be greater
722 * than in_regions_needed, as the resv_map may have been modified since
723 * the region_chg call. In this case, we need to make sure that we
724 * allocate extra entries, such that we have enough for all the
725 * existing adds_in_progress, plus the excess needed for this
726 * operation.
727 */
728 if (actual_regions_needed > in_regions_needed &&
729 resv->region_cache_count <
730 resv->adds_in_progress +
731 (actual_regions_needed - in_regions_needed)) {
732 /* region_add operation of range 1 should never need to
733 * allocate file_region entries.
734 */
735 VM_BUG_ON(t - f <= 1);
736
737 if (allocate_file_region_entries(
738 resv, actual_regions_needed - in_regions_needed)) {
739 return -ENOMEM;
740 }
741
742 goto retry;
743 }
744
745 add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
746
747 resv->adds_in_progress -= in_regions_needed;
748
749 spin_unlock(&resv->lock);
750 return add;
751}
752
753/*
754 * Examine the existing reserve map and determine how many
755 * huge pages in the specified range [f, t) are NOT currently
756 * represented. This routine is called before a subsequent
757 * call to region_add that will actually modify the reserve
758 * map to add the specified range [f, t). region_chg does
759 * not change the number of huge pages represented by the
760 * map. A number of new file_region structures is added to the cache as a
761 * placeholder, for the subsequent region_add call to use. At least 1
762 * file_region structure is added.
763 *
764 * out_regions_needed is the number of regions added to the
765 * resv->adds_in_progress. This value needs to be provided to a follow up call
766 * to region_add or region_abort for proper accounting.
767 *
768 * Returns the number of huge pages that need to be added to the existing
769 * reservation map for the range [f, t). This number is greater or equal to
770 * zero. -ENOMEM is returned if a new file_region structure or cache entry
771 * is needed and can not be allocated.
772 */
773static long region_chg(struct resv_map *resv, long f, long t,
774 long *out_regions_needed)
775{
776 long chg = 0;
777
778 spin_lock(&resv->lock);
779
780 /* Count how many hugepages in this range are NOT represented. */
781 chg = add_reservation_in_range(resv, f, t, NULL, NULL,
782 out_regions_needed);
783
784 if (*out_regions_needed == 0)
785 *out_regions_needed = 1;
786
787 if (allocate_file_region_entries(resv, *out_regions_needed))
788 return -ENOMEM;
789
790 resv->adds_in_progress += *out_regions_needed;
791
792 spin_unlock(&resv->lock);
793 return chg;
794}
795
796/*
797 * Abort the in progress add operation. The adds_in_progress field
798 * of the resv_map keeps track of the operations in progress between
799 * calls to region_chg and region_add. Operations are sometimes
800 * aborted after the call to region_chg. In such cases, region_abort
801 * is called to decrement the adds_in_progress counter. regions_needed
802 * is the value returned by the region_chg call, it is used to decrement
803 * the adds_in_progress counter.
804 *
805 * NOTE: The range arguments [f, t) are not needed or used in this
806 * routine. They are kept to make reading the calling code easier as
807 * arguments will match the associated region_chg call.
808 */
809static void region_abort(struct resv_map *resv, long f, long t,
810 long regions_needed)
811{
812 spin_lock(&resv->lock);
813 VM_BUG_ON(!resv->region_cache_count);
814 resv->adds_in_progress -= regions_needed;
815 spin_unlock(&resv->lock);
816}
817
818/*
819 * Delete the specified range [f, t) from the reserve map. If the
820 * t parameter is LONG_MAX, this indicates that ALL regions after f
821 * should be deleted. Locate the regions which intersect [f, t)
822 * and either trim, delete or split the existing regions.
823 *
824 * Returns the number of huge pages deleted from the reserve map.
825 * In the normal case, the return value is zero or more. In the
826 * case where a region must be split, a new region descriptor must
827 * be allocated. If the allocation fails, -ENOMEM will be returned.
828 * NOTE: If the parameter t == LONG_MAX, then we will never split
829 * a region and possibly return -ENOMEM. Callers specifying
830 * t == LONG_MAX do not need to check for -ENOMEM error.
831 */
832static long region_del(struct resv_map *resv, long f, long t)
833{
834 struct list_head *head = &resv->regions;
835 struct file_region *rg, *trg;
836 struct file_region *nrg = NULL;
837 long del = 0;
838
839retry:
840 spin_lock(&resv->lock);
841 list_for_each_entry_safe(rg, trg, head, link) {
842 /*
843 * Skip regions before the range to be deleted. file_region
844 * ranges are normally of the form [from, to). However, there
845 * may be a "placeholder" entry in the map which is of the form
846 * (from, to) with from == to. Check for placeholder entries
847 * at the beginning of the range to be deleted.
848 */
849 if (rg->to <= f && (rg->to != rg->from || rg->to != f))
850 continue;
851
852 if (rg->from >= t)
853 break;
854
855 if (f > rg->from && t < rg->to) { /* Must split region */
856 /*
857 * Check for an entry in the cache before dropping
858 * lock and attempting allocation.
859 */
860 if (!nrg &&
861 resv->region_cache_count > resv->adds_in_progress) {
862 nrg = list_first_entry(&resv->region_cache,
863 struct file_region,
864 link);
865 list_del(&nrg->link);
866 resv->region_cache_count--;
867 }
868
869 if (!nrg) {
870 spin_unlock(&resv->lock);
871 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
872 if (!nrg)
873 return -ENOMEM;
874 goto retry;
875 }
876
877 del += t - f;
878 hugetlb_cgroup_uncharge_file_region(
879 resv, rg, t - f, false);
880
881 /* New entry for end of split region */
882 nrg->from = t;
883 nrg->to = rg->to;
884
885 copy_hugetlb_cgroup_uncharge_info(nrg, rg);
886
887 INIT_LIST_HEAD(&nrg->link);
888
889 /* Original entry is trimmed */
890 rg->to = f;
891
892 list_add(&nrg->link, &rg->link);
893 nrg = NULL;
894 break;
895 }
896
897 if (f <= rg->from && t >= rg->to) { /* Remove entire region */
898 del += rg->to - rg->from;
899 hugetlb_cgroup_uncharge_file_region(resv, rg,
900 rg->to - rg->from, true);
901 list_del(&rg->link);
902 kfree(rg);
903 continue;
904 }
905
906 if (f <= rg->from) { /* Trim beginning of region */
907 hugetlb_cgroup_uncharge_file_region(resv, rg,
908 t - rg->from, false);
909
910 del += t - rg->from;
911 rg->from = t;
912 } else { /* Trim end of region */
913 hugetlb_cgroup_uncharge_file_region(resv, rg,
914 rg->to - f, false);
915
916 del += rg->to - f;
917 rg->to = f;
918 }
919 }
920
921 spin_unlock(&resv->lock);
922 kfree(nrg);
923 return del;
924}
925
926/*
927 * A rare out of memory error was encountered which prevented removal of
928 * the reserve map region for a page. The huge page itself was free'ed
929 * and removed from the page cache. This routine will adjust the subpool
930 * usage count, and the global reserve count if needed. By incrementing
931 * these counts, the reserve map entry which could not be deleted will
932 * appear as a "reserved" entry instead of simply dangling with incorrect
933 * counts.
934 */
935void hugetlb_fix_reserve_counts(struct inode *inode)
936{
937 struct hugepage_subpool *spool = subpool_inode(inode);
938 long rsv_adjust;
939 bool reserved = false;
940
941 rsv_adjust = hugepage_subpool_get_pages(spool, 1);
942 if (rsv_adjust > 0) {
943 struct hstate *h = hstate_inode(inode);
944
945 if (!hugetlb_acct_memory(h, 1))
946 reserved = true;
947 } else if (!rsv_adjust) {
948 reserved = true;
949 }
950
951 if (!reserved)
952 pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
953}
954
955/*
956 * Count and return the number of huge pages in the reserve map
957 * that intersect with the range [f, t).
958 */
959static long region_count(struct resv_map *resv, long f, long t)
960{
961 struct list_head *head = &resv->regions;
962 struct file_region *rg;
963 long chg = 0;
964
965 spin_lock(&resv->lock);
966 /* Locate each segment we overlap with, and count that overlap. */
967 list_for_each_entry(rg, head, link) {
968 long seg_from;
969 long seg_to;
970
971 if (rg->to <= f)
972 continue;
973 if (rg->from >= t)
974 break;
975
976 seg_from = max(rg->from, f);
977 seg_to = min(rg->to, t);
978
979 chg += seg_to - seg_from;
980 }
981 spin_unlock(&resv->lock);
982
983 return chg;
984}
985
986/*
987 * Convert the address within this vma to the page offset within
988 * the mapping, huge page units here.
989 */
990static pgoff_t vma_hugecache_offset(struct hstate *h,
991 struct vm_area_struct *vma, unsigned long address)
992{
993 return ((address - vma->vm_start) >> huge_page_shift(h)) +
994 (vma->vm_pgoff >> huge_page_order(h));
995}
996
997/**
998 * vma_kernel_pagesize - Page size granularity for this VMA.
999 * @vma: The user mapping.
1000 *
1001 * Folios in this VMA will be aligned to, and at least the size of the
1002 * number of bytes returned by this function.
1003 *
1004 * Return: The default size of the folios allocated when backing a VMA.
1005 */
1006unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
1007{
1008 if (vma->vm_ops && vma->vm_ops->pagesize)
1009 return vma->vm_ops->pagesize(vma);
1010 return PAGE_SIZE;
1011}
1012EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
1013
1014/*
1015 * Return the page size being used by the MMU to back a VMA. In the majority
1016 * of cases, the page size used by the kernel matches the MMU size. On
1017 * architectures where it differs, an architecture-specific 'strong'
1018 * version of this symbol is required.
1019 */
1020__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
1021{
1022 return vma_kernel_pagesize(vma);
1023}
1024
1025/*
1026 * Flags for MAP_PRIVATE reservations. These are stored in the bottom
1027 * bits of the reservation map pointer, which are always clear due to
1028 * alignment.
1029 */
1030#define HPAGE_RESV_OWNER (1UL << 0)
1031#define HPAGE_RESV_UNMAPPED (1UL << 1)
1032#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
1033
1034/*
1035 * These helpers are used to track how many pages are reserved for
1036 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
1037 * is guaranteed to have their future faults succeed.
1038 *
1039 * With the exception of hugetlb_dup_vma_private() which is called at fork(),
1040 * the reserve counters are updated with the hugetlb_lock held. It is safe
1041 * to reset the VMA at fork() time as it is not in use yet and there is no
1042 * chance of the global counters getting corrupted as a result of the values.
1043 *
1044 * The private mapping reservation is represented in a subtly different
1045 * manner to a shared mapping. A shared mapping has a region map associated
1046 * with the underlying file, this region map represents the backing file
1047 * pages which have ever had a reservation assigned which this persists even
1048 * after the page is instantiated. A private mapping has a region map
1049 * associated with the original mmap which is attached to all VMAs which
1050 * reference it, this region map represents those offsets which have consumed
1051 * reservation ie. where pages have been instantiated.
1052 */
1053static unsigned long get_vma_private_data(struct vm_area_struct *vma)
1054{
1055 return (unsigned long)vma->vm_private_data;
1056}
1057
1058static void set_vma_private_data(struct vm_area_struct *vma,
1059 unsigned long value)
1060{
1061 vma->vm_private_data = (void *)value;
1062}
1063
1064static void
1065resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
1066 struct hugetlb_cgroup *h_cg,
1067 struct hstate *h)
1068{
1069#ifdef CONFIG_CGROUP_HUGETLB
1070 if (!h_cg || !h) {
1071 resv_map->reservation_counter = NULL;
1072 resv_map->pages_per_hpage = 0;
1073 resv_map->css = NULL;
1074 } else {
1075 resv_map->reservation_counter =
1076 &h_cg->rsvd_hugepage[hstate_index(h)];
1077 resv_map->pages_per_hpage = pages_per_huge_page(h);
1078 resv_map->css = &h_cg->css;
1079 }
1080#endif
1081}
1082
1083struct resv_map *resv_map_alloc(void)
1084{
1085 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
1086 struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
1087
1088 if (!resv_map || !rg) {
1089 kfree(resv_map);
1090 kfree(rg);
1091 return NULL;
1092 }
1093
1094 kref_init(&resv_map->refs);
1095 spin_lock_init(&resv_map->lock);
1096 INIT_LIST_HEAD(&resv_map->regions);
1097 init_rwsem(&resv_map->rw_sema);
1098
1099 resv_map->adds_in_progress = 0;
1100 /*
1101 * Initialize these to 0. On shared mappings, 0's here indicate these
1102 * fields don't do cgroup accounting. On private mappings, these will be
1103 * re-initialized to the proper values, to indicate that hugetlb cgroup
1104 * reservations are to be un-charged from here.
1105 */
1106 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
1107
1108 INIT_LIST_HEAD(&resv_map->region_cache);
1109 list_add(&rg->link, &resv_map->region_cache);
1110 resv_map->region_cache_count = 1;
1111
1112 return resv_map;
1113}
1114
1115void resv_map_release(struct kref *ref)
1116{
1117 struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
1118 struct list_head *head = &resv_map->region_cache;
1119 struct file_region *rg, *trg;
1120
1121 /* Clear out any active regions before we release the map. */
1122 region_del(resv_map, 0, LONG_MAX);
1123
1124 /* ... and any entries left in the cache */
1125 list_for_each_entry_safe(rg, trg, head, link) {
1126 list_del(&rg->link);
1127 kfree(rg);
1128 }
1129
1130 VM_BUG_ON(resv_map->adds_in_progress);
1131
1132 kfree(resv_map);
1133}
1134
1135static inline struct resv_map *inode_resv_map(struct inode *inode)
1136{
1137 /*
1138 * At inode evict time, i_mapping may not point to the original
1139 * address space within the inode. This original address space
1140 * contains the pointer to the resv_map. So, always use the
1141 * address space embedded within the inode.
1142 * The VERY common case is inode->mapping == &inode->i_data but,
1143 * this may not be true for device special inodes.
1144 */
1145 return (struct resv_map *)(&inode->i_data)->i_private_data;
1146}
1147
1148static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
1149{
1150 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1151 if (vma->vm_flags & VM_MAYSHARE) {
1152 struct address_space *mapping = vma->vm_file->f_mapping;
1153 struct inode *inode = mapping->host;
1154
1155 return inode_resv_map(inode);
1156
1157 } else {
1158 return (struct resv_map *)(get_vma_private_data(vma) &
1159 ~HPAGE_RESV_MASK);
1160 }
1161}
1162
1163static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
1164{
1165 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1166 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
1167
1168 set_vma_private_data(vma, (unsigned long)map);
1169}
1170
1171static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
1172{
1173 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1174 VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
1175
1176 set_vma_private_data(vma, get_vma_private_data(vma) | flags);
1177}
1178
1179static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
1180{
1181 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1182
1183 return (get_vma_private_data(vma) & flag) != 0;
1184}
1185
1186bool __vma_private_lock(struct vm_area_struct *vma)
1187{
1188 return !(vma->vm_flags & VM_MAYSHARE) &&
1189 get_vma_private_data(vma) & ~HPAGE_RESV_MASK &&
1190 is_vma_resv_set(vma, HPAGE_RESV_OWNER);
1191}
1192
1193void hugetlb_dup_vma_private(struct vm_area_struct *vma)
1194{
1195 VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1196 /*
1197 * Clear vm_private_data
1198 * - For shared mappings this is a per-vma semaphore that may be
1199 * allocated in a subsequent call to hugetlb_vm_op_open.
1200 * Before clearing, make sure pointer is not associated with vma
1201 * as this will leak the structure. This is the case when called
1202 * via clear_vma_resv_huge_pages() and hugetlb_vm_op_open has already
1203 * been called to allocate a new structure.
1204 * - For MAP_PRIVATE mappings, this is the reserve map which does
1205 * not apply to children. Faults generated by the children are
1206 * not guaranteed to succeed, even if read-only.
1207 */
1208 if (vma->vm_flags & VM_MAYSHARE) {
1209 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
1210
1211 if (vma_lock && vma_lock->vma != vma)
1212 vma->vm_private_data = NULL;
1213 } else
1214 vma->vm_private_data = NULL;
1215}
1216
1217/*
1218 * Reset and decrement one ref on hugepage private reservation.
1219 * Called with mm->mmap_lock writer semaphore held.
1220 * This function should be only used by move_vma() and operate on
1221 * same sized vma. It should never come here with last ref on the
1222 * reservation.
1223 */
1224void clear_vma_resv_huge_pages(struct vm_area_struct *vma)
1225{
1226 /*
1227 * Clear the old hugetlb private page reservation.
1228 * It has already been transferred to new_vma.
1229 *
1230 * During a mremap() operation of a hugetlb vma we call move_vma()
1231 * which copies vma into new_vma and unmaps vma. After the copy
1232 * operation both new_vma and vma share a reference to the resv_map
1233 * struct, and at that point vma is about to be unmapped. We don't
1234 * want to return the reservation to the pool at unmap of vma because
1235 * the reservation still lives on in new_vma, so simply decrement the
1236 * ref here and remove the resv_map reference from this vma.
1237 */
1238 struct resv_map *reservations = vma_resv_map(vma);
1239
1240 if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1241 resv_map_put_hugetlb_cgroup_uncharge_info(reservations);
1242 kref_put(&reservations->refs, resv_map_release);
1243 }
1244
1245 hugetlb_dup_vma_private(vma);
1246}
1247
1248/* Returns true if the VMA has associated reserve pages */
1249static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
1250{
1251 if (vma->vm_flags & VM_NORESERVE) {
1252 /*
1253 * This address is already reserved by other process(chg == 0),
1254 * so, we should decrement reserved count. Without decrementing,
1255 * reserve count remains after releasing inode, because this
1256 * allocated page will go into page cache and is regarded as
1257 * coming from reserved pool in releasing step. Currently, we
1258 * don't have any other solution to deal with this situation
1259 * properly, so add work-around here.
1260 */
1261 if (vma->vm_flags & VM_MAYSHARE && chg == 0)
1262 return true;
1263 else
1264 return false;
1265 }
1266
1267 /* Shared mappings always use reserves */
1268 if (vma->vm_flags & VM_MAYSHARE) {
1269 /*
1270 * We know VM_NORESERVE is not set. Therefore, there SHOULD
1271 * be a region map for all pages. The only situation where
1272 * there is no region map is if a hole was punched via
1273 * fallocate. In this case, there really are no reserves to
1274 * use. This situation is indicated if chg != 0.
1275 */
1276 if (chg)
1277 return false;
1278 else
1279 return true;
1280 }
1281
1282 /*
1283 * Only the process that called mmap() has reserves for
1284 * private mappings.
1285 */
1286 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1287 /*
1288 * Like the shared case above, a hole punch or truncate
1289 * could have been performed on the private mapping.
1290 * Examine the value of chg to determine if reserves
1291 * actually exist or were previously consumed.
1292 * Very Subtle - The value of chg comes from a previous
1293 * call to vma_needs_reserves(). The reserve map for
1294 * private mappings has different (opposite) semantics
1295 * than that of shared mappings. vma_needs_reserves()
1296 * has already taken this difference in semantics into
1297 * account. Therefore, the meaning of chg is the same
1298 * as in the shared case above. Code could easily be
1299 * combined, but keeping it separate draws attention to
1300 * subtle differences.
1301 */
1302 if (chg)
1303 return false;
1304 else
1305 return true;
1306 }
1307
1308 return false;
1309}
1310
1311static void enqueue_hugetlb_folio(struct hstate *h, struct folio *folio)
1312{
1313 int nid = folio_nid(folio);
1314
1315 lockdep_assert_held(&hugetlb_lock);
1316 VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
1317
1318 list_move(&folio->lru, &h->hugepage_freelists[nid]);
1319 h->free_huge_pages++;
1320 h->free_huge_pages_node[nid]++;
1321 folio_set_hugetlb_freed(folio);
1322}
1323
1324static struct folio *dequeue_hugetlb_folio_node_exact(struct hstate *h,
1325 int nid)
1326{
1327 struct folio *folio;
1328 bool pin = !!(current->flags & PF_MEMALLOC_PIN);
1329
1330 lockdep_assert_held(&hugetlb_lock);
1331 list_for_each_entry(folio, &h->hugepage_freelists[nid], lru) {
1332 if (pin && !folio_is_longterm_pinnable(folio))
1333 continue;
1334
1335 if (folio_test_hwpoison(folio))
1336 continue;
1337
1338 list_move(&folio->lru, &h->hugepage_activelist);
1339 folio_ref_unfreeze(folio, 1);
1340 folio_clear_hugetlb_freed(folio);
1341 h->free_huge_pages--;
1342 h->free_huge_pages_node[nid]--;
1343 return folio;
1344 }
1345
1346 return NULL;
1347}
1348
1349static struct folio *dequeue_hugetlb_folio_nodemask(struct hstate *h, gfp_t gfp_mask,
1350 int nid, nodemask_t *nmask)
1351{
1352 unsigned int cpuset_mems_cookie;
1353 struct zonelist *zonelist;
1354 struct zone *zone;
1355 struct zoneref *z;
1356 int node = NUMA_NO_NODE;
1357
1358 zonelist = node_zonelist(nid, gfp_mask);
1359
1360retry_cpuset:
1361 cpuset_mems_cookie = read_mems_allowed_begin();
1362 for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
1363 struct folio *folio;
1364
1365 if (!cpuset_zone_allowed(zone, gfp_mask))
1366 continue;
1367 /*
1368 * no need to ask again on the same node. Pool is node rather than
1369 * zone aware
1370 */
1371 if (zone_to_nid(zone) == node)
1372 continue;
1373 node = zone_to_nid(zone);
1374
1375 folio = dequeue_hugetlb_folio_node_exact(h, node);
1376 if (folio)
1377 return folio;
1378 }
1379 if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
1380 goto retry_cpuset;
1381
1382 return NULL;
1383}
1384
1385static unsigned long available_huge_pages(struct hstate *h)
1386{
1387 return h->free_huge_pages - h->resv_huge_pages;
1388}
1389
1390static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h,
1391 struct vm_area_struct *vma,
1392 unsigned long address, int avoid_reserve,
1393 long chg)
1394{
1395 struct folio *folio = NULL;
1396 struct mempolicy *mpol;
1397 gfp_t gfp_mask;
1398 nodemask_t *nodemask;
1399 int nid;
1400
1401 /*
1402 * A child process with MAP_PRIVATE mappings created by their parent
1403 * have no page reserves. This check ensures that reservations are
1404 * not "stolen". The child may still get SIGKILLed
1405 */
1406 if (!vma_has_reserves(vma, chg) && !available_huge_pages(h))
1407 goto err;
1408
1409 /* If reserves cannot be used, ensure enough pages are in the pool */
1410 if (avoid_reserve && !available_huge_pages(h))
1411 goto err;
1412
1413 gfp_mask = htlb_alloc_mask(h);
1414 nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1415
1416 if (mpol_is_preferred_many(mpol)) {
1417 folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
1418 nid, nodemask);
1419
1420 /* Fallback to all nodes if page==NULL */
1421 nodemask = NULL;
1422 }
1423
1424 if (!folio)
1425 folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
1426 nid, nodemask);
1427
1428 if (folio && !avoid_reserve && vma_has_reserves(vma, chg)) {
1429 folio_set_hugetlb_restore_reserve(folio);
1430 h->resv_huge_pages--;
1431 }
1432
1433 mpol_cond_put(mpol);
1434 return folio;
1435
1436err:
1437 return NULL;
1438}
1439
1440/*
1441 * common helper functions for hstate_next_node_to_{alloc|free}.
1442 * We may have allocated or freed a huge page based on a different
1443 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
1444 * be outside of *nodes_allowed. Ensure that we use an allowed
1445 * node for alloc or free.
1446 */
1447static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
1448{
1449 nid = next_node_in(nid, *nodes_allowed);
1450 VM_BUG_ON(nid >= MAX_NUMNODES);
1451
1452 return nid;
1453}
1454
1455static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
1456{
1457 if (!node_isset(nid, *nodes_allowed))
1458 nid = next_node_allowed(nid, nodes_allowed);
1459 return nid;
1460}
1461
1462/*
1463 * returns the previously saved node ["this node"] from which to
1464 * allocate a persistent huge page for the pool and advance the
1465 * next node from which to allocate, handling wrap at end of node
1466 * mask.
1467 */
1468static int hstate_next_node_to_alloc(int *next_node,
1469 nodemask_t *nodes_allowed)
1470{
1471 int nid;
1472
1473 VM_BUG_ON(!nodes_allowed);
1474
1475 nid = get_valid_node_allowed(*next_node, nodes_allowed);
1476 *next_node = next_node_allowed(nid, nodes_allowed);
1477
1478 return nid;
1479}
1480
1481/*
1482 * helper for remove_pool_hugetlb_folio() - return the previously saved
1483 * node ["this node"] from which to free a huge page. Advance the
1484 * next node id whether or not we find a free huge page to free so
1485 * that the next attempt to free addresses the next node.
1486 */
1487static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
1488{
1489 int nid;
1490
1491 VM_BUG_ON(!nodes_allowed);
1492
1493 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
1494 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
1495
1496 return nid;
1497}
1498
1499#define for_each_node_mask_to_alloc(next_node, nr_nodes, node, mask) \
1500 for (nr_nodes = nodes_weight(*mask); \
1501 nr_nodes > 0 && \
1502 ((node = hstate_next_node_to_alloc(next_node, mask)) || 1); \
1503 nr_nodes--)
1504
1505#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
1506 for (nr_nodes = nodes_weight(*mask); \
1507 nr_nodes > 0 && \
1508 ((node = hstate_next_node_to_free(hs, mask)) || 1); \
1509 nr_nodes--)
1510
1511/* used to demote non-gigantic_huge pages as well */
1512static void __destroy_compound_gigantic_folio(struct folio *folio,
1513 unsigned int order, bool demote)
1514{
1515 int i;
1516 int nr_pages = 1 << order;
1517 struct page *p;
1518
1519 atomic_set(&folio->_entire_mapcount, 0);
1520 atomic_set(&folio->_nr_pages_mapped, 0);
1521 atomic_set(&folio->_pincount, 0);
1522
1523 for (i = 1; i < nr_pages; i++) {
1524 p = folio_page(folio, i);
1525 p->flags &= ~PAGE_FLAGS_CHECK_AT_FREE;
1526 p->mapping = NULL;
1527 clear_compound_head(p);
1528 if (!demote)
1529 set_page_refcounted(p);
1530 }
1531
1532 __folio_clear_head(folio);
1533}
1534
1535static void destroy_compound_hugetlb_folio_for_demote(struct folio *folio,
1536 unsigned int order)
1537{
1538 __destroy_compound_gigantic_folio(folio, order, true);
1539}
1540
1541#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1542static void destroy_compound_gigantic_folio(struct folio *folio,
1543 unsigned int order)
1544{
1545 __destroy_compound_gigantic_folio(folio, order, false);
1546}
1547
1548static void free_gigantic_folio(struct folio *folio, unsigned int order)
1549{
1550 /*
1551 * If the page isn't allocated using the cma allocator,
1552 * cma_release() returns false.
1553 */
1554#ifdef CONFIG_CMA
1555 int nid = folio_nid(folio);
1556
1557 if (cma_release(hugetlb_cma[nid], &folio->page, 1 << order))
1558 return;
1559#endif
1560
1561 free_contig_range(folio_pfn(folio), 1 << order);
1562}
1563
1564#ifdef CONFIG_CONTIG_ALLOC
1565static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask,
1566 int nid, nodemask_t *nodemask)
1567{
1568 struct page *page;
1569 unsigned long nr_pages = pages_per_huge_page(h);
1570 if (nid == NUMA_NO_NODE)
1571 nid = numa_mem_id();
1572
1573#ifdef CONFIG_CMA
1574 {
1575 int node;
1576
1577 if (hugetlb_cma[nid]) {
1578 page = cma_alloc(hugetlb_cma[nid], nr_pages,
1579 huge_page_order(h), true);
1580 if (page)
1581 return page_folio(page);
1582 }
1583
1584 if (!(gfp_mask & __GFP_THISNODE)) {
1585 for_each_node_mask(node, *nodemask) {
1586 if (node == nid || !hugetlb_cma[node])
1587 continue;
1588
1589 page = cma_alloc(hugetlb_cma[node], nr_pages,
1590 huge_page_order(h), true);
1591 if (page)
1592 return page_folio(page);
1593 }
1594 }
1595 }
1596#endif
1597
1598 page = alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1599 return page ? page_folio(page) : NULL;
1600}
1601
1602#else /* !CONFIG_CONTIG_ALLOC */
1603static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask,
1604 int nid, nodemask_t *nodemask)
1605{
1606 return NULL;
1607}
1608#endif /* CONFIG_CONTIG_ALLOC */
1609
1610#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1611static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask,
1612 int nid, nodemask_t *nodemask)
1613{
1614 return NULL;
1615}
1616static inline void free_gigantic_folio(struct folio *folio,
1617 unsigned int order) { }
1618static inline void destroy_compound_gigantic_folio(struct folio *folio,
1619 unsigned int order) { }
1620#endif
1621
1622static inline void __clear_hugetlb_destructor(struct hstate *h,
1623 struct folio *folio)
1624{
1625 lockdep_assert_held(&hugetlb_lock);
1626
1627 __folio_clear_hugetlb(folio);
1628}
1629
1630/*
1631 * Remove hugetlb folio from lists.
1632 * If vmemmap exists for the folio, update dtor so that the folio appears
1633 * as just a compound page. Otherwise, wait until after allocating vmemmap
1634 * to update dtor.
1635 *
1636 * A reference is held on the folio, except in the case of demote.
1637 *
1638 * Must be called with hugetlb lock held.
1639 */
1640static void __remove_hugetlb_folio(struct hstate *h, struct folio *folio,
1641 bool adjust_surplus,
1642 bool demote)
1643{
1644 int nid = folio_nid(folio);
1645
1646 VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio(folio), folio);
1647 VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio_rsvd(folio), folio);
1648
1649 lockdep_assert_held(&hugetlb_lock);
1650 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1651 return;
1652
1653 list_del(&folio->lru);
1654
1655 if (folio_test_hugetlb_freed(folio)) {
1656 h->free_huge_pages--;
1657 h->free_huge_pages_node[nid]--;
1658 }
1659 if (adjust_surplus) {
1660 h->surplus_huge_pages--;
1661 h->surplus_huge_pages_node[nid]--;
1662 }
1663
1664 /*
1665 * We can only clear the hugetlb destructor after allocating vmemmap
1666 * pages. Otherwise, someone (memory error handling) may try to write
1667 * to tail struct pages.
1668 */
1669 if (!folio_test_hugetlb_vmemmap_optimized(folio))
1670 __clear_hugetlb_destructor(h, folio);
1671
1672 /*
1673 * In the case of demote we do not ref count the page as it will soon
1674 * be turned into a page of smaller size.
1675 */
1676 if (!demote)
1677 folio_ref_unfreeze(folio, 1);
1678
1679 h->nr_huge_pages--;
1680 h->nr_huge_pages_node[nid]--;
1681}
1682
1683static void remove_hugetlb_folio(struct hstate *h, struct folio *folio,
1684 bool adjust_surplus)
1685{
1686 __remove_hugetlb_folio(h, folio, adjust_surplus, false);
1687}
1688
1689static void remove_hugetlb_folio_for_demote(struct hstate *h, struct folio *folio,
1690 bool adjust_surplus)
1691{
1692 __remove_hugetlb_folio(h, folio, adjust_surplus, true);
1693}
1694
1695static void add_hugetlb_folio(struct hstate *h, struct folio *folio,
1696 bool adjust_surplus)
1697{
1698 int zeroed;
1699 int nid = folio_nid(folio);
1700
1701 VM_BUG_ON_FOLIO(!folio_test_hugetlb_vmemmap_optimized(folio), folio);
1702
1703 lockdep_assert_held(&hugetlb_lock);
1704
1705 INIT_LIST_HEAD(&folio->lru);
1706 h->nr_huge_pages++;
1707 h->nr_huge_pages_node[nid]++;
1708
1709 if (adjust_surplus) {
1710 h->surplus_huge_pages++;
1711 h->surplus_huge_pages_node[nid]++;
1712 }
1713
1714 __folio_set_hugetlb(folio);
1715 folio_change_private(folio, NULL);
1716 /*
1717 * We have to set hugetlb_vmemmap_optimized again as above
1718 * folio_change_private(folio, NULL) cleared it.
1719 */
1720 folio_set_hugetlb_vmemmap_optimized(folio);
1721
1722 /*
1723 * This folio is about to be managed by the hugetlb allocator and
1724 * should have no users. Drop our reference, and check for others
1725 * just in case.
1726 */
1727 zeroed = folio_put_testzero(folio);
1728 if (unlikely(!zeroed))
1729 /*
1730 * It is VERY unlikely soneone else has taken a ref
1731 * on the folio. In this case, we simply return as
1732 * free_huge_folio() will be called when this other ref
1733 * is dropped.
1734 */
1735 return;
1736
1737 arch_clear_hugepage_flags(&folio->page);
1738 enqueue_hugetlb_folio(h, folio);
1739}
1740
1741static void __update_and_free_hugetlb_folio(struct hstate *h,
1742 struct folio *folio)
1743{
1744 bool clear_dtor = folio_test_hugetlb_vmemmap_optimized(folio);
1745
1746 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1747 return;
1748
1749 /*
1750 * If we don't know which subpages are hwpoisoned, we can't free
1751 * the hugepage, so it's leaked intentionally.
1752 */
1753 if (folio_test_hugetlb_raw_hwp_unreliable(folio))
1754 return;
1755
1756 /*
1757 * If folio is not vmemmap optimized (!clear_dtor), then the folio
1758 * is no longer identified as a hugetlb page. hugetlb_vmemmap_restore_folio
1759 * can only be passed hugetlb pages and will BUG otherwise.
1760 */
1761 if (clear_dtor && hugetlb_vmemmap_restore_folio(h, folio)) {
1762 spin_lock_irq(&hugetlb_lock);
1763 /*
1764 * If we cannot allocate vmemmap pages, just refuse to free the
1765 * page and put the page back on the hugetlb free list and treat
1766 * as a surplus page.
1767 */
1768 add_hugetlb_folio(h, folio, true);
1769 spin_unlock_irq(&hugetlb_lock);
1770 return;
1771 }
1772
1773 /*
1774 * Move PageHWPoison flag from head page to the raw error pages,
1775 * which makes any healthy subpages reusable.
1776 */
1777 if (unlikely(folio_test_hwpoison(folio)))
1778 folio_clear_hugetlb_hwpoison(folio);
1779
1780 /*
1781 * If vmemmap pages were allocated above, then we need to clear the
1782 * hugetlb destructor under the hugetlb lock.
1783 */
1784 if (folio_test_hugetlb(folio)) {
1785 spin_lock_irq(&hugetlb_lock);
1786 __clear_hugetlb_destructor(h, folio);
1787 spin_unlock_irq(&hugetlb_lock);
1788 }
1789
1790 /*
1791 * Non-gigantic pages demoted from CMA allocated gigantic pages
1792 * need to be given back to CMA in free_gigantic_folio.
1793 */
1794 if (hstate_is_gigantic(h) ||
1795 hugetlb_cma_folio(folio, huge_page_order(h))) {
1796 destroy_compound_gigantic_folio(folio, huge_page_order(h));
1797 free_gigantic_folio(folio, huge_page_order(h));
1798 } else {
1799 __free_pages(&folio->page, huge_page_order(h));
1800 }
1801}
1802
1803/*
1804 * As update_and_free_hugetlb_folio() can be called under any context, so we cannot
1805 * use GFP_KERNEL to allocate vmemmap pages. However, we can defer the
1806 * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate
1807 * the vmemmap pages.
1808 *
1809 * free_hpage_workfn() locklessly retrieves the linked list of pages to be
1810 * freed and frees them one-by-one. As the page->mapping pointer is going
1811 * to be cleared in free_hpage_workfn() anyway, it is reused as the llist_node
1812 * structure of a lockless linked list of huge pages to be freed.
1813 */
1814static LLIST_HEAD(hpage_freelist);
1815
1816static void free_hpage_workfn(struct work_struct *work)
1817{
1818 struct llist_node *node;
1819
1820 node = llist_del_all(&hpage_freelist);
1821
1822 while (node) {
1823 struct folio *folio;
1824 struct hstate *h;
1825
1826 folio = container_of((struct address_space **)node,
1827 struct folio, mapping);
1828 node = node->next;
1829 folio->mapping = NULL;
1830 /*
1831 * The VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio) in
1832 * folio_hstate() is going to trigger because a previous call to
1833 * remove_hugetlb_folio() will clear the hugetlb bit, so do
1834 * not use folio_hstate() directly.
1835 */
1836 h = size_to_hstate(folio_size(folio));
1837
1838 __update_and_free_hugetlb_folio(h, folio);
1839
1840 cond_resched();
1841 }
1842}
1843static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
1844
1845static inline void flush_free_hpage_work(struct hstate *h)
1846{
1847 if (hugetlb_vmemmap_optimizable(h))
1848 flush_work(&free_hpage_work);
1849}
1850
1851static void update_and_free_hugetlb_folio(struct hstate *h, struct folio *folio,
1852 bool atomic)
1853{
1854 if (!folio_test_hugetlb_vmemmap_optimized(folio) || !atomic) {
1855 __update_and_free_hugetlb_folio(h, folio);
1856 return;
1857 }
1858
1859 /*
1860 * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap pages.
1861 *
1862 * Only call schedule_work() if hpage_freelist is previously
1863 * empty. Otherwise, schedule_work() had been called but the workfn
1864 * hasn't retrieved the list yet.
1865 */
1866 if (llist_add((struct llist_node *)&folio->mapping, &hpage_freelist))
1867 schedule_work(&free_hpage_work);
1868}
1869
1870static void bulk_vmemmap_restore_error(struct hstate *h,
1871 struct list_head *folio_list,
1872 struct list_head *non_hvo_folios)
1873{
1874 struct folio *folio, *t_folio;
1875
1876 if (!list_empty(non_hvo_folios)) {
1877 /*
1878 * Free any restored hugetlb pages so that restore of the
1879 * entire list can be retried.
1880 * The idea is that in the common case of ENOMEM errors freeing
1881 * hugetlb pages with vmemmap we will free up memory so that we
1882 * can allocate vmemmap for more hugetlb pages.
1883 */
1884 list_for_each_entry_safe(folio, t_folio, non_hvo_folios, lru) {
1885 list_del(&folio->lru);
1886 spin_lock_irq(&hugetlb_lock);
1887 __clear_hugetlb_destructor(h, folio);
1888 spin_unlock_irq(&hugetlb_lock);
1889 update_and_free_hugetlb_folio(h, folio, false);
1890 cond_resched();
1891 }
1892 } else {
1893 /*
1894 * In the case where there are no folios which can be
1895 * immediately freed, we loop through the list trying to restore
1896 * vmemmap individually in the hope that someone elsewhere may
1897 * have done something to cause success (such as freeing some
1898 * memory). If unable to restore a hugetlb page, the hugetlb
1899 * page is made a surplus page and removed from the list.
1900 * If are able to restore vmemmap and free one hugetlb page, we
1901 * quit processing the list to retry the bulk operation.
1902 */
1903 list_for_each_entry_safe(folio, t_folio, folio_list, lru)
1904 if (hugetlb_vmemmap_restore_folio(h, folio)) {
1905 list_del(&folio->lru);
1906 spin_lock_irq(&hugetlb_lock);
1907 add_hugetlb_folio(h, folio, true);
1908 spin_unlock_irq(&hugetlb_lock);
1909 } else {
1910 list_del(&folio->lru);
1911 spin_lock_irq(&hugetlb_lock);
1912 __clear_hugetlb_destructor(h, folio);
1913 spin_unlock_irq(&hugetlb_lock);
1914 update_and_free_hugetlb_folio(h, folio, false);
1915 cond_resched();
1916 break;
1917 }
1918 }
1919}
1920
1921static void update_and_free_pages_bulk(struct hstate *h,
1922 struct list_head *folio_list)
1923{
1924 long ret;
1925 struct folio *folio, *t_folio;
1926 LIST_HEAD(non_hvo_folios);
1927
1928 /*
1929 * First allocate required vmemmmap (if necessary) for all folios.
1930 * Carefully handle errors and free up any available hugetlb pages
1931 * in an effort to make forward progress.
1932 */
1933retry:
1934 ret = hugetlb_vmemmap_restore_folios(h, folio_list, &non_hvo_folios);
1935 if (ret < 0) {
1936 bulk_vmemmap_restore_error(h, folio_list, &non_hvo_folios);
1937 goto retry;
1938 }
1939
1940 /*
1941 * At this point, list should be empty, ret should be >= 0 and there
1942 * should only be pages on the non_hvo_folios list.
1943 * Do note that the non_hvo_folios list could be empty.
1944 * Without HVO enabled, ret will be 0 and there is no need to call
1945 * __clear_hugetlb_destructor as this was done previously.
1946 */
1947 VM_WARN_ON(!list_empty(folio_list));
1948 VM_WARN_ON(ret < 0);
1949 if (!list_empty(&non_hvo_folios) && ret) {
1950 spin_lock_irq(&hugetlb_lock);
1951 list_for_each_entry(folio, &non_hvo_folios, lru)
1952 __clear_hugetlb_destructor(h, folio);
1953 spin_unlock_irq(&hugetlb_lock);
1954 }
1955
1956 list_for_each_entry_safe(folio, t_folio, &non_hvo_folios, lru) {
1957 update_and_free_hugetlb_folio(h, folio, false);
1958 cond_resched();
1959 }
1960}
1961
1962struct hstate *size_to_hstate(unsigned long size)
1963{
1964 struct hstate *h;
1965
1966 for_each_hstate(h) {
1967 if (huge_page_size(h) == size)
1968 return h;
1969 }
1970 return NULL;
1971}
1972
1973void free_huge_folio(struct folio *folio)
1974{
1975 /*
1976 * Can't pass hstate in here because it is called from the
1977 * compound page destructor.
1978 */
1979 struct hstate *h = folio_hstate(folio);
1980 int nid = folio_nid(folio);
1981 struct hugepage_subpool *spool = hugetlb_folio_subpool(folio);
1982 bool restore_reserve;
1983 unsigned long flags;
1984
1985 VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
1986 VM_BUG_ON_FOLIO(folio_mapcount(folio), folio);
1987
1988 hugetlb_set_folio_subpool(folio, NULL);
1989 if (folio_test_anon(folio))
1990 __ClearPageAnonExclusive(&folio->page);
1991 folio->mapping = NULL;
1992 restore_reserve = folio_test_hugetlb_restore_reserve(folio);
1993 folio_clear_hugetlb_restore_reserve(folio);
1994
1995 /*
1996 * If HPageRestoreReserve was set on page, page allocation consumed a
1997 * reservation. If the page was associated with a subpool, there
1998 * would have been a page reserved in the subpool before allocation
1999 * via hugepage_subpool_get_pages(). Since we are 'restoring' the
2000 * reservation, do not call hugepage_subpool_put_pages() as this will
2001 * remove the reserved page from the subpool.
2002 */
2003 if (!restore_reserve) {
2004 /*
2005 * A return code of zero implies that the subpool will be
2006 * under its minimum size if the reservation is not restored
2007 * after page is free. Therefore, force restore_reserve
2008 * operation.
2009 */
2010 if (hugepage_subpool_put_pages(spool, 1) == 0)
2011 restore_reserve = true;
2012 }
2013
2014 spin_lock_irqsave(&hugetlb_lock, flags);
2015 folio_clear_hugetlb_migratable(folio);
2016 hugetlb_cgroup_uncharge_folio(hstate_index(h),
2017 pages_per_huge_page(h), folio);
2018 hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h),
2019 pages_per_huge_page(h), folio);
2020 mem_cgroup_uncharge(folio);
2021 if (restore_reserve)
2022 h->resv_huge_pages++;
2023
2024 if (folio_test_hugetlb_temporary(folio)) {
2025 remove_hugetlb_folio(h, folio, false);
2026 spin_unlock_irqrestore(&hugetlb_lock, flags);
2027 update_and_free_hugetlb_folio(h, folio, true);
2028 } else if (h->surplus_huge_pages_node[nid]) {
2029 /* remove the page from active list */
2030 remove_hugetlb_folio(h, folio, true);
2031 spin_unlock_irqrestore(&hugetlb_lock, flags);
2032 update_and_free_hugetlb_folio(h, folio, true);
2033 } else {
2034 arch_clear_hugepage_flags(&folio->page);
2035 enqueue_hugetlb_folio(h, folio);
2036 spin_unlock_irqrestore(&hugetlb_lock, flags);
2037 }
2038}
2039
2040/*
2041 * Must be called with the hugetlb lock held
2042 */
2043static void __prep_account_new_huge_page(struct hstate *h, int nid)
2044{
2045 lockdep_assert_held(&hugetlb_lock);
2046 h->nr_huge_pages++;
2047 h->nr_huge_pages_node[nid]++;
2048}
2049
2050static void init_new_hugetlb_folio(struct hstate *h, struct folio *folio)
2051{
2052 __folio_set_hugetlb(folio);
2053 INIT_LIST_HEAD(&folio->lru);
2054 hugetlb_set_folio_subpool(folio, NULL);
2055 set_hugetlb_cgroup(folio, NULL);
2056 set_hugetlb_cgroup_rsvd(folio, NULL);
2057}
2058
2059static void __prep_new_hugetlb_folio(struct hstate *h, struct folio *folio)
2060{
2061 init_new_hugetlb_folio(h, folio);
2062 hugetlb_vmemmap_optimize_folio(h, folio);
2063}
2064
2065static void prep_new_hugetlb_folio(struct hstate *h, struct folio *folio, int nid)
2066{
2067 __prep_new_hugetlb_folio(h, folio);
2068 spin_lock_irq(&hugetlb_lock);
2069 __prep_account_new_huge_page(h, nid);
2070 spin_unlock_irq(&hugetlb_lock);
2071}
2072
2073static bool __prep_compound_gigantic_folio(struct folio *folio,
2074 unsigned int order, bool demote)
2075{
2076 int i, j;
2077 int nr_pages = 1 << order;
2078 struct page *p;
2079
2080 __folio_clear_reserved(folio);
2081 for (i = 0; i < nr_pages; i++) {
2082 p = folio_page(folio, i);
2083
2084 /*
2085 * For gigantic hugepages allocated through bootmem at
2086 * boot, it's safer to be consistent with the not-gigantic
2087 * hugepages and clear the PG_reserved bit from all tail pages
2088 * too. Otherwise drivers using get_user_pages() to access tail
2089 * pages may get the reference counting wrong if they see
2090 * PG_reserved set on a tail page (despite the head page not
2091 * having PG_reserved set). Enforcing this consistency between
2092 * head and tail pages allows drivers to optimize away a check
2093 * on the head page when they need know if put_page() is needed
2094 * after get_user_pages().
2095 */
2096 if (i != 0) /* head page cleared above */
2097 __ClearPageReserved(p);
2098 /*
2099 * Subtle and very unlikely
2100 *
2101 * Gigantic 'page allocators' such as memblock or cma will
2102 * return a set of pages with each page ref counted. We need
2103 * to turn this set of pages into a compound page with tail
2104 * page ref counts set to zero. Code such as speculative page
2105 * cache adding could take a ref on a 'to be' tail page.
2106 * We need to respect any increased ref count, and only set
2107 * the ref count to zero if count is currently 1. If count
2108 * is not 1, we return an error. An error return indicates
2109 * the set of pages can not be converted to a gigantic page.
2110 * The caller who allocated the pages should then discard the
2111 * pages using the appropriate free interface.
2112 *
2113 * In the case of demote, the ref count will be zero.
2114 */
2115 if (!demote) {
2116 if (!page_ref_freeze(p, 1)) {
2117 pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
2118 goto out_error;
2119 }
2120 } else {
2121 VM_BUG_ON_PAGE(page_count(p), p);
2122 }
2123 if (i != 0)
2124 set_compound_head(p, &folio->page);
2125 }
2126 __folio_set_head(folio);
2127 /* we rely on prep_new_hugetlb_folio to set the destructor */
2128 folio_set_order(folio, order);
2129 atomic_set(&folio->_entire_mapcount, -1);
2130 atomic_set(&folio->_nr_pages_mapped, 0);
2131 atomic_set(&folio->_pincount, 0);
2132 return true;
2133
2134out_error:
2135 /* undo page modifications made above */
2136 for (j = 0; j < i; j++) {
2137 p = folio_page(folio, j);
2138 if (j != 0)
2139 clear_compound_head(p);
2140 set_page_refcounted(p);
2141 }
2142 /* need to clear PG_reserved on remaining tail pages */
2143 for (; j < nr_pages; j++) {
2144 p = folio_page(folio, j);
2145 __ClearPageReserved(p);
2146 }
2147 return false;
2148}
2149
2150static bool prep_compound_gigantic_folio(struct folio *folio,
2151 unsigned int order)
2152{
2153 return __prep_compound_gigantic_folio(folio, order, false);
2154}
2155
2156static bool prep_compound_gigantic_folio_for_demote(struct folio *folio,
2157 unsigned int order)
2158{
2159 return __prep_compound_gigantic_folio(folio, order, true);
2160}
2161
2162/*
2163 * Find and lock address space (mapping) in write mode.
2164 *
2165 * Upon entry, the page is locked which means that page_mapping() is
2166 * stable. Due to locking order, we can only trylock_write. If we can
2167 * not get the lock, simply return NULL to caller.
2168 */
2169struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
2170{
2171 struct address_space *mapping = page_mapping(hpage);
2172
2173 if (!mapping)
2174 return mapping;
2175
2176 if (i_mmap_trylock_write(mapping))
2177 return mapping;
2178
2179 return NULL;
2180}
2181
2182static struct folio *alloc_buddy_hugetlb_folio(struct hstate *h,
2183 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2184 nodemask_t *node_alloc_noretry)
2185{
2186 int order = huge_page_order(h);
2187 struct page *page;
2188 bool alloc_try_hard = true;
2189 bool retry = true;
2190
2191 /*
2192 * By default we always try hard to allocate the page with
2193 * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
2194 * a loop (to adjust global huge page counts) and previous allocation
2195 * failed, do not continue to try hard on the same node. Use the
2196 * node_alloc_noretry bitmap to manage this state information.
2197 */
2198 if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
2199 alloc_try_hard = false;
2200 gfp_mask |= __GFP_COMP|__GFP_NOWARN;
2201 if (alloc_try_hard)
2202 gfp_mask |= __GFP_RETRY_MAYFAIL;
2203 if (nid == NUMA_NO_NODE)
2204 nid = numa_mem_id();
2205retry:
2206 page = __alloc_pages(gfp_mask, order, nid, nmask);
2207
2208 /* Freeze head page */
2209 if (page && !page_ref_freeze(page, 1)) {
2210 __free_pages(page, order);
2211 if (retry) { /* retry once */
2212 retry = false;
2213 goto retry;
2214 }
2215 /* WOW! twice in a row. */
2216 pr_warn("HugeTLB head page unexpected inflated ref count\n");
2217 page = NULL;
2218 }
2219
2220 /*
2221 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
2222 * indicates an overall state change. Clear bit so that we resume
2223 * normal 'try hard' allocations.
2224 */
2225 if (node_alloc_noretry && page && !alloc_try_hard)
2226 node_clear(nid, *node_alloc_noretry);
2227
2228 /*
2229 * If we tried hard to get a page but failed, set bit so that
2230 * subsequent attempts will not try as hard until there is an
2231 * overall state change.
2232 */
2233 if (node_alloc_noretry && !page && alloc_try_hard)
2234 node_set(nid, *node_alloc_noretry);
2235
2236 if (!page) {
2237 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
2238 return NULL;
2239 }
2240
2241 __count_vm_event(HTLB_BUDDY_PGALLOC);
2242 return page_folio(page);
2243}
2244
2245static struct folio *__alloc_fresh_hugetlb_folio(struct hstate *h,
2246 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2247 nodemask_t *node_alloc_noretry)
2248{
2249 struct folio *folio;
2250 bool retry = false;
2251
2252retry:
2253 if (hstate_is_gigantic(h))
2254 folio = alloc_gigantic_folio(h, gfp_mask, nid, nmask);
2255 else
2256 folio = alloc_buddy_hugetlb_folio(h, gfp_mask,
2257 nid, nmask, node_alloc_noretry);
2258 if (!folio)
2259 return NULL;
2260
2261 if (hstate_is_gigantic(h)) {
2262 if (!prep_compound_gigantic_folio(folio, huge_page_order(h))) {
2263 /*
2264 * Rare failure to convert pages to compound page.
2265 * Free pages and try again - ONCE!
2266 */
2267 free_gigantic_folio(folio, huge_page_order(h));
2268 if (!retry) {
2269 retry = true;
2270 goto retry;
2271 }
2272 return NULL;
2273 }
2274 }
2275
2276 return folio;
2277}
2278
2279static struct folio *only_alloc_fresh_hugetlb_folio(struct hstate *h,
2280 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2281 nodemask_t *node_alloc_noretry)
2282{
2283 struct folio *folio;
2284
2285 folio = __alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask,
2286 node_alloc_noretry);
2287 if (folio)
2288 init_new_hugetlb_folio(h, folio);
2289 return folio;
2290}
2291
2292/*
2293 * Common helper to allocate a fresh hugetlb page. All specific allocators
2294 * should use this function to get new hugetlb pages
2295 *
2296 * Note that returned page is 'frozen': ref count of head page and all tail
2297 * pages is zero.
2298 */
2299static struct folio *alloc_fresh_hugetlb_folio(struct hstate *h,
2300 gfp_t gfp_mask, int nid, nodemask_t *nmask,
2301 nodemask_t *node_alloc_noretry)
2302{
2303 struct folio *folio;
2304
2305 folio = __alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask,
2306 node_alloc_noretry);
2307 if (!folio)
2308 return NULL;
2309
2310 prep_new_hugetlb_folio(h, folio, folio_nid(folio));
2311 return folio;
2312}
2313
2314static void prep_and_add_allocated_folios(struct hstate *h,
2315 struct list_head *folio_list)
2316{
2317 unsigned long flags;
2318 struct folio *folio, *tmp_f;
2319
2320 /* Send list for bulk vmemmap optimization processing */
2321 hugetlb_vmemmap_optimize_folios(h, folio_list);
2322
2323 /* Add all new pool pages to free lists in one lock cycle */
2324 spin_lock_irqsave(&hugetlb_lock, flags);
2325 list_for_each_entry_safe(folio, tmp_f, folio_list, lru) {
2326 __prep_account_new_huge_page(h, folio_nid(folio));
2327 enqueue_hugetlb_folio(h, folio);
2328 }
2329 spin_unlock_irqrestore(&hugetlb_lock, flags);
2330}
2331
2332/*
2333 * Allocates a fresh hugetlb page in a node interleaved manner. The page
2334 * will later be added to the appropriate hugetlb pool.
2335 */
2336static struct folio *alloc_pool_huge_folio(struct hstate *h,
2337 nodemask_t *nodes_allowed,
2338 nodemask_t *node_alloc_noretry,
2339 int *next_node)
2340{
2341 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
2342 int nr_nodes, node;
2343
2344 for_each_node_mask_to_alloc(next_node, nr_nodes, node, nodes_allowed) {
2345 struct folio *folio;
2346
2347 folio = only_alloc_fresh_hugetlb_folio(h, gfp_mask, node,
2348 nodes_allowed, node_alloc_noretry);
2349 if (folio)
2350 return folio;
2351 }
2352
2353 return NULL;
2354}
2355
2356/*
2357 * Remove huge page from pool from next node to free. Attempt to keep
2358 * persistent huge pages more or less balanced over allowed nodes.
2359 * This routine only 'removes' the hugetlb page. The caller must make
2360 * an additional call to free the page to low level allocators.
2361 * Called with hugetlb_lock locked.
2362 */
2363static struct folio *remove_pool_hugetlb_folio(struct hstate *h,
2364 nodemask_t *nodes_allowed, bool acct_surplus)
2365{
2366 int nr_nodes, node;
2367 struct folio *folio = NULL;
2368
2369 lockdep_assert_held(&hugetlb_lock);
2370 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
2371 /*
2372 * If we're returning unused surplus pages, only examine
2373 * nodes with surplus pages.
2374 */
2375 if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
2376 !list_empty(&h->hugepage_freelists[node])) {
2377 folio = list_entry(h->hugepage_freelists[node].next,
2378 struct folio, lru);
2379 remove_hugetlb_folio(h, folio, acct_surplus);
2380 break;
2381 }
2382 }
2383
2384 return folio;
2385}
2386
2387/*
2388 * Dissolve a given free hugepage into free buddy pages. This function does
2389 * nothing for in-use hugepages and non-hugepages.
2390 * This function returns values like below:
2391 *
2392 * -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages
2393 * when the system is under memory pressure and the feature of
2394 * freeing unused vmemmap pages associated with each hugetlb page
2395 * is enabled.
2396 * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
2397 * (allocated or reserved.)
2398 * 0: successfully dissolved free hugepages or the page is not a
2399 * hugepage (considered as already dissolved)
2400 */
2401int dissolve_free_huge_page(struct page *page)
2402{
2403 int rc = -EBUSY;
2404 struct folio *folio = page_folio(page);
2405
2406retry:
2407 /* Not to disrupt normal path by vainly holding hugetlb_lock */
2408 if (!folio_test_hugetlb(folio))
2409 return 0;
2410
2411 spin_lock_irq(&hugetlb_lock);
2412 if (!folio_test_hugetlb(folio)) {
2413 rc = 0;
2414 goto out;
2415 }
2416
2417 if (!folio_ref_count(folio)) {
2418 struct hstate *h = folio_hstate(folio);
2419 if (!available_huge_pages(h))
2420 goto out;
2421
2422 /*
2423 * We should make sure that the page is already on the free list
2424 * when it is dissolved.
2425 */
2426 if (unlikely(!folio_test_hugetlb_freed(folio))) {
2427 spin_unlock_irq(&hugetlb_lock);
2428 cond_resched();
2429
2430 /*
2431 * Theoretically, we should return -EBUSY when we
2432 * encounter this race. In fact, we have a chance
2433 * to successfully dissolve the page if we do a
2434 * retry. Because the race window is quite small.
2435 * If we seize this opportunity, it is an optimization
2436 * for increasing the success rate of dissolving page.
2437 */
2438 goto retry;
2439 }
2440
2441 remove_hugetlb_folio(h, folio, false);
2442 h->max_huge_pages--;
2443 spin_unlock_irq(&hugetlb_lock);
2444
2445 /*
2446 * Normally update_and_free_hugtlb_folio will allocate required vmemmmap
2447 * before freeing the page. update_and_free_hugtlb_folio will fail to
2448 * free the page if it can not allocate required vmemmap. We
2449 * need to adjust max_huge_pages if the page is not freed.
2450 * Attempt to allocate vmemmmap here so that we can take
2451 * appropriate action on failure.
2452 *
2453 * The folio_test_hugetlb check here is because
2454 * remove_hugetlb_folio will clear hugetlb folio flag for
2455 * non-vmemmap optimized hugetlb folios.
2456 */
2457 if (folio_test_hugetlb(folio)) {
2458 rc = hugetlb_vmemmap_restore_folio(h, folio);
2459 if (rc) {
2460 spin_lock_irq(&hugetlb_lock);
2461 add_hugetlb_folio(h, folio, false);
2462 h->max_huge_pages++;
2463 goto out;
2464 }
2465 } else
2466 rc = 0;
2467
2468 update_and_free_hugetlb_folio(h, folio, false);
2469 return rc;
2470 }
2471out:
2472 spin_unlock_irq(&hugetlb_lock);
2473 return rc;
2474}
2475
2476/*
2477 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
2478 * make specified memory blocks removable from the system.
2479 * Note that this will dissolve a free gigantic hugepage completely, if any
2480 * part of it lies within the given range.
2481 * Also note that if dissolve_free_huge_page() returns with an error, all
2482 * free hugepages that were dissolved before that error are lost.
2483 */
2484int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
2485{
2486 unsigned long pfn;
2487 struct page *page;
2488 int rc = 0;
2489 unsigned int order;
2490 struct hstate *h;
2491
2492 if (!hugepages_supported())
2493 return rc;
2494
2495 order = huge_page_order(&default_hstate);
2496 for_each_hstate(h)
2497 order = min(order, huge_page_order(h));
2498
2499 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) {
2500 page = pfn_to_page(pfn);
2501 rc = dissolve_free_huge_page(page);
2502 if (rc)
2503 break;
2504 }
2505
2506 return rc;
2507}
2508
2509/*
2510 * Allocates a fresh surplus page from the page allocator.
2511 */
2512static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h,
2513 gfp_t gfp_mask, int nid, nodemask_t *nmask)
2514{
2515 struct folio *folio = NULL;
2516
2517 if (hstate_is_gigantic(h))
2518 return NULL;
2519
2520 spin_lock_irq(&hugetlb_lock);
2521 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
2522 goto out_unlock;
2523 spin_unlock_irq(&hugetlb_lock);
2524
2525 folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL);
2526 if (!folio)
2527 return NULL;
2528
2529 spin_lock_irq(&hugetlb_lock);
2530 /*
2531 * We could have raced with the pool size change.
2532 * Double check that and simply deallocate the new page
2533 * if we would end up overcommiting the surpluses. Abuse
2534 * temporary page to workaround the nasty free_huge_folio
2535 * codeflow
2536 */
2537 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
2538 folio_set_hugetlb_temporary(folio);
2539 spin_unlock_irq(&hugetlb_lock);
2540 free_huge_folio(folio);
2541 return NULL;
2542 }
2543
2544 h->surplus_huge_pages++;
2545 h->surplus_huge_pages_node[folio_nid(folio)]++;
2546
2547out_unlock:
2548 spin_unlock_irq(&hugetlb_lock);
2549
2550 return folio;
2551}
2552
2553static struct folio *alloc_migrate_hugetlb_folio(struct hstate *h, gfp_t gfp_mask,
2554 int nid, nodemask_t *nmask)
2555{
2556 struct folio *folio;
2557
2558 if (hstate_is_gigantic(h))
2559 return NULL;
2560
2561 folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL);
2562 if (!folio)
2563 return NULL;
2564
2565 /* fresh huge pages are frozen */
2566 folio_ref_unfreeze(folio, 1);
2567 /*
2568 * We do not account these pages as surplus because they are only
2569 * temporary and will be released properly on the last reference
2570 */
2571 folio_set_hugetlb_temporary(folio);
2572
2573 return folio;
2574}
2575
2576/*
2577 * Use the VMA's mpolicy to allocate a huge page from the buddy.
2578 */
2579static
2580struct folio *alloc_buddy_hugetlb_folio_with_mpol(struct hstate *h,
2581 struct vm_area_struct *vma, unsigned long addr)
2582{
2583 struct folio *folio = NULL;
2584 struct mempolicy *mpol;
2585 gfp_t gfp_mask = htlb_alloc_mask(h);
2586 int nid;
2587 nodemask_t *nodemask;
2588
2589 nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
2590 if (mpol_is_preferred_many(mpol)) {
2591 gfp_t gfp = gfp_mask | __GFP_NOWARN;
2592
2593 gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
2594 folio = alloc_surplus_hugetlb_folio(h, gfp, nid, nodemask);
2595
2596 /* Fallback to all nodes if page==NULL */
2597 nodemask = NULL;
2598 }
2599
2600 if (!folio)
2601 folio = alloc_surplus_hugetlb_folio(h, gfp_mask, nid, nodemask);
2602 mpol_cond_put(mpol);
2603 return folio;
2604}
2605
2606/* folio migration callback function */
2607struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
2608 nodemask_t *nmask, gfp_t gfp_mask)
2609{
2610 spin_lock_irq(&hugetlb_lock);
2611 if (available_huge_pages(h)) {
2612 struct folio *folio;
2613
2614 folio = dequeue_hugetlb_folio_nodemask(h, gfp_mask,
2615 preferred_nid, nmask);
2616 if (folio) {
2617 spin_unlock_irq(&hugetlb_lock);
2618 return folio;
2619 }
2620 }
2621 spin_unlock_irq(&hugetlb_lock);
2622
2623 return alloc_migrate_hugetlb_folio(h, gfp_mask, preferred_nid, nmask);
2624}
2625
2626/*
2627 * Increase the hugetlb pool such that it can accommodate a reservation
2628 * of size 'delta'.
2629 */
2630static int gather_surplus_pages(struct hstate *h, long delta)
2631 __must_hold(&hugetlb_lock)
2632{
2633 LIST_HEAD(surplus_list);
2634 struct folio *folio, *tmp;
2635 int ret;
2636 long i;
2637 long needed, allocated;
2638 bool alloc_ok = true;
2639
2640 lockdep_assert_held(&hugetlb_lock);
2641 needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2642 if (needed <= 0) {
2643 h->resv_huge_pages += delta;
2644 return 0;
2645 }
2646
2647 allocated = 0;
2648
2649 ret = -ENOMEM;
2650retry:
2651 spin_unlock_irq(&hugetlb_lock);
2652 for (i = 0; i < needed; i++) {
2653 folio = alloc_surplus_hugetlb_folio(h, htlb_alloc_mask(h),
2654 NUMA_NO_NODE, NULL);
2655 if (!folio) {
2656 alloc_ok = false;
2657 break;
2658 }
2659 list_add(&folio->lru, &surplus_list);
2660 cond_resched();
2661 }
2662 allocated += i;
2663
2664 /*
2665 * After retaking hugetlb_lock, we need to recalculate 'needed'
2666 * because either resv_huge_pages or free_huge_pages may have changed.
2667 */
2668 spin_lock_irq(&hugetlb_lock);
2669 needed = (h->resv_huge_pages + delta) -
2670 (h->free_huge_pages + allocated);
2671 if (needed > 0) {
2672 if (alloc_ok)
2673 goto retry;
2674 /*
2675 * We were not able to allocate enough pages to
2676 * satisfy the entire reservation so we free what
2677 * we've allocated so far.
2678 */
2679 goto free;
2680 }
2681 /*
2682 * The surplus_list now contains _at_least_ the number of extra pages
2683 * needed to accommodate the reservation. Add the appropriate number
2684 * of pages to the hugetlb pool and free the extras back to the buddy
2685 * allocator. Commit the entire reservation here to prevent another
2686 * process from stealing the pages as they are added to the pool but
2687 * before they are reserved.
2688 */
2689 needed += allocated;
2690 h->resv_huge_pages += delta;
2691 ret = 0;
2692
2693 /* Free the needed pages to the hugetlb pool */
2694 list_for_each_entry_safe(folio, tmp, &surplus_list, lru) {
2695 if ((--needed) < 0)
2696 break;
2697 /* Add the page to the hugetlb allocator */
2698 enqueue_hugetlb_folio(h, folio);
2699 }
2700free:
2701 spin_unlock_irq(&hugetlb_lock);
2702
2703 /*
2704 * Free unnecessary surplus pages to the buddy allocator.
2705 * Pages have no ref count, call free_huge_folio directly.
2706 */
2707 list_for_each_entry_safe(folio, tmp, &surplus_list, lru)
2708 free_huge_folio(folio);
2709 spin_lock_irq(&hugetlb_lock);
2710
2711 return ret;
2712}
2713
2714/*
2715 * This routine has two main purposes:
2716 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
2717 * in unused_resv_pages. This corresponds to the prior adjustments made
2718 * to the associated reservation map.
2719 * 2) Free any unused surplus pages that may have been allocated to satisfy
2720 * the reservation. As many as unused_resv_pages may be freed.
2721 */
2722static void return_unused_surplus_pages(struct hstate *h,
2723 unsigned long unused_resv_pages)
2724{
2725 unsigned long nr_pages;
2726 LIST_HEAD(page_list);
2727
2728 lockdep_assert_held(&hugetlb_lock);
2729 /* Uncommit the reservation */
2730 h->resv_huge_pages -= unused_resv_pages;
2731
2732 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
2733 goto out;
2734
2735 /*
2736 * Part (or even all) of the reservation could have been backed
2737 * by pre-allocated pages. Only free surplus pages.
2738 */
2739 nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2740
2741 /*
2742 * We want to release as many surplus pages as possible, spread
2743 * evenly across all nodes with memory. Iterate across these nodes
2744 * until we can no longer free unreserved surplus pages. This occurs
2745 * when the nodes with surplus pages have no free pages.
2746 * remove_pool_hugetlb_folio() will balance the freed pages across the
2747 * on-line nodes with memory and will handle the hstate accounting.
2748 */
2749 while (nr_pages--) {
2750 struct folio *folio;
2751
2752 folio = remove_pool_hugetlb_folio(h, &node_states[N_MEMORY], 1);
2753 if (!folio)
2754 goto out;
2755
2756 list_add(&folio->lru, &page_list);
2757 }
2758
2759out:
2760 spin_unlock_irq(&hugetlb_lock);
2761 update_and_free_pages_bulk(h, &page_list);
2762 spin_lock_irq(&hugetlb_lock);
2763}
2764
2765
2766/*
2767 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2768 * are used by the huge page allocation routines to manage reservations.
2769 *
2770 * vma_needs_reservation is called to determine if the huge page at addr
2771 * within the vma has an associated reservation. If a reservation is
2772 * needed, the value 1 is returned. The caller is then responsible for
2773 * managing the global reservation and subpool usage counts. After
2774 * the huge page has been allocated, vma_commit_reservation is called
2775 * to add the page to the reservation map. If the page allocation fails,
2776 * the reservation must be ended instead of committed. vma_end_reservation
2777 * is called in such cases.
2778 *
2779 * In the normal case, vma_commit_reservation returns the same value
2780 * as the preceding vma_needs_reservation call. The only time this
2781 * is not the case is if a reserve map was changed between calls. It
2782 * is the responsibility of the caller to notice the difference and
2783 * take appropriate action.
2784 *
2785 * vma_add_reservation is used in error paths where a reservation must
2786 * be restored when a newly allocated huge page must be freed. It is
2787 * to be called after calling vma_needs_reservation to determine if a
2788 * reservation exists.
2789 *
2790 * vma_del_reservation is used in error paths where an entry in the reserve
2791 * map was created during huge page allocation and must be removed. It is to
2792 * be called after calling vma_needs_reservation to determine if a reservation
2793 * exists.
2794 */
2795enum vma_resv_mode {
2796 VMA_NEEDS_RESV,
2797 VMA_COMMIT_RESV,
2798 VMA_END_RESV,
2799 VMA_ADD_RESV,
2800 VMA_DEL_RESV,
2801};
2802static long __vma_reservation_common(struct hstate *h,
2803 struct vm_area_struct *vma, unsigned long addr,
2804 enum vma_resv_mode mode)
2805{
2806 struct resv_map *resv;
2807 pgoff_t idx;
2808 long ret;
2809 long dummy_out_regions_needed;
2810
2811 resv = vma_resv_map(vma);
2812 if (!resv)
2813 return 1;
2814
2815 idx = vma_hugecache_offset(h, vma, addr);
2816 switch (mode) {
2817 case VMA_NEEDS_RESV:
2818 ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
2819 /* We assume that vma_reservation_* routines always operate on
2820 * 1 page, and that adding to resv map a 1 page entry can only
2821 * ever require 1 region.
2822 */
2823 VM_BUG_ON(dummy_out_regions_needed != 1);
2824 break;
2825 case VMA_COMMIT_RESV:
2826 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2827 /* region_add calls of range 1 should never fail. */
2828 VM_BUG_ON(ret < 0);
2829 break;
2830 case VMA_END_RESV:
2831 region_abort(resv, idx, idx + 1, 1);
2832 ret = 0;
2833 break;
2834 case VMA_ADD_RESV:
2835 if (vma->vm_flags & VM_MAYSHARE) {
2836 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2837 /* region_add calls of range 1 should never fail. */
2838 VM_BUG_ON(ret < 0);
2839 } else {
2840 region_abort(resv, idx, idx + 1, 1);
2841 ret = region_del(resv, idx, idx + 1);
2842 }
2843 break;
2844 case VMA_DEL_RESV:
2845 if (vma->vm_flags & VM_MAYSHARE) {
2846 region_abort(resv, idx, idx + 1, 1);
2847 ret = region_del(resv, idx, idx + 1);
2848 } else {
2849 ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2850 /* region_add calls of range 1 should never fail. */
2851 VM_BUG_ON(ret < 0);
2852 }
2853 break;
2854 default:
2855 BUG();
2856 }
2857
2858 if (vma->vm_flags & VM_MAYSHARE || mode == VMA_DEL_RESV)
2859 return ret;
2860 /*
2861 * We know private mapping must have HPAGE_RESV_OWNER set.
2862 *
2863 * In most cases, reserves always exist for private mappings.
2864 * However, a file associated with mapping could have been
2865 * hole punched or truncated after reserves were consumed.
2866 * As subsequent fault on such a range will not use reserves.
2867 * Subtle - The reserve map for private mappings has the
2868 * opposite meaning than that of shared mappings. If NO
2869 * entry is in the reserve map, it means a reservation exists.
2870 * If an entry exists in the reserve map, it means the
2871 * reservation has already been consumed. As a result, the
2872 * return value of this routine is the opposite of the
2873 * value returned from reserve map manipulation routines above.
2874 */
2875 if (ret > 0)
2876 return 0;
2877 if (ret == 0)
2878 return 1;
2879 return ret;
2880}
2881
2882static long vma_needs_reservation(struct hstate *h,
2883 struct vm_area_struct *vma, unsigned long addr)
2884{
2885 return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2886}
2887
2888static long vma_commit_reservation(struct hstate *h,
2889 struct vm_area_struct *vma, unsigned long addr)
2890{
2891 return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
2892}
2893
2894static void vma_end_reservation(struct hstate *h,
2895 struct vm_area_struct *vma, unsigned long addr)
2896{
2897 (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2898}
2899
2900static long vma_add_reservation(struct hstate *h,
2901 struct vm_area_struct *vma, unsigned long addr)
2902{
2903 return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
2904}
2905
2906static long vma_del_reservation(struct hstate *h,
2907 struct vm_area_struct *vma, unsigned long addr)
2908{
2909 return __vma_reservation_common(h, vma, addr, VMA_DEL_RESV);
2910}
2911
2912/*
2913 * This routine is called to restore reservation information on error paths.
2914 * It should ONLY be called for folios allocated via alloc_hugetlb_folio(),
2915 * and the hugetlb mutex should remain held when calling this routine.
2916 *
2917 * It handles two specific cases:
2918 * 1) A reservation was in place and the folio consumed the reservation.
2919 * hugetlb_restore_reserve is set in the folio.
2920 * 2) No reservation was in place for the page, so hugetlb_restore_reserve is
2921 * not set. However, alloc_hugetlb_folio always updates the reserve map.
2922 *
2923 * In case 1, free_huge_folio later in the error path will increment the
2924 * global reserve count. But, free_huge_folio does not have enough context
2925 * to adjust the reservation map. This case deals primarily with private
2926 * mappings. Adjust the reserve map here to be consistent with global
2927 * reserve count adjustments to be made by free_huge_folio. Make sure the
2928 * reserve map indicates there is a reservation present.
2929 *
2930 * In case 2, simply undo reserve map modifications done by alloc_hugetlb_folio.
2931 */
2932void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
2933 unsigned long address, struct folio *folio)
2934{
2935 long rc = vma_needs_reservation(h, vma, address);
2936
2937 if (folio_test_hugetlb_restore_reserve(folio)) {
2938 if (unlikely(rc < 0))
2939 /*
2940 * Rare out of memory condition in reserve map
2941 * manipulation. Clear hugetlb_restore_reserve so
2942 * that global reserve count will not be incremented
2943 * by free_huge_folio. This will make it appear
2944 * as though the reservation for this folio was
2945 * consumed. This may prevent the task from
2946 * faulting in the folio at a later time. This
2947 * is better than inconsistent global huge page
2948 * accounting of reserve counts.
2949 */
2950 folio_clear_hugetlb_restore_reserve(folio);
2951 else if (rc)
2952 (void)vma_add_reservation(h, vma, address);
2953 else
2954 vma_end_reservation(h, vma, address);
2955 } else {
2956 if (!rc) {
2957 /*
2958 * This indicates there is an entry in the reserve map
2959 * not added by alloc_hugetlb_folio. We know it was added
2960 * before the alloc_hugetlb_folio call, otherwise
2961 * hugetlb_restore_reserve would be set on the folio.
2962 * Remove the entry so that a subsequent allocation
2963 * does not consume a reservation.
2964 */
2965 rc = vma_del_reservation(h, vma, address);
2966 if (rc < 0)
2967 /*
2968 * VERY rare out of memory condition. Since
2969 * we can not delete the entry, set
2970 * hugetlb_restore_reserve so that the reserve
2971 * count will be incremented when the folio
2972 * is freed. This reserve will be consumed
2973 * on a subsequent allocation.
2974 */
2975 folio_set_hugetlb_restore_reserve(folio);
2976 } else if (rc < 0) {
2977 /*
2978 * Rare out of memory condition from
2979 * vma_needs_reservation call. Memory allocation is
2980 * only attempted if a new entry is needed. Therefore,
2981 * this implies there is not an entry in the
2982 * reserve map.
2983 *
2984 * For shared mappings, no entry in the map indicates
2985 * no reservation. We are done.
2986 */
2987 if (!(vma->vm_flags & VM_MAYSHARE))
2988 /*
2989 * For private mappings, no entry indicates
2990 * a reservation is present. Since we can
2991 * not add an entry, set hugetlb_restore_reserve
2992 * on the folio so reserve count will be
2993 * incremented when freed. This reserve will
2994 * be consumed on a subsequent allocation.
2995 */
2996 folio_set_hugetlb_restore_reserve(folio);
2997 } else
2998 /*
2999 * No reservation present, do nothing
3000 */
3001 vma_end_reservation(h, vma, address);
3002 }
3003}
3004
3005/*
3006 * alloc_and_dissolve_hugetlb_folio - Allocate a new folio and dissolve
3007 * the old one
3008 * @h: struct hstate old page belongs to
3009 * @old_folio: Old folio to dissolve
3010 * @list: List to isolate the page in case we need to
3011 * Returns 0 on success, otherwise negated error.
3012 */
3013static int alloc_and_dissolve_hugetlb_folio(struct hstate *h,
3014 struct folio *old_folio, struct list_head *list)
3015{
3016 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
3017 int nid = folio_nid(old_folio);
3018 struct folio *new_folio = NULL;
3019 int ret = 0;
3020
3021retry:
3022 spin_lock_irq(&hugetlb_lock);
3023 if (!folio_test_hugetlb(old_folio)) {
3024 /*
3025 * Freed from under us. Drop new_folio too.
3026 */
3027 goto free_new;
3028 } else if (folio_ref_count(old_folio)) {
3029 bool isolated;
3030
3031 /*
3032 * Someone has grabbed the folio, try to isolate it here.
3033 * Fail with -EBUSY if not possible.
3034 */
3035 spin_unlock_irq(&hugetlb_lock);
3036 isolated = isolate_hugetlb(old_folio, list);
3037 ret = isolated ? 0 : -EBUSY;
3038 spin_lock_irq(&hugetlb_lock);
3039 goto free_new;
3040 } else if (!folio_test_hugetlb_freed(old_folio)) {
3041 /*
3042 * Folio's refcount is 0 but it has not been enqueued in the
3043 * freelist yet. Race window is small, so we can succeed here if
3044 * we retry.
3045 */
3046 spin_unlock_irq(&hugetlb_lock);
3047 cond_resched();
3048 goto retry;
3049 } else {
3050 if (!new_folio) {
3051 spin_unlock_irq(&hugetlb_lock);
3052 new_folio = alloc_buddy_hugetlb_folio(h, gfp_mask, nid,
3053 NULL, NULL);
3054 if (!new_folio)
3055 return -ENOMEM;
3056 __prep_new_hugetlb_folio(h, new_folio);
3057 goto retry;
3058 }
3059
3060 /*
3061 * Ok, old_folio is still a genuine free hugepage. Remove it from
3062 * the freelist and decrease the counters. These will be
3063 * incremented again when calling __prep_account_new_huge_page()
3064 * and enqueue_hugetlb_folio() for new_folio. The counters will
3065 * remain stable since this happens under the lock.
3066 */
3067 remove_hugetlb_folio(h, old_folio, false);
3068
3069 /*
3070 * Ref count on new_folio is already zero as it was dropped
3071 * earlier. It can be directly added to the pool free list.
3072 */
3073 __prep_account_new_huge_page(h, nid);
3074 enqueue_hugetlb_folio(h, new_folio);
3075
3076 /*
3077 * Folio has been replaced, we can safely free the old one.
3078 */
3079 spin_unlock_irq(&hugetlb_lock);
3080 update_and_free_hugetlb_folio(h, old_folio, false);
3081 }
3082
3083 return ret;
3084
3085free_new:
3086 spin_unlock_irq(&hugetlb_lock);
3087 if (new_folio) {
3088 /* Folio has a zero ref count, but needs a ref to be freed */
3089 folio_ref_unfreeze(new_folio, 1);
3090 update_and_free_hugetlb_folio(h, new_folio, false);
3091 }
3092
3093 return ret;
3094}
3095
3096int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
3097{
3098 struct hstate *h;
3099 struct folio *folio = page_folio(page);
3100 int ret = -EBUSY;
3101
3102 /*
3103 * The page might have been dissolved from under our feet, so make sure
3104 * to carefully check the state under the lock.
3105 * Return success when racing as if we dissolved the page ourselves.
3106 */
3107 spin_lock_irq(&hugetlb_lock);
3108 if (folio_test_hugetlb(folio)) {
3109 h = folio_hstate(folio);
3110 } else {
3111 spin_unlock_irq(&hugetlb_lock);
3112 return 0;
3113 }
3114 spin_unlock_irq(&hugetlb_lock);
3115
3116 /*
3117 * Fence off gigantic pages as there is a cyclic dependency between
3118 * alloc_contig_range and them. Return -ENOMEM as this has the effect
3119 * of bailing out right away without further retrying.
3120 */
3121 if (hstate_is_gigantic(h))
3122 return -ENOMEM;
3123
3124 if (folio_ref_count(folio) && isolate_hugetlb(folio, list))
3125 ret = 0;
3126 else if (!folio_ref_count(folio))
3127 ret = alloc_and_dissolve_hugetlb_folio(h, folio, list);
3128
3129 return ret;
3130}
3131
3132struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
3133 unsigned long addr, int avoid_reserve)
3134{
3135 struct hugepage_subpool *spool = subpool_vma(vma);
3136 struct hstate *h = hstate_vma(vma);
3137 struct folio *folio;
3138 long map_chg, map_commit, nr_pages = pages_per_huge_page(h);
3139 long gbl_chg;
3140 int memcg_charge_ret, ret, idx;
3141 struct hugetlb_cgroup *h_cg = NULL;
3142 struct mem_cgroup *memcg;
3143 bool deferred_reserve;
3144 gfp_t gfp = htlb_alloc_mask(h) | __GFP_RETRY_MAYFAIL;
3145
3146 memcg = get_mem_cgroup_from_current();
3147 memcg_charge_ret = mem_cgroup_hugetlb_try_charge(memcg, gfp, nr_pages);
3148 if (memcg_charge_ret == -ENOMEM) {
3149 mem_cgroup_put(memcg);
3150 return ERR_PTR(-ENOMEM);
3151 }
3152
3153 idx = hstate_index(h);
3154 /*
3155 * Examine the region/reserve map to determine if the process
3156 * has a reservation for the page to be allocated. A return
3157 * code of zero indicates a reservation exists (no change).
3158 */
3159 map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
3160 if (map_chg < 0) {
3161 if (!memcg_charge_ret)
3162 mem_cgroup_cancel_charge(memcg, nr_pages);
3163 mem_cgroup_put(memcg);
3164 return ERR_PTR(-ENOMEM);
3165 }
3166
3167 /*
3168 * Processes that did not create the mapping will have no
3169 * reserves as indicated by the region/reserve map. Check
3170 * that the allocation will not exceed the subpool limit.
3171 * Allocations for MAP_NORESERVE mappings also need to be
3172 * checked against any subpool limit.
3173 */
3174 if (map_chg || avoid_reserve) {
3175 gbl_chg = hugepage_subpool_get_pages(spool, 1);
3176 if (gbl_chg < 0)
3177 goto out_end_reservation;
3178
3179 /*
3180 * Even though there was no reservation in the region/reserve
3181 * map, there could be reservations associated with the
3182 * subpool that can be used. This would be indicated if the
3183 * return value of hugepage_subpool_get_pages() is zero.
3184 * However, if avoid_reserve is specified we still avoid even
3185 * the subpool reservations.
3186 */
3187 if (avoid_reserve)
3188 gbl_chg = 1;
3189 }
3190
3191 /* If this allocation is not consuming a reservation, charge it now.
3192 */
3193 deferred_reserve = map_chg || avoid_reserve;
3194 if (deferred_reserve) {
3195 ret = hugetlb_cgroup_charge_cgroup_rsvd(
3196 idx, pages_per_huge_page(h), &h_cg);
3197 if (ret)
3198 goto out_subpool_put;
3199 }
3200
3201 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
3202 if (ret)
3203 goto out_uncharge_cgroup_reservation;
3204
3205 spin_lock_irq(&hugetlb_lock);
3206 /*
3207 * glb_chg is passed to indicate whether or not a page must be taken
3208 * from the global free pool (global change). gbl_chg == 0 indicates
3209 * a reservation exists for the allocation.
3210 */
3211 folio = dequeue_hugetlb_folio_vma(h, vma, addr, avoid_reserve, gbl_chg);
3212 if (!folio) {
3213 spin_unlock_irq(&hugetlb_lock);
3214 folio = alloc_buddy_hugetlb_folio_with_mpol(h, vma, addr);
3215 if (!folio)
3216 goto out_uncharge_cgroup;
3217 spin_lock_irq(&hugetlb_lock);
3218 if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
3219 folio_set_hugetlb_restore_reserve(folio);
3220 h->resv_huge_pages--;
3221 }
3222 list_add(&folio->lru, &h->hugepage_activelist);
3223 folio_ref_unfreeze(folio, 1);
3224 /* Fall through */
3225 }
3226
3227 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, folio);
3228 /* If allocation is not consuming a reservation, also store the
3229 * hugetlb_cgroup pointer on the page.
3230 */
3231 if (deferred_reserve) {
3232 hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
3233 h_cg, folio);
3234 }
3235
3236 spin_unlock_irq(&hugetlb_lock);
3237
3238 hugetlb_set_folio_subpool(folio, spool);
3239
3240 map_commit = vma_commit_reservation(h, vma, addr);
3241 if (unlikely(map_chg > map_commit)) {
3242 /*
3243 * The page was added to the reservation map between
3244 * vma_needs_reservation and vma_commit_reservation.
3245 * This indicates a race with hugetlb_reserve_pages.
3246 * Adjust for the subpool count incremented above AND
3247 * in hugetlb_reserve_pages for the same page. Also,
3248 * the reservation count added in hugetlb_reserve_pages
3249 * no longer applies.
3250 */
3251 long rsv_adjust;
3252
3253 rsv_adjust = hugepage_subpool_put_pages(spool, 1);
3254 hugetlb_acct_memory(h, -rsv_adjust);
3255 if (deferred_reserve) {
3256 spin_lock_irq(&hugetlb_lock);
3257 hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h),
3258 pages_per_huge_page(h), folio);
3259 spin_unlock_irq(&hugetlb_lock);
3260 }
3261 }
3262
3263 if (!memcg_charge_ret)
3264 mem_cgroup_commit_charge(folio, memcg);
3265 mem_cgroup_put(memcg);
3266
3267 return folio;
3268
3269out_uncharge_cgroup:
3270 hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
3271out_uncharge_cgroup_reservation:
3272 if (deferred_reserve)
3273 hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
3274 h_cg);
3275out_subpool_put:
3276 if (map_chg || avoid_reserve)
3277 hugepage_subpool_put_pages(spool, 1);
3278out_end_reservation:
3279 vma_end_reservation(h, vma, addr);
3280 if (!memcg_charge_ret)
3281 mem_cgroup_cancel_charge(memcg, nr_pages);
3282 mem_cgroup_put(memcg);
3283 return ERR_PTR(-ENOSPC);
3284}
3285
3286int alloc_bootmem_huge_page(struct hstate *h, int nid)
3287 __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
3288int __alloc_bootmem_huge_page(struct hstate *h, int nid)
3289{
3290 struct huge_bootmem_page *m = NULL; /* initialize for clang */
3291 int nr_nodes, node = nid;
3292
3293 /* do node specific alloc */
3294 if (nid != NUMA_NO_NODE) {
3295 m = memblock_alloc_try_nid_raw(huge_page_size(h), huge_page_size(h),
3296 0, MEMBLOCK_ALLOC_ACCESSIBLE, nid);
3297 if (!m)
3298 return 0;
3299 goto found;
3300 }
3301 /* allocate from next node when distributing huge pages */
3302 for_each_node_mask_to_alloc(&h->next_nid_to_alloc, nr_nodes, node, &node_states[N_MEMORY]) {
3303 m = memblock_alloc_try_nid_raw(
3304 huge_page_size(h), huge_page_size(h),
3305 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
3306 /*
3307 * Use the beginning of the huge page to store the
3308 * huge_bootmem_page struct (until gather_bootmem
3309 * puts them into the mem_map).
3310 */
3311 if (!m)
3312 return 0;
3313 goto found;
3314 }
3315
3316found:
3317
3318 /*
3319 * Only initialize the head struct page in memmap_init_reserved_pages,
3320 * rest of the struct pages will be initialized by the HugeTLB
3321 * subsystem itself.
3322 * The head struct page is used to get folio information by the HugeTLB
3323 * subsystem like zone id and node id.
3324 */
3325 memblock_reserved_mark_noinit(virt_to_phys((void *)m + PAGE_SIZE),
3326 huge_page_size(h) - PAGE_SIZE);
3327 /* Put them into a private list first because mem_map is not up yet */
3328 INIT_LIST_HEAD(&m->list);
3329 list_add(&m->list, &huge_boot_pages[node]);
3330 m->hstate = h;
3331 return 1;
3332}
3333
3334/* Initialize [start_page:end_page_number] tail struct pages of a hugepage */
3335static void __init hugetlb_folio_init_tail_vmemmap(struct folio *folio,
3336 unsigned long start_page_number,
3337 unsigned long end_page_number)
3338{
3339 enum zone_type zone = zone_idx(folio_zone(folio));
3340 int nid = folio_nid(folio);
3341 unsigned long head_pfn = folio_pfn(folio);
3342 unsigned long pfn, end_pfn = head_pfn + end_page_number;
3343 int ret;
3344
3345 for (pfn = head_pfn + start_page_number; pfn < end_pfn; pfn++) {
3346 struct page *page = pfn_to_page(pfn);
3347
3348 __init_single_page(page, pfn, zone, nid);
3349 prep_compound_tail((struct page *)folio, pfn - head_pfn);
3350 ret = page_ref_freeze(page, 1);
3351 VM_BUG_ON(!ret);
3352 }
3353}
3354
3355static void __init hugetlb_folio_init_vmemmap(struct folio *folio,
3356 struct hstate *h,
3357 unsigned long nr_pages)
3358{
3359 int ret;
3360
3361 /* Prepare folio head */
3362 __folio_clear_reserved(folio);
3363 __folio_set_head(folio);
3364 ret = folio_ref_freeze(folio, 1);
3365 VM_BUG_ON(!ret);
3366 /* Initialize the necessary tail struct pages */
3367 hugetlb_folio_init_tail_vmemmap(folio, 1, nr_pages);
3368 prep_compound_head((struct page *)folio, huge_page_order(h));
3369}
3370
3371static void __init prep_and_add_bootmem_folios(struct hstate *h,
3372 struct list_head *folio_list)
3373{
3374 unsigned long flags;
3375 struct folio *folio, *tmp_f;
3376
3377 /* Send list for bulk vmemmap optimization processing */
3378 hugetlb_vmemmap_optimize_folios(h, folio_list);
3379
3380 list_for_each_entry_safe(folio, tmp_f, folio_list, lru) {
3381 if (!folio_test_hugetlb_vmemmap_optimized(folio)) {
3382 /*
3383 * If HVO fails, initialize all tail struct pages
3384 * We do not worry about potential long lock hold
3385 * time as this is early in boot and there should
3386 * be no contention.
3387 */
3388 hugetlb_folio_init_tail_vmemmap(folio,
3389 HUGETLB_VMEMMAP_RESERVE_PAGES,
3390 pages_per_huge_page(h));
3391 }
3392 /* Subdivide locks to achieve better parallel performance */
3393 spin_lock_irqsave(&hugetlb_lock, flags);
3394 __prep_account_new_huge_page(h, folio_nid(folio));
3395 enqueue_hugetlb_folio(h, folio);
3396 spin_unlock_irqrestore(&hugetlb_lock, flags);
3397 }
3398}
3399
3400/*
3401 * Put bootmem huge pages into the standard lists after mem_map is up.
3402 * Note: This only applies to gigantic (order > MAX_PAGE_ORDER) pages.
3403 */
3404static void __init gather_bootmem_prealloc_node(unsigned long nid)
3405{
3406 LIST_HEAD(folio_list);
3407 struct huge_bootmem_page *m;
3408 struct hstate *h = NULL, *prev_h = NULL;
3409
3410 list_for_each_entry(m, &huge_boot_pages[nid], list) {
3411 struct page *page = virt_to_page(m);
3412 struct folio *folio = (void *)page;
3413
3414 h = m->hstate;
3415 /*
3416 * It is possible to have multiple huge page sizes (hstates)
3417 * in this list. If so, process each size separately.
3418 */
3419 if (h != prev_h && prev_h != NULL)
3420 prep_and_add_bootmem_folios(prev_h, &folio_list);
3421 prev_h = h;
3422
3423 VM_BUG_ON(!hstate_is_gigantic(h));
3424 WARN_ON(folio_ref_count(folio) != 1);
3425
3426 hugetlb_folio_init_vmemmap(folio, h,
3427 HUGETLB_VMEMMAP_RESERVE_PAGES);
3428 init_new_hugetlb_folio(h, folio);
3429 list_add(&folio->lru, &folio_list);
3430
3431 /*
3432 * We need to restore the 'stolen' pages to totalram_pages
3433 * in order to fix confusing memory reports from free(1) and
3434 * other side-effects, like CommitLimit going negative.
3435 */
3436 adjust_managed_page_count(page, pages_per_huge_page(h));
3437 cond_resched();
3438 }
3439
3440 prep_and_add_bootmem_folios(h, &folio_list);
3441}
3442
3443static void __init gather_bootmem_prealloc_parallel(unsigned long start,
3444 unsigned long end, void *arg)
3445{
3446 int nid;
3447
3448 for (nid = start; nid < end; nid++)
3449 gather_bootmem_prealloc_node(nid);
3450}
3451
3452static void __init gather_bootmem_prealloc(void)
3453{
3454 struct padata_mt_job job = {
3455 .thread_fn = gather_bootmem_prealloc_parallel,
3456 .fn_arg = NULL,
3457 .start = 0,
3458 .size = num_node_state(N_MEMORY),
3459 .align = 1,
3460 .min_chunk = 1,
3461 .max_threads = num_node_state(N_MEMORY),
3462 .numa_aware = true,
3463 };
3464
3465 padata_do_multithreaded(&job);
3466}
3467
3468static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
3469{
3470 unsigned long i;
3471 char buf[32];
3472
3473 for (i = 0; i < h->max_huge_pages_node[nid]; ++i) {
3474 if (hstate_is_gigantic(h)) {
3475 if (!alloc_bootmem_huge_page(h, nid))
3476 break;
3477 } else {
3478 struct folio *folio;
3479 gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
3480
3481 folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid,
3482 &node_states[N_MEMORY], NULL);
3483 if (!folio)
3484 break;
3485 free_huge_folio(folio); /* free it into the hugepage allocator */
3486 }
3487 cond_resched();
3488 }
3489 if (i == h->max_huge_pages_node[nid])
3490 return;
3491
3492 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
3493 pr_warn("HugeTLB: allocating %u of page size %s failed node%d. Only allocated %lu hugepages.\n",
3494 h->max_huge_pages_node[nid], buf, nid, i);
3495 h->max_huge_pages -= (h->max_huge_pages_node[nid] - i);
3496 h->max_huge_pages_node[nid] = i;
3497}
3498
3499static bool __init hugetlb_hstate_alloc_pages_specific_nodes(struct hstate *h)
3500{
3501 int i;
3502 bool node_specific_alloc = false;
3503
3504 for_each_online_node(i) {
3505 if (h->max_huge_pages_node[i] > 0) {
3506 hugetlb_hstate_alloc_pages_onenode(h, i);
3507 node_specific_alloc = true;
3508 }
3509 }
3510
3511 return node_specific_alloc;
3512}
3513
3514static void __init hugetlb_hstate_alloc_pages_errcheck(unsigned long allocated, struct hstate *h)
3515{
3516 if (allocated < h->max_huge_pages) {
3517 char buf[32];
3518
3519 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
3520 pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
3521 h->max_huge_pages, buf, allocated);
3522 h->max_huge_pages = allocated;
3523 }
3524}
3525
3526static void __init hugetlb_pages_alloc_boot_node(unsigned long start, unsigned long end, void *arg)
3527{
3528 struct hstate *h = (struct hstate *)arg;
3529 int i, num = end - start;
3530 nodemask_t node_alloc_noretry;
3531 LIST_HEAD(folio_list);
3532 int next_node = first_online_node;
3533
3534 /* Bit mask controlling how hard we retry per-node allocations.*/
3535 nodes_clear(node_alloc_noretry);
3536
3537 for (i = 0; i < num; ++i) {
3538 struct folio *folio = alloc_pool_huge_folio(h, &node_states[N_MEMORY],
3539 &node_alloc_noretry, &next_node);
3540 if (!folio)
3541 break;
3542
3543 list_move(&folio->lru, &folio_list);
3544 cond_resched();
3545 }
3546
3547 prep_and_add_allocated_folios(h, &folio_list);
3548}
3549
3550static unsigned long __init hugetlb_gigantic_pages_alloc_boot(struct hstate *h)
3551{
3552 unsigned long i;
3553
3554 for (i = 0; i < h->max_huge_pages; ++i) {
3555 if (!alloc_bootmem_huge_page(h, NUMA_NO_NODE))
3556 break;
3557 cond_resched();
3558 }
3559
3560 return i;
3561}
3562
3563static unsigned long __init hugetlb_pages_alloc_boot(struct hstate *h)
3564{
3565 struct padata_mt_job job = {
3566 .fn_arg = h,
3567 .align = 1,
3568 .numa_aware = true
3569 };
3570
3571 job.thread_fn = hugetlb_pages_alloc_boot_node;
3572 job.start = 0;
3573 job.size = h->max_huge_pages;
3574
3575 /*
3576 * job.max_threads is twice the num_node_state(N_MEMORY),
3577 *
3578 * Tests below indicate that a multiplier of 2 significantly improves
3579 * performance, and although larger values also provide improvements,
3580 * the gains are marginal.
3581 *
3582 * Therefore, choosing 2 as the multiplier strikes a good balance between
3583 * enhancing parallel processing capabilities and maintaining efficient
3584 * resource management.
3585 *
3586 * +------------+-------+-------+-------+-------+-------+
3587 * | multiplier | 1 | 2 | 3 | 4 | 5 |
3588 * +------------+-------+-------+-------+-------+-------+
3589 * | 256G 2node | 358ms | 215ms | 157ms | 134ms | 126ms |
3590 * | 2T 4node | 979ms | 679ms | 543ms | 489ms | 481ms |
3591 * | 50G 2node | 71ms | 44ms | 37ms | 30ms | 31ms |
3592 * +------------+-------+-------+-------+-------+-------+
3593 */
3594 job.max_threads = num_node_state(N_MEMORY) * 2;
3595 job.min_chunk = h->max_huge_pages / num_node_state(N_MEMORY) / 2;
3596 padata_do_multithreaded(&job);
3597
3598 return h->nr_huge_pages;
3599}
3600
3601/*
3602 * NOTE: this routine is called in different contexts for gigantic and
3603 * non-gigantic pages.
3604 * - For gigantic pages, this is called early in the boot process and
3605 * pages are allocated from memblock allocated or something similar.
3606 * Gigantic pages are actually added to pools later with the routine
3607 * gather_bootmem_prealloc.
3608 * - For non-gigantic pages, this is called later in the boot process after
3609 * all of mm is up and functional. Pages are allocated from buddy and
3610 * then added to hugetlb pools.
3611 */
3612static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
3613{
3614 unsigned long allocated;
3615 static bool initialized __initdata;
3616
3617 /* skip gigantic hugepages allocation if hugetlb_cma enabled */
3618 if (hstate_is_gigantic(h) && hugetlb_cma_size) {
3619 pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
3620 return;
3621 }
3622
3623 /* hugetlb_hstate_alloc_pages will be called many times, initialize huge_boot_pages once */
3624 if (!initialized) {
3625 int i = 0;
3626
3627 for (i = 0; i < MAX_NUMNODES; i++)
3628 INIT_LIST_HEAD(&huge_boot_pages[i]);
3629 initialized = true;
3630 }
3631
3632 /* do node specific alloc */
3633 if (hugetlb_hstate_alloc_pages_specific_nodes(h))
3634 return;
3635
3636 /* below will do all node balanced alloc */
3637 if (hstate_is_gigantic(h))
3638 allocated = hugetlb_gigantic_pages_alloc_boot(h);
3639 else
3640 allocated = hugetlb_pages_alloc_boot(h);
3641
3642 hugetlb_hstate_alloc_pages_errcheck(allocated, h);
3643}
3644
3645static void __init hugetlb_init_hstates(void)
3646{
3647 struct hstate *h, *h2;
3648
3649 for_each_hstate(h) {
3650 /* oversize hugepages were init'ed in early boot */
3651 if (!hstate_is_gigantic(h))
3652 hugetlb_hstate_alloc_pages(h);
3653
3654 /*
3655 * Set demote order for each hstate. Note that
3656 * h->demote_order is initially 0.
3657 * - We can not demote gigantic pages if runtime freeing
3658 * is not supported, so skip this.
3659 * - If CMA allocation is possible, we can not demote
3660 * HUGETLB_PAGE_ORDER or smaller size pages.
3661 */
3662 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
3663 continue;
3664 if (hugetlb_cma_size && h->order <= HUGETLB_PAGE_ORDER)
3665 continue;
3666 for_each_hstate(h2) {
3667 if (h2 == h)
3668 continue;
3669 if (h2->order < h->order &&
3670 h2->order > h->demote_order)
3671 h->demote_order = h2->order;
3672 }
3673 }
3674}
3675
3676static void __init report_hugepages(void)
3677{
3678 struct hstate *h;
3679
3680 for_each_hstate(h) {
3681 char buf[32];
3682
3683 string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
3684 pr_info("HugeTLB: registered %s page size, pre-allocated %ld pages\n",
3685 buf, h->free_huge_pages);
3686 pr_info("HugeTLB: %d KiB vmemmap can be freed for a %s page\n",
3687 hugetlb_vmemmap_optimizable_size(h) / SZ_1K, buf);
3688 }
3689}
3690
3691#ifdef CONFIG_HIGHMEM
3692static void try_to_free_low(struct hstate *h, unsigned long count,
3693 nodemask_t *nodes_allowed)
3694{
3695 int i;
3696 LIST_HEAD(page_list);
3697
3698 lockdep_assert_held(&hugetlb_lock);
3699 if (hstate_is_gigantic(h))
3700 return;
3701
3702 /*
3703 * Collect pages to be freed on a list, and free after dropping lock
3704 */
3705 for_each_node_mask(i, *nodes_allowed) {
3706 struct folio *folio, *next;
3707 struct list_head *freel = &h->hugepage_freelists[i];
3708 list_for_each_entry_safe(folio, next, freel, lru) {
3709 if (count >= h->nr_huge_pages)
3710 goto out;
3711 if (folio_test_highmem(folio))
3712 continue;
3713 remove_hugetlb_folio(h, folio, false);
3714 list_add(&folio->lru, &page_list);
3715 }
3716 }
3717
3718out:
3719 spin_unlock_irq(&hugetlb_lock);
3720 update_and_free_pages_bulk(h, &page_list);
3721 spin_lock_irq(&hugetlb_lock);
3722}
3723#else
3724static inline void try_to_free_low(struct hstate *h, unsigned long count,
3725 nodemask_t *nodes_allowed)
3726{
3727}
3728#endif
3729
3730/*
3731 * Increment or decrement surplus_huge_pages. Keep node-specific counters
3732 * balanced by operating on them in a round-robin fashion.
3733 * Returns 1 if an adjustment was made.
3734 */
3735static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
3736 int delta)
3737{
3738 int nr_nodes, node;
3739
3740 lockdep_assert_held(&hugetlb_lock);
3741 VM_BUG_ON(delta != -1 && delta != 1);
3742
3743 if (delta < 0) {
3744 for_each_node_mask_to_alloc(&h->next_nid_to_alloc, nr_nodes, node, nodes_allowed) {
3745 if (h->surplus_huge_pages_node[node])
3746 goto found;
3747 }
3748 } else {
3749 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
3750 if (h->surplus_huge_pages_node[node] <
3751 h->nr_huge_pages_node[node])
3752 goto found;
3753 }
3754 }
3755 return 0;
3756
3757found:
3758 h->surplus_huge_pages += delta;
3759 h->surplus_huge_pages_node[node] += delta;
3760 return 1;
3761}
3762
3763#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
3764static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
3765 nodemask_t *nodes_allowed)
3766{
3767 unsigned long min_count;
3768 unsigned long allocated;
3769 struct folio *folio;
3770 LIST_HEAD(page_list);
3771 NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
3772
3773 /*
3774 * Bit mask controlling how hard we retry per-node allocations.
3775 * If we can not allocate the bit mask, do not attempt to allocate
3776 * the requested huge pages.
3777 */
3778 if (node_alloc_noretry)
3779 nodes_clear(*node_alloc_noretry);
3780 else
3781 return -ENOMEM;
3782
3783 /*
3784 * resize_lock mutex prevents concurrent adjustments to number of
3785 * pages in hstate via the proc/sysfs interfaces.
3786 */
3787 mutex_lock(&h->resize_lock);
3788 flush_free_hpage_work(h);
3789 spin_lock_irq(&hugetlb_lock);
3790
3791 /*
3792 * Check for a node specific request.
3793 * Changing node specific huge page count may require a corresponding
3794 * change to the global count. In any case, the passed node mask
3795 * (nodes_allowed) will restrict alloc/free to the specified node.
3796 */
3797 if (nid != NUMA_NO_NODE) {
3798 unsigned long old_count = count;
3799
3800 count += persistent_huge_pages(h) -
3801 (h->nr_huge_pages_node[nid] -
3802 h->surplus_huge_pages_node[nid]);
3803 /*
3804 * User may have specified a large count value which caused the
3805 * above calculation to overflow. In this case, they wanted
3806 * to allocate as many huge pages as possible. Set count to
3807 * largest possible value to align with their intention.
3808 */
3809 if (count < old_count)
3810 count = ULONG_MAX;
3811 }
3812
3813 /*
3814 * Gigantic pages runtime allocation depend on the capability for large
3815 * page range allocation.
3816 * If the system does not provide this feature, return an error when
3817 * the user tries to allocate gigantic pages but let the user free the
3818 * boottime allocated gigantic pages.
3819 */
3820 if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
3821 if (count > persistent_huge_pages(h)) {
3822 spin_unlock_irq(&hugetlb_lock);
3823 mutex_unlock(&h->resize_lock);
3824 NODEMASK_FREE(node_alloc_noretry);
3825 return -EINVAL;
3826 }
3827 /* Fall through to decrease pool */
3828 }
3829
3830 /*
3831 * Increase the pool size
3832 * First take pages out of surplus state. Then make up the
3833 * remaining difference by allocating fresh huge pages.
3834 *
3835 * We might race with alloc_surplus_hugetlb_folio() here and be unable
3836 * to convert a surplus huge page to a normal huge page. That is
3837 * not critical, though, it just means the overall size of the
3838 * pool might be one hugepage larger than it needs to be, but
3839 * within all the constraints specified by the sysctls.
3840 */
3841 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
3842 if (!adjust_pool_surplus(h, nodes_allowed, -1))
3843 break;
3844 }
3845
3846 allocated = 0;
3847 while (count > (persistent_huge_pages(h) + allocated)) {
3848 /*
3849 * If this allocation races such that we no longer need the
3850 * page, free_huge_folio will handle it by freeing the page
3851 * and reducing the surplus.
3852 */
3853 spin_unlock_irq(&hugetlb_lock);
3854
3855 /* yield cpu to avoid soft lockup */
3856 cond_resched();
3857
3858 folio = alloc_pool_huge_folio(h, nodes_allowed,
3859 node_alloc_noretry,
3860 &h->next_nid_to_alloc);
3861 if (!folio) {
3862 prep_and_add_allocated_folios(h, &page_list);
3863 spin_lock_irq(&hugetlb_lock);
3864 goto out;
3865 }
3866
3867 list_add(&folio->lru, &page_list);
3868 allocated++;
3869
3870 /* Bail for signals. Probably ctrl-c from user */
3871 if (signal_pending(current)) {
3872 prep_and_add_allocated_folios(h, &page_list);
3873 spin_lock_irq(&hugetlb_lock);
3874 goto out;
3875 }
3876
3877 spin_lock_irq(&hugetlb_lock);
3878 }
3879
3880 /* Add allocated pages to the pool */
3881 if (!list_empty(&page_list)) {
3882 spin_unlock_irq(&hugetlb_lock);
3883 prep_and_add_allocated_folios(h, &page_list);
3884 spin_lock_irq(&hugetlb_lock);
3885 }
3886
3887 /*
3888 * Decrease the pool size
3889 * First return free pages to the buddy allocator (being careful
3890 * to keep enough around to satisfy reservations). Then place
3891 * pages into surplus state as needed so the pool will shrink
3892 * to the desired size as pages become free.
3893 *
3894 * By placing pages into the surplus state independent of the
3895 * overcommit value, we are allowing the surplus pool size to
3896 * exceed overcommit. There are few sane options here. Since
3897 * alloc_surplus_hugetlb_folio() is checking the global counter,
3898 * though, we'll note that we're not allowed to exceed surplus
3899 * and won't grow the pool anywhere else. Not until one of the
3900 * sysctls are changed, or the surplus pages go out of use.
3901 */
3902 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
3903 min_count = max(count, min_count);
3904 try_to_free_low(h, min_count, nodes_allowed);
3905
3906 /*
3907 * Collect pages to be removed on list without dropping lock
3908 */
3909 while (min_count < persistent_huge_pages(h)) {
3910 folio = remove_pool_hugetlb_folio(h, nodes_allowed, 0);
3911 if (!folio)
3912 break;
3913
3914 list_add(&folio->lru, &page_list);
3915 }
3916 /* free the pages after dropping lock */
3917 spin_unlock_irq(&hugetlb_lock);
3918 update_and_free_pages_bulk(h, &page_list);
3919 flush_free_hpage_work(h);
3920 spin_lock_irq(&hugetlb_lock);
3921
3922 while (count < persistent_huge_pages(h)) {
3923 if (!adjust_pool_surplus(h, nodes_allowed, 1))
3924 break;
3925 }
3926out:
3927 h->max_huge_pages = persistent_huge_pages(h);
3928 spin_unlock_irq(&hugetlb_lock);
3929 mutex_unlock(&h->resize_lock);
3930
3931 NODEMASK_FREE(node_alloc_noretry);
3932
3933 return 0;
3934}
3935
3936static int demote_free_hugetlb_folio(struct hstate *h, struct folio *folio)
3937{
3938 int i, nid = folio_nid(folio);
3939 struct hstate *target_hstate;
3940 struct page *subpage;
3941 struct folio *inner_folio;
3942 int rc = 0;
3943
3944 target_hstate = size_to_hstate(PAGE_SIZE << h->demote_order);
3945
3946 remove_hugetlb_folio_for_demote(h, folio, false);
3947 spin_unlock_irq(&hugetlb_lock);
3948
3949 /*
3950 * If vmemmap already existed for folio, the remove routine above would
3951 * have cleared the hugetlb folio flag. Hence the folio is technically
3952 * no longer a hugetlb folio. hugetlb_vmemmap_restore_folio can only be
3953 * passed hugetlb folios and will BUG otherwise.
3954 */
3955 if (folio_test_hugetlb(folio)) {
3956 rc = hugetlb_vmemmap_restore_folio(h, folio);
3957 if (rc) {
3958 /* Allocation of vmemmmap failed, we can not demote folio */
3959 spin_lock_irq(&hugetlb_lock);
3960 folio_ref_unfreeze(folio, 1);
3961 add_hugetlb_folio(h, folio, false);
3962 return rc;
3963 }
3964 }
3965
3966 /*
3967 * Use destroy_compound_hugetlb_folio_for_demote for all huge page
3968 * sizes as it will not ref count folios.
3969 */
3970 destroy_compound_hugetlb_folio_for_demote(folio, huge_page_order(h));
3971
3972 /*
3973 * Taking target hstate mutex synchronizes with set_max_huge_pages.
3974 * Without the mutex, pages added to target hstate could be marked
3975 * as surplus.
3976 *
3977 * Note that we already hold h->resize_lock. To prevent deadlock,
3978 * use the convention of always taking larger size hstate mutex first.
3979 */
3980 mutex_lock(&target_hstate->resize_lock);
3981 for (i = 0; i < pages_per_huge_page(h);
3982 i += pages_per_huge_page(target_hstate)) {
3983 subpage = folio_page(folio, i);
3984 inner_folio = page_folio(subpage);
3985 if (hstate_is_gigantic(target_hstate))
3986 prep_compound_gigantic_folio_for_demote(inner_folio,
3987 target_hstate->order);
3988 else
3989 prep_compound_page(subpage, target_hstate->order);
3990 folio_change_private(inner_folio, NULL);
3991 prep_new_hugetlb_folio(target_hstate, inner_folio, nid);
3992 free_huge_folio(inner_folio);
3993 }
3994 mutex_unlock(&target_hstate->resize_lock);
3995
3996 spin_lock_irq(&hugetlb_lock);
3997
3998 /*
3999 * Not absolutely necessary, but for consistency update max_huge_pages
4000 * based on pool changes for the demoted page.
4001 */
4002 h->max_huge_pages--;
4003 target_hstate->max_huge_pages +=
4004 pages_per_huge_page(h) / pages_per_huge_page(target_hstate);
4005
4006 return rc;
4007}
4008
4009static int demote_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
4010 __must_hold(&hugetlb_lock)
4011{
4012 int nr_nodes, node;
4013 struct folio *folio;
4014
4015 lockdep_assert_held(&hugetlb_lock);
4016
4017 /* We should never get here if no demote order */
4018 if (!h->demote_order) {
4019 pr_warn("HugeTLB: NULL demote order passed to demote_pool_huge_page.\n");
4020 return -EINVAL; /* internal error */
4021 }
4022
4023 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
4024 list_for_each_entry(folio, &h->hugepage_freelists[node], lru) {
4025 if (folio_test_hwpoison(folio))
4026 continue;
4027 return demote_free_hugetlb_folio(h, folio);
4028 }
4029 }
4030
4031 /*
4032 * Only way to get here is if all pages on free lists are poisoned.
4033 * Return -EBUSY so that caller will not retry.
4034 */
4035 return -EBUSY;
4036}
4037
4038#define HSTATE_ATTR_RO(_name) \
4039 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
4040
4041#define HSTATE_ATTR_WO(_name) \
4042 static struct kobj_attribute _name##_attr = __ATTR_WO(_name)
4043
4044#define HSTATE_ATTR(_name) \
4045 static struct kobj_attribute _name##_attr = __ATTR_RW(_name)
4046
4047static struct kobject *hugepages_kobj;
4048static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
4049
4050static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
4051
4052static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
4053{
4054 int i;
4055
4056 for (i = 0; i < HUGE_MAX_HSTATE; i++)
4057 if (hstate_kobjs[i] == kobj) {
4058 if (nidp)
4059 *nidp = NUMA_NO_NODE;
4060 return &hstates[i];
4061 }
4062
4063 return kobj_to_node_hstate(kobj, nidp);
4064}
4065
4066static ssize_t nr_hugepages_show_common(struct kobject *kobj,
4067 struct kobj_attribute *attr, char *buf)
4068{
4069 struct hstate *h;
4070 unsigned long nr_huge_pages;
4071 int nid;
4072
4073 h = kobj_to_hstate(kobj, &nid);
4074 if (nid == NUMA_NO_NODE)
4075 nr_huge_pages = h->nr_huge_pages;
4076 else
4077 nr_huge_pages = h->nr_huge_pages_node[nid];
4078
4079 return sysfs_emit(buf, "%lu\n", nr_huge_pages);
4080}
4081
4082static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
4083 struct hstate *h, int nid,
4084 unsigned long count, size_t len)
4085{
4086 int err;
4087 nodemask_t nodes_allowed, *n_mask;
4088
4089 if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
4090 return -EINVAL;
4091
4092 if (nid == NUMA_NO_NODE) {
4093 /*
4094 * global hstate attribute
4095 */
4096 if (!(obey_mempolicy &&
4097 init_nodemask_of_mempolicy(&nodes_allowed)))
4098 n_mask = &node_states[N_MEMORY];
4099 else
4100 n_mask = &nodes_allowed;
4101 } else {
4102 /*
4103 * Node specific request. count adjustment happens in
4104 * set_max_huge_pages() after acquiring hugetlb_lock.
4105 */
4106 init_nodemask_of_node(&nodes_allowed, nid);
4107 n_mask = &nodes_allowed;
4108 }
4109
4110 err = set_max_huge_pages(h, count, nid, n_mask);
4111
4112 return err ? err : len;
4113}
4114
4115static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
4116 struct kobject *kobj, const char *buf,
4117 size_t len)
4118{
4119 struct hstate *h;
4120 unsigned long count;
4121 int nid;
4122 int err;
4123
4124 err = kstrtoul(buf, 10, &count);
4125 if (err)
4126 return err;
4127
4128 h = kobj_to_hstate(kobj, &nid);
4129 return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
4130}
4131
4132static ssize_t nr_hugepages_show(struct kobject *kobj,
4133 struct kobj_attribute *attr, char *buf)
4134{
4135 return nr_hugepages_show_common(kobj, attr, buf);
4136}
4137
4138static ssize_t nr_hugepages_store(struct kobject *kobj,
4139 struct kobj_attribute *attr, const char *buf, size_t len)
4140{
4141 return nr_hugepages_store_common(false, kobj, buf, len);
4142}
4143HSTATE_ATTR(nr_hugepages);
4144
4145#ifdef CONFIG_NUMA
4146
4147/*
4148 * hstate attribute for optionally mempolicy-based constraint on persistent
4149 * huge page alloc/free.
4150 */
4151static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
4152 struct kobj_attribute *attr,
4153 char *buf)
4154{
4155 return nr_hugepages_show_common(kobj, attr, buf);
4156}
4157
4158static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
4159 struct kobj_attribute *attr, const char *buf, size_t len)
4160{
4161 return nr_hugepages_store_common(true, kobj, buf, len);
4162}
4163HSTATE_ATTR(nr_hugepages_mempolicy);
4164#endif
4165
4166
4167static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
4168 struct kobj_attribute *attr, char *buf)
4169{
4170 struct hstate *h = kobj_to_hstate(kobj, NULL);
4171 return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages);
4172}
4173
4174static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
4175 struct kobj_attribute *attr, const char *buf, size_t count)
4176{
4177 int err;
4178 unsigned long input;
4179 struct hstate *h = kobj_to_hstate(kobj, NULL);
4180
4181 if (hstate_is_gigantic(h))
4182 return -EINVAL;
4183
4184 err = kstrtoul(buf, 10, &input);
4185 if (err)
4186 return err;
4187
4188 spin_lock_irq(&hugetlb_lock);
4189 h->nr_overcommit_huge_pages = input;
4190 spin_unlock_irq(&hugetlb_lock);
4191
4192 return count;
4193}
4194HSTATE_ATTR(nr_overcommit_hugepages);
4195
4196static ssize_t free_hugepages_show(struct kobject *kobj,
4197 struct kobj_attribute *attr, char *buf)
4198{
4199 struct hstate *h;
4200 unsigned long free_huge_pages;
4201 int nid;
4202
4203 h = kobj_to_hstate(kobj, &nid);
4204 if (nid == NUMA_NO_NODE)
4205 free_huge_pages = h->free_huge_pages;
4206 else
4207 free_huge_pages = h->free_huge_pages_node[nid];
4208
4209 return sysfs_emit(buf, "%lu\n", free_huge_pages);
4210}
4211HSTATE_ATTR_RO(free_hugepages);
4212
4213static ssize_t resv_hugepages_show(struct kobject *kobj,
4214 struct kobj_attribute *attr, char *buf)
4215{
4216 struct hstate *h = kobj_to_hstate(kobj, NULL);
4217 return sysfs_emit(buf, "%lu\n", h->resv_huge_pages);
4218}
4219HSTATE_ATTR_RO(resv_hugepages);
4220
4221static ssize_t surplus_hugepages_show(struct kobject *kobj,
4222 struct kobj_attribute *attr, char *buf)
4223{
4224 struct hstate *h;
4225 unsigned long surplus_huge_pages;
4226 int nid;
4227
4228 h = kobj_to_hstate(kobj, &nid);
4229 if (nid == NUMA_NO_NODE)
4230 surplus_huge_pages = h->surplus_huge_pages;
4231 else
4232 surplus_huge_pages = h->surplus_huge_pages_node[nid];
4233
4234 return sysfs_emit(buf, "%lu\n", surplus_huge_pages);
4235}
4236HSTATE_ATTR_RO(surplus_hugepages);
4237
4238static ssize_t demote_store(struct kobject *kobj,
4239 struct kobj_attribute *attr, const char *buf, size_t len)
4240{
4241 unsigned long nr_demote;
4242 unsigned long nr_available;
4243 nodemask_t nodes_allowed, *n_mask;
4244 struct hstate *h;
4245 int err;
4246 int nid;
4247
4248 err = kstrtoul(buf, 10, &nr_demote);
4249 if (err)
4250 return err;
4251 h = kobj_to_hstate(kobj, &nid);
4252
4253 if (nid != NUMA_NO_NODE) {
4254 init_nodemask_of_node(&nodes_allowed, nid);
4255 n_mask = &nodes_allowed;
4256 } else {
4257 n_mask = &node_states[N_MEMORY];
4258 }
4259
4260 /* Synchronize with other sysfs operations modifying huge pages */
4261 mutex_lock(&h->resize_lock);
4262 spin_lock_irq(&hugetlb_lock);
4263
4264 while (nr_demote) {
4265 /*
4266 * Check for available pages to demote each time thorough the
4267 * loop as demote_pool_huge_page will drop hugetlb_lock.
4268 */
4269 if (nid != NUMA_NO_NODE)
4270 nr_available = h->free_huge_pages_node[nid];
4271 else
4272 nr_available = h->free_huge_pages;
4273 nr_available -= h->resv_huge_pages;
4274 if (!nr_available)
4275 break;
4276
4277 err = demote_pool_huge_page(h, n_mask);
4278 if (err)
4279 break;
4280
4281 nr_demote--;
4282 }
4283
4284 spin_unlock_irq(&hugetlb_lock);
4285 mutex_unlock(&h->resize_lock);
4286
4287 if (err)
4288 return err;
4289 return len;
4290}
4291HSTATE_ATTR_WO(demote);
4292
4293static ssize_t demote_size_show(struct kobject *kobj,
4294 struct kobj_attribute *attr, char *buf)
4295{
4296 struct hstate *h = kobj_to_hstate(kobj, NULL);
4297 unsigned long demote_size = (PAGE_SIZE << h->demote_order) / SZ_1K;
4298
4299 return sysfs_emit(buf, "%lukB\n", demote_size);
4300}
4301
4302static ssize_t demote_size_store(struct kobject *kobj,
4303 struct kobj_attribute *attr,
4304 const char *buf, size_t count)
4305{
4306 struct hstate *h, *demote_hstate;
4307 unsigned long demote_size;
4308 unsigned int demote_order;
4309
4310 demote_size = (unsigned long)memparse(buf, NULL);
4311
4312 demote_hstate = size_to_hstate(demote_size);
4313 if (!demote_hstate)
4314 return -EINVAL;
4315 demote_order = demote_hstate->order;
4316 if (demote_order < HUGETLB_PAGE_ORDER)
4317 return -EINVAL;
4318
4319 /* demote order must be smaller than hstate order */
4320 h = kobj_to_hstate(kobj, NULL);
4321 if (demote_order >= h->order)
4322 return -EINVAL;
4323
4324 /* resize_lock synchronizes access to demote size and writes */
4325 mutex_lock(&h->resize_lock);
4326 h->demote_order = demote_order;
4327 mutex_unlock(&h->resize_lock);
4328
4329 return count;
4330}
4331HSTATE_ATTR(demote_size);
4332
4333static struct attribute *hstate_attrs[] = {
4334 &nr_hugepages_attr.attr,
4335 &nr_overcommit_hugepages_attr.attr,
4336 &free_hugepages_attr.attr,
4337 &resv_hugepages_attr.attr,
4338 &surplus_hugepages_attr.attr,
4339#ifdef CONFIG_NUMA
4340 &nr_hugepages_mempolicy_attr.attr,
4341#endif
4342 NULL,
4343};
4344
4345static const struct attribute_group hstate_attr_group = {
4346 .attrs = hstate_attrs,
4347};
4348
4349static struct attribute *hstate_demote_attrs[] = {
4350 &demote_size_attr.attr,
4351 &demote_attr.attr,
4352 NULL,
4353};
4354
4355static const struct attribute_group hstate_demote_attr_group = {
4356 .attrs = hstate_demote_attrs,
4357};
4358
4359static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
4360 struct kobject **hstate_kobjs,
4361 const struct attribute_group *hstate_attr_group)
4362{
4363 int retval;
4364 int hi = hstate_index(h);
4365
4366 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
4367 if (!hstate_kobjs[hi])
4368 return -ENOMEM;
4369
4370 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
4371 if (retval) {
4372 kobject_put(hstate_kobjs[hi]);
4373 hstate_kobjs[hi] = NULL;
4374 return retval;
4375 }
4376
4377 if (h->demote_order) {
4378 retval = sysfs_create_group(hstate_kobjs[hi],
4379 &hstate_demote_attr_group);
4380 if (retval) {
4381 pr_warn("HugeTLB unable to create demote interfaces for %s\n", h->name);
4382 sysfs_remove_group(hstate_kobjs[hi], hstate_attr_group);
4383 kobject_put(hstate_kobjs[hi]);
4384 hstate_kobjs[hi] = NULL;
4385 return retval;
4386 }
4387 }
4388
4389 return 0;
4390}
4391
4392#ifdef CONFIG_NUMA
4393static bool hugetlb_sysfs_initialized __ro_after_init;
4394
4395/*
4396 * node_hstate/s - associate per node hstate attributes, via their kobjects,
4397 * with node devices in node_devices[] using a parallel array. The array
4398 * index of a node device or _hstate == node id.
4399 * This is here to avoid any static dependency of the node device driver, in
4400 * the base kernel, on the hugetlb module.
4401 */
4402struct node_hstate {
4403 struct kobject *hugepages_kobj;
4404 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
4405};
4406static struct node_hstate node_hstates[MAX_NUMNODES];
4407
4408/*
4409 * A subset of global hstate attributes for node devices
4410 */
4411static struct attribute *per_node_hstate_attrs[] = {
4412 &nr_hugepages_attr.attr,
4413 &free_hugepages_attr.attr,
4414 &surplus_hugepages_attr.attr,
4415 NULL,
4416};
4417
4418static const struct attribute_group per_node_hstate_attr_group = {
4419 .attrs = per_node_hstate_attrs,
4420};
4421
4422/*
4423 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
4424 * Returns node id via non-NULL nidp.
4425 */
4426static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
4427{
4428 int nid;
4429
4430 for (nid = 0; nid < nr_node_ids; nid++) {
4431 struct node_hstate *nhs = &node_hstates[nid];
4432 int i;
4433 for (i = 0; i < HUGE_MAX_HSTATE; i++)
4434 if (nhs->hstate_kobjs[i] == kobj) {
4435 if (nidp)
4436 *nidp = nid;
4437 return &hstates[i];
4438 }
4439 }
4440
4441 BUG();
4442 return NULL;
4443}
4444
4445/*
4446 * Unregister hstate attributes from a single node device.
4447 * No-op if no hstate attributes attached.
4448 */
4449void hugetlb_unregister_node(struct node *node)
4450{
4451 struct hstate *h;
4452 struct node_hstate *nhs = &node_hstates[node->dev.id];
4453
4454 if (!nhs->hugepages_kobj)
4455 return; /* no hstate attributes */
4456
4457 for_each_hstate(h) {
4458 int idx = hstate_index(h);
4459 struct kobject *hstate_kobj = nhs->hstate_kobjs[idx];
4460
4461 if (!hstate_kobj)
4462 continue;
4463 if (h->demote_order)
4464 sysfs_remove_group(hstate_kobj, &hstate_demote_attr_group);
4465 sysfs_remove_group(hstate_kobj, &per_node_hstate_attr_group);
4466 kobject_put(hstate_kobj);
4467 nhs->hstate_kobjs[idx] = NULL;
4468 }
4469
4470 kobject_put(nhs->hugepages_kobj);
4471 nhs->hugepages_kobj = NULL;
4472}
4473
4474
4475/*
4476 * Register hstate attributes for a single node device.
4477 * No-op if attributes already registered.
4478 */
4479void hugetlb_register_node(struct node *node)
4480{
4481 struct hstate *h;
4482 struct node_hstate *nhs = &node_hstates[node->dev.id];
4483 int err;
4484
4485 if (!hugetlb_sysfs_initialized)
4486 return;
4487
4488 if (nhs->hugepages_kobj)
4489 return; /* already allocated */
4490
4491 nhs->hugepages_kobj = kobject_create_and_add("hugepages",
4492 &node->dev.kobj);
4493 if (!nhs->hugepages_kobj)
4494 return;
4495
4496 for_each_hstate(h) {
4497 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
4498 nhs->hstate_kobjs,
4499 &per_node_hstate_attr_group);
4500 if (err) {
4501 pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
4502 h->name, node->dev.id);
4503 hugetlb_unregister_node(node);
4504 break;
4505 }
4506 }
4507}
4508
4509/*
4510 * hugetlb init time: register hstate attributes for all registered node
4511 * devices of nodes that have memory. All on-line nodes should have
4512 * registered their associated device by this time.
4513 */
4514static void __init hugetlb_register_all_nodes(void)
4515{
4516 int nid;
4517
4518 for_each_online_node(nid)
4519 hugetlb_register_node(node_devices[nid]);
4520}
4521#else /* !CONFIG_NUMA */
4522
4523static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
4524{
4525 BUG();
4526 if (nidp)
4527 *nidp = -1;
4528 return NULL;
4529}
4530
4531static void hugetlb_register_all_nodes(void) { }
4532
4533#endif
4534
4535#ifdef CONFIG_CMA
4536static void __init hugetlb_cma_check(void);
4537#else
4538static inline __init void hugetlb_cma_check(void)
4539{
4540}
4541#endif
4542
4543static void __init hugetlb_sysfs_init(void)
4544{
4545 struct hstate *h;
4546 int err;
4547
4548 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
4549 if (!hugepages_kobj)
4550 return;
4551
4552 for_each_hstate(h) {
4553 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
4554 hstate_kobjs, &hstate_attr_group);
4555 if (err)
4556 pr_err("HugeTLB: Unable to add hstate %s", h->name);
4557 }
4558
4559#ifdef CONFIG_NUMA
4560 hugetlb_sysfs_initialized = true;
4561#endif
4562 hugetlb_register_all_nodes();
4563}
4564
4565#ifdef CONFIG_SYSCTL
4566static void hugetlb_sysctl_init(void);
4567#else
4568static inline void hugetlb_sysctl_init(void) { }
4569#endif
4570
4571static int __init hugetlb_init(void)
4572{
4573 int i;
4574
4575 BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
4576 __NR_HPAGEFLAGS);
4577
4578 if (!hugepages_supported()) {
4579 if (hugetlb_max_hstate || default_hstate_max_huge_pages)
4580 pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
4581 return 0;
4582 }
4583
4584 /*
4585 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
4586 * architectures depend on setup being done here.
4587 */
4588 hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
4589 if (!parsed_default_hugepagesz) {
4590 /*
4591 * If we did not parse a default huge page size, set
4592 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
4593 * number of huge pages for this default size was implicitly
4594 * specified, set that here as well.
4595 * Note that the implicit setting will overwrite an explicit
4596 * setting. A warning will be printed in this case.
4597 */
4598 default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
4599 if (default_hstate_max_huge_pages) {
4600 if (default_hstate.max_huge_pages) {
4601 char buf[32];
4602
4603 string_get_size(huge_page_size(&default_hstate),
4604 1, STRING_UNITS_2, buf, 32);
4605 pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
4606 default_hstate.max_huge_pages, buf);
4607 pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
4608 default_hstate_max_huge_pages);
4609 }
4610 default_hstate.max_huge_pages =
4611 default_hstate_max_huge_pages;
4612
4613 for_each_online_node(i)
4614 default_hstate.max_huge_pages_node[i] =
4615 default_hugepages_in_node[i];
4616 }
4617 }
4618
4619 hugetlb_cma_check();
4620 hugetlb_init_hstates();
4621 gather_bootmem_prealloc();
4622 report_hugepages();
4623
4624 hugetlb_sysfs_init();
4625 hugetlb_cgroup_file_init();
4626 hugetlb_sysctl_init();
4627
4628#ifdef CONFIG_SMP
4629 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
4630#else
4631 num_fault_mutexes = 1;
4632#endif
4633 hugetlb_fault_mutex_table =
4634 kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
4635 GFP_KERNEL);
4636 BUG_ON(!hugetlb_fault_mutex_table);
4637
4638 for (i = 0; i < num_fault_mutexes; i++)
4639 mutex_init(&hugetlb_fault_mutex_table[i]);
4640 return 0;
4641}
4642subsys_initcall(hugetlb_init);
4643
4644/* Overwritten by architectures with more huge page sizes */
4645bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
4646{
4647 return size == HPAGE_SIZE;
4648}
4649
4650void __init hugetlb_add_hstate(unsigned int order)
4651{
4652 struct hstate *h;
4653 unsigned long i;
4654
4655 if (size_to_hstate(PAGE_SIZE << order)) {
4656 return;
4657 }
4658 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
4659 BUG_ON(order < order_base_2(__NR_USED_SUBPAGE));
4660 h = &hstates[hugetlb_max_hstate++];
4661 mutex_init(&h->resize_lock);
4662 h->order = order;
4663 h->mask = ~(huge_page_size(h) - 1);
4664 for (i = 0; i < MAX_NUMNODES; ++i)
4665 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
4666 INIT_LIST_HEAD(&h->hugepage_activelist);
4667 h->next_nid_to_alloc = first_memory_node;
4668 h->next_nid_to_free = first_memory_node;
4669 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
4670 huge_page_size(h)/SZ_1K);
4671
4672 parsed_hstate = h;
4673}
4674
4675bool __init __weak hugetlb_node_alloc_supported(void)
4676{
4677 return true;
4678}
4679
4680static void __init hugepages_clear_pages_in_node(void)
4681{
4682 if (!hugetlb_max_hstate) {
4683 default_hstate_max_huge_pages = 0;
4684 memset(default_hugepages_in_node, 0,
4685 sizeof(default_hugepages_in_node));
4686 } else {
4687 parsed_hstate->max_huge_pages = 0;
4688 memset(parsed_hstate->max_huge_pages_node, 0,
4689 sizeof(parsed_hstate->max_huge_pages_node));
4690 }
4691}
4692
4693/*
4694 * hugepages command line processing
4695 * hugepages normally follows a valid hugepagsz or default_hugepagsz
4696 * specification. If not, ignore the hugepages value. hugepages can also
4697 * be the first huge page command line option in which case it implicitly
4698 * specifies the number of huge pages for the default size.
4699 */
4700static int __init hugepages_setup(char *s)
4701{
4702 unsigned long *mhp;
4703 static unsigned long *last_mhp;
4704 int node = NUMA_NO_NODE;
4705 int count;
4706 unsigned long tmp;
4707 char *p = s;
4708
4709 if (!parsed_valid_hugepagesz) {
4710 pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
4711 parsed_valid_hugepagesz = true;
4712 return 1;
4713 }
4714
4715 /*
4716 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
4717 * yet, so this hugepages= parameter goes to the "default hstate".
4718 * Otherwise, it goes with the previously parsed hugepagesz or
4719 * default_hugepagesz.
4720 */
4721 else if (!hugetlb_max_hstate)
4722 mhp = &default_hstate_max_huge_pages;
4723 else
4724 mhp = &parsed_hstate->max_huge_pages;
4725
4726 if (mhp == last_mhp) {
4727 pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
4728 return 1;
4729 }
4730
4731 while (*p) {
4732 count = 0;
4733 if (sscanf(p, "%lu%n", &tmp, &count) != 1)
4734 goto invalid;
4735 /* Parameter is node format */
4736 if (p[count] == ':') {
4737 if (!hugetlb_node_alloc_supported()) {
4738 pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n");
4739 return 1;
4740 }
4741 if (tmp >= MAX_NUMNODES || !node_online(tmp))
4742 goto invalid;
4743 node = array_index_nospec(tmp, MAX_NUMNODES);
4744 p += count + 1;
4745 /* Parse hugepages */
4746 if (sscanf(p, "%lu%n", &tmp, &count) != 1)
4747 goto invalid;
4748 if (!hugetlb_max_hstate)
4749 default_hugepages_in_node[node] = tmp;
4750 else
4751 parsed_hstate->max_huge_pages_node[node] = tmp;
4752 *mhp += tmp;
4753 /* Go to parse next node*/
4754 if (p[count] == ',')
4755 p += count + 1;
4756 else
4757 break;
4758 } else {
4759 if (p != s)
4760 goto invalid;
4761 *mhp = tmp;
4762 break;
4763 }
4764 }
4765
4766 /*
4767 * Global state is always initialized later in hugetlb_init.
4768 * But we need to allocate gigantic hstates here early to still
4769 * use the bootmem allocator.
4770 */
4771 if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate))
4772 hugetlb_hstate_alloc_pages(parsed_hstate);
4773
4774 last_mhp = mhp;
4775
4776 return 1;
4777
4778invalid:
4779 pr_warn("HugeTLB: Invalid hugepages parameter %s\n", p);
4780 hugepages_clear_pages_in_node();
4781 return 1;
4782}
4783__setup("hugepages=", hugepages_setup);
4784
4785/*
4786 * hugepagesz command line processing
4787 * A specific huge page size can only be specified once with hugepagesz.
4788 * hugepagesz is followed by hugepages on the command line. The global
4789 * variable 'parsed_valid_hugepagesz' is used to determine if prior
4790 * hugepagesz argument was valid.
4791 */
4792static int __init hugepagesz_setup(char *s)
4793{
4794 unsigned long size;
4795 struct hstate *h;
4796
4797 parsed_valid_hugepagesz = false;
4798 size = (unsigned long)memparse(s, NULL);
4799
4800 if (!arch_hugetlb_valid_size(size)) {
4801 pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
4802 return 1;
4803 }
4804
4805 h = size_to_hstate(size);
4806 if (h) {
4807 /*
4808 * hstate for this size already exists. This is normally
4809 * an error, but is allowed if the existing hstate is the
4810 * default hstate. More specifically, it is only allowed if
4811 * the number of huge pages for the default hstate was not
4812 * previously specified.
4813 */
4814 if (!parsed_default_hugepagesz || h != &default_hstate ||
4815 default_hstate.max_huge_pages) {
4816 pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
4817 return 1;
4818 }
4819
4820 /*
4821 * No need to call hugetlb_add_hstate() as hstate already
4822 * exists. But, do set parsed_hstate so that a following
4823 * hugepages= parameter will be applied to this hstate.
4824 */
4825 parsed_hstate = h;
4826 parsed_valid_hugepagesz = true;
4827 return 1;
4828 }
4829
4830 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
4831 parsed_valid_hugepagesz = true;
4832 return 1;
4833}
4834__setup("hugepagesz=", hugepagesz_setup);
4835
4836/*
4837 * default_hugepagesz command line input
4838 * Only one instance of default_hugepagesz allowed on command line.
4839 */
4840static int __init default_hugepagesz_setup(char *s)
4841{
4842 unsigned long size;
4843 int i;
4844
4845 parsed_valid_hugepagesz = false;
4846 if (parsed_default_hugepagesz) {
4847 pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
4848 return 1;
4849 }
4850
4851 size = (unsigned long)memparse(s, NULL);
4852
4853 if (!arch_hugetlb_valid_size(size)) {
4854 pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
4855 return 1;
4856 }
4857
4858 hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
4859 parsed_valid_hugepagesz = true;
4860 parsed_default_hugepagesz = true;
4861 default_hstate_idx = hstate_index(size_to_hstate(size));
4862
4863 /*
4864 * The number of default huge pages (for this size) could have been
4865 * specified as the first hugetlb parameter: hugepages=X. If so,
4866 * then default_hstate_max_huge_pages is set. If the default huge
4867 * page size is gigantic (> MAX_PAGE_ORDER), then the pages must be
4868 * allocated here from bootmem allocator.
4869 */
4870 if (default_hstate_max_huge_pages) {
4871 default_hstate.max_huge_pages = default_hstate_max_huge_pages;
4872 for_each_online_node(i)
4873 default_hstate.max_huge_pages_node[i] =
4874 default_hugepages_in_node[i];
4875 if (hstate_is_gigantic(&default_hstate))
4876 hugetlb_hstate_alloc_pages(&default_hstate);
4877 default_hstate_max_huge_pages = 0;
4878 }
4879
4880 return 1;
4881}
4882__setup("default_hugepagesz=", default_hugepagesz_setup);
4883
4884static nodemask_t *policy_mbind_nodemask(gfp_t gfp)
4885{
4886#ifdef CONFIG_NUMA
4887 struct mempolicy *mpol = get_task_policy(current);
4888
4889 /*
4890 * Only enforce MPOL_BIND policy which overlaps with cpuset policy
4891 * (from policy_nodemask) specifically for hugetlb case
4892 */
4893 if (mpol->mode == MPOL_BIND &&
4894 (apply_policy_zone(mpol, gfp_zone(gfp)) &&
4895 cpuset_nodemask_valid_mems_allowed(&mpol->nodes)))
4896 return &mpol->nodes;
4897#endif
4898 return NULL;
4899}
4900
4901static unsigned int allowed_mems_nr(struct hstate *h)
4902{
4903 int node;
4904 unsigned int nr = 0;
4905 nodemask_t *mbind_nodemask;
4906 unsigned int *array = h->free_huge_pages_node;
4907 gfp_t gfp_mask = htlb_alloc_mask(h);
4908
4909 mbind_nodemask = policy_mbind_nodemask(gfp_mask);
4910 for_each_node_mask(node, cpuset_current_mems_allowed) {
4911 if (!mbind_nodemask || node_isset(node, *mbind_nodemask))
4912 nr += array[node];
4913 }
4914
4915 return nr;
4916}
4917
4918#ifdef CONFIG_SYSCTL
4919static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
4920 void *buffer, size_t *length,
4921 loff_t *ppos, unsigned long *out)
4922{
4923 struct ctl_table dup_table;
4924
4925 /*
4926 * In order to avoid races with __do_proc_doulongvec_minmax(), we
4927 * can duplicate the @table and alter the duplicate of it.
4928 */
4929 dup_table = *table;
4930 dup_table.data = out;
4931
4932 return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
4933}
4934
4935static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
4936 struct ctl_table *table, int write,
4937 void *buffer, size_t *length, loff_t *ppos)
4938{
4939 struct hstate *h = &default_hstate;
4940 unsigned long tmp = h->max_huge_pages;
4941 int ret;
4942
4943 if (!hugepages_supported())
4944 return -EOPNOTSUPP;
4945
4946 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
4947 &tmp);
4948 if (ret)
4949 goto out;
4950
4951 if (write)
4952 ret = __nr_hugepages_store_common(obey_mempolicy, h,
4953 NUMA_NO_NODE, tmp, *length);
4954out:
4955 return ret;
4956}
4957
4958static int hugetlb_sysctl_handler(struct ctl_table *table, int write,
4959 void *buffer, size_t *length, loff_t *ppos)
4960{
4961
4962 return hugetlb_sysctl_handler_common(false, table, write,
4963 buffer, length, ppos);
4964}
4965
4966#ifdef CONFIG_NUMA
4967static int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
4968 void *buffer, size_t *length, loff_t *ppos)
4969{
4970 return hugetlb_sysctl_handler_common(true, table, write,
4971 buffer, length, ppos);
4972}
4973#endif /* CONFIG_NUMA */
4974
4975static int hugetlb_overcommit_handler(struct ctl_table *table, int write,
4976 void *buffer, size_t *length, loff_t *ppos)
4977{
4978 struct hstate *h = &default_hstate;
4979 unsigned long tmp;
4980 int ret;
4981
4982 if (!hugepages_supported())
4983 return -EOPNOTSUPP;
4984
4985 tmp = h->nr_overcommit_huge_pages;
4986
4987 if (write && hstate_is_gigantic(h))
4988 return -EINVAL;
4989
4990 ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
4991 &tmp);
4992 if (ret)
4993 goto out;
4994
4995 if (write) {
4996 spin_lock_irq(&hugetlb_lock);
4997 h->nr_overcommit_huge_pages = tmp;
4998 spin_unlock_irq(&hugetlb_lock);
4999 }
5000out:
5001 return ret;
5002}
5003
5004static struct ctl_table hugetlb_table[] = {
5005 {
5006 .procname = "nr_hugepages",
5007 .data = NULL,
5008 .maxlen = sizeof(unsigned long),
5009 .mode = 0644,
5010 .proc_handler = hugetlb_sysctl_handler,
5011 },
5012#ifdef CONFIG_NUMA
5013 {
5014 .procname = "nr_hugepages_mempolicy",
5015 .data = NULL,
5016 .maxlen = sizeof(unsigned long),
5017 .mode = 0644,
5018 .proc_handler = &hugetlb_mempolicy_sysctl_handler,
5019 },
5020#endif
5021 {
5022 .procname = "hugetlb_shm_group",
5023 .data = &sysctl_hugetlb_shm_group,
5024 .maxlen = sizeof(gid_t),
5025 .mode = 0644,
5026 .proc_handler = proc_dointvec,
5027 },
5028 {
5029 .procname = "nr_overcommit_hugepages",
5030 .data = NULL,
5031 .maxlen = sizeof(unsigned long),
5032 .mode = 0644,
5033 .proc_handler = hugetlb_overcommit_handler,
5034 },
5035 { }
5036};
5037
5038static void hugetlb_sysctl_init(void)
5039{
5040 register_sysctl_init("vm", hugetlb_table);
5041}
5042#endif /* CONFIG_SYSCTL */
5043
5044void hugetlb_report_meminfo(struct seq_file *m)
5045{
5046 struct hstate *h;
5047 unsigned long total = 0;
5048
5049 if (!hugepages_supported())
5050 return;
5051
5052 for_each_hstate(h) {
5053 unsigned long count = h->nr_huge_pages;
5054
5055 total += huge_page_size(h) * count;
5056
5057 if (h == &default_hstate)
5058 seq_printf(m,
5059 "HugePages_Total: %5lu\n"
5060 "HugePages_Free: %5lu\n"
5061 "HugePages_Rsvd: %5lu\n"
5062 "HugePages_Surp: %5lu\n"
5063 "Hugepagesize: %8lu kB\n",
5064 count,
5065 h->free_huge_pages,
5066 h->resv_huge_pages,
5067 h->surplus_huge_pages,
5068 huge_page_size(h) / SZ_1K);
5069 }
5070
5071 seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K);
5072}
5073
5074int hugetlb_report_node_meminfo(char *buf, int len, int nid)
5075{
5076 struct hstate *h = &default_hstate;
5077
5078 if (!hugepages_supported())
5079 return 0;
5080
5081 return sysfs_emit_at(buf, len,
5082 "Node %d HugePages_Total: %5u\n"
5083 "Node %d HugePages_Free: %5u\n"
5084 "Node %d HugePages_Surp: %5u\n",
5085 nid, h->nr_huge_pages_node[nid],
5086 nid, h->free_huge_pages_node[nid],
5087 nid, h->surplus_huge_pages_node[nid]);
5088}
5089
5090void hugetlb_show_meminfo_node(int nid)
5091{
5092 struct hstate *h;
5093
5094 if (!hugepages_supported())
5095 return;
5096
5097 for_each_hstate(h)
5098 printk("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
5099 nid,
5100 h->nr_huge_pages_node[nid],
5101 h->free_huge_pages_node[nid],
5102 h->surplus_huge_pages_node[nid],
5103 huge_page_size(h) / SZ_1K);
5104}
5105
5106void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
5107{
5108 seq_printf(m, "HugetlbPages:\t%8lu kB\n",
5109 K(atomic_long_read(&mm->hugetlb_usage)));
5110}
5111
5112/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
5113unsigned long hugetlb_total_pages(void)
5114{
5115 struct hstate *h;
5116 unsigned long nr_total_pages = 0;
5117
5118 for_each_hstate(h)
5119 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
5120 return nr_total_pages;
5121}
5122
5123static int hugetlb_acct_memory(struct hstate *h, long delta)
5124{
5125 int ret = -ENOMEM;
5126
5127 if (!delta)
5128 return 0;
5129
5130 spin_lock_irq(&hugetlb_lock);
5131 /*
5132 * When cpuset is configured, it breaks the strict hugetlb page
5133 * reservation as the accounting is done on a global variable. Such
5134 * reservation is completely rubbish in the presence of cpuset because
5135 * the reservation is not checked against page availability for the
5136 * current cpuset. Application can still potentially OOM'ed by kernel
5137 * with lack of free htlb page in cpuset that the task is in.
5138 * Attempt to enforce strict accounting with cpuset is almost
5139 * impossible (or too ugly) because cpuset is too fluid that
5140 * task or memory node can be dynamically moved between cpusets.
5141 *
5142 * The change of semantics for shared hugetlb mapping with cpuset is
5143 * undesirable. However, in order to preserve some of the semantics,
5144 * we fall back to check against current free page availability as
5145 * a best attempt and hopefully to minimize the impact of changing
5146 * semantics that cpuset has.
5147 *
5148 * Apart from cpuset, we also have memory policy mechanism that
5149 * also determines from which node the kernel will allocate memory
5150 * in a NUMA system. So similar to cpuset, we also should consider
5151 * the memory policy of the current task. Similar to the description
5152 * above.
5153 */
5154 if (delta > 0) {
5155 if (gather_surplus_pages(h, delta) < 0)
5156 goto out;
5157
5158 if (delta > allowed_mems_nr(h)) {
5159 return_unused_surplus_pages(h, delta);
5160 goto out;
5161 }
5162 }
5163
5164 ret = 0;
5165 if (delta < 0)
5166 return_unused_surplus_pages(h, (unsigned long) -delta);
5167
5168out:
5169 spin_unlock_irq(&hugetlb_lock);
5170 return ret;
5171}
5172
5173static void hugetlb_vm_op_open(struct vm_area_struct *vma)
5174{
5175 struct resv_map *resv = vma_resv_map(vma);
5176
5177 /*
5178 * HPAGE_RESV_OWNER indicates a private mapping.
5179 * This new VMA should share its siblings reservation map if present.
5180 * The VMA will only ever have a valid reservation map pointer where
5181 * it is being copied for another still existing VMA. As that VMA
5182 * has a reference to the reservation map it cannot disappear until
5183 * after this open call completes. It is therefore safe to take a
5184 * new reference here without additional locking.
5185 */
5186 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
5187 resv_map_dup_hugetlb_cgroup_uncharge_info(resv);
5188 kref_get(&resv->refs);
5189 }
5190
5191 /*
5192 * vma_lock structure for sharable mappings is vma specific.
5193 * Clear old pointer (if copied via vm_area_dup) and allocate
5194 * new structure. Before clearing, make sure vma_lock is not
5195 * for this vma.
5196 */
5197 if (vma->vm_flags & VM_MAYSHARE) {
5198 struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
5199
5200 if (vma_lock) {
5201 if (vma_lock->vma != vma) {
5202 vma->vm_private_data = NULL;
5203 hugetlb_vma_lock_alloc(vma);
5204 } else
5205 pr_warn("HugeTLB: vma_lock already exists in %s.\n", __func__);
5206 } else
5207 hugetlb_vma_lock_alloc(vma);
5208 }
5209}
5210
5211static void hugetlb_vm_op_close(struct vm_area_struct *vma)
5212{
5213 struct hstate *h = hstate_vma(vma);
5214 struct resv_map *resv;
5215 struct hugepage_subpool *spool = subpool_vma(vma);
5216 unsigned long reserve, start, end;
5217 long gbl_reserve;
5218
5219 hugetlb_vma_lock_free(vma);
5220
5221 resv = vma_resv_map(vma);
5222 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
5223 return;
5224
5225 start = vma_hugecache_offset(h, vma, vma->vm_start);
5226 end = vma_hugecache_offset(h, vma, vma->vm_end);
5227
5228 reserve = (end - start) - region_count(resv, start, end);
5229 hugetlb_cgroup_uncharge_counter(resv, start, end);
5230 if (reserve) {
5231 /*
5232 * Decrement reserve counts. The global reserve count may be
5233 * adjusted if the subpool has a minimum size.
5234 */
5235 gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
5236 hugetlb_acct_memory(h, -gbl_reserve);
5237 }
5238
5239 kref_put(&resv->refs, resv_map_release);
5240}
5241
5242static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
5243{
5244 if (addr & ~(huge_page_mask(hstate_vma(vma))))
5245 return -EINVAL;
5246
5247 /*
5248 * PMD sharing is only possible for PUD_SIZE-aligned address ranges
5249 * in HugeTLB VMAs. If we will lose PUD_SIZE alignment due to this
5250 * split, unshare PMDs in the PUD_SIZE interval surrounding addr now.
5251 */
5252 if (addr & ~PUD_MASK) {
5253 /*
5254 * hugetlb_vm_op_split is called right before we attempt to
5255 * split the VMA. We will need to unshare PMDs in the old and
5256 * new VMAs, so let's unshare before we split.
5257 */
5258 unsigned long floor = addr & PUD_MASK;
5259 unsigned long ceil = floor + PUD_SIZE;
5260
5261 if (floor >= vma->vm_start && ceil <= vma->vm_end)
5262 hugetlb_unshare_pmds(vma, floor, ceil);
5263 }
5264
5265 return 0;
5266}
5267
5268static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
5269{
5270 return huge_page_size(hstate_vma(vma));
5271}
5272
5273/*
5274 * We cannot handle pagefaults against hugetlb pages at all. They cause
5275 * handle_mm_fault() to try to instantiate regular-sized pages in the
5276 * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get
5277 * this far.
5278 */
5279static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
5280{
5281 BUG();
5282 return 0;
5283}
5284
5285/*
5286 * When a new function is introduced to vm_operations_struct and added
5287 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
5288 * This is because under System V memory model, mappings created via
5289 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
5290 * their original vm_ops are overwritten with shm_vm_ops.
5291 */
5292const struct vm_operations_struct hugetlb_vm_ops = {
5293 .fault = hugetlb_vm_op_fault,
5294 .open = hugetlb_vm_op_open,
5295 .close = hugetlb_vm_op_close,
5296 .may_split = hugetlb_vm_op_split,
5297 .pagesize = hugetlb_vm_op_pagesize,
5298};
5299
5300static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
5301 int writable)
5302{
5303 pte_t entry;
5304 unsigned int shift = huge_page_shift(hstate_vma(vma));
5305
5306 if (writable) {
5307 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
5308 vma->vm_page_prot)));
5309 } else {
5310 entry = huge_pte_wrprotect(mk_huge_pte(page,
5311 vma->vm_page_prot));
5312 }
5313 entry = pte_mkyoung(entry);
5314 entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
5315
5316 return entry;
5317}
5318
5319static void set_huge_ptep_writable(struct vm_area_struct *vma,
5320 unsigned long address, pte_t *ptep)
5321{
5322 pte_t entry;
5323
5324 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
5325 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
5326 update_mmu_cache(vma, address, ptep);
5327}
5328
5329bool is_hugetlb_entry_migration(pte_t pte)
5330{
5331 swp_entry_t swp;
5332
5333 if (huge_pte_none(pte) || pte_present(pte))
5334 return false;
5335 swp = pte_to_swp_entry(pte);
5336 if (is_migration_entry(swp))
5337 return true;
5338 else
5339 return false;
5340}
5341
5342bool is_hugetlb_entry_hwpoisoned(pte_t pte)
5343{
5344 swp_entry_t swp;
5345
5346 if (huge_pte_none(pte) || pte_present(pte))
5347 return false;
5348 swp = pte_to_swp_entry(pte);
5349 if (is_hwpoison_entry(swp))
5350 return true;
5351 else
5352 return false;
5353}
5354
5355static void
5356hugetlb_install_folio(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr,
5357 struct folio *new_folio, pte_t old, unsigned long sz)
5358{
5359 pte_t newpte = make_huge_pte(vma, &new_folio->page, 1);
5360
5361 __folio_mark_uptodate(new_folio);
5362 hugetlb_add_new_anon_rmap(new_folio, vma, addr);
5363 if (userfaultfd_wp(vma) && huge_pte_uffd_wp(old))
5364 newpte = huge_pte_mkuffd_wp(newpte);
5365 set_huge_pte_at(vma->vm_mm, addr, ptep, newpte, sz);
5366 hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm);
5367 folio_set_hugetlb_migratable(new_folio);
5368}
5369
5370int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
5371 struct vm_area_struct *dst_vma,
5372 struct vm_area_struct *src_vma)
5373{
5374 pte_t *src_pte, *dst_pte, entry;
5375 struct folio *pte_folio;
5376 unsigned long addr;
5377 bool cow = is_cow_mapping(src_vma->vm_flags);
5378 struct hstate *h = hstate_vma(src_vma);
5379 unsigned long sz = huge_page_size(h);
5380 unsigned long npages = pages_per_huge_page(h);
5381 struct mmu_notifier_range range;
5382 unsigned long last_addr_mask;
5383 int ret = 0;
5384
5385 if (cow) {
5386 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, src,
5387 src_vma->vm_start,
5388 src_vma->vm_end);
5389 mmu_notifier_invalidate_range_start(&range);
5390 vma_assert_write_locked(src_vma);
5391 raw_write_seqcount_begin(&src->write_protect_seq);
5392 } else {
5393 /*
5394 * For shared mappings the vma lock must be held before
5395 * calling hugetlb_walk() in the src vma. Otherwise, the
5396 * returned ptep could go away if part of a shared pmd and
5397 * another thread calls huge_pmd_unshare.
5398 */
5399 hugetlb_vma_lock_read(src_vma);
5400 }
5401
5402 last_addr_mask = hugetlb_mask_last_page(h);
5403 for (addr = src_vma->vm_start; addr < src_vma->vm_end; addr += sz) {
5404 spinlock_t *src_ptl, *dst_ptl;
5405 src_pte = hugetlb_walk(src_vma, addr, sz);
5406 if (!src_pte) {
5407 addr |= last_addr_mask;
5408 continue;
5409 }
5410 dst_pte = huge_pte_alloc(dst, dst_vma, addr, sz);
5411 if (!dst_pte) {
5412 ret = -ENOMEM;
5413 break;
5414 }
5415
5416 /*
5417 * If the pagetables are shared don't copy or take references.
5418 *
5419 * dst_pte == src_pte is the common case of src/dest sharing.
5420 * However, src could have 'unshared' and dst shares with
5421 * another vma. So page_count of ptep page is checked instead
5422 * to reliably determine whether pte is shared.
5423 */
5424 if (page_count(virt_to_page(dst_pte)) > 1) {
5425 addr |= last_addr_mask;
5426 continue;
5427 }
5428
5429 dst_ptl = huge_pte_lock(h, dst, dst_pte);
5430 src_ptl = huge_pte_lockptr(h, src, src_pte);
5431 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
5432 entry = huge_ptep_get(src_pte);
5433again:
5434 if (huge_pte_none(entry)) {
5435 /*
5436 * Skip if src entry none.
5437 */
5438 ;
5439 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) {
5440 if (!userfaultfd_wp(dst_vma))
5441 entry = huge_pte_clear_uffd_wp(entry);
5442 set_huge_pte_at(dst, addr, dst_pte, entry, sz);
5443 } else if (unlikely(is_hugetlb_entry_migration(entry))) {
5444 swp_entry_t swp_entry = pte_to_swp_entry(entry);
5445 bool uffd_wp = pte_swp_uffd_wp(entry);
5446
5447 if (!is_readable_migration_entry(swp_entry) && cow) {
5448 /*
5449 * COW mappings require pages in both
5450 * parent and child to be set to read.
5451 */
5452 swp_entry = make_readable_migration_entry(
5453 swp_offset(swp_entry));
5454 entry = swp_entry_to_pte(swp_entry);
5455 if (userfaultfd_wp(src_vma) && uffd_wp)
5456 entry = pte_swp_mkuffd_wp(entry);
5457 set_huge_pte_at(src, addr, src_pte, entry, sz);
5458 }
5459 if (!userfaultfd_wp(dst_vma))
5460 entry = huge_pte_clear_uffd_wp(entry);
5461 set_huge_pte_at(dst, addr, dst_pte, entry, sz);
5462 } else if (unlikely(is_pte_marker(entry))) {
5463 pte_marker marker = copy_pte_marker(
5464 pte_to_swp_entry(entry), dst_vma);
5465
5466 if (marker)
5467 set_huge_pte_at(dst, addr, dst_pte,
5468 make_pte_marker(marker), sz);
5469 } else {
5470 entry = huge_ptep_get(src_pte);
5471 pte_folio = page_folio(pte_page(entry));
5472 folio_get(pte_folio);
5473
5474 /*
5475 * Failing to duplicate the anon rmap is a rare case
5476 * where we see pinned hugetlb pages while they're
5477 * prone to COW. We need to do the COW earlier during
5478 * fork.
5479 *
5480 * When pre-allocating the page or copying data, we
5481 * need to be without the pgtable locks since we could
5482 * sleep during the process.
5483 */
5484 if (!folio_test_anon(pte_folio)) {
5485 hugetlb_add_file_rmap(pte_folio);
5486 } else if (hugetlb_try_dup_anon_rmap(pte_folio, src_vma)) {
5487 pte_t src_pte_old = entry;
5488 struct folio *new_folio;
5489
5490 spin_unlock(src_ptl);
5491 spin_unlock(dst_ptl);
5492 /* Do not use reserve as it's private owned */
5493 new_folio = alloc_hugetlb_folio(dst_vma, addr, 1);
5494 if (IS_ERR(new_folio)) {
5495 folio_put(pte_folio);
5496 ret = PTR_ERR(new_folio);
5497 break;
5498 }
5499 ret = copy_user_large_folio(new_folio,
5500 pte_folio,
5501 addr, dst_vma);
5502 folio_put(pte_folio);
5503 if (ret) {
5504 folio_put(new_folio);
5505 break;
5506 }
5507
5508 /* Install the new hugetlb folio if src pte stable */
5509 dst_ptl = huge_pte_lock(h, dst, dst_pte);
5510 src_ptl = huge_pte_lockptr(h, src, src_pte);
5511 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
5512 entry = huge_ptep_get(src_pte);
5513 if (!pte_same(src_pte_old, entry)) {
5514 restore_reserve_on_error(h, dst_vma, addr,
5515 new_folio);
5516 folio_put(new_folio);
5517 /* huge_ptep of dst_pte won't change as in child */
5518 goto again;
5519 }
5520 hugetlb_install_folio(dst_vma, dst_pte, addr,
5521 new_folio, src_pte_old, sz);
5522 spin_unlock(src_ptl);
5523 spin_unlock(dst_ptl);
5524 continue;
5525 }
5526
5527 if (cow) {
5528 /*
5529 * No need to notify as we are downgrading page
5530 * table protection not changing it to point
5531 * to a new page.
5532 *
5533 * See Documentation/mm/mmu_notifier.rst
5534 */
5535 huge_ptep_set_wrprotect(src, addr, src_pte);
5536 entry = huge_pte_wrprotect(entry);
5537 }
5538
5539 if (!userfaultfd_wp(dst_vma))
5540 entry = huge_pte_clear_uffd_wp(entry);
5541
5542 set_huge_pte_at(dst, addr, dst_pte, entry, sz);
5543 hugetlb_count_add(npages, dst);
5544 }
5545 spin_unlock(src_ptl);
5546 spin_unlock(dst_ptl);
5547 }
5548
5549 if (cow) {
5550 raw_write_seqcount_end(&src->write_protect_seq);
5551 mmu_notifier_invalidate_range_end(&range);
5552 } else {
5553 hugetlb_vma_unlock_read(src_vma);
5554 }
5555
5556 return ret;
5557}
5558
5559static void move_huge_pte(struct vm_area_struct *vma, unsigned long old_addr,
5560 unsigned long new_addr, pte_t *src_pte, pte_t *dst_pte,
5561 unsigned long sz)
5562{
5563 struct hstate *h = hstate_vma(vma);
5564 struct mm_struct *mm = vma->vm_mm;
5565 spinlock_t *src_ptl, *dst_ptl;
5566 pte_t pte;
5567
5568 dst_ptl = huge_pte_lock(h, mm, dst_pte);
5569 src_ptl = huge_pte_lockptr(h, mm, src_pte);
5570
5571 /*
5572 * We don't have to worry about the ordering of src and dst ptlocks
5573 * because exclusive mmap_lock (or the i_mmap_lock) prevents deadlock.
5574 */
5575 if (src_ptl != dst_ptl)
5576 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
5577
5578 pte = huge_ptep_get_and_clear(mm, old_addr, src_pte);
5579 set_huge_pte_at(mm, new_addr, dst_pte, pte, sz);
5580
5581 if (src_ptl != dst_ptl)
5582 spin_unlock(src_ptl);
5583 spin_unlock(dst_ptl);
5584}
5585
5586int move_hugetlb_page_tables(struct vm_area_struct *vma,
5587 struct vm_area_struct *new_vma,
5588 unsigned long old_addr, unsigned long new_addr,
5589 unsigned long len)
5590{
5591 struct hstate *h = hstate_vma(vma);
5592 struct address_space *mapping = vma->vm_file->f_mapping;
5593 unsigned long sz = huge_page_size(h);
5594 struct mm_struct *mm = vma->vm_mm;
5595 unsigned long old_end = old_addr + len;
5596 unsigned long last_addr_mask;
5597 pte_t *src_pte, *dst_pte;
5598 struct mmu_notifier_range range;
5599 bool shared_pmd = false;
5600
5601 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, old_addr,
5602 old_end);
5603 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5604 /*
5605 * In case of shared PMDs, we should cover the maximum possible
5606 * range.
5607 */
5608 flush_cache_range(vma, range.start, range.end);
5609
5610 mmu_notifier_invalidate_range_start(&range);
5611 last_addr_mask = hugetlb_mask_last_page(h);
5612 /* Prevent race with file truncation */
5613 hugetlb_vma_lock_write(vma);
5614 i_mmap_lock_write(mapping);
5615 for (; old_addr < old_end; old_addr += sz, new_addr += sz) {
5616 src_pte = hugetlb_walk(vma, old_addr, sz);
5617 if (!src_pte) {
5618 old_addr |= last_addr_mask;
5619 new_addr |= last_addr_mask;
5620 continue;
5621 }
5622 if (huge_pte_none(huge_ptep_get(src_pte)))
5623 continue;
5624
5625 if (huge_pmd_unshare(mm, vma, old_addr, src_pte)) {
5626 shared_pmd = true;
5627 old_addr |= last_addr_mask;
5628 new_addr |= last_addr_mask;
5629 continue;
5630 }
5631
5632 dst_pte = huge_pte_alloc(mm, new_vma, new_addr, sz);
5633 if (!dst_pte)
5634 break;
5635
5636 move_huge_pte(vma, old_addr, new_addr, src_pte, dst_pte, sz);
5637 }
5638
5639 if (shared_pmd)
5640 flush_hugetlb_tlb_range(vma, range.start, range.end);
5641 else
5642 flush_hugetlb_tlb_range(vma, old_end - len, old_end);
5643 mmu_notifier_invalidate_range_end(&range);
5644 i_mmap_unlock_write(mapping);
5645 hugetlb_vma_unlock_write(vma);
5646
5647 return len + old_addr - old_end;
5648}
5649
5650void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
5651 unsigned long start, unsigned long end,
5652 struct page *ref_page, zap_flags_t zap_flags)
5653{
5654 struct mm_struct *mm = vma->vm_mm;
5655 unsigned long address;
5656 pte_t *ptep;
5657 pte_t pte;
5658 spinlock_t *ptl;
5659 struct page *page;
5660 struct hstate *h = hstate_vma(vma);
5661 unsigned long sz = huge_page_size(h);
5662 bool adjust_reservation = false;
5663 unsigned long last_addr_mask;
5664 bool force_flush = false;
5665
5666 WARN_ON(!is_vm_hugetlb_page(vma));
5667 BUG_ON(start & ~huge_page_mask(h));
5668 BUG_ON(end & ~huge_page_mask(h));
5669
5670 /*
5671 * This is a hugetlb vma, all the pte entries should point
5672 * to huge page.
5673 */
5674 tlb_change_page_size(tlb, sz);
5675 tlb_start_vma(tlb, vma);
5676
5677 last_addr_mask = hugetlb_mask_last_page(h);
5678 address = start;
5679 for (; address < end; address += sz) {
5680 ptep = hugetlb_walk(vma, address, sz);
5681 if (!ptep) {
5682 address |= last_addr_mask;
5683 continue;
5684 }
5685
5686 ptl = huge_pte_lock(h, mm, ptep);
5687 if (huge_pmd_unshare(mm, vma, address, ptep)) {
5688 spin_unlock(ptl);
5689 tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE);
5690 force_flush = true;
5691 address |= last_addr_mask;
5692 continue;
5693 }
5694
5695 pte = huge_ptep_get(ptep);
5696 if (huge_pte_none(pte)) {
5697 spin_unlock(ptl);
5698 continue;
5699 }
5700
5701 /*
5702 * Migrating hugepage or HWPoisoned hugepage is already
5703 * unmapped and its refcount is dropped, so just clear pte here.
5704 */
5705 if (unlikely(!pte_present(pte))) {
5706 /*
5707 * If the pte was wr-protected by uffd-wp in any of the
5708 * swap forms, meanwhile the caller does not want to
5709 * drop the uffd-wp bit in this zap, then replace the
5710 * pte with a marker.
5711 */
5712 if (pte_swp_uffd_wp_any(pte) &&
5713 !(zap_flags & ZAP_FLAG_DROP_MARKER))
5714 set_huge_pte_at(mm, address, ptep,
5715 make_pte_marker(PTE_MARKER_UFFD_WP),
5716 sz);
5717 else
5718 huge_pte_clear(mm, address, ptep, sz);
5719 spin_unlock(ptl);
5720 continue;
5721 }
5722
5723 page = pte_page(pte);
5724 /*
5725 * If a reference page is supplied, it is because a specific
5726 * page is being unmapped, not a range. Ensure the page we
5727 * are about to unmap is the actual page of interest.
5728 */
5729 if (ref_page) {
5730 if (page != ref_page) {
5731 spin_unlock(ptl);
5732 continue;
5733 }
5734 /*
5735 * Mark the VMA as having unmapped its page so that
5736 * future faults in this VMA will fail rather than
5737 * looking like data was lost
5738 */
5739 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
5740 }
5741
5742 pte = huge_ptep_get_and_clear(mm, address, ptep);
5743 tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
5744 if (huge_pte_dirty(pte))
5745 set_page_dirty(page);
5746 /* Leave a uffd-wp pte marker if needed */
5747 if (huge_pte_uffd_wp(pte) &&
5748 !(zap_flags & ZAP_FLAG_DROP_MARKER))
5749 set_huge_pte_at(mm, address, ptep,
5750 make_pte_marker(PTE_MARKER_UFFD_WP),
5751 sz);
5752 hugetlb_count_sub(pages_per_huge_page(h), mm);
5753 hugetlb_remove_rmap(page_folio(page));
5754
5755 /*
5756 * Restore the reservation for anonymous page, otherwise the
5757 * backing page could be stolen by someone.
5758 * If there we are freeing a surplus, do not set the restore
5759 * reservation bit.
5760 */
5761 if (!h->surplus_huge_pages && __vma_private_lock(vma) &&
5762 folio_test_anon(page_folio(page))) {
5763 folio_set_hugetlb_restore_reserve(page_folio(page));
5764 /* Reservation to be adjusted after the spin lock */
5765 adjust_reservation = true;
5766 }
5767
5768 spin_unlock(ptl);
5769
5770 /*
5771 * Adjust the reservation for the region that will have the
5772 * reserve restored. Keep in mind that vma_needs_reservation() changes
5773 * resv->adds_in_progress if it succeeds. If this is not done,
5774 * do_exit() will not see it, and will keep the reservation
5775 * forever.
5776 */
5777 if (adjust_reservation && vma_needs_reservation(h, vma, address))
5778 vma_add_reservation(h, vma, address);
5779
5780 tlb_remove_page_size(tlb, page, huge_page_size(h));
5781 /*
5782 * Bail out after unmapping reference page if supplied
5783 */
5784 if (ref_page)
5785 break;
5786 }
5787 tlb_end_vma(tlb, vma);
5788
5789 /*
5790 * If we unshared PMDs, the TLB flush was not recorded in mmu_gather. We
5791 * could defer the flush until now, since by holding i_mmap_rwsem we
5792 * guaranteed that the last refernece would not be dropped. But we must
5793 * do the flushing before we return, as otherwise i_mmap_rwsem will be
5794 * dropped and the last reference to the shared PMDs page might be
5795 * dropped as well.
5796 *
5797 * In theory we could defer the freeing of the PMD pages as well, but
5798 * huge_pmd_unshare() relies on the exact page_count for the PMD page to
5799 * detect sharing, so we cannot defer the release of the page either.
5800 * Instead, do flush now.
5801 */
5802 if (force_flush)
5803 tlb_flush_mmu_tlbonly(tlb);
5804}
5805
5806void __hugetlb_zap_begin(struct vm_area_struct *vma,
5807 unsigned long *start, unsigned long *end)
5808{
5809 if (!vma->vm_file) /* hugetlbfs_file_mmap error */
5810 return;
5811
5812 adjust_range_if_pmd_sharing_possible(vma, start, end);
5813 hugetlb_vma_lock_write(vma);
5814 if (vma->vm_file)
5815 i_mmap_lock_write(vma->vm_file->f_mapping);
5816}
5817
5818void __hugetlb_zap_end(struct vm_area_struct *vma,
5819 struct zap_details *details)
5820{
5821 zap_flags_t zap_flags = details ? details->zap_flags : 0;
5822
5823 if (!vma->vm_file) /* hugetlbfs_file_mmap error */
5824 return;
5825
5826 if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */
5827 /*
5828 * Unlock and free the vma lock before releasing i_mmap_rwsem.
5829 * When the vma_lock is freed, this makes the vma ineligible
5830 * for pmd sharing. And, i_mmap_rwsem is required to set up
5831 * pmd sharing. This is important as page tables for this
5832 * unmapped range will be asynchrously deleted. If the page
5833 * tables are shared, there will be issues when accessed by
5834 * someone else.
5835 */
5836 __hugetlb_vma_unlock_write_free(vma);
5837 } else {
5838 hugetlb_vma_unlock_write(vma);
5839 }
5840
5841 if (vma->vm_file)
5842 i_mmap_unlock_write(vma->vm_file->f_mapping);
5843}
5844
5845void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
5846 unsigned long end, struct page *ref_page,
5847 zap_flags_t zap_flags)
5848{
5849 struct mmu_notifier_range range;
5850 struct mmu_gather tlb;
5851
5852 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm,
5853 start, end);
5854 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5855 mmu_notifier_invalidate_range_start(&range);
5856 tlb_gather_mmu(&tlb, vma->vm_mm);
5857
5858 __unmap_hugepage_range(&tlb, vma, start, end, ref_page, zap_flags);
5859
5860 mmu_notifier_invalidate_range_end(&range);
5861 tlb_finish_mmu(&tlb);
5862}
5863
5864/*
5865 * This is called when the original mapper is failing to COW a MAP_PRIVATE
5866 * mapping it owns the reserve page for. The intention is to unmap the page
5867 * from other VMAs and let the children be SIGKILLed if they are faulting the
5868 * same region.
5869 */
5870static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
5871 struct page *page, unsigned long address)
5872{
5873 struct hstate *h = hstate_vma(vma);
5874 struct vm_area_struct *iter_vma;
5875 struct address_space *mapping;
5876 pgoff_t pgoff;
5877
5878 /*
5879 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
5880 * from page cache lookup which is in HPAGE_SIZE units.
5881 */
5882 address = address & huge_page_mask(h);
5883 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
5884 vma->vm_pgoff;
5885 mapping = vma->vm_file->f_mapping;
5886
5887 /*
5888 * Take the mapping lock for the duration of the table walk. As
5889 * this mapping should be shared between all the VMAs,
5890 * __unmap_hugepage_range() is called as the lock is already held
5891 */
5892 i_mmap_lock_write(mapping);
5893 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
5894 /* Do not unmap the current VMA */
5895 if (iter_vma == vma)
5896 continue;
5897
5898 /*
5899 * Shared VMAs have their own reserves and do not affect
5900 * MAP_PRIVATE accounting but it is possible that a shared
5901 * VMA is using the same page so check and skip such VMAs.
5902 */
5903 if (iter_vma->vm_flags & VM_MAYSHARE)
5904 continue;
5905
5906 /*
5907 * Unmap the page from other VMAs without their own reserves.
5908 * They get marked to be SIGKILLed if they fault in these
5909 * areas. This is because a future no-page fault on this VMA
5910 * could insert a zeroed page instead of the data existing
5911 * from the time of fork. This would look like data corruption
5912 */
5913 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
5914 unmap_hugepage_range(iter_vma, address,
5915 address + huge_page_size(h), page, 0);
5916 }
5917 i_mmap_unlock_write(mapping);
5918}
5919
5920/*
5921 * hugetlb_wp() should be called with page lock of the original hugepage held.
5922 * Called with hugetlb_fault_mutex_table held and pte_page locked so we
5923 * cannot race with other handlers or page migration.
5924 * Keep the pte_same checks anyway to make transition from the mutex easier.
5925 */
5926static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
5927 unsigned long address, pte_t *ptep, unsigned int flags,
5928 struct folio *pagecache_folio, spinlock_t *ptl,
5929 struct vm_fault *vmf)
5930{
5931 const bool unshare = flags & FAULT_FLAG_UNSHARE;
5932 pte_t pte = huge_ptep_get(ptep);
5933 struct hstate *h = hstate_vma(vma);
5934 struct folio *old_folio;
5935 struct folio *new_folio;
5936 int outside_reserve = 0;
5937 vm_fault_t ret = 0;
5938 unsigned long haddr = address & huge_page_mask(h);
5939 struct mmu_notifier_range range;
5940
5941 /*
5942 * Never handle CoW for uffd-wp protected pages. It should be only
5943 * handled when the uffd-wp protection is removed.
5944 *
5945 * Note that only the CoW optimization path (in hugetlb_no_page())
5946 * can trigger this, because hugetlb_fault() will always resolve
5947 * uffd-wp bit first.
5948 */
5949 if (!unshare && huge_pte_uffd_wp(pte))
5950 return 0;
5951
5952 /*
5953 * hugetlb does not support FOLL_FORCE-style write faults that keep the
5954 * PTE mapped R/O such as maybe_mkwrite() would do.
5955 */
5956 if (WARN_ON_ONCE(!unshare && !(vma->vm_flags & VM_WRITE)))
5957 return VM_FAULT_SIGSEGV;
5958
5959 /* Let's take out MAP_SHARED mappings first. */
5960 if (vma->vm_flags & VM_MAYSHARE) {
5961 set_huge_ptep_writable(vma, haddr, ptep);
5962 return 0;
5963 }
5964
5965 old_folio = page_folio(pte_page(pte));
5966
5967 delayacct_wpcopy_start();
5968
5969retry_avoidcopy:
5970 /*
5971 * If no-one else is actually using this page, we're the exclusive
5972 * owner and can reuse this page.
5973 */
5974 if (folio_mapcount(old_folio) == 1 && folio_test_anon(old_folio)) {
5975 if (!PageAnonExclusive(&old_folio->page)) {
5976 folio_move_anon_rmap(old_folio, vma);
5977 SetPageAnonExclusive(&old_folio->page);
5978 }
5979 if (likely(!unshare))
5980 set_huge_ptep_writable(vma, haddr, ptep);
5981
5982 delayacct_wpcopy_end();
5983 return 0;
5984 }
5985 VM_BUG_ON_PAGE(folio_test_anon(old_folio) &&
5986 PageAnonExclusive(&old_folio->page), &old_folio->page);
5987
5988 /*
5989 * If the process that created a MAP_PRIVATE mapping is about to
5990 * perform a COW due to a shared page count, attempt to satisfy
5991 * the allocation without using the existing reserves. The pagecache
5992 * page is used to determine if the reserve at this address was
5993 * consumed or not. If reserves were used, a partial faulted mapping
5994 * at the time of fork() could consume its reserves on COW instead
5995 * of the full address range.
5996 */
5997 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
5998 old_folio != pagecache_folio)
5999 outside_reserve = 1;
6000
6001 folio_get(old_folio);
6002
6003 /*
6004 * Drop page table lock as buddy allocator may be called. It will
6005 * be acquired again before returning to the caller, as expected.
6006 */
6007 spin_unlock(ptl);
6008 new_folio = alloc_hugetlb_folio(vma, haddr, outside_reserve);
6009
6010 if (IS_ERR(new_folio)) {
6011 /*
6012 * If a process owning a MAP_PRIVATE mapping fails to COW,
6013 * it is due to references held by a child and an insufficient
6014 * huge page pool. To guarantee the original mappers
6015 * reliability, unmap the page from child processes. The child
6016 * may get SIGKILLed if it later faults.
6017 */
6018 if (outside_reserve) {
6019 struct address_space *mapping = vma->vm_file->f_mapping;
6020 pgoff_t idx;
6021 u32 hash;
6022
6023 folio_put(old_folio);
6024 /*
6025 * Drop hugetlb_fault_mutex and vma_lock before
6026 * unmapping. unmapping needs to hold vma_lock
6027 * in write mode. Dropping vma_lock in read mode
6028 * here is OK as COW mappings do not interact with
6029 * PMD sharing.
6030 *
6031 * Reacquire both after unmap operation.
6032 */
6033 idx = vma_hugecache_offset(h, vma, haddr);
6034 hash = hugetlb_fault_mutex_hash(mapping, idx);
6035 hugetlb_vma_unlock_read(vma);
6036 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6037
6038 unmap_ref_private(mm, vma, &old_folio->page, haddr);
6039
6040 mutex_lock(&hugetlb_fault_mutex_table[hash]);
6041 hugetlb_vma_lock_read(vma);
6042 spin_lock(ptl);
6043 ptep = hugetlb_walk(vma, haddr, huge_page_size(h));
6044 if (likely(ptep &&
6045 pte_same(huge_ptep_get(ptep), pte)))
6046 goto retry_avoidcopy;
6047 /*
6048 * race occurs while re-acquiring page table
6049 * lock, and our job is done.
6050 */
6051 delayacct_wpcopy_end();
6052 return 0;
6053 }
6054
6055 ret = vmf_error(PTR_ERR(new_folio));
6056 goto out_release_old;
6057 }
6058
6059 /*
6060 * When the original hugepage is shared one, it does not have
6061 * anon_vma prepared.
6062 */
6063 ret = vmf_anon_prepare(vmf);
6064 if (unlikely(ret))
6065 goto out_release_all;
6066
6067 if (copy_user_large_folio(new_folio, old_folio, address, vma)) {
6068 ret = VM_FAULT_HWPOISON_LARGE;
6069 goto out_release_all;
6070 }
6071 __folio_mark_uptodate(new_folio);
6072
6073 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, haddr,
6074 haddr + huge_page_size(h));
6075 mmu_notifier_invalidate_range_start(&range);
6076
6077 /*
6078 * Retake the page table lock to check for racing updates
6079 * before the page tables are altered
6080 */
6081 spin_lock(ptl);
6082 ptep = hugetlb_walk(vma, haddr, huge_page_size(h));
6083 if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
6084 pte_t newpte = make_huge_pte(vma, &new_folio->page, !unshare);
6085
6086 /* Break COW or unshare */
6087 huge_ptep_clear_flush(vma, haddr, ptep);
6088 hugetlb_remove_rmap(old_folio);
6089 hugetlb_add_new_anon_rmap(new_folio, vma, haddr);
6090 if (huge_pte_uffd_wp(pte))
6091 newpte = huge_pte_mkuffd_wp(newpte);
6092 set_huge_pte_at(mm, haddr, ptep, newpte, huge_page_size(h));
6093 folio_set_hugetlb_migratable(new_folio);
6094 /* Make the old page be freed below */
6095 new_folio = old_folio;
6096 }
6097 spin_unlock(ptl);
6098 mmu_notifier_invalidate_range_end(&range);
6099out_release_all:
6100 /*
6101 * No restore in case of successful pagetable update (Break COW or
6102 * unshare)
6103 */
6104 if (new_folio != old_folio)
6105 restore_reserve_on_error(h, vma, haddr, new_folio);
6106 folio_put(new_folio);
6107out_release_old:
6108 folio_put(old_folio);
6109
6110 spin_lock(ptl); /* Caller expects lock to be held */
6111
6112 delayacct_wpcopy_end();
6113 return ret;
6114}
6115
6116/*
6117 * Return whether there is a pagecache page to back given address within VMA.
6118 */
6119static bool hugetlbfs_pagecache_present(struct hstate *h,
6120 struct vm_area_struct *vma, unsigned long address)
6121{
6122 struct address_space *mapping = vma->vm_file->f_mapping;
6123 pgoff_t idx = linear_page_index(vma, address);
6124 struct folio *folio;
6125
6126 folio = filemap_get_folio(mapping, idx);
6127 if (IS_ERR(folio))
6128 return false;
6129 folio_put(folio);
6130 return true;
6131}
6132
6133int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping,
6134 pgoff_t idx)
6135{
6136 struct inode *inode = mapping->host;
6137 struct hstate *h = hstate_inode(inode);
6138 int err;
6139
6140 idx <<= huge_page_order(h);
6141 __folio_set_locked(folio);
6142 err = __filemap_add_folio(mapping, folio, idx, GFP_KERNEL, NULL);
6143
6144 if (unlikely(err)) {
6145 __folio_clear_locked(folio);
6146 return err;
6147 }
6148 folio_clear_hugetlb_restore_reserve(folio);
6149
6150 /*
6151 * mark folio dirty so that it will not be removed from cache/file
6152 * by non-hugetlbfs specific code paths.
6153 */
6154 folio_mark_dirty(folio);
6155
6156 spin_lock(&inode->i_lock);
6157 inode->i_blocks += blocks_per_huge_page(h);
6158 spin_unlock(&inode->i_lock);
6159 return 0;
6160}
6161
6162static inline vm_fault_t hugetlb_handle_userfault(struct vm_fault *vmf,
6163 struct address_space *mapping,
6164 unsigned long reason)
6165{
6166 u32 hash;
6167
6168 /*
6169 * vma_lock and hugetlb_fault_mutex must be dropped before handling
6170 * userfault. Also mmap_lock could be dropped due to handling
6171 * userfault, any vma operation should be careful from here.
6172 */
6173 hugetlb_vma_unlock_read(vmf->vma);
6174 hash = hugetlb_fault_mutex_hash(mapping, vmf->pgoff);
6175 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6176 return handle_userfault(vmf, reason);
6177}
6178
6179/*
6180 * Recheck pte with pgtable lock. Returns true if pte didn't change, or
6181 * false if pte changed or is changing.
6182 */
6183static bool hugetlb_pte_stable(struct hstate *h, struct mm_struct *mm,
6184 pte_t *ptep, pte_t old_pte)
6185{
6186 spinlock_t *ptl;
6187 bool same;
6188
6189 ptl = huge_pte_lock(h, mm, ptep);
6190 same = pte_same(huge_ptep_get(ptep), old_pte);
6191 spin_unlock(ptl);
6192
6193 return same;
6194}
6195
6196static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
6197 struct vm_area_struct *vma,
6198 struct address_space *mapping, pgoff_t idx,
6199 unsigned long address, pte_t *ptep,
6200 pte_t old_pte, unsigned int flags,
6201 struct vm_fault *vmf)
6202{
6203 struct hstate *h = hstate_vma(vma);
6204 vm_fault_t ret = VM_FAULT_SIGBUS;
6205 int anon_rmap = 0;
6206 unsigned long size;
6207 struct folio *folio;
6208 pte_t new_pte;
6209 spinlock_t *ptl;
6210 unsigned long haddr = address & huge_page_mask(h);
6211 bool new_folio, new_pagecache_folio = false;
6212 u32 hash = hugetlb_fault_mutex_hash(mapping, idx);
6213
6214 /*
6215 * Currently, we are forced to kill the process in the event the
6216 * original mapper has unmapped pages from the child due to a failed
6217 * COW/unsharing. Warn that such a situation has occurred as it may not
6218 * be obvious.
6219 */
6220 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
6221 pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
6222 current->pid);
6223 goto out;
6224 }
6225
6226 /*
6227 * Use page lock to guard against racing truncation
6228 * before we get page_table_lock.
6229 */
6230 new_folio = false;
6231 folio = filemap_lock_hugetlb_folio(h, mapping, idx);
6232 if (IS_ERR(folio)) {
6233 size = i_size_read(mapping->host) >> huge_page_shift(h);
6234 if (idx >= size)
6235 goto out;
6236 /* Check for page in userfault range */
6237 if (userfaultfd_missing(vma)) {
6238 /*
6239 * Since hugetlb_no_page() was examining pte
6240 * without pgtable lock, we need to re-test under
6241 * lock because the pte may not be stable and could
6242 * have changed from under us. Try to detect
6243 * either changed or during-changing ptes and retry
6244 * properly when needed.
6245 *
6246 * Note that userfaultfd is actually fine with
6247 * false positives (e.g. caused by pte changed),
6248 * but not wrong logical events (e.g. caused by
6249 * reading a pte during changing). The latter can
6250 * confuse the userspace, so the strictness is very
6251 * much preferred. E.g., MISSING event should
6252 * never happen on the page after UFFDIO_COPY has
6253 * correctly installed the page and returned.
6254 */
6255 if (!hugetlb_pte_stable(h, mm, ptep, old_pte)) {
6256 ret = 0;
6257 goto out;
6258 }
6259
6260 return hugetlb_handle_userfault(vmf, mapping,
6261 VM_UFFD_MISSING);
6262 }
6263
6264 if (!(vma->vm_flags & VM_MAYSHARE)) {
6265 ret = vmf_anon_prepare(vmf);
6266 if (unlikely(ret))
6267 goto out;
6268 }
6269
6270 folio = alloc_hugetlb_folio(vma, haddr, 0);
6271 if (IS_ERR(folio)) {
6272 /*
6273 * Returning error will result in faulting task being
6274 * sent SIGBUS. The hugetlb fault mutex prevents two
6275 * tasks from racing to fault in the same page which
6276 * could result in false unable to allocate errors.
6277 * Page migration does not take the fault mutex, but
6278 * does a clear then write of pte's under page table
6279 * lock. Page fault code could race with migration,
6280 * notice the clear pte and try to allocate a page
6281 * here. Before returning error, get ptl and make
6282 * sure there really is no pte entry.
6283 */
6284 if (hugetlb_pte_stable(h, mm, ptep, old_pte))
6285 ret = vmf_error(PTR_ERR(folio));
6286 else
6287 ret = 0;
6288 goto out;
6289 }
6290 clear_huge_page(&folio->page, address, pages_per_huge_page(h));
6291 __folio_mark_uptodate(folio);
6292 new_folio = true;
6293
6294 if (vma->vm_flags & VM_MAYSHARE) {
6295 int err = hugetlb_add_to_page_cache(folio, mapping, idx);
6296 if (err) {
6297 /*
6298 * err can't be -EEXIST which implies someone
6299 * else consumed the reservation since hugetlb
6300 * fault mutex is held when add a hugetlb page
6301 * to the page cache. So it's safe to call
6302 * restore_reserve_on_error() here.
6303 */
6304 restore_reserve_on_error(h, vma, haddr, folio);
6305 folio_put(folio);
6306 ret = VM_FAULT_SIGBUS;
6307 goto out;
6308 }
6309 new_pagecache_folio = true;
6310 } else {
6311 folio_lock(folio);
6312 anon_rmap = 1;
6313 }
6314 } else {
6315 /*
6316 * If memory error occurs between mmap() and fault, some process
6317 * don't have hwpoisoned swap entry for errored virtual address.
6318 * So we need to block hugepage fault by PG_hwpoison bit check.
6319 */
6320 if (unlikely(folio_test_hwpoison(folio))) {
6321 ret = VM_FAULT_HWPOISON_LARGE |
6322 VM_FAULT_SET_HINDEX(hstate_index(h));
6323 goto backout_unlocked;
6324 }
6325
6326 /* Check for page in userfault range. */
6327 if (userfaultfd_minor(vma)) {
6328 folio_unlock(folio);
6329 folio_put(folio);
6330 /* See comment in userfaultfd_missing() block above */
6331 if (!hugetlb_pte_stable(h, mm, ptep, old_pte)) {
6332 ret = 0;
6333 goto out;
6334 }
6335 return hugetlb_handle_userfault(vmf, mapping,
6336 VM_UFFD_MINOR);
6337 }
6338 }
6339
6340 /*
6341 * If we are going to COW a private mapping later, we examine the
6342 * pending reservations for this page now. This will ensure that
6343 * any allocations necessary to record that reservation occur outside
6344 * the spinlock.
6345 */
6346 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
6347 if (vma_needs_reservation(h, vma, haddr) < 0) {
6348 ret = VM_FAULT_OOM;
6349 goto backout_unlocked;
6350 }
6351 /* Just decrements count, does not deallocate */
6352 vma_end_reservation(h, vma, haddr);
6353 }
6354
6355 ptl = huge_pte_lock(h, mm, ptep);
6356 ret = 0;
6357 /* If pte changed from under us, retry */
6358 if (!pte_same(huge_ptep_get(ptep), old_pte))
6359 goto backout;
6360
6361 if (anon_rmap)
6362 hugetlb_add_new_anon_rmap(folio, vma, haddr);
6363 else
6364 hugetlb_add_file_rmap(folio);
6365 new_pte = make_huge_pte(vma, &folio->page, ((vma->vm_flags & VM_WRITE)
6366 && (vma->vm_flags & VM_SHARED)));
6367 /*
6368 * If this pte was previously wr-protected, keep it wr-protected even
6369 * if populated.
6370 */
6371 if (unlikely(pte_marker_uffd_wp(old_pte)))
6372 new_pte = huge_pte_mkuffd_wp(new_pte);
6373 set_huge_pte_at(mm, haddr, ptep, new_pte, huge_page_size(h));
6374
6375 hugetlb_count_add(pages_per_huge_page(h), mm);
6376 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
6377 /* Optimization, do the COW without a second fault */
6378 ret = hugetlb_wp(mm, vma, address, ptep, flags, folio, ptl, vmf);
6379 }
6380
6381 spin_unlock(ptl);
6382
6383 /*
6384 * Only set hugetlb_migratable in newly allocated pages. Existing pages
6385 * found in the pagecache may not have hugetlb_migratable if they have
6386 * been isolated for migration.
6387 */
6388 if (new_folio)
6389 folio_set_hugetlb_migratable(folio);
6390
6391 folio_unlock(folio);
6392out:
6393 hugetlb_vma_unlock_read(vma);
6394 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6395 return ret;
6396
6397backout:
6398 spin_unlock(ptl);
6399backout_unlocked:
6400 if (new_folio && !new_pagecache_folio)
6401 restore_reserve_on_error(h, vma, haddr, folio);
6402
6403 folio_unlock(folio);
6404 folio_put(folio);
6405 goto out;
6406}
6407
6408#ifdef CONFIG_SMP
6409u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
6410{
6411 unsigned long key[2];
6412 u32 hash;
6413
6414 key[0] = (unsigned long) mapping;
6415 key[1] = idx;
6416
6417 hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
6418
6419 return hash & (num_fault_mutexes - 1);
6420}
6421#else
6422/*
6423 * For uniprocessor systems we always use a single mutex, so just
6424 * return 0 and avoid the hashing overhead.
6425 */
6426u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
6427{
6428 return 0;
6429}
6430#endif
6431
6432vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
6433 unsigned long address, unsigned int flags)
6434{
6435 pte_t *ptep, entry;
6436 spinlock_t *ptl;
6437 vm_fault_t ret;
6438 u32 hash;
6439 struct folio *folio = NULL;
6440 struct folio *pagecache_folio = NULL;
6441 struct hstate *h = hstate_vma(vma);
6442 struct address_space *mapping;
6443 int need_wait_lock = 0;
6444 unsigned long haddr = address & huge_page_mask(h);
6445 struct vm_fault vmf = {
6446 .vma = vma,
6447 .address = haddr,
6448 .real_address = address,
6449 .flags = flags,
6450 .pgoff = vma_hugecache_offset(h, vma, haddr),
6451 /* TODO: Track hugetlb faults using vm_fault */
6452
6453 /*
6454 * Some fields may not be initialized, be careful as it may
6455 * be hard to debug if called functions make assumptions
6456 */
6457 };
6458
6459 /*
6460 * Serialize hugepage allocation and instantiation, so that we don't
6461 * get spurious allocation failures if two CPUs race to instantiate
6462 * the same page in the page cache.
6463 */
6464 mapping = vma->vm_file->f_mapping;
6465 hash = hugetlb_fault_mutex_hash(mapping, vmf.pgoff);
6466 mutex_lock(&hugetlb_fault_mutex_table[hash]);
6467
6468 /*
6469 * Acquire vma lock before calling huge_pte_alloc and hold
6470 * until finished with ptep. This prevents huge_pmd_unshare from
6471 * being called elsewhere and making the ptep no longer valid.
6472 */
6473 hugetlb_vma_lock_read(vma);
6474 ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h));
6475 if (!ptep) {
6476 hugetlb_vma_unlock_read(vma);
6477 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6478 return VM_FAULT_OOM;
6479 }
6480
6481 entry = huge_ptep_get(ptep);
6482 if (huge_pte_none_mostly(entry)) {
6483 if (is_pte_marker(entry)) {
6484 pte_marker marker =
6485 pte_marker_get(pte_to_swp_entry(entry));
6486
6487 if (marker & PTE_MARKER_POISONED) {
6488 ret = VM_FAULT_HWPOISON_LARGE;
6489 goto out_mutex;
6490 }
6491 }
6492
6493 /*
6494 * Other PTE markers should be handled the same way as none PTE.
6495 *
6496 * hugetlb_no_page will drop vma lock and hugetlb fault
6497 * mutex internally, which make us return immediately.
6498 */
6499 return hugetlb_no_page(mm, vma, mapping, vmf.pgoff, address,
6500 ptep, entry, flags, &vmf);
6501 }
6502
6503 ret = 0;
6504
6505 /*
6506 * entry could be a migration/hwpoison entry at this point, so this
6507 * check prevents the kernel from going below assuming that we have
6508 * an active hugepage in pagecache. This goto expects the 2nd page
6509 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
6510 * properly handle it.
6511 */
6512 if (!pte_present(entry)) {
6513 if (unlikely(is_hugetlb_entry_migration(entry))) {
6514 /*
6515 * Release the hugetlb fault lock now, but retain
6516 * the vma lock, because it is needed to guard the
6517 * huge_pte_lockptr() later in
6518 * migration_entry_wait_huge(). The vma lock will
6519 * be released there.
6520 */
6521 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6522 migration_entry_wait_huge(vma, ptep);
6523 return 0;
6524 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
6525 ret = VM_FAULT_HWPOISON_LARGE |
6526 VM_FAULT_SET_HINDEX(hstate_index(h));
6527 goto out_mutex;
6528 }
6529
6530 /*
6531 * If we are going to COW/unshare the mapping later, we examine the
6532 * pending reservations for this page now. This will ensure that any
6533 * allocations necessary to record that reservation occur outside the
6534 * spinlock. Also lookup the pagecache page now as it is used to
6535 * determine if a reservation has been consumed.
6536 */
6537 if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) &&
6538 !(vma->vm_flags & VM_MAYSHARE) && !huge_pte_write(entry)) {
6539 if (vma_needs_reservation(h, vma, haddr) < 0) {
6540 ret = VM_FAULT_OOM;
6541 goto out_mutex;
6542 }
6543 /* Just decrements count, does not deallocate */
6544 vma_end_reservation(h, vma, haddr);
6545
6546 pagecache_folio = filemap_lock_hugetlb_folio(h, mapping,
6547 vmf.pgoff);
6548 if (IS_ERR(pagecache_folio))
6549 pagecache_folio = NULL;
6550 }
6551
6552 ptl = huge_pte_lock(h, mm, ptep);
6553
6554 /* Check for a racing update before calling hugetlb_wp() */
6555 if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
6556 goto out_ptl;
6557
6558 /* Handle userfault-wp first, before trying to lock more pages */
6559 if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) &&
6560 (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
6561 if (!userfaultfd_wp_async(vma)) {
6562 spin_unlock(ptl);
6563 if (pagecache_folio) {
6564 folio_unlock(pagecache_folio);
6565 folio_put(pagecache_folio);
6566 }
6567 hugetlb_vma_unlock_read(vma);
6568 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6569 return handle_userfault(&vmf, VM_UFFD_WP);
6570 }
6571
6572 entry = huge_pte_clear_uffd_wp(entry);
6573 set_huge_pte_at(mm, haddr, ptep, entry,
6574 huge_page_size(hstate_vma(vma)));
6575 /* Fallthrough to CoW */
6576 }
6577
6578 /*
6579 * hugetlb_wp() requires page locks of pte_page(entry) and
6580 * pagecache_folio, so here we need take the former one
6581 * when folio != pagecache_folio or !pagecache_folio.
6582 */
6583 folio = page_folio(pte_page(entry));
6584 if (folio != pagecache_folio)
6585 if (!folio_trylock(folio)) {
6586 need_wait_lock = 1;
6587 goto out_ptl;
6588 }
6589
6590 folio_get(folio);
6591
6592 if (flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) {
6593 if (!huge_pte_write(entry)) {
6594 ret = hugetlb_wp(mm, vma, address, ptep, flags,
6595 pagecache_folio, ptl, &vmf);
6596 goto out_put_page;
6597 } else if (likely(flags & FAULT_FLAG_WRITE)) {
6598 entry = huge_pte_mkdirty(entry);
6599 }
6600 }
6601 entry = pte_mkyoung(entry);
6602 if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
6603 flags & FAULT_FLAG_WRITE))
6604 update_mmu_cache(vma, haddr, ptep);
6605out_put_page:
6606 if (folio != pagecache_folio)
6607 folio_unlock(folio);
6608 folio_put(folio);
6609out_ptl:
6610 spin_unlock(ptl);
6611
6612 if (pagecache_folio) {
6613 folio_unlock(pagecache_folio);
6614 folio_put(pagecache_folio);
6615 }
6616out_mutex:
6617 hugetlb_vma_unlock_read(vma);
6618 mutex_unlock(&hugetlb_fault_mutex_table[hash]);
6619 /*
6620 * Generally it's safe to hold refcount during waiting page lock. But
6621 * here we just wait to defer the next page fault to avoid busy loop and
6622 * the page is not used after unlocked before returning from the current
6623 * page fault. So we are safe from accessing freed page, even if we wait
6624 * here without taking refcount.
6625 */
6626 if (need_wait_lock)
6627 folio_wait_locked(folio);
6628 return ret;
6629}
6630
6631#ifdef CONFIG_USERFAULTFD
6632/*
6633 * Can probably be eliminated, but still used by hugetlb_mfill_atomic_pte().
6634 */
6635static struct folio *alloc_hugetlb_folio_vma(struct hstate *h,
6636 struct vm_area_struct *vma, unsigned long address)
6637{
6638 struct mempolicy *mpol;
6639 nodemask_t *nodemask;
6640 struct folio *folio;
6641 gfp_t gfp_mask;
6642 int node;
6643
6644 gfp_mask = htlb_alloc_mask(h);
6645 node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
6646 folio = alloc_hugetlb_folio_nodemask(h, node, nodemask, gfp_mask);
6647 mpol_cond_put(mpol);
6648
6649 return folio;
6650}
6651
6652/*
6653 * Used by userfaultfd UFFDIO_* ioctls. Based on userfaultfd's mfill_atomic_pte
6654 * with modifications for hugetlb pages.
6655 */
6656int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
6657 struct vm_area_struct *dst_vma,
6658 unsigned long dst_addr,
6659 unsigned long src_addr,
6660 uffd_flags_t flags,
6661 struct folio **foliop)
6662{
6663 struct mm_struct *dst_mm = dst_vma->vm_mm;
6664 bool is_continue = uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE);
6665 bool wp_enabled = (flags & MFILL_ATOMIC_WP);
6666 struct hstate *h = hstate_vma(dst_vma);
6667 struct address_space *mapping = dst_vma->vm_file->f_mapping;
6668 pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
6669 unsigned long size;
6670 int vm_shared = dst_vma->vm_flags & VM_SHARED;
6671 pte_t _dst_pte;
6672 spinlock_t *ptl;
6673 int ret = -ENOMEM;
6674 struct folio *folio;
6675 int writable;
6676 bool folio_in_pagecache = false;
6677
6678 if (uffd_flags_mode_is(flags, MFILL_ATOMIC_POISON)) {
6679 ptl = huge_pte_lock(h, dst_mm, dst_pte);
6680
6681 /* Don't overwrite any existing PTEs (even markers) */
6682 if (!huge_pte_none(huge_ptep_get(dst_pte))) {
6683 spin_unlock(ptl);
6684 return -EEXIST;
6685 }
6686
6687 _dst_pte = make_pte_marker(PTE_MARKER_POISONED);
6688 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte,
6689 huge_page_size(h));
6690
6691 /* No need to invalidate - it was non-present before */
6692 update_mmu_cache(dst_vma, dst_addr, dst_pte);
6693
6694 spin_unlock(ptl);
6695 return 0;
6696 }
6697
6698 if (is_continue) {
6699 ret = -EFAULT;
6700 folio = filemap_lock_hugetlb_folio(h, mapping, idx);
6701 if (IS_ERR(folio))
6702 goto out;
6703 folio_in_pagecache = true;
6704 } else if (!*foliop) {
6705 /* If a folio already exists, then it's UFFDIO_COPY for
6706 * a non-missing case. Return -EEXIST.
6707 */
6708 if (vm_shared &&
6709 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
6710 ret = -EEXIST;
6711 goto out;
6712 }
6713
6714 folio = alloc_hugetlb_folio(dst_vma, dst_addr, 0);
6715 if (IS_ERR(folio)) {
6716 ret = -ENOMEM;
6717 goto out;
6718 }
6719
6720 ret = copy_folio_from_user(folio, (const void __user *) src_addr,
6721 false);
6722
6723 /* fallback to copy_from_user outside mmap_lock */
6724 if (unlikely(ret)) {
6725 ret = -ENOENT;
6726 /* Free the allocated folio which may have
6727 * consumed a reservation.
6728 */
6729 restore_reserve_on_error(h, dst_vma, dst_addr, folio);
6730 folio_put(folio);
6731
6732 /* Allocate a temporary folio to hold the copied
6733 * contents.
6734 */
6735 folio = alloc_hugetlb_folio_vma(h, dst_vma, dst_addr);
6736 if (!folio) {
6737 ret = -ENOMEM;
6738 goto out;
6739 }
6740 *foliop = folio;
6741 /* Set the outparam foliop and return to the caller to
6742 * copy the contents outside the lock. Don't free the
6743 * folio.
6744 */
6745 goto out;
6746 }
6747 } else {
6748 if (vm_shared &&
6749 hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
6750 folio_put(*foliop);
6751 ret = -EEXIST;
6752 *foliop = NULL;
6753 goto out;
6754 }
6755
6756 folio = alloc_hugetlb_folio(dst_vma, dst_addr, 0);
6757 if (IS_ERR(folio)) {
6758 folio_put(*foliop);
6759 ret = -ENOMEM;
6760 *foliop = NULL;
6761 goto out;
6762 }
6763 ret = copy_user_large_folio(folio, *foliop, dst_addr, dst_vma);
6764 folio_put(*foliop);
6765 *foliop = NULL;
6766 if (ret) {
6767 folio_put(folio);
6768 goto out;
6769 }
6770 }
6771
6772 /*
6773 * If we just allocated a new page, we need a memory barrier to ensure
6774 * that preceding stores to the page become visible before the
6775 * set_pte_at() write. The memory barrier inside __folio_mark_uptodate
6776 * is what we need.
6777 *
6778 * In the case where we have not allocated a new page (is_continue),
6779 * the page must already be uptodate. UFFDIO_CONTINUE already includes
6780 * an earlier smp_wmb() to ensure that prior stores will be visible
6781 * before the set_pte_at() write.
6782 */
6783 if (!is_continue)
6784 __folio_mark_uptodate(folio);
6785 else
6786 WARN_ON_ONCE(!folio_test_uptodate(folio));
6787
6788 /* Add shared, newly allocated pages to the page cache. */
6789 if (vm_shared && !is_continue) {
6790 size = i_size_read(mapping->host) >> huge_page_shift(h);
6791 ret = -EFAULT;
6792 if (idx >= size)
6793 goto out_release_nounlock;
6794
6795 /*
6796 * Serialization between remove_inode_hugepages() and
6797 * hugetlb_add_to_page_cache() below happens through the
6798 * hugetlb_fault_mutex_table that here must be hold by
6799 * the caller.
6800 */
6801 ret = hugetlb_add_to_page_cache(folio, mapping, idx);
6802 if (ret)
6803 goto out_release_nounlock;
6804 folio_in_pagecache = true;
6805 }
6806
6807 ptl = huge_pte_lock(h, dst_mm, dst_pte);
6808
6809 ret = -EIO;
6810 if (folio_test_hwpoison(folio))
6811 goto out_release_unlock;
6812
6813 /*
6814 * We allow to overwrite a pte marker: consider when both MISSING|WP
6815 * registered, we firstly wr-protect a none pte which has no page cache
6816 * page backing it, then access the page.
6817 */
6818 ret = -EEXIST;
6819 if (!huge_pte_none_mostly(huge_ptep_get(dst_pte)))
6820 goto out_release_unlock;
6821
6822 if (folio_in_pagecache)
6823 hugetlb_add_file_rmap(folio);
6824 else
6825 hugetlb_add_new_anon_rmap(folio, dst_vma, dst_addr);
6826
6827 /*
6828 * For either: (1) CONTINUE on a non-shared VMA, or (2) UFFDIO_COPY
6829 * with wp flag set, don't set pte write bit.
6830 */
6831 if (wp_enabled || (is_continue && !vm_shared))
6832 writable = 0;
6833 else
6834 writable = dst_vma->vm_flags & VM_WRITE;
6835
6836 _dst_pte = make_huge_pte(dst_vma, &folio->page, writable);
6837 /*
6838 * Always mark UFFDIO_COPY page dirty; note that this may not be
6839 * extremely important for hugetlbfs for now since swapping is not
6840 * supported, but we should still be clear in that this page cannot be
6841 * thrown away at will, even if write bit not set.
6842 */
6843 _dst_pte = huge_pte_mkdirty(_dst_pte);
6844 _dst_pte = pte_mkyoung(_dst_pte);
6845
6846 if (wp_enabled)
6847 _dst_pte = huge_pte_mkuffd_wp(_dst_pte);
6848
6849 set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte, huge_page_size(h));
6850
6851 hugetlb_count_add(pages_per_huge_page(h), dst_mm);
6852
6853 /* No need to invalidate - it was non-present before */
6854 update_mmu_cache(dst_vma, dst_addr, dst_pte);
6855
6856 spin_unlock(ptl);
6857 if (!is_continue)
6858 folio_set_hugetlb_migratable(folio);
6859 if (vm_shared || is_continue)
6860 folio_unlock(folio);
6861 ret = 0;
6862out:
6863 return ret;
6864out_release_unlock:
6865 spin_unlock(ptl);
6866 if (vm_shared || is_continue)
6867 folio_unlock(folio);
6868out_release_nounlock:
6869 if (!folio_in_pagecache)
6870 restore_reserve_on_error(h, dst_vma, dst_addr, folio);
6871 folio_put(folio);
6872 goto out;
6873}
6874#endif /* CONFIG_USERFAULTFD */
6875
6876struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
6877 unsigned long address, unsigned int flags,
6878 unsigned int *page_mask)
6879{
6880 struct hstate *h = hstate_vma(vma);
6881 struct mm_struct *mm = vma->vm_mm;
6882 unsigned long haddr = address & huge_page_mask(h);
6883 struct page *page = NULL;
6884 spinlock_t *ptl;
6885 pte_t *pte, entry;
6886 int ret;
6887
6888 hugetlb_vma_lock_read(vma);
6889 pte = hugetlb_walk(vma, haddr, huge_page_size(h));
6890 if (!pte)
6891 goto out_unlock;
6892
6893 ptl = huge_pte_lock(h, mm, pte);
6894 entry = huge_ptep_get(pte);
6895 if (pte_present(entry)) {
6896 page = pte_page(entry);
6897
6898 if (!huge_pte_write(entry)) {
6899 if (flags & FOLL_WRITE) {
6900 page = NULL;
6901 goto out;
6902 }
6903
6904 if (gup_must_unshare(vma, flags, page)) {
6905 /* Tell the caller to do unsharing */
6906 page = ERR_PTR(-EMLINK);
6907 goto out;
6908 }
6909 }
6910
6911 page = nth_page(page, ((address & ~huge_page_mask(h)) >> PAGE_SHIFT));
6912
6913 /*
6914 * Note that page may be a sub-page, and with vmemmap
6915 * optimizations the page struct may be read only.
6916 * try_grab_page() will increase the ref count on the
6917 * head page, so this will be OK.
6918 *
6919 * try_grab_page() should always be able to get the page here,
6920 * because we hold the ptl lock and have verified pte_present().
6921 */
6922 ret = try_grab_page(page, flags);
6923
6924 if (WARN_ON_ONCE(ret)) {
6925 page = ERR_PTR(ret);
6926 goto out;
6927 }
6928
6929 *page_mask = (1U << huge_page_order(h)) - 1;
6930 }
6931out:
6932 spin_unlock(ptl);
6933out_unlock:
6934 hugetlb_vma_unlock_read(vma);
6935
6936 /*
6937 * Fixup retval for dump requests: if pagecache doesn't exist,
6938 * don't try to allocate a new page but just skip it.
6939 */
6940 if (!page && (flags & FOLL_DUMP) &&
6941 !hugetlbfs_pagecache_present(h, vma, address))
6942 page = ERR_PTR(-EFAULT);
6943
6944 return page;
6945}
6946
6947long hugetlb_change_protection(struct vm_area_struct *vma,
6948 unsigned long address, unsigned long end,
6949 pgprot_t newprot, unsigned long cp_flags)
6950{
6951 struct mm_struct *mm = vma->vm_mm;
6952 unsigned long start = address;
6953 pte_t *ptep;
6954 pte_t pte;
6955 struct hstate *h = hstate_vma(vma);
6956 long pages = 0, psize = huge_page_size(h);
6957 bool shared_pmd = false;
6958 struct mmu_notifier_range range;
6959 unsigned long last_addr_mask;
6960 bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
6961 bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
6962
6963 /*
6964 * In the case of shared PMDs, the area to flush could be beyond
6965 * start/end. Set range.start/range.end to cover the maximum possible
6966 * range if PMD sharing is possible.
6967 */
6968 mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
6969 0, mm, start, end);
6970 adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
6971
6972 BUG_ON(address >= end);
6973 flush_cache_range(vma, range.start, range.end);
6974
6975 mmu_notifier_invalidate_range_start(&range);
6976 hugetlb_vma_lock_write(vma);
6977 i_mmap_lock_write(vma->vm_file->f_mapping);
6978 last_addr_mask = hugetlb_mask_last_page(h);
6979 for (; address < end; address += psize) {
6980 spinlock_t *ptl;
6981 ptep = hugetlb_walk(vma, address, psize);
6982 if (!ptep) {
6983 if (!uffd_wp) {
6984 address |= last_addr_mask;
6985 continue;
6986 }
6987 /*
6988 * Userfaultfd wr-protect requires pgtable
6989 * pre-allocations to install pte markers.
6990 */
6991 ptep = huge_pte_alloc(mm, vma, address, psize);
6992 if (!ptep) {
6993 pages = -ENOMEM;
6994 break;
6995 }
6996 }
6997 ptl = huge_pte_lock(h, mm, ptep);
6998 if (huge_pmd_unshare(mm, vma, address, ptep)) {
6999 /*
7000 * When uffd-wp is enabled on the vma, unshare
7001 * shouldn't happen at all. Warn about it if it
7002 * happened due to some reason.
7003 */
7004 WARN_ON_ONCE(uffd_wp || uffd_wp_resolve);
7005 pages++;
7006 spin_unlock(ptl);
7007 shared_pmd = true;
7008 address |= last_addr_mask;
7009 continue;
7010 }
7011 pte = huge_ptep_get(ptep);
7012 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
7013 /* Nothing to do. */
7014 } else if (unlikely(is_hugetlb_entry_migration(pte))) {
7015 swp_entry_t entry = pte_to_swp_entry(pte);
7016 struct page *page = pfn_swap_entry_to_page(entry);
7017 pte_t newpte = pte;
7018
7019 if (is_writable_migration_entry(entry)) {
7020 if (PageAnon(page))
7021 entry = make_readable_exclusive_migration_entry(
7022 swp_offset(entry));
7023 else
7024 entry = make_readable_migration_entry(
7025 swp_offset(entry));
7026 newpte = swp_entry_to_pte(entry);
7027 pages++;
7028 }
7029
7030 if (uffd_wp)
7031 newpte = pte_swp_mkuffd_wp(newpte);
7032 else if (uffd_wp_resolve)
7033 newpte = pte_swp_clear_uffd_wp(newpte);
7034 if (!pte_same(pte, newpte))
7035 set_huge_pte_at(mm, address, ptep, newpte, psize);
7036 } else if (unlikely(is_pte_marker(pte))) {
7037 /*
7038 * Do nothing on a poison marker; page is
7039 * corrupted, permissons do not apply. Here
7040 * pte_marker_uffd_wp()==true implies !poison
7041 * because they're mutual exclusive.
7042 */
7043 if (pte_marker_uffd_wp(pte) && uffd_wp_resolve)
7044 /* Safe to modify directly (non-present->none). */
7045 huge_pte_clear(mm, address, ptep, psize);
7046 } else if (!huge_pte_none(pte)) {
7047 pte_t old_pte;
7048 unsigned int shift = huge_page_shift(hstate_vma(vma));
7049
7050 old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
7051 pte = huge_pte_modify(old_pte, newprot);
7052 pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
7053 if (uffd_wp)
7054 pte = huge_pte_mkuffd_wp(pte);
7055 else if (uffd_wp_resolve)
7056 pte = huge_pte_clear_uffd_wp(pte);
7057 huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
7058 pages++;
7059 } else {
7060 /* None pte */
7061 if (unlikely(uffd_wp))
7062 /* Safe to modify directly (none->non-present). */
7063 set_huge_pte_at(mm, address, ptep,
7064 make_pte_marker(PTE_MARKER_UFFD_WP),
7065 psize);
7066 }
7067 spin_unlock(ptl);
7068 }
7069 /*
7070 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
7071 * may have cleared our pud entry and done put_page on the page table:
7072 * once we release i_mmap_rwsem, another task can do the final put_page
7073 * and that page table be reused and filled with junk. If we actually
7074 * did unshare a page of pmds, flush the range corresponding to the pud.
7075 */
7076 if (shared_pmd)
7077 flush_hugetlb_tlb_range(vma, range.start, range.end);
7078 else
7079 flush_hugetlb_tlb_range(vma, start, end);
7080 /*
7081 * No need to call mmu_notifier_arch_invalidate_secondary_tlbs() we are
7082 * downgrading page table protection not changing it to point to a new
7083 * page.
7084 *
7085 * See Documentation/mm/mmu_notifier.rst
7086 */
7087 i_mmap_unlock_write(vma->vm_file->f_mapping);
7088 hugetlb_vma_unlock_write(vma);
7089 mmu_notifier_invalidate_range_end(&range);
7090
7091 return pages > 0 ? (pages << h->order) : pages;
7092}
7093
7094/* Return true if reservation was successful, false otherwise. */
7095bool hugetlb_reserve_pages(struct inode *inode,
7096 long from, long to,
7097 struct vm_area_struct *vma,
7098 vm_flags_t vm_flags)
7099{
7100 long chg = -1, add = -1;
7101 struct hstate *h = hstate_inode(inode);
7102 struct hugepage_subpool *spool = subpool_inode(inode);
7103 struct resv_map *resv_map;
7104 struct hugetlb_cgroup *h_cg = NULL;
7105 long gbl_reserve, regions_needed = 0;
7106
7107 /* This should never happen */
7108 if (from > to) {
7109 VM_WARN(1, "%s called with a negative range\n", __func__);
7110 return false;
7111 }
7112
7113 /*
7114 * vma specific semaphore used for pmd sharing and fault/truncation
7115 * synchronization
7116 */
7117 hugetlb_vma_lock_alloc(vma);
7118
7119 /*
7120 * Only apply hugepage reservation if asked. At fault time, an
7121 * attempt will be made for VM_NORESERVE to allocate a page
7122 * without using reserves
7123 */
7124 if (vm_flags & VM_NORESERVE)
7125 return true;
7126
7127 /*
7128 * Shared mappings base their reservation on the number of pages that
7129 * are already allocated on behalf of the file. Private mappings need
7130 * to reserve the full area even if read-only as mprotect() may be
7131 * called to make the mapping read-write. Assume !vma is a shm mapping
7132 */
7133 if (!vma || vma->vm_flags & VM_MAYSHARE) {
7134 /*
7135 * resv_map can not be NULL as hugetlb_reserve_pages is only
7136 * called for inodes for which resv_maps were created (see
7137 * hugetlbfs_get_inode).
7138 */
7139 resv_map = inode_resv_map(inode);
7140
7141 chg = region_chg(resv_map, from, to, ®ions_needed);
7142 } else {
7143 /* Private mapping. */
7144 resv_map = resv_map_alloc();
7145 if (!resv_map)
7146 goto out_err;
7147
7148 chg = to - from;
7149
7150 set_vma_resv_map(vma, resv_map);
7151 set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
7152 }
7153
7154 if (chg < 0)
7155 goto out_err;
7156
7157 if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h),
7158 chg * pages_per_huge_page(h), &h_cg) < 0)
7159 goto out_err;
7160
7161 if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
7162 /* For private mappings, the hugetlb_cgroup uncharge info hangs
7163 * of the resv_map.
7164 */
7165 resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
7166 }
7167
7168 /*
7169 * There must be enough pages in the subpool for the mapping. If
7170 * the subpool has a minimum size, there may be some global
7171 * reservations already in place (gbl_reserve).
7172 */
7173 gbl_reserve = hugepage_subpool_get_pages(spool, chg);
7174 if (gbl_reserve < 0)
7175 goto out_uncharge_cgroup;
7176
7177 /*
7178 * Check enough hugepages are available for the reservation.
7179 * Hand the pages back to the subpool if there are not
7180 */
7181 if (hugetlb_acct_memory(h, gbl_reserve) < 0)
7182 goto out_put_pages;
7183
7184 /*
7185 * Account for the reservations made. Shared mappings record regions
7186 * that have reservations as they are shared by multiple VMAs.
7187 * When the last VMA disappears, the region map says how much
7188 * the reservation was and the page cache tells how much of
7189 * the reservation was consumed. Private mappings are per-VMA and
7190 * only the consumed reservations are tracked. When the VMA
7191 * disappears, the original reservation is the VMA size and the
7192 * consumed reservations are stored in the map. Hence, nothing
7193 * else has to be done for private mappings here
7194 */
7195 if (!vma || vma->vm_flags & VM_MAYSHARE) {
7196 add = region_add(resv_map, from, to, regions_needed, h, h_cg);
7197
7198 if (unlikely(add < 0)) {
7199 hugetlb_acct_memory(h, -gbl_reserve);
7200 goto out_put_pages;
7201 } else if (unlikely(chg > add)) {
7202 /*
7203 * pages in this range were added to the reserve
7204 * map between region_chg and region_add. This
7205 * indicates a race with alloc_hugetlb_folio. Adjust
7206 * the subpool and reserve counts modified above
7207 * based on the difference.
7208 */
7209 long rsv_adjust;
7210
7211 /*
7212 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
7213 * reference to h_cg->css. See comment below for detail.
7214 */
7215 hugetlb_cgroup_uncharge_cgroup_rsvd(
7216 hstate_index(h),
7217 (chg - add) * pages_per_huge_page(h), h_cg);
7218
7219 rsv_adjust = hugepage_subpool_put_pages(spool,
7220 chg - add);
7221 hugetlb_acct_memory(h, -rsv_adjust);
7222 } else if (h_cg) {
7223 /*
7224 * The file_regions will hold their own reference to
7225 * h_cg->css. So we should release the reference held
7226 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
7227 * done.
7228 */
7229 hugetlb_cgroup_put_rsvd_cgroup(h_cg);
7230 }
7231 }
7232 return true;
7233
7234out_put_pages:
7235 /* put back original number of pages, chg */
7236 (void)hugepage_subpool_put_pages(spool, chg);
7237out_uncharge_cgroup:
7238 hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
7239 chg * pages_per_huge_page(h), h_cg);
7240out_err:
7241 hugetlb_vma_lock_free(vma);
7242 if (!vma || vma->vm_flags & VM_MAYSHARE)
7243 /* Only call region_abort if the region_chg succeeded but the
7244 * region_add failed or didn't run.
7245 */
7246 if (chg >= 0 && add < 0)
7247 region_abort(resv_map, from, to, regions_needed);
7248 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
7249 kref_put(&resv_map->refs, resv_map_release);
7250 set_vma_resv_map(vma, NULL);
7251 }
7252 return false;
7253}
7254
7255long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
7256 long freed)
7257{
7258 struct hstate *h = hstate_inode(inode);
7259 struct resv_map *resv_map = inode_resv_map(inode);
7260 long chg = 0;
7261 struct hugepage_subpool *spool = subpool_inode(inode);
7262 long gbl_reserve;
7263
7264 /*
7265 * Since this routine can be called in the evict inode path for all
7266 * hugetlbfs inodes, resv_map could be NULL.
7267 */
7268 if (resv_map) {
7269 chg = region_del(resv_map, start, end);
7270 /*
7271 * region_del() can fail in the rare case where a region
7272 * must be split and another region descriptor can not be
7273 * allocated. If end == LONG_MAX, it will not fail.
7274 */
7275 if (chg < 0)
7276 return chg;
7277 }
7278
7279 spin_lock(&inode->i_lock);
7280 inode->i_blocks -= (blocks_per_huge_page(h) * freed);
7281 spin_unlock(&inode->i_lock);
7282
7283 /*
7284 * If the subpool has a minimum size, the number of global
7285 * reservations to be released may be adjusted.
7286 *
7287 * Note that !resv_map implies freed == 0. So (chg - freed)
7288 * won't go negative.
7289 */
7290 gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
7291 hugetlb_acct_memory(h, -gbl_reserve);
7292
7293 return 0;
7294}
7295
7296#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
7297static unsigned long page_table_shareable(struct vm_area_struct *svma,
7298 struct vm_area_struct *vma,
7299 unsigned long addr, pgoff_t idx)
7300{
7301 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
7302 svma->vm_start;
7303 unsigned long sbase = saddr & PUD_MASK;
7304 unsigned long s_end = sbase + PUD_SIZE;
7305
7306 /* Allow segments to share if only one is marked locked */
7307 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED_MASK;
7308 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED_MASK;
7309
7310 /*
7311 * match the virtual addresses, permission and the alignment of the
7312 * page table page.
7313 *
7314 * Also, vma_lock (vm_private_data) is required for sharing.
7315 */
7316 if (pmd_index(addr) != pmd_index(saddr) ||
7317 vm_flags != svm_flags ||
7318 !range_in_vma(svma, sbase, s_end) ||
7319 !svma->vm_private_data)
7320 return 0;
7321
7322 return saddr;
7323}
7324
7325bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
7326{
7327 unsigned long start = addr & PUD_MASK;
7328 unsigned long end = start + PUD_SIZE;
7329
7330#ifdef CONFIG_USERFAULTFD
7331 if (uffd_disable_huge_pmd_share(vma))
7332 return false;
7333#endif
7334 /*
7335 * check on proper vm_flags and page table alignment
7336 */
7337 if (!(vma->vm_flags & VM_MAYSHARE))
7338 return false;
7339 if (!vma->vm_private_data) /* vma lock required for sharing */
7340 return false;
7341 if (!range_in_vma(vma, start, end))
7342 return false;
7343 return true;
7344}
7345
7346/*
7347 * Determine if start,end range within vma could be mapped by shared pmd.
7348 * If yes, adjust start and end to cover range associated with possible
7349 * shared pmd mappings.
7350 */
7351void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
7352 unsigned long *start, unsigned long *end)
7353{
7354 unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
7355 v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
7356
7357 /*
7358 * vma needs to span at least one aligned PUD size, and the range
7359 * must be at least partially within in.
7360 */
7361 if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
7362 (*end <= v_start) || (*start >= v_end))
7363 return;
7364
7365 /* Extend the range to be PUD aligned for a worst case scenario */
7366 if (*start > v_start)
7367 *start = ALIGN_DOWN(*start, PUD_SIZE);
7368
7369 if (*end < v_end)
7370 *end = ALIGN(*end, PUD_SIZE);
7371}
7372
7373/*
7374 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
7375 * and returns the corresponding pte. While this is not necessary for the
7376 * !shared pmd case because we can allocate the pmd later as well, it makes the
7377 * code much cleaner. pmd allocation is essential for the shared case because
7378 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
7379 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
7380 * bad pmd for sharing.
7381 */
7382pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
7383 unsigned long addr, pud_t *pud)
7384{
7385 struct address_space *mapping = vma->vm_file->f_mapping;
7386 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
7387 vma->vm_pgoff;
7388 struct vm_area_struct *svma;
7389 unsigned long saddr;
7390 pte_t *spte = NULL;
7391 pte_t *pte;
7392
7393 i_mmap_lock_read(mapping);
7394 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
7395 if (svma == vma)
7396 continue;
7397
7398 saddr = page_table_shareable(svma, vma, addr, idx);
7399 if (saddr) {
7400 spte = hugetlb_walk(svma, saddr,
7401 vma_mmu_pagesize(svma));
7402 if (spte) {
7403 get_page(virt_to_page(spte));
7404 break;
7405 }
7406 }
7407 }
7408
7409 if (!spte)
7410 goto out;
7411
7412 spin_lock(&mm->page_table_lock);
7413 if (pud_none(*pud)) {
7414 pud_populate(mm, pud,
7415 (pmd_t *)((unsigned long)spte & PAGE_MASK));
7416 mm_inc_nr_pmds(mm);
7417 } else {
7418 put_page(virt_to_page(spte));
7419 }
7420 spin_unlock(&mm->page_table_lock);
7421out:
7422 pte = (pte_t *)pmd_alloc(mm, pud, addr);
7423 i_mmap_unlock_read(mapping);
7424 return pte;
7425}
7426
7427/*
7428 * unmap huge page backed by shared pte.
7429 *
7430 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
7431 * indicated by page_count > 1, unmap is achieved by clearing pud and
7432 * decrementing the ref count. If count == 1, the pte page is not shared.
7433 *
7434 * Called with page table lock held.
7435 *
7436 * returns: 1 successfully unmapped a shared pte page
7437 * 0 the underlying pte page is not shared, or it is the last user
7438 */
7439int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
7440 unsigned long addr, pte_t *ptep)
7441{
7442 pgd_t *pgd = pgd_offset(mm, addr);
7443 p4d_t *p4d = p4d_offset(pgd, addr);
7444 pud_t *pud = pud_offset(p4d, addr);
7445
7446 i_mmap_assert_write_locked(vma->vm_file->f_mapping);
7447 hugetlb_vma_assert_locked(vma);
7448 BUG_ON(page_count(virt_to_page(ptep)) == 0);
7449 if (page_count(virt_to_page(ptep)) == 1)
7450 return 0;
7451
7452 pud_clear(pud);
7453 put_page(virt_to_page(ptep));
7454 mm_dec_nr_pmds(mm);
7455 return 1;
7456}
7457
7458#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
7459
7460pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
7461 unsigned long addr, pud_t *pud)
7462{
7463 return NULL;
7464}
7465
7466int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
7467 unsigned long addr, pte_t *ptep)
7468{
7469 return 0;
7470}
7471
7472void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
7473 unsigned long *start, unsigned long *end)
7474{
7475}
7476
7477bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
7478{
7479 return false;
7480}
7481#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
7482
7483#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
7484pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
7485 unsigned long addr, unsigned long sz)
7486{
7487 pgd_t *pgd;
7488 p4d_t *p4d;
7489 pud_t *pud;
7490 pte_t *pte = NULL;
7491
7492 pgd = pgd_offset(mm, addr);
7493 p4d = p4d_alloc(mm, pgd, addr);
7494 if (!p4d)
7495 return NULL;
7496 pud = pud_alloc(mm, p4d, addr);
7497 if (pud) {
7498 if (sz == PUD_SIZE) {
7499 pte = (pte_t *)pud;
7500 } else {
7501 BUG_ON(sz != PMD_SIZE);
7502 if (want_pmd_share(vma, addr) && pud_none(*pud))
7503 pte = huge_pmd_share(mm, vma, addr, pud);
7504 else
7505 pte = (pte_t *)pmd_alloc(mm, pud, addr);
7506 }
7507 }
7508
7509 if (pte) {
7510 pte_t pteval = ptep_get_lockless(pte);
7511
7512 BUG_ON(pte_present(pteval) && !pte_huge(pteval));
7513 }
7514
7515 return pte;
7516}
7517
7518/*
7519 * huge_pte_offset() - Walk the page table to resolve the hugepage
7520 * entry at address @addr
7521 *
7522 * Return: Pointer to page table entry (PUD or PMD) for
7523 * address @addr, or NULL if a !p*d_present() entry is encountered and the
7524 * size @sz doesn't match the hugepage size at this level of the page
7525 * table.
7526 */
7527pte_t *huge_pte_offset(struct mm_struct *mm,
7528 unsigned long addr, unsigned long sz)
7529{
7530 pgd_t *pgd;
7531 p4d_t *p4d;
7532 pud_t *pud;
7533 pmd_t *pmd;
7534
7535 pgd = pgd_offset(mm, addr);
7536 if (!pgd_present(*pgd))
7537 return NULL;
7538 p4d = p4d_offset(pgd, addr);
7539 if (!p4d_present(*p4d))
7540 return NULL;
7541
7542 pud = pud_offset(p4d, addr);
7543 if (sz == PUD_SIZE)
7544 /* must be pud huge, non-present or none */
7545 return (pte_t *)pud;
7546 if (!pud_present(*pud))
7547 return NULL;
7548 /* must have a valid entry and size to go further */
7549
7550 pmd = pmd_offset(pud, addr);
7551 /* must be pmd huge, non-present or none */
7552 return (pte_t *)pmd;
7553}
7554
7555/*
7556 * Return a mask that can be used to update an address to the last huge
7557 * page in a page table page mapping size. Used to skip non-present
7558 * page table entries when linearly scanning address ranges. Architectures
7559 * with unique huge page to page table relationships can define their own
7560 * version of this routine.
7561 */
7562unsigned long hugetlb_mask_last_page(struct hstate *h)
7563{
7564 unsigned long hp_size = huge_page_size(h);
7565
7566 if (hp_size == PUD_SIZE)
7567 return P4D_SIZE - PUD_SIZE;
7568 else if (hp_size == PMD_SIZE)
7569 return PUD_SIZE - PMD_SIZE;
7570 else
7571 return 0UL;
7572}
7573
7574#else
7575
7576/* See description above. Architectures can provide their own version. */
7577__weak unsigned long hugetlb_mask_last_page(struct hstate *h)
7578{
7579#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
7580 if (huge_page_size(h) == PMD_SIZE)
7581 return PUD_SIZE - PMD_SIZE;
7582#endif
7583 return 0UL;
7584}
7585
7586#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
7587
7588/*
7589 * These functions are overwritable if your architecture needs its own
7590 * behavior.
7591 */
7592bool isolate_hugetlb(struct folio *folio, struct list_head *list)
7593{
7594 bool ret = true;
7595
7596 spin_lock_irq(&hugetlb_lock);
7597 if (!folio_test_hugetlb(folio) ||
7598 !folio_test_hugetlb_migratable(folio) ||
7599 !folio_try_get(folio)) {
7600 ret = false;
7601 goto unlock;
7602 }
7603 folio_clear_hugetlb_migratable(folio);
7604 list_move_tail(&folio->lru, list);
7605unlock:
7606 spin_unlock_irq(&hugetlb_lock);
7607 return ret;
7608}
7609
7610int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison)
7611{
7612 int ret = 0;
7613
7614 *hugetlb = false;
7615 spin_lock_irq(&hugetlb_lock);
7616 if (folio_test_hugetlb(folio)) {
7617 *hugetlb = true;
7618 if (folio_test_hugetlb_freed(folio))
7619 ret = 0;
7620 else if (folio_test_hugetlb_migratable(folio) || unpoison)
7621 ret = folio_try_get(folio);
7622 else
7623 ret = -EBUSY;
7624 }
7625 spin_unlock_irq(&hugetlb_lock);
7626 return ret;
7627}
7628
7629int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
7630 bool *migratable_cleared)
7631{
7632 int ret;
7633
7634 spin_lock_irq(&hugetlb_lock);
7635 ret = __get_huge_page_for_hwpoison(pfn, flags, migratable_cleared);
7636 spin_unlock_irq(&hugetlb_lock);
7637 return ret;
7638}
7639
7640void folio_putback_active_hugetlb(struct folio *folio)
7641{
7642 spin_lock_irq(&hugetlb_lock);
7643 folio_set_hugetlb_migratable(folio);
7644 list_move_tail(&folio->lru, &(folio_hstate(folio))->hugepage_activelist);
7645 spin_unlock_irq(&hugetlb_lock);
7646 folio_put(folio);
7647}
7648
7649void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason)
7650{
7651 struct hstate *h = folio_hstate(old_folio);
7652
7653 hugetlb_cgroup_migrate(old_folio, new_folio);
7654 set_page_owner_migrate_reason(&new_folio->page, reason);
7655
7656 /*
7657 * transfer temporary state of the new hugetlb folio. This is
7658 * reverse to other transitions because the newpage is going to
7659 * be final while the old one will be freed so it takes over
7660 * the temporary status.
7661 *
7662 * Also note that we have to transfer the per-node surplus state
7663 * here as well otherwise the global surplus count will not match
7664 * the per-node's.
7665 */
7666 if (folio_test_hugetlb_temporary(new_folio)) {
7667 int old_nid = folio_nid(old_folio);
7668 int new_nid = folio_nid(new_folio);
7669
7670 folio_set_hugetlb_temporary(old_folio);
7671 folio_clear_hugetlb_temporary(new_folio);
7672
7673
7674 /*
7675 * There is no need to transfer the per-node surplus state
7676 * when we do not cross the node.
7677 */
7678 if (new_nid == old_nid)
7679 return;
7680 spin_lock_irq(&hugetlb_lock);
7681 if (h->surplus_huge_pages_node[old_nid]) {
7682 h->surplus_huge_pages_node[old_nid]--;
7683 h->surplus_huge_pages_node[new_nid]++;
7684 }
7685 spin_unlock_irq(&hugetlb_lock);
7686 }
7687}
7688
7689static void hugetlb_unshare_pmds(struct vm_area_struct *vma,
7690 unsigned long start,
7691 unsigned long end)
7692{
7693 struct hstate *h = hstate_vma(vma);
7694 unsigned long sz = huge_page_size(h);
7695 struct mm_struct *mm = vma->vm_mm;
7696 struct mmu_notifier_range range;
7697 unsigned long address;
7698 spinlock_t *ptl;
7699 pte_t *ptep;
7700
7701 if (!(vma->vm_flags & VM_MAYSHARE))
7702 return;
7703
7704 if (start >= end)
7705 return;
7706
7707 flush_cache_range(vma, start, end);
7708 /*
7709 * No need to call adjust_range_if_pmd_sharing_possible(), because
7710 * we have already done the PUD_SIZE alignment.
7711 */
7712 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm,
7713 start, end);
7714 mmu_notifier_invalidate_range_start(&range);
7715 hugetlb_vma_lock_write(vma);
7716 i_mmap_lock_write(vma->vm_file->f_mapping);
7717 for (address = start; address < end; address += PUD_SIZE) {
7718 ptep = hugetlb_walk(vma, address, sz);
7719 if (!ptep)
7720 continue;
7721 ptl = huge_pte_lock(h, mm, ptep);
7722 huge_pmd_unshare(mm, vma, address, ptep);
7723 spin_unlock(ptl);
7724 }
7725 flush_hugetlb_tlb_range(vma, start, end);
7726 i_mmap_unlock_write(vma->vm_file->f_mapping);
7727 hugetlb_vma_unlock_write(vma);
7728 /*
7729 * No need to call mmu_notifier_arch_invalidate_secondary_tlbs(), see
7730 * Documentation/mm/mmu_notifier.rst.
7731 */
7732 mmu_notifier_invalidate_range_end(&range);
7733}
7734
7735/*
7736 * This function will unconditionally remove all the shared pmd pgtable entries
7737 * within the specific vma for a hugetlbfs memory range.
7738 */
7739void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
7740{
7741 hugetlb_unshare_pmds(vma, ALIGN(vma->vm_start, PUD_SIZE),
7742 ALIGN_DOWN(vma->vm_end, PUD_SIZE));
7743}
7744
7745#ifdef CONFIG_CMA
7746static bool cma_reserve_called __initdata;
7747
7748static int __init cmdline_parse_hugetlb_cma(char *p)
7749{
7750 int nid, count = 0;
7751 unsigned long tmp;
7752 char *s = p;
7753
7754 while (*s) {
7755 if (sscanf(s, "%lu%n", &tmp, &count) != 1)
7756 break;
7757
7758 if (s[count] == ':') {
7759 if (tmp >= MAX_NUMNODES)
7760 break;
7761 nid = array_index_nospec(tmp, MAX_NUMNODES);
7762
7763 s += count + 1;
7764 tmp = memparse(s, &s);
7765 hugetlb_cma_size_in_node[nid] = tmp;
7766 hugetlb_cma_size += tmp;
7767
7768 /*
7769 * Skip the separator if have one, otherwise
7770 * break the parsing.
7771 */
7772 if (*s == ',')
7773 s++;
7774 else
7775 break;
7776 } else {
7777 hugetlb_cma_size = memparse(p, &p);
7778 break;
7779 }
7780 }
7781
7782 return 0;
7783}
7784
7785early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
7786
7787void __init hugetlb_cma_reserve(int order)
7788{
7789 unsigned long size, reserved, per_node;
7790 bool node_specific_cma_alloc = false;
7791 int nid;
7792
7793 /*
7794 * HugeTLB CMA reservation is required for gigantic
7795 * huge pages which could not be allocated via the
7796 * page allocator. Just warn if there is any change
7797 * breaking this assumption.
7798 */
7799 VM_WARN_ON(order <= MAX_PAGE_ORDER);
7800 cma_reserve_called = true;
7801
7802 if (!hugetlb_cma_size)
7803 return;
7804
7805 for (nid = 0; nid < MAX_NUMNODES; nid++) {
7806 if (hugetlb_cma_size_in_node[nid] == 0)
7807 continue;
7808
7809 if (!node_online(nid)) {
7810 pr_warn("hugetlb_cma: invalid node %d specified\n", nid);
7811 hugetlb_cma_size -= hugetlb_cma_size_in_node[nid];
7812 hugetlb_cma_size_in_node[nid] = 0;
7813 continue;
7814 }
7815
7816 if (hugetlb_cma_size_in_node[nid] < (PAGE_SIZE << order)) {
7817 pr_warn("hugetlb_cma: cma area of node %d should be at least %lu MiB\n",
7818 nid, (PAGE_SIZE << order) / SZ_1M);
7819 hugetlb_cma_size -= hugetlb_cma_size_in_node[nid];
7820 hugetlb_cma_size_in_node[nid] = 0;
7821 } else {
7822 node_specific_cma_alloc = true;
7823 }
7824 }
7825
7826 /* Validate the CMA size again in case some invalid nodes specified. */
7827 if (!hugetlb_cma_size)
7828 return;
7829
7830 if (hugetlb_cma_size < (PAGE_SIZE << order)) {
7831 pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
7832 (PAGE_SIZE << order) / SZ_1M);
7833 hugetlb_cma_size = 0;
7834 return;
7835 }
7836
7837 if (!node_specific_cma_alloc) {
7838 /*
7839 * If 3 GB area is requested on a machine with 4 numa nodes,
7840 * let's allocate 1 GB on first three nodes and ignore the last one.
7841 */
7842 per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
7843 pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
7844 hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
7845 }
7846
7847 reserved = 0;
7848 for_each_online_node(nid) {
7849 int res;
7850 char name[CMA_MAX_NAME];
7851
7852 if (node_specific_cma_alloc) {
7853 if (hugetlb_cma_size_in_node[nid] == 0)
7854 continue;
7855
7856 size = hugetlb_cma_size_in_node[nid];
7857 } else {
7858 size = min(per_node, hugetlb_cma_size - reserved);
7859 }
7860
7861 size = round_up(size, PAGE_SIZE << order);
7862
7863 snprintf(name, sizeof(name), "hugetlb%d", nid);
7864 /*
7865 * Note that 'order per bit' is based on smallest size that
7866 * may be returned to CMA allocator in the case of
7867 * huge page demotion.
7868 */
7869 res = cma_declare_contiguous_nid(0, size, 0,
7870 PAGE_SIZE << HUGETLB_PAGE_ORDER,
7871 0, false, name,
7872 &hugetlb_cma[nid], nid);
7873 if (res) {
7874 pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
7875 res, nid);
7876 continue;
7877 }
7878
7879 reserved += size;
7880 pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
7881 size / SZ_1M, nid);
7882
7883 if (reserved >= hugetlb_cma_size)
7884 break;
7885 }
7886
7887 if (!reserved)
7888 /*
7889 * hugetlb_cma_size is used to determine if allocations from
7890 * cma are possible. Set to zero if no cma regions are set up.
7891 */
7892 hugetlb_cma_size = 0;
7893}
7894
7895static void __init hugetlb_cma_check(void)
7896{
7897 if (!hugetlb_cma_size || cma_reserve_called)
7898 return;
7899
7900 pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
7901}
7902
7903#endif /* CONFIG_CMA */