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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Slab allocator functions that are independent of the allocator strategy
4 *
5 * (C) 2012 Christoph Lameter <cl@linux.com>
6 */
7#include <linux/slab.h>
8
9#include <linux/mm.h>
10#include <linux/poison.h>
11#include <linux/interrupt.h>
12#include <linux/memory.h>
13#include <linux/cache.h>
14#include <linux/compiler.h>
15#include <linux/module.h>
16#include <linux/cpu.h>
17#include <linux/uaccess.h>
18#include <linux/seq_file.h>
19#include <linux/proc_fs.h>
20#include <linux/debugfs.h>
21#include <asm/cacheflush.h>
22#include <asm/tlbflush.h>
23#include <asm/page.h>
24#include <linux/memcontrol.h>
25
26#define CREATE_TRACE_POINTS
27#include <trace/events/kmem.h>
28
29#include "internal.h"
30
31#include "slab.h"
32
33enum slab_state slab_state;
34LIST_HEAD(slab_caches);
35DEFINE_MUTEX(slab_mutex);
36struct kmem_cache *kmem_cache;
37
38#ifdef CONFIG_HARDENED_USERCOPY
39bool usercopy_fallback __ro_after_init =
40 IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
41module_param(usercopy_fallback, bool, 0400);
42MODULE_PARM_DESC(usercopy_fallback,
43 "WARN instead of reject usercopy whitelist violations");
44#endif
45
46static LIST_HEAD(slab_caches_to_rcu_destroy);
47static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
48static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
49 slab_caches_to_rcu_destroy_workfn);
50
51/*
52 * Set of flags that will prevent slab merging
53 */
54#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
55 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
56 SLAB_FAILSLAB | SLAB_KASAN)
57
58#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
59 SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
60
61/*
62 * Merge control. If this is set then no merging of slab caches will occur.
63 */
64static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
65
66static int __init setup_slab_nomerge(char *str)
67{
68 slab_nomerge = true;
69 return 1;
70}
71
72#ifdef CONFIG_SLUB
73__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
74#endif
75
76__setup("slab_nomerge", setup_slab_nomerge);
77
78/*
79 * Determine the size of a slab object
80 */
81unsigned int kmem_cache_size(struct kmem_cache *s)
82{
83 return s->object_size;
84}
85EXPORT_SYMBOL(kmem_cache_size);
86
87#ifdef CONFIG_DEBUG_VM
88static int kmem_cache_sanity_check(const char *name, unsigned int size)
89{
90 if (!name || in_interrupt() || size < sizeof(void *) ||
91 size > KMALLOC_MAX_SIZE) {
92 pr_err("kmem_cache_create(%s) integrity check failed\n", name);
93 return -EINVAL;
94 }
95
96 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
97 return 0;
98}
99#else
100static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
101{
102 return 0;
103}
104#endif
105
106void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
107{
108 size_t i;
109
110 for (i = 0; i < nr; i++) {
111 if (s)
112 kmem_cache_free(s, p[i]);
113 else
114 kfree(p[i]);
115 }
116}
117
118int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
119 void **p)
120{
121 size_t i;
122
123 for (i = 0; i < nr; i++) {
124 void *x = p[i] = kmem_cache_alloc(s, flags);
125 if (!x) {
126 __kmem_cache_free_bulk(s, i, p);
127 return 0;
128 }
129 }
130 return i;
131}
132
133/*
134 * Figure out what the alignment of the objects will be given a set of
135 * flags, a user specified alignment and the size of the objects.
136 */
137static unsigned int calculate_alignment(slab_flags_t flags,
138 unsigned int align, unsigned int size)
139{
140 /*
141 * If the user wants hardware cache aligned objects then follow that
142 * suggestion if the object is sufficiently large.
143 *
144 * The hardware cache alignment cannot override the specified
145 * alignment though. If that is greater then use it.
146 */
147 if (flags & SLAB_HWCACHE_ALIGN) {
148 unsigned int ralign;
149
150 ralign = cache_line_size();
151 while (size <= ralign / 2)
152 ralign /= 2;
153 align = max(align, ralign);
154 }
155
156 if (align < ARCH_SLAB_MINALIGN)
157 align = ARCH_SLAB_MINALIGN;
158
159 return ALIGN(align, sizeof(void *));
160}
161
162/*
163 * Find a mergeable slab cache
164 */
165int slab_unmergeable(struct kmem_cache *s)
166{
167 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
168 return 1;
169
170 if (s->ctor)
171 return 1;
172
173 if (s->usersize)
174 return 1;
175
176 /*
177 * We may have set a slab to be unmergeable during bootstrap.
178 */
179 if (s->refcount < 0)
180 return 1;
181
182 return 0;
183}
184
185struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
186 slab_flags_t flags, const char *name, void (*ctor)(void *))
187{
188 struct kmem_cache *s;
189
190 if (slab_nomerge)
191 return NULL;
192
193 if (ctor)
194 return NULL;
195
196 size = ALIGN(size, sizeof(void *));
197 align = calculate_alignment(flags, align, size);
198 size = ALIGN(size, align);
199 flags = kmem_cache_flags(size, flags, name, NULL);
200
201 if (flags & SLAB_NEVER_MERGE)
202 return NULL;
203
204 list_for_each_entry_reverse(s, &slab_caches, list) {
205 if (slab_unmergeable(s))
206 continue;
207
208 if (size > s->size)
209 continue;
210
211 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
212 continue;
213 /*
214 * Check if alignment is compatible.
215 * Courtesy of Adrian Drzewiecki
216 */
217 if ((s->size & ~(align - 1)) != s->size)
218 continue;
219
220 if (s->size - size >= sizeof(void *))
221 continue;
222
223 if (IS_ENABLED(CONFIG_SLAB) && align &&
224 (align > s->align || s->align % align))
225 continue;
226
227 return s;
228 }
229 return NULL;
230}
231
232static struct kmem_cache *create_cache(const char *name,
233 unsigned int object_size, unsigned int align,
234 slab_flags_t flags, unsigned int useroffset,
235 unsigned int usersize, void (*ctor)(void *),
236 struct kmem_cache *root_cache)
237{
238 struct kmem_cache *s;
239 int err;
240
241 if (WARN_ON(useroffset + usersize > object_size))
242 useroffset = usersize = 0;
243
244 err = -ENOMEM;
245 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
246 if (!s)
247 goto out;
248
249 s->name = name;
250 s->size = s->object_size = object_size;
251 s->align = align;
252 s->ctor = ctor;
253 s->useroffset = useroffset;
254 s->usersize = usersize;
255
256 err = __kmem_cache_create(s, flags);
257 if (err)
258 goto out_free_cache;
259
260 s->refcount = 1;
261 list_add(&s->list, &slab_caches);
262out:
263 if (err)
264 return ERR_PTR(err);
265 return s;
266
267out_free_cache:
268 kmem_cache_free(kmem_cache, s);
269 goto out;
270}
271
272/**
273 * kmem_cache_create_usercopy - Create a cache with a region suitable
274 * for copying to userspace
275 * @name: A string which is used in /proc/slabinfo to identify this cache.
276 * @size: The size of objects to be created in this cache.
277 * @align: The required alignment for the objects.
278 * @flags: SLAB flags
279 * @useroffset: Usercopy region offset
280 * @usersize: Usercopy region size
281 * @ctor: A constructor for the objects.
282 *
283 * Cannot be called within a interrupt, but can be interrupted.
284 * The @ctor is run when new pages are allocated by the cache.
285 *
286 * The flags are
287 *
288 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
289 * to catch references to uninitialised memory.
290 *
291 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
292 * for buffer overruns.
293 *
294 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
295 * cacheline. This can be beneficial if you're counting cycles as closely
296 * as davem.
297 *
298 * Return: a pointer to the cache on success, NULL on failure.
299 */
300struct kmem_cache *
301kmem_cache_create_usercopy(const char *name,
302 unsigned int size, unsigned int align,
303 slab_flags_t flags,
304 unsigned int useroffset, unsigned int usersize,
305 void (*ctor)(void *))
306{
307 struct kmem_cache *s = NULL;
308 const char *cache_name;
309 int err;
310
311 get_online_cpus();
312 get_online_mems();
313
314 mutex_lock(&slab_mutex);
315
316 err = kmem_cache_sanity_check(name, size);
317 if (err) {
318 goto out_unlock;
319 }
320
321 /* Refuse requests with allocator specific flags */
322 if (flags & ~SLAB_FLAGS_PERMITTED) {
323 err = -EINVAL;
324 goto out_unlock;
325 }
326
327 /*
328 * Some allocators will constraint the set of valid flags to a subset
329 * of all flags. We expect them to define CACHE_CREATE_MASK in this
330 * case, and we'll just provide them with a sanitized version of the
331 * passed flags.
332 */
333 flags &= CACHE_CREATE_MASK;
334
335 /* Fail closed on bad usersize of useroffset values. */
336 if (WARN_ON(!usersize && useroffset) ||
337 WARN_ON(size < usersize || size - usersize < useroffset))
338 usersize = useroffset = 0;
339
340 if (!usersize)
341 s = __kmem_cache_alias(name, size, align, flags, ctor);
342 if (s)
343 goto out_unlock;
344
345 cache_name = kstrdup_const(name, GFP_KERNEL);
346 if (!cache_name) {
347 err = -ENOMEM;
348 goto out_unlock;
349 }
350
351 s = create_cache(cache_name, size,
352 calculate_alignment(flags, align, size),
353 flags, useroffset, usersize, ctor, NULL);
354 if (IS_ERR(s)) {
355 err = PTR_ERR(s);
356 kfree_const(cache_name);
357 }
358
359out_unlock:
360 mutex_unlock(&slab_mutex);
361
362 put_online_mems();
363 put_online_cpus();
364
365 if (err) {
366 if (flags & SLAB_PANIC)
367 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
368 name, err);
369 else {
370 pr_warn("kmem_cache_create(%s) failed with error %d\n",
371 name, err);
372 dump_stack();
373 }
374 return NULL;
375 }
376 return s;
377}
378EXPORT_SYMBOL(kmem_cache_create_usercopy);
379
380/**
381 * kmem_cache_create - Create a cache.
382 * @name: A string which is used in /proc/slabinfo to identify this cache.
383 * @size: The size of objects to be created in this cache.
384 * @align: The required alignment for the objects.
385 * @flags: SLAB flags
386 * @ctor: A constructor for the objects.
387 *
388 * Cannot be called within a interrupt, but can be interrupted.
389 * The @ctor is run when new pages are allocated by the cache.
390 *
391 * The flags are
392 *
393 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
394 * to catch references to uninitialised memory.
395 *
396 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
397 * for buffer overruns.
398 *
399 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
400 * cacheline. This can be beneficial if you're counting cycles as closely
401 * as davem.
402 *
403 * Return: a pointer to the cache on success, NULL on failure.
404 */
405struct kmem_cache *
406kmem_cache_create(const char *name, unsigned int size, unsigned int align,
407 slab_flags_t flags, void (*ctor)(void *))
408{
409 return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
410 ctor);
411}
412EXPORT_SYMBOL(kmem_cache_create);
413
414static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
415{
416 LIST_HEAD(to_destroy);
417 struct kmem_cache *s, *s2;
418
419 /*
420 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
421 * @slab_caches_to_rcu_destroy list. The slab pages are freed
422 * through RCU and the associated kmem_cache are dereferenced
423 * while freeing the pages, so the kmem_caches should be freed only
424 * after the pending RCU operations are finished. As rcu_barrier()
425 * is a pretty slow operation, we batch all pending destructions
426 * asynchronously.
427 */
428 mutex_lock(&slab_mutex);
429 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
430 mutex_unlock(&slab_mutex);
431
432 if (list_empty(&to_destroy))
433 return;
434
435 rcu_barrier();
436
437 list_for_each_entry_safe(s, s2, &to_destroy, list) {
438#ifdef SLAB_SUPPORTS_SYSFS
439 sysfs_slab_release(s);
440#else
441 slab_kmem_cache_release(s);
442#endif
443 }
444}
445
446static int shutdown_cache(struct kmem_cache *s)
447{
448 /* free asan quarantined objects */
449 kasan_cache_shutdown(s);
450
451 if (__kmem_cache_shutdown(s) != 0)
452 return -EBUSY;
453
454 list_del(&s->list);
455
456 if (s->flags & SLAB_TYPESAFE_BY_RCU) {
457#ifdef SLAB_SUPPORTS_SYSFS
458 sysfs_slab_unlink(s);
459#endif
460 list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
461 schedule_work(&slab_caches_to_rcu_destroy_work);
462 } else {
463#ifdef SLAB_SUPPORTS_SYSFS
464 sysfs_slab_unlink(s);
465 sysfs_slab_release(s);
466#else
467 slab_kmem_cache_release(s);
468#endif
469 }
470
471 return 0;
472}
473
474void slab_kmem_cache_release(struct kmem_cache *s)
475{
476 __kmem_cache_release(s);
477 kfree_const(s->name);
478 kmem_cache_free(kmem_cache, s);
479}
480
481void kmem_cache_destroy(struct kmem_cache *s)
482{
483 int err;
484
485 if (unlikely(!s))
486 return;
487
488 get_online_cpus();
489 get_online_mems();
490
491 mutex_lock(&slab_mutex);
492
493 s->refcount--;
494 if (s->refcount)
495 goto out_unlock;
496
497 err = shutdown_cache(s);
498 if (err) {
499 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
500 s->name);
501 dump_stack();
502 }
503out_unlock:
504 mutex_unlock(&slab_mutex);
505
506 put_online_mems();
507 put_online_cpus();
508}
509EXPORT_SYMBOL(kmem_cache_destroy);
510
511/**
512 * kmem_cache_shrink - Shrink a cache.
513 * @cachep: The cache to shrink.
514 *
515 * Releases as many slabs as possible for a cache.
516 * To help debugging, a zero exit status indicates all slabs were released.
517 *
518 * Return: %0 if all slabs were released, non-zero otherwise
519 */
520int kmem_cache_shrink(struct kmem_cache *cachep)
521{
522 int ret;
523
524 get_online_cpus();
525 get_online_mems();
526 kasan_cache_shrink(cachep);
527 ret = __kmem_cache_shrink(cachep);
528 put_online_mems();
529 put_online_cpus();
530 return ret;
531}
532EXPORT_SYMBOL(kmem_cache_shrink);
533
534bool slab_is_available(void)
535{
536 return slab_state >= UP;
537}
538
539#ifndef CONFIG_SLOB
540/* Create a cache during boot when no slab services are available yet */
541void __init create_boot_cache(struct kmem_cache *s, const char *name,
542 unsigned int size, slab_flags_t flags,
543 unsigned int useroffset, unsigned int usersize)
544{
545 int err;
546 unsigned int align = ARCH_KMALLOC_MINALIGN;
547
548 s->name = name;
549 s->size = s->object_size = size;
550
551 /*
552 * For power of two sizes, guarantee natural alignment for kmalloc
553 * caches, regardless of SL*B debugging options.
554 */
555 if (is_power_of_2(size))
556 align = max(align, size);
557 s->align = calculate_alignment(flags, align, size);
558
559 s->useroffset = useroffset;
560 s->usersize = usersize;
561
562 err = __kmem_cache_create(s, flags);
563
564 if (err)
565 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
566 name, size, err);
567
568 s->refcount = -1; /* Exempt from merging for now */
569}
570
571struct kmem_cache *__init create_kmalloc_cache(const char *name,
572 unsigned int size, slab_flags_t flags,
573 unsigned int useroffset, unsigned int usersize)
574{
575 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
576
577 if (!s)
578 panic("Out of memory when creating slab %s\n", name);
579
580 create_boot_cache(s, name, size, flags, useroffset, usersize);
581 list_add(&s->list, &slab_caches);
582 s->refcount = 1;
583 return s;
584}
585
586struct kmem_cache *
587kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
588{ /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
589EXPORT_SYMBOL(kmalloc_caches);
590
591/*
592 * Conversion table for small slabs sizes / 8 to the index in the
593 * kmalloc array. This is necessary for slabs < 192 since we have non power
594 * of two cache sizes there. The size of larger slabs can be determined using
595 * fls.
596 */
597static u8 size_index[24] __ro_after_init = {
598 3, /* 8 */
599 4, /* 16 */
600 5, /* 24 */
601 5, /* 32 */
602 6, /* 40 */
603 6, /* 48 */
604 6, /* 56 */
605 6, /* 64 */
606 1, /* 72 */
607 1, /* 80 */
608 1, /* 88 */
609 1, /* 96 */
610 7, /* 104 */
611 7, /* 112 */
612 7, /* 120 */
613 7, /* 128 */
614 2, /* 136 */
615 2, /* 144 */
616 2, /* 152 */
617 2, /* 160 */
618 2, /* 168 */
619 2, /* 176 */
620 2, /* 184 */
621 2 /* 192 */
622};
623
624static inline unsigned int size_index_elem(unsigned int bytes)
625{
626 return (bytes - 1) / 8;
627}
628
629/*
630 * Find the kmem_cache structure that serves a given size of
631 * allocation
632 */
633struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
634{
635 unsigned int index;
636
637 if (size <= 192) {
638 if (!size)
639 return ZERO_SIZE_PTR;
640
641 index = size_index[size_index_elem(size)];
642 } else {
643 if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
644 return NULL;
645 index = fls(size - 1);
646 }
647
648 return kmalloc_caches[kmalloc_type(flags)][index];
649}
650
651#ifdef CONFIG_ZONE_DMA
652#define INIT_KMALLOC_INFO(__size, __short_size) \
653{ \
654 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
655 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
656 .name[KMALLOC_DMA] = "dma-kmalloc-" #__short_size, \
657 .size = __size, \
658}
659#else
660#define INIT_KMALLOC_INFO(__size, __short_size) \
661{ \
662 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
663 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
664 .size = __size, \
665}
666#endif
667
668/*
669 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
670 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
671 * kmalloc-67108864.
672 */
673const struct kmalloc_info_struct kmalloc_info[] __initconst = {
674 INIT_KMALLOC_INFO(0, 0),
675 INIT_KMALLOC_INFO(96, 96),
676 INIT_KMALLOC_INFO(192, 192),
677 INIT_KMALLOC_INFO(8, 8),
678 INIT_KMALLOC_INFO(16, 16),
679 INIT_KMALLOC_INFO(32, 32),
680 INIT_KMALLOC_INFO(64, 64),
681 INIT_KMALLOC_INFO(128, 128),
682 INIT_KMALLOC_INFO(256, 256),
683 INIT_KMALLOC_INFO(512, 512),
684 INIT_KMALLOC_INFO(1024, 1k),
685 INIT_KMALLOC_INFO(2048, 2k),
686 INIT_KMALLOC_INFO(4096, 4k),
687 INIT_KMALLOC_INFO(8192, 8k),
688 INIT_KMALLOC_INFO(16384, 16k),
689 INIT_KMALLOC_INFO(32768, 32k),
690 INIT_KMALLOC_INFO(65536, 64k),
691 INIT_KMALLOC_INFO(131072, 128k),
692 INIT_KMALLOC_INFO(262144, 256k),
693 INIT_KMALLOC_INFO(524288, 512k),
694 INIT_KMALLOC_INFO(1048576, 1M),
695 INIT_KMALLOC_INFO(2097152, 2M),
696 INIT_KMALLOC_INFO(4194304, 4M),
697 INIT_KMALLOC_INFO(8388608, 8M),
698 INIT_KMALLOC_INFO(16777216, 16M),
699 INIT_KMALLOC_INFO(33554432, 32M),
700 INIT_KMALLOC_INFO(67108864, 64M)
701};
702
703/*
704 * Patch up the size_index table if we have strange large alignment
705 * requirements for the kmalloc array. This is only the case for
706 * MIPS it seems. The standard arches will not generate any code here.
707 *
708 * Largest permitted alignment is 256 bytes due to the way we
709 * handle the index determination for the smaller caches.
710 *
711 * Make sure that nothing crazy happens if someone starts tinkering
712 * around with ARCH_KMALLOC_MINALIGN
713 */
714void __init setup_kmalloc_cache_index_table(void)
715{
716 unsigned int i;
717
718 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
719 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
720
721 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
722 unsigned int elem = size_index_elem(i);
723
724 if (elem >= ARRAY_SIZE(size_index))
725 break;
726 size_index[elem] = KMALLOC_SHIFT_LOW;
727 }
728
729 if (KMALLOC_MIN_SIZE >= 64) {
730 /*
731 * The 96 byte size cache is not used if the alignment
732 * is 64 byte.
733 */
734 for (i = 64 + 8; i <= 96; i += 8)
735 size_index[size_index_elem(i)] = 7;
736
737 }
738
739 if (KMALLOC_MIN_SIZE >= 128) {
740 /*
741 * The 192 byte sized cache is not used if the alignment
742 * is 128 byte. Redirect kmalloc to use the 256 byte cache
743 * instead.
744 */
745 for (i = 128 + 8; i <= 192; i += 8)
746 size_index[size_index_elem(i)] = 8;
747 }
748}
749
750static void __init
751new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
752{
753 if (type == KMALLOC_RECLAIM)
754 flags |= SLAB_RECLAIM_ACCOUNT;
755
756 kmalloc_caches[type][idx] = create_kmalloc_cache(
757 kmalloc_info[idx].name[type],
758 kmalloc_info[idx].size, flags, 0,
759 kmalloc_info[idx].size);
760}
761
762/*
763 * Create the kmalloc array. Some of the regular kmalloc arrays
764 * may already have been created because they were needed to
765 * enable allocations for slab creation.
766 */
767void __init create_kmalloc_caches(slab_flags_t flags)
768{
769 int i;
770 enum kmalloc_cache_type type;
771
772 for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
773 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
774 if (!kmalloc_caches[type][i])
775 new_kmalloc_cache(i, type, flags);
776
777 /*
778 * Caches that are not of the two-to-the-power-of size.
779 * These have to be created immediately after the
780 * earlier power of two caches
781 */
782 if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
783 !kmalloc_caches[type][1])
784 new_kmalloc_cache(1, type, flags);
785 if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
786 !kmalloc_caches[type][2])
787 new_kmalloc_cache(2, type, flags);
788 }
789 }
790
791 /* Kmalloc array is now usable */
792 slab_state = UP;
793
794#ifdef CONFIG_ZONE_DMA
795 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
796 struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
797
798 if (s) {
799 kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
800 kmalloc_info[i].name[KMALLOC_DMA],
801 kmalloc_info[i].size,
802 SLAB_CACHE_DMA | flags, 0,
803 kmalloc_info[i].size);
804 }
805 }
806#endif
807}
808#endif /* !CONFIG_SLOB */
809
810gfp_t kmalloc_fix_flags(gfp_t flags)
811{
812 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
813
814 flags &= ~GFP_SLAB_BUG_MASK;
815 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
816 invalid_mask, &invalid_mask, flags, &flags);
817 dump_stack();
818
819 return flags;
820}
821
822/*
823 * To avoid unnecessary overhead, we pass through large allocation requests
824 * directly to the page allocator. We use __GFP_COMP, because we will need to
825 * know the allocation order to free the pages properly in kfree.
826 */
827void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
828{
829 void *ret = NULL;
830 struct page *page;
831
832 if (unlikely(flags & GFP_SLAB_BUG_MASK))
833 flags = kmalloc_fix_flags(flags);
834
835 flags |= __GFP_COMP;
836 page = alloc_pages(flags, order);
837 if (likely(page)) {
838 ret = page_address(page);
839 mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
840 PAGE_SIZE << order);
841 }
842 ret = kasan_kmalloc_large(ret, size, flags);
843 /* As ret might get tagged, call kmemleak hook after KASAN. */
844 kmemleak_alloc(ret, size, 1, flags);
845 return ret;
846}
847EXPORT_SYMBOL(kmalloc_order);
848
849#ifdef CONFIG_TRACING
850void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
851{
852 void *ret = kmalloc_order(size, flags, order);
853 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
854 return ret;
855}
856EXPORT_SYMBOL(kmalloc_order_trace);
857#endif
858
859#ifdef CONFIG_SLAB_FREELIST_RANDOM
860/* Randomize a generic freelist */
861static void freelist_randomize(struct rnd_state *state, unsigned int *list,
862 unsigned int count)
863{
864 unsigned int rand;
865 unsigned int i;
866
867 for (i = 0; i < count; i++)
868 list[i] = i;
869
870 /* Fisher-Yates shuffle */
871 for (i = count - 1; i > 0; i--) {
872 rand = prandom_u32_state(state);
873 rand %= (i + 1);
874 swap(list[i], list[rand]);
875 }
876}
877
878/* Create a random sequence per cache */
879int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
880 gfp_t gfp)
881{
882 struct rnd_state state;
883
884 if (count < 2 || cachep->random_seq)
885 return 0;
886
887 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
888 if (!cachep->random_seq)
889 return -ENOMEM;
890
891 /* Get best entropy at this stage of boot */
892 prandom_seed_state(&state, get_random_long());
893
894 freelist_randomize(&state, cachep->random_seq, count);
895 return 0;
896}
897
898/* Destroy the per-cache random freelist sequence */
899void cache_random_seq_destroy(struct kmem_cache *cachep)
900{
901 kfree(cachep->random_seq);
902 cachep->random_seq = NULL;
903}
904#endif /* CONFIG_SLAB_FREELIST_RANDOM */
905
906#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
907#ifdef CONFIG_SLAB
908#define SLABINFO_RIGHTS (0600)
909#else
910#define SLABINFO_RIGHTS (0400)
911#endif
912
913static void print_slabinfo_header(struct seq_file *m)
914{
915 /*
916 * Output format version, so at least we can change it
917 * without _too_ many complaints.
918 */
919#ifdef CONFIG_DEBUG_SLAB
920 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
921#else
922 seq_puts(m, "slabinfo - version: 2.1\n");
923#endif
924 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
925 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
926 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
927#ifdef CONFIG_DEBUG_SLAB
928 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
929 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
930#endif
931 seq_putc(m, '\n');
932}
933
934void *slab_start(struct seq_file *m, loff_t *pos)
935{
936 mutex_lock(&slab_mutex);
937 return seq_list_start(&slab_caches, *pos);
938}
939
940void *slab_next(struct seq_file *m, void *p, loff_t *pos)
941{
942 return seq_list_next(p, &slab_caches, pos);
943}
944
945void slab_stop(struct seq_file *m, void *p)
946{
947 mutex_unlock(&slab_mutex);
948}
949
950static void cache_show(struct kmem_cache *s, struct seq_file *m)
951{
952 struct slabinfo sinfo;
953
954 memset(&sinfo, 0, sizeof(sinfo));
955 get_slabinfo(s, &sinfo);
956
957 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
958 s->name, sinfo.active_objs, sinfo.num_objs, s->size,
959 sinfo.objects_per_slab, (1 << sinfo.cache_order));
960
961 seq_printf(m, " : tunables %4u %4u %4u",
962 sinfo.limit, sinfo.batchcount, sinfo.shared);
963 seq_printf(m, " : slabdata %6lu %6lu %6lu",
964 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
965 slabinfo_show_stats(m, s);
966 seq_putc(m, '\n');
967}
968
969static int slab_show(struct seq_file *m, void *p)
970{
971 struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
972
973 if (p == slab_caches.next)
974 print_slabinfo_header(m);
975 cache_show(s, m);
976 return 0;
977}
978
979void dump_unreclaimable_slab(void)
980{
981 struct kmem_cache *s, *s2;
982 struct slabinfo sinfo;
983
984 /*
985 * Here acquiring slab_mutex is risky since we don't prefer to get
986 * sleep in oom path. But, without mutex hold, it may introduce a
987 * risk of crash.
988 * Use mutex_trylock to protect the list traverse, dump nothing
989 * without acquiring the mutex.
990 */
991 if (!mutex_trylock(&slab_mutex)) {
992 pr_warn("excessive unreclaimable slab but cannot dump stats\n");
993 return;
994 }
995
996 pr_info("Unreclaimable slab info:\n");
997 pr_info("Name Used Total\n");
998
999 list_for_each_entry_safe(s, s2, &slab_caches, list) {
1000 if (s->flags & SLAB_RECLAIM_ACCOUNT)
1001 continue;
1002
1003 get_slabinfo(s, &sinfo);
1004
1005 if (sinfo.num_objs > 0)
1006 pr_info("%-17s %10luKB %10luKB\n", s->name,
1007 (sinfo.active_objs * s->size) / 1024,
1008 (sinfo.num_objs * s->size) / 1024);
1009 }
1010 mutex_unlock(&slab_mutex);
1011}
1012
1013#if defined(CONFIG_MEMCG_KMEM)
1014int memcg_slab_show(struct seq_file *m, void *p)
1015{
1016 /*
1017 * Deprecated.
1018 * Please, take a look at tools/cgroup/slabinfo.py .
1019 */
1020 return 0;
1021}
1022#endif
1023
1024/*
1025 * slabinfo_op - iterator that generates /proc/slabinfo
1026 *
1027 * Output layout:
1028 * cache-name
1029 * num-active-objs
1030 * total-objs
1031 * object size
1032 * num-active-slabs
1033 * total-slabs
1034 * num-pages-per-slab
1035 * + further values on SMP and with statistics enabled
1036 */
1037static const struct seq_operations slabinfo_op = {
1038 .start = slab_start,
1039 .next = slab_next,
1040 .stop = slab_stop,
1041 .show = slab_show,
1042};
1043
1044static int slabinfo_open(struct inode *inode, struct file *file)
1045{
1046 return seq_open(file, &slabinfo_op);
1047}
1048
1049static const struct proc_ops slabinfo_proc_ops = {
1050 .proc_flags = PROC_ENTRY_PERMANENT,
1051 .proc_open = slabinfo_open,
1052 .proc_read = seq_read,
1053 .proc_write = slabinfo_write,
1054 .proc_lseek = seq_lseek,
1055 .proc_release = seq_release,
1056};
1057
1058static int __init slab_proc_init(void)
1059{
1060 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
1061 return 0;
1062}
1063module_init(slab_proc_init);
1064
1065#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
1066
1067static __always_inline void *__do_krealloc(const void *p, size_t new_size,
1068 gfp_t flags)
1069{
1070 void *ret;
1071 size_t ks;
1072
1073 ks = ksize(p);
1074
1075 if (ks >= new_size) {
1076 p = kasan_krealloc((void *)p, new_size, flags);
1077 return (void *)p;
1078 }
1079
1080 ret = kmalloc_track_caller(new_size, flags);
1081 if (ret && p)
1082 memcpy(ret, p, ks);
1083
1084 return ret;
1085}
1086
1087/**
1088 * krealloc - reallocate memory. The contents will remain unchanged.
1089 * @p: object to reallocate memory for.
1090 * @new_size: how many bytes of memory are required.
1091 * @flags: the type of memory to allocate.
1092 *
1093 * The contents of the object pointed to are preserved up to the
1094 * lesser of the new and old sizes. If @p is %NULL, krealloc()
1095 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
1096 * %NULL pointer, the object pointed to is freed.
1097 *
1098 * Return: pointer to the allocated memory or %NULL in case of error
1099 */
1100void *krealloc(const void *p, size_t new_size, gfp_t flags)
1101{
1102 void *ret;
1103
1104 if (unlikely(!new_size)) {
1105 kfree(p);
1106 return ZERO_SIZE_PTR;
1107 }
1108
1109 ret = __do_krealloc(p, new_size, flags);
1110 if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
1111 kfree(p);
1112
1113 return ret;
1114}
1115EXPORT_SYMBOL(krealloc);
1116
1117/**
1118 * kfree_sensitive - Clear sensitive information in memory before freeing
1119 * @p: object to free memory of
1120 *
1121 * The memory of the object @p points to is zeroed before freed.
1122 * If @p is %NULL, kfree_sensitive() does nothing.
1123 *
1124 * Note: this function zeroes the whole allocated buffer which can be a good
1125 * deal bigger than the requested buffer size passed to kmalloc(). So be
1126 * careful when using this function in performance sensitive code.
1127 */
1128void kfree_sensitive(const void *p)
1129{
1130 size_t ks;
1131 void *mem = (void *)p;
1132
1133 ks = ksize(mem);
1134 if (ks)
1135 memzero_explicit(mem, ks);
1136 kfree(mem);
1137}
1138EXPORT_SYMBOL(kfree_sensitive);
1139
1140/**
1141 * ksize - get the actual amount of memory allocated for a given object
1142 * @objp: Pointer to the object
1143 *
1144 * kmalloc may internally round up allocations and return more memory
1145 * than requested. ksize() can be used to determine the actual amount of
1146 * memory allocated. The caller may use this additional memory, even though
1147 * a smaller amount of memory was initially specified with the kmalloc call.
1148 * The caller must guarantee that objp points to a valid object previously
1149 * allocated with either kmalloc() or kmem_cache_alloc(). The object
1150 * must not be freed during the duration of the call.
1151 *
1152 * Return: size of the actual memory used by @objp in bytes
1153 */
1154size_t ksize(const void *objp)
1155{
1156 size_t size;
1157
1158 /*
1159 * We need to check that the pointed to object is valid, and only then
1160 * unpoison the shadow memory below. We use __kasan_check_read(), to
1161 * generate a more useful report at the time ksize() is called (rather
1162 * than later where behaviour is undefined due to potential
1163 * use-after-free or double-free).
1164 *
1165 * If the pointed to memory is invalid we return 0, to avoid users of
1166 * ksize() writing to and potentially corrupting the memory region.
1167 *
1168 * We want to perform the check before __ksize(), to avoid potentially
1169 * crashing in __ksize() due to accessing invalid metadata.
1170 */
1171 if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1))
1172 return 0;
1173
1174 size = __ksize(objp);
1175 /*
1176 * We assume that ksize callers could use whole allocated area,
1177 * so we need to unpoison this area.
1178 */
1179 kasan_unpoison_shadow(objp, size);
1180 return size;
1181}
1182EXPORT_SYMBOL(ksize);
1183
1184/* Tracepoints definitions. */
1185EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1186EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1187EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
1188EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
1189EXPORT_TRACEPOINT_SYMBOL(kfree);
1190EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1191
1192int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
1193{
1194 if (__should_failslab(s, gfpflags))
1195 return -ENOMEM;
1196 return 0;
1197}
1198ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Slab allocator functions that are independent of the allocator strategy
4 *
5 * (C) 2012 Christoph Lameter <cl@linux.com>
6 */
7#include <linux/slab.h>
8
9#include <linux/mm.h>
10#include <linux/poison.h>
11#include <linux/interrupt.h>
12#include <linux/memory.h>
13#include <linux/cache.h>
14#include <linux/compiler.h>
15#include <linux/module.h>
16#include <linux/cpu.h>
17#include <linux/uaccess.h>
18#include <linux/seq_file.h>
19#include <linux/proc_fs.h>
20#include <asm/cacheflush.h>
21#include <asm/tlbflush.h>
22#include <asm/page.h>
23#include <linux/memcontrol.h>
24
25#define CREATE_TRACE_POINTS
26#include <trace/events/kmem.h>
27
28#include "slab.h"
29
30enum slab_state slab_state;
31LIST_HEAD(slab_caches);
32DEFINE_MUTEX(slab_mutex);
33struct kmem_cache *kmem_cache;
34
35#ifdef CONFIG_HARDENED_USERCOPY
36bool usercopy_fallback __ro_after_init =
37 IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
38module_param(usercopy_fallback, bool, 0400);
39MODULE_PARM_DESC(usercopy_fallback,
40 "WARN instead of reject usercopy whitelist violations");
41#endif
42
43static LIST_HEAD(slab_caches_to_rcu_destroy);
44static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
45static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
46 slab_caches_to_rcu_destroy_workfn);
47
48/*
49 * Set of flags that will prevent slab merging
50 */
51#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
52 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
53 SLAB_FAILSLAB | SLAB_KASAN)
54
55#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
56 SLAB_ACCOUNT)
57
58/*
59 * Merge control. If this is set then no merging of slab caches will occur.
60 */
61static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
62
63static int __init setup_slab_nomerge(char *str)
64{
65 slab_nomerge = true;
66 return 1;
67}
68
69#ifdef CONFIG_SLUB
70__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
71#endif
72
73__setup("slab_nomerge", setup_slab_nomerge);
74
75/*
76 * Determine the size of a slab object
77 */
78unsigned int kmem_cache_size(struct kmem_cache *s)
79{
80 return s->object_size;
81}
82EXPORT_SYMBOL(kmem_cache_size);
83
84#ifdef CONFIG_DEBUG_VM
85static int kmem_cache_sanity_check(const char *name, unsigned int size)
86{
87 if (!name || in_interrupt() || size < sizeof(void *) ||
88 size > KMALLOC_MAX_SIZE) {
89 pr_err("kmem_cache_create(%s) integrity check failed\n", name);
90 return -EINVAL;
91 }
92
93 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
94 return 0;
95}
96#else
97static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
98{
99 return 0;
100}
101#endif
102
103void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
104{
105 size_t i;
106
107 for (i = 0; i < nr; i++) {
108 if (s)
109 kmem_cache_free(s, p[i]);
110 else
111 kfree(p[i]);
112 }
113}
114
115int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
116 void **p)
117{
118 size_t i;
119
120 for (i = 0; i < nr; i++) {
121 void *x = p[i] = kmem_cache_alloc(s, flags);
122 if (!x) {
123 __kmem_cache_free_bulk(s, i, p);
124 return 0;
125 }
126 }
127 return i;
128}
129
130#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
131
132LIST_HEAD(slab_root_caches);
133
134void slab_init_memcg_params(struct kmem_cache *s)
135{
136 s->memcg_params.root_cache = NULL;
137 RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
138 INIT_LIST_HEAD(&s->memcg_params.children);
139}
140
141static int init_memcg_params(struct kmem_cache *s,
142 struct mem_cgroup *memcg, struct kmem_cache *root_cache)
143{
144 struct memcg_cache_array *arr;
145
146 if (root_cache) {
147 s->memcg_params.root_cache = root_cache;
148 s->memcg_params.memcg = memcg;
149 INIT_LIST_HEAD(&s->memcg_params.children_node);
150 INIT_LIST_HEAD(&s->memcg_params.kmem_caches_node);
151 return 0;
152 }
153
154 slab_init_memcg_params(s);
155
156 if (!memcg_nr_cache_ids)
157 return 0;
158
159 arr = kvzalloc(sizeof(struct memcg_cache_array) +
160 memcg_nr_cache_ids * sizeof(void *),
161 GFP_KERNEL);
162 if (!arr)
163 return -ENOMEM;
164
165 RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr);
166 return 0;
167}
168
169static void destroy_memcg_params(struct kmem_cache *s)
170{
171 if (is_root_cache(s))
172 kvfree(rcu_access_pointer(s->memcg_params.memcg_caches));
173}
174
175static void free_memcg_params(struct rcu_head *rcu)
176{
177 struct memcg_cache_array *old;
178
179 old = container_of(rcu, struct memcg_cache_array, rcu);
180 kvfree(old);
181}
182
183static int update_memcg_params(struct kmem_cache *s, int new_array_size)
184{
185 struct memcg_cache_array *old, *new;
186
187 new = kvzalloc(sizeof(struct memcg_cache_array) +
188 new_array_size * sizeof(void *), GFP_KERNEL);
189 if (!new)
190 return -ENOMEM;
191
192 old = rcu_dereference_protected(s->memcg_params.memcg_caches,
193 lockdep_is_held(&slab_mutex));
194 if (old)
195 memcpy(new->entries, old->entries,
196 memcg_nr_cache_ids * sizeof(void *));
197
198 rcu_assign_pointer(s->memcg_params.memcg_caches, new);
199 if (old)
200 call_rcu(&old->rcu, free_memcg_params);
201 return 0;
202}
203
204int memcg_update_all_caches(int num_memcgs)
205{
206 struct kmem_cache *s;
207 int ret = 0;
208
209 mutex_lock(&slab_mutex);
210 list_for_each_entry(s, &slab_root_caches, root_caches_node) {
211 ret = update_memcg_params(s, num_memcgs);
212 /*
213 * Instead of freeing the memory, we'll just leave the caches
214 * up to this point in an updated state.
215 */
216 if (ret)
217 break;
218 }
219 mutex_unlock(&slab_mutex);
220 return ret;
221}
222
223void memcg_link_cache(struct kmem_cache *s)
224{
225 if (is_root_cache(s)) {
226 list_add(&s->root_caches_node, &slab_root_caches);
227 } else {
228 list_add(&s->memcg_params.children_node,
229 &s->memcg_params.root_cache->memcg_params.children);
230 list_add(&s->memcg_params.kmem_caches_node,
231 &s->memcg_params.memcg->kmem_caches);
232 }
233}
234
235static void memcg_unlink_cache(struct kmem_cache *s)
236{
237 if (is_root_cache(s)) {
238 list_del(&s->root_caches_node);
239 } else {
240 list_del(&s->memcg_params.children_node);
241 list_del(&s->memcg_params.kmem_caches_node);
242 }
243}
244#else
245static inline int init_memcg_params(struct kmem_cache *s,
246 struct mem_cgroup *memcg, struct kmem_cache *root_cache)
247{
248 return 0;
249}
250
251static inline void destroy_memcg_params(struct kmem_cache *s)
252{
253}
254
255static inline void memcg_unlink_cache(struct kmem_cache *s)
256{
257}
258#endif /* CONFIG_MEMCG && !CONFIG_SLOB */
259
260/*
261 * Figure out what the alignment of the objects will be given a set of
262 * flags, a user specified alignment and the size of the objects.
263 */
264static unsigned int calculate_alignment(slab_flags_t flags,
265 unsigned int align, unsigned int size)
266{
267 /*
268 * If the user wants hardware cache aligned objects then follow that
269 * suggestion if the object is sufficiently large.
270 *
271 * The hardware cache alignment cannot override the specified
272 * alignment though. If that is greater then use it.
273 */
274 if (flags & SLAB_HWCACHE_ALIGN) {
275 unsigned int ralign;
276
277 ralign = cache_line_size();
278 while (size <= ralign / 2)
279 ralign /= 2;
280 align = max(align, ralign);
281 }
282
283 if (align < ARCH_SLAB_MINALIGN)
284 align = ARCH_SLAB_MINALIGN;
285
286 return ALIGN(align, sizeof(void *));
287}
288
289/*
290 * Find a mergeable slab cache
291 */
292int slab_unmergeable(struct kmem_cache *s)
293{
294 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
295 return 1;
296
297 if (!is_root_cache(s))
298 return 1;
299
300 if (s->ctor)
301 return 1;
302
303 if (s->usersize)
304 return 1;
305
306 /*
307 * We may have set a slab to be unmergeable during bootstrap.
308 */
309 if (s->refcount < 0)
310 return 1;
311
312 return 0;
313}
314
315struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
316 slab_flags_t flags, const char *name, void (*ctor)(void *))
317{
318 struct kmem_cache *s;
319
320 if (slab_nomerge)
321 return NULL;
322
323 if (ctor)
324 return NULL;
325
326 size = ALIGN(size, sizeof(void *));
327 align = calculate_alignment(flags, align, size);
328 size = ALIGN(size, align);
329 flags = kmem_cache_flags(size, flags, name, NULL);
330
331 if (flags & SLAB_NEVER_MERGE)
332 return NULL;
333
334 list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) {
335 if (slab_unmergeable(s))
336 continue;
337
338 if (size > s->size)
339 continue;
340
341 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
342 continue;
343 /*
344 * Check if alignment is compatible.
345 * Courtesy of Adrian Drzewiecki
346 */
347 if ((s->size & ~(align - 1)) != s->size)
348 continue;
349
350 if (s->size - size >= sizeof(void *))
351 continue;
352
353 if (IS_ENABLED(CONFIG_SLAB) && align &&
354 (align > s->align || s->align % align))
355 continue;
356
357 return s;
358 }
359 return NULL;
360}
361
362static struct kmem_cache *create_cache(const char *name,
363 unsigned int object_size, unsigned int align,
364 slab_flags_t flags, unsigned int useroffset,
365 unsigned int usersize, void (*ctor)(void *),
366 struct mem_cgroup *memcg, struct kmem_cache *root_cache)
367{
368 struct kmem_cache *s;
369 int err;
370
371 if (WARN_ON(useroffset + usersize > object_size))
372 useroffset = usersize = 0;
373
374 err = -ENOMEM;
375 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
376 if (!s)
377 goto out;
378
379 s->name = name;
380 s->size = s->object_size = object_size;
381 s->align = align;
382 s->ctor = ctor;
383 s->useroffset = useroffset;
384 s->usersize = usersize;
385
386 err = init_memcg_params(s, memcg, root_cache);
387 if (err)
388 goto out_free_cache;
389
390 err = __kmem_cache_create(s, flags);
391 if (err)
392 goto out_free_cache;
393
394 s->refcount = 1;
395 list_add(&s->list, &slab_caches);
396 memcg_link_cache(s);
397out:
398 if (err)
399 return ERR_PTR(err);
400 return s;
401
402out_free_cache:
403 destroy_memcg_params(s);
404 kmem_cache_free(kmem_cache, s);
405 goto out;
406}
407
408/*
409 * kmem_cache_create_usercopy - Create a cache.
410 * @name: A string which is used in /proc/slabinfo to identify this cache.
411 * @size: The size of objects to be created in this cache.
412 * @align: The required alignment for the objects.
413 * @flags: SLAB flags
414 * @useroffset: Usercopy region offset
415 * @usersize: Usercopy region size
416 * @ctor: A constructor for the objects.
417 *
418 * Returns a ptr to the cache on success, NULL on failure.
419 * Cannot be called within a interrupt, but can be interrupted.
420 * The @ctor is run when new pages are allocated by the cache.
421 *
422 * The flags are
423 *
424 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
425 * to catch references to uninitialised memory.
426 *
427 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
428 * for buffer overruns.
429 *
430 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
431 * cacheline. This can be beneficial if you're counting cycles as closely
432 * as davem.
433 */
434struct kmem_cache *
435kmem_cache_create_usercopy(const char *name,
436 unsigned int size, unsigned int align,
437 slab_flags_t flags,
438 unsigned int useroffset, unsigned int usersize,
439 void (*ctor)(void *))
440{
441 struct kmem_cache *s = NULL;
442 const char *cache_name;
443 int err;
444
445 get_online_cpus();
446 get_online_mems();
447 memcg_get_cache_ids();
448
449 mutex_lock(&slab_mutex);
450
451 err = kmem_cache_sanity_check(name, size);
452 if (err) {
453 goto out_unlock;
454 }
455
456 /* Refuse requests with allocator specific flags */
457 if (flags & ~SLAB_FLAGS_PERMITTED) {
458 err = -EINVAL;
459 goto out_unlock;
460 }
461
462 /*
463 * Some allocators will constraint the set of valid flags to a subset
464 * of all flags. We expect them to define CACHE_CREATE_MASK in this
465 * case, and we'll just provide them with a sanitized version of the
466 * passed flags.
467 */
468 flags &= CACHE_CREATE_MASK;
469
470 /* Fail closed on bad usersize of useroffset values. */
471 if (WARN_ON(!usersize && useroffset) ||
472 WARN_ON(size < usersize || size - usersize < useroffset))
473 usersize = useroffset = 0;
474
475 if (!usersize)
476 s = __kmem_cache_alias(name, size, align, flags, ctor);
477 if (s)
478 goto out_unlock;
479
480 cache_name = kstrdup_const(name, GFP_KERNEL);
481 if (!cache_name) {
482 err = -ENOMEM;
483 goto out_unlock;
484 }
485
486 s = create_cache(cache_name, size,
487 calculate_alignment(flags, align, size),
488 flags, useroffset, usersize, ctor, NULL, NULL);
489 if (IS_ERR(s)) {
490 err = PTR_ERR(s);
491 kfree_const(cache_name);
492 }
493
494out_unlock:
495 mutex_unlock(&slab_mutex);
496
497 memcg_put_cache_ids();
498 put_online_mems();
499 put_online_cpus();
500
501 if (err) {
502 if (flags & SLAB_PANIC)
503 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
504 name, err);
505 else {
506 pr_warn("kmem_cache_create(%s) failed with error %d\n",
507 name, err);
508 dump_stack();
509 }
510 return NULL;
511 }
512 return s;
513}
514EXPORT_SYMBOL(kmem_cache_create_usercopy);
515
516struct kmem_cache *
517kmem_cache_create(const char *name, unsigned int size, unsigned int align,
518 slab_flags_t flags, void (*ctor)(void *))
519{
520 return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
521 ctor);
522}
523EXPORT_SYMBOL(kmem_cache_create);
524
525static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
526{
527 LIST_HEAD(to_destroy);
528 struct kmem_cache *s, *s2;
529
530 /*
531 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
532 * @slab_caches_to_rcu_destroy list. The slab pages are freed
533 * through RCU and and the associated kmem_cache are dereferenced
534 * while freeing the pages, so the kmem_caches should be freed only
535 * after the pending RCU operations are finished. As rcu_barrier()
536 * is a pretty slow operation, we batch all pending destructions
537 * asynchronously.
538 */
539 mutex_lock(&slab_mutex);
540 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
541 mutex_unlock(&slab_mutex);
542
543 if (list_empty(&to_destroy))
544 return;
545
546 rcu_barrier();
547
548 list_for_each_entry_safe(s, s2, &to_destroy, list) {
549#ifdef SLAB_SUPPORTS_SYSFS
550 sysfs_slab_release(s);
551#else
552 slab_kmem_cache_release(s);
553#endif
554 }
555}
556
557static int shutdown_cache(struct kmem_cache *s)
558{
559 /* free asan quarantined objects */
560 kasan_cache_shutdown(s);
561
562 if (__kmem_cache_shutdown(s) != 0)
563 return -EBUSY;
564
565 memcg_unlink_cache(s);
566 list_del(&s->list);
567
568 if (s->flags & SLAB_TYPESAFE_BY_RCU) {
569 list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
570 schedule_work(&slab_caches_to_rcu_destroy_work);
571 } else {
572#ifdef SLAB_SUPPORTS_SYSFS
573 sysfs_slab_release(s);
574#else
575 slab_kmem_cache_release(s);
576#endif
577 }
578
579 return 0;
580}
581
582#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
583/*
584 * memcg_create_kmem_cache - Create a cache for a memory cgroup.
585 * @memcg: The memory cgroup the new cache is for.
586 * @root_cache: The parent of the new cache.
587 *
588 * This function attempts to create a kmem cache that will serve allocation
589 * requests going from @memcg to @root_cache. The new cache inherits properties
590 * from its parent.
591 */
592void memcg_create_kmem_cache(struct mem_cgroup *memcg,
593 struct kmem_cache *root_cache)
594{
595 static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
596 struct cgroup_subsys_state *css = &memcg->css;
597 struct memcg_cache_array *arr;
598 struct kmem_cache *s = NULL;
599 char *cache_name;
600 int idx;
601
602 get_online_cpus();
603 get_online_mems();
604
605 mutex_lock(&slab_mutex);
606
607 /*
608 * The memory cgroup could have been offlined while the cache
609 * creation work was pending.
610 */
611 if (memcg->kmem_state != KMEM_ONLINE)
612 goto out_unlock;
613
614 idx = memcg_cache_id(memcg);
615 arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches,
616 lockdep_is_held(&slab_mutex));
617
618 /*
619 * Since per-memcg caches are created asynchronously on first
620 * allocation (see memcg_kmem_get_cache()), several threads can try to
621 * create the same cache, but only one of them may succeed.
622 */
623 if (arr->entries[idx])
624 goto out_unlock;
625
626 cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf));
627 cache_name = kasprintf(GFP_KERNEL, "%s(%llu:%s)", root_cache->name,
628 css->serial_nr, memcg_name_buf);
629 if (!cache_name)
630 goto out_unlock;
631
632 s = create_cache(cache_name, root_cache->object_size,
633 root_cache->align,
634 root_cache->flags & CACHE_CREATE_MASK,
635 root_cache->useroffset, root_cache->usersize,
636 root_cache->ctor, memcg, root_cache);
637 /*
638 * If we could not create a memcg cache, do not complain, because
639 * that's not critical at all as we can always proceed with the root
640 * cache.
641 */
642 if (IS_ERR(s)) {
643 kfree(cache_name);
644 goto out_unlock;
645 }
646
647 /*
648 * Since readers won't lock (see cache_from_memcg_idx()), we need a
649 * barrier here to ensure nobody will see the kmem_cache partially
650 * initialized.
651 */
652 smp_wmb();
653 arr->entries[idx] = s;
654
655out_unlock:
656 mutex_unlock(&slab_mutex);
657
658 put_online_mems();
659 put_online_cpus();
660}
661
662static void kmemcg_deactivate_workfn(struct work_struct *work)
663{
664 struct kmem_cache *s = container_of(work, struct kmem_cache,
665 memcg_params.deact_work);
666
667 get_online_cpus();
668 get_online_mems();
669
670 mutex_lock(&slab_mutex);
671
672 s->memcg_params.deact_fn(s);
673
674 mutex_unlock(&slab_mutex);
675
676 put_online_mems();
677 put_online_cpus();
678
679 /* done, put the ref from slab_deactivate_memcg_cache_rcu_sched() */
680 css_put(&s->memcg_params.memcg->css);
681}
682
683static void kmemcg_deactivate_rcufn(struct rcu_head *head)
684{
685 struct kmem_cache *s = container_of(head, struct kmem_cache,
686 memcg_params.deact_rcu_head);
687
688 /*
689 * We need to grab blocking locks. Bounce to ->deact_work. The
690 * work item shares the space with the RCU head and can't be
691 * initialized eariler.
692 */
693 INIT_WORK(&s->memcg_params.deact_work, kmemcg_deactivate_workfn);
694 queue_work(memcg_kmem_cache_wq, &s->memcg_params.deact_work);
695}
696
697/**
698 * slab_deactivate_memcg_cache_rcu_sched - schedule deactivation after a
699 * sched RCU grace period
700 * @s: target kmem_cache
701 * @deact_fn: deactivation function to call
702 *
703 * Schedule @deact_fn to be invoked with online cpus, mems and slab_mutex
704 * held after a sched RCU grace period. The slab is guaranteed to stay
705 * alive until @deact_fn is finished. This is to be used from
706 * __kmemcg_cache_deactivate().
707 */
708void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
709 void (*deact_fn)(struct kmem_cache *))
710{
711 if (WARN_ON_ONCE(is_root_cache(s)) ||
712 WARN_ON_ONCE(s->memcg_params.deact_fn))
713 return;
714
715 /* pin memcg so that @s doesn't get destroyed in the middle */
716 css_get(&s->memcg_params.memcg->css);
717
718 s->memcg_params.deact_fn = deact_fn;
719 call_rcu_sched(&s->memcg_params.deact_rcu_head, kmemcg_deactivate_rcufn);
720}
721
722void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg)
723{
724 int idx;
725 struct memcg_cache_array *arr;
726 struct kmem_cache *s, *c;
727
728 idx = memcg_cache_id(memcg);
729
730 get_online_cpus();
731 get_online_mems();
732
733 mutex_lock(&slab_mutex);
734 list_for_each_entry(s, &slab_root_caches, root_caches_node) {
735 arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
736 lockdep_is_held(&slab_mutex));
737 c = arr->entries[idx];
738 if (!c)
739 continue;
740
741 __kmemcg_cache_deactivate(c);
742 arr->entries[idx] = NULL;
743 }
744 mutex_unlock(&slab_mutex);
745
746 put_online_mems();
747 put_online_cpus();
748}
749
750void memcg_destroy_kmem_caches(struct mem_cgroup *memcg)
751{
752 struct kmem_cache *s, *s2;
753
754 get_online_cpus();
755 get_online_mems();
756
757 mutex_lock(&slab_mutex);
758 list_for_each_entry_safe(s, s2, &memcg->kmem_caches,
759 memcg_params.kmem_caches_node) {
760 /*
761 * The cgroup is about to be freed and therefore has no charges
762 * left. Hence, all its caches must be empty by now.
763 */
764 BUG_ON(shutdown_cache(s));
765 }
766 mutex_unlock(&slab_mutex);
767
768 put_online_mems();
769 put_online_cpus();
770}
771
772static int shutdown_memcg_caches(struct kmem_cache *s)
773{
774 struct memcg_cache_array *arr;
775 struct kmem_cache *c, *c2;
776 LIST_HEAD(busy);
777 int i;
778
779 BUG_ON(!is_root_cache(s));
780
781 /*
782 * First, shutdown active caches, i.e. caches that belong to online
783 * memory cgroups.
784 */
785 arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
786 lockdep_is_held(&slab_mutex));
787 for_each_memcg_cache_index(i) {
788 c = arr->entries[i];
789 if (!c)
790 continue;
791 if (shutdown_cache(c))
792 /*
793 * The cache still has objects. Move it to a temporary
794 * list so as not to try to destroy it for a second
795 * time while iterating over inactive caches below.
796 */
797 list_move(&c->memcg_params.children_node, &busy);
798 else
799 /*
800 * The cache is empty and will be destroyed soon. Clear
801 * the pointer to it in the memcg_caches array so that
802 * it will never be accessed even if the root cache
803 * stays alive.
804 */
805 arr->entries[i] = NULL;
806 }
807
808 /*
809 * Second, shutdown all caches left from memory cgroups that are now
810 * offline.
811 */
812 list_for_each_entry_safe(c, c2, &s->memcg_params.children,
813 memcg_params.children_node)
814 shutdown_cache(c);
815
816 list_splice(&busy, &s->memcg_params.children);
817
818 /*
819 * A cache being destroyed must be empty. In particular, this means
820 * that all per memcg caches attached to it must be empty too.
821 */
822 if (!list_empty(&s->memcg_params.children))
823 return -EBUSY;
824 return 0;
825}
826#else
827static inline int shutdown_memcg_caches(struct kmem_cache *s)
828{
829 return 0;
830}
831#endif /* CONFIG_MEMCG && !CONFIG_SLOB */
832
833void slab_kmem_cache_release(struct kmem_cache *s)
834{
835 __kmem_cache_release(s);
836 destroy_memcg_params(s);
837 kfree_const(s->name);
838 kmem_cache_free(kmem_cache, s);
839}
840
841void kmem_cache_destroy(struct kmem_cache *s)
842{
843 int err;
844
845 if (unlikely(!s))
846 return;
847
848 get_online_cpus();
849 get_online_mems();
850
851 mutex_lock(&slab_mutex);
852
853 s->refcount--;
854 if (s->refcount)
855 goto out_unlock;
856
857 err = shutdown_memcg_caches(s);
858 if (!err)
859 err = shutdown_cache(s);
860
861 if (err) {
862 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
863 s->name);
864 dump_stack();
865 }
866out_unlock:
867 mutex_unlock(&slab_mutex);
868
869 put_online_mems();
870 put_online_cpus();
871}
872EXPORT_SYMBOL(kmem_cache_destroy);
873
874/**
875 * kmem_cache_shrink - Shrink a cache.
876 * @cachep: The cache to shrink.
877 *
878 * Releases as many slabs as possible for a cache.
879 * To help debugging, a zero exit status indicates all slabs were released.
880 */
881int kmem_cache_shrink(struct kmem_cache *cachep)
882{
883 int ret;
884
885 get_online_cpus();
886 get_online_mems();
887 kasan_cache_shrink(cachep);
888 ret = __kmem_cache_shrink(cachep);
889 put_online_mems();
890 put_online_cpus();
891 return ret;
892}
893EXPORT_SYMBOL(kmem_cache_shrink);
894
895bool slab_is_available(void)
896{
897 return slab_state >= UP;
898}
899
900#ifndef CONFIG_SLOB
901/* Create a cache during boot when no slab services are available yet */
902void __init create_boot_cache(struct kmem_cache *s, const char *name,
903 unsigned int size, slab_flags_t flags,
904 unsigned int useroffset, unsigned int usersize)
905{
906 int err;
907
908 s->name = name;
909 s->size = s->object_size = size;
910 s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
911 s->useroffset = useroffset;
912 s->usersize = usersize;
913
914 slab_init_memcg_params(s);
915
916 err = __kmem_cache_create(s, flags);
917
918 if (err)
919 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
920 name, size, err);
921
922 s->refcount = -1; /* Exempt from merging for now */
923}
924
925struct kmem_cache *__init create_kmalloc_cache(const char *name,
926 unsigned int size, slab_flags_t flags,
927 unsigned int useroffset, unsigned int usersize)
928{
929 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
930
931 if (!s)
932 panic("Out of memory when creating slab %s\n", name);
933
934 create_boot_cache(s, name, size, flags, useroffset, usersize);
935 list_add(&s->list, &slab_caches);
936 memcg_link_cache(s);
937 s->refcount = 1;
938 return s;
939}
940
941struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1] __ro_after_init;
942EXPORT_SYMBOL(kmalloc_caches);
943
944#ifdef CONFIG_ZONE_DMA
945struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1] __ro_after_init;
946EXPORT_SYMBOL(kmalloc_dma_caches);
947#endif
948
949/*
950 * Conversion table for small slabs sizes / 8 to the index in the
951 * kmalloc array. This is necessary for slabs < 192 since we have non power
952 * of two cache sizes there. The size of larger slabs can be determined using
953 * fls.
954 */
955static u8 size_index[24] __ro_after_init = {
956 3, /* 8 */
957 4, /* 16 */
958 5, /* 24 */
959 5, /* 32 */
960 6, /* 40 */
961 6, /* 48 */
962 6, /* 56 */
963 6, /* 64 */
964 1, /* 72 */
965 1, /* 80 */
966 1, /* 88 */
967 1, /* 96 */
968 7, /* 104 */
969 7, /* 112 */
970 7, /* 120 */
971 7, /* 128 */
972 2, /* 136 */
973 2, /* 144 */
974 2, /* 152 */
975 2, /* 160 */
976 2, /* 168 */
977 2, /* 176 */
978 2, /* 184 */
979 2 /* 192 */
980};
981
982static inline unsigned int size_index_elem(unsigned int bytes)
983{
984 return (bytes - 1) / 8;
985}
986
987/*
988 * Find the kmem_cache structure that serves a given size of
989 * allocation
990 */
991struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
992{
993 unsigned int index;
994
995 if (unlikely(size > KMALLOC_MAX_SIZE)) {
996 WARN_ON_ONCE(!(flags & __GFP_NOWARN));
997 return NULL;
998 }
999
1000 if (size <= 192) {
1001 if (!size)
1002 return ZERO_SIZE_PTR;
1003
1004 index = size_index[size_index_elem(size)];
1005 } else
1006 index = fls(size - 1);
1007
1008#ifdef CONFIG_ZONE_DMA
1009 if (unlikely((flags & GFP_DMA)))
1010 return kmalloc_dma_caches[index];
1011
1012#endif
1013 return kmalloc_caches[index];
1014}
1015
1016/*
1017 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
1018 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
1019 * kmalloc-67108864.
1020 */
1021const struct kmalloc_info_struct kmalloc_info[] __initconst = {
1022 {NULL, 0}, {"kmalloc-96", 96},
1023 {"kmalloc-192", 192}, {"kmalloc-8", 8},
1024 {"kmalloc-16", 16}, {"kmalloc-32", 32},
1025 {"kmalloc-64", 64}, {"kmalloc-128", 128},
1026 {"kmalloc-256", 256}, {"kmalloc-512", 512},
1027 {"kmalloc-1024", 1024}, {"kmalloc-2048", 2048},
1028 {"kmalloc-4096", 4096}, {"kmalloc-8192", 8192},
1029 {"kmalloc-16384", 16384}, {"kmalloc-32768", 32768},
1030 {"kmalloc-65536", 65536}, {"kmalloc-131072", 131072},
1031 {"kmalloc-262144", 262144}, {"kmalloc-524288", 524288},
1032 {"kmalloc-1048576", 1048576}, {"kmalloc-2097152", 2097152},
1033 {"kmalloc-4194304", 4194304}, {"kmalloc-8388608", 8388608},
1034 {"kmalloc-16777216", 16777216}, {"kmalloc-33554432", 33554432},
1035 {"kmalloc-67108864", 67108864}
1036};
1037
1038/*
1039 * Patch up the size_index table if we have strange large alignment
1040 * requirements for the kmalloc array. This is only the case for
1041 * MIPS it seems. The standard arches will not generate any code here.
1042 *
1043 * Largest permitted alignment is 256 bytes due to the way we
1044 * handle the index determination for the smaller caches.
1045 *
1046 * Make sure that nothing crazy happens if someone starts tinkering
1047 * around with ARCH_KMALLOC_MINALIGN
1048 */
1049void __init setup_kmalloc_cache_index_table(void)
1050{
1051 unsigned int i;
1052
1053 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
1054 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
1055
1056 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
1057 unsigned int elem = size_index_elem(i);
1058
1059 if (elem >= ARRAY_SIZE(size_index))
1060 break;
1061 size_index[elem] = KMALLOC_SHIFT_LOW;
1062 }
1063
1064 if (KMALLOC_MIN_SIZE >= 64) {
1065 /*
1066 * The 96 byte size cache is not used if the alignment
1067 * is 64 byte.
1068 */
1069 for (i = 64 + 8; i <= 96; i += 8)
1070 size_index[size_index_elem(i)] = 7;
1071
1072 }
1073
1074 if (KMALLOC_MIN_SIZE >= 128) {
1075 /*
1076 * The 192 byte sized cache is not used if the alignment
1077 * is 128 byte. Redirect kmalloc to use the 256 byte cache
1078 * instead.
1079 */
1080 for (i = 128 + 8; i <= 192; i += 8)
1081 size_index[size_index_elem(i)] = 8;
1082 }
1083}
1084
1085static void __init new_kmalloc_cache(int idx, slab_flags_t flags)
1086{
1087 kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name,
1088 kmalloc_info[idx].size, flags, 0,
1089 kmalloc_info[idx].size);
1090}
1091
1092/*
1093 * Create the kmalloc array. Some of the regular kmalloc arrays
1094 * may already have been created because they were needed to
1095 * enable allocations for slab creation.
1096 */
1097void __init create_kmalloc_caches(slab_flags_t flags)
1098{
1099 int i;
1100
1101 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
1102 if (!kmalloc_caches[i])
1103 new_kmalloc_cache(i, flags);
1104
1105 /*
1106 * Caches that are not of the two-to-the-power-of size.
1107 * These have to be created immediately after the
1108 * earlier power of two caches
1109 */
1110 if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
1111 new_kmalloc_cache(1, flags);
1112 if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
1113 new_kmalloc_cache(2, flags);
1114 }
1115
1116 /* Kmalloc array is now usable */
1117 slab_state = UP;
1118
1119#ifdef CONFIG_ZONE_DMA
1120 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
1121 struct kmem_cache *s = kmalloc_caches[i];
1122
1123 if (s) {
1124 unsigned int size = kmalloc_size(i);
1125 char *n = kasprintf(GFP_NOWAIT,
1126 "dma-kmalloc-%u", size);
1127
1128 BUG_ON(!n);
1129 kmalloc_dma_caches[i] = create_kmalloc_cache(n,
1130 size, SLAB_CACHE_DMA | flags, 0, 0);
1131 }
1132 }
1133#endif
1134}
1135#endif /* !CONFIG_SLOB */
1136
1137/*
1138 * To avoid unnecessary overhead, we pass through large allocation requests
1139 * directly to the page allocator. We use __GFP_COMP, because we will need to
1140 * know the allocation order to free the pages properly in kfree.
1141 */
1142void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
1143{
1144 void *ret;
1145 struct page *page;
1146
1147 flags |= __GFP_COMP;
1148 page = alloc_pages(flags, order);
1149 ret = page ? page_address(page) : NULL;
1150 kmemleak_alloc(ret, size, 1, flags);
1151 kasan_kmalloc_large(ret, size, flags);
1152 return ret;
1153}
1154EXPORT_SYMBOL(kmalloc_order);
1155
1156#ifdef CONFIG_TRACING
1157void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
1158{
1159 void *ret = kmalloc_order(size, flags, order);
1160 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
1161 return ret;
1162}
1163EXPORT_SYMBOL(kmalloc_order_trace);
1164#endif
1165
1166#ifdef CONFIG_SLAB_FREELIST_RANDOM
1167/* Randomize a generic freelist */
1168static void freelist_randomize(struct rnd_state *state, unsigned int *list,
1169 unsigned int count)
1170{
1171 unsigned int rand;
1172 unsigned int i;
1173
1174 for (i = 0; i < count; i++)
1175 list[i] = i;
1176
1177 /* Fisher-Yates shuffle */
1178 for (i = count - 1; i > 0; i--) {
1179 rand = prandom_u32_state(state);
1180 rand %= (i + 1);
1181 swap(list[i], list[rand]);
1182 }
1183}
1184
1185/* Create a random sequence per cache */
1186int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
1187 gfp_t gfp)
1188{
1189 struct rnd_state state;
1190
1191 if (count < 2 || cachep->random_seq)
1192 return 0;
1193
1194 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
1195 if (!cachep->random_seq)
1196 return -ENOMEM;
1197
1198 /* Get best entropy at this stage of boot */
1199 prandom_seed_state(&state, get_random_long());
1200
1201 freelist_randomize(&state, cachep->random_seq, count);
1202 return 0;
1203}
1204
1205/* Destroy the per-cache random freelist sequence */
1206void cache_random_seq_destroy(struct kmem_cache *cachep)
1207{
1208 kfree(cachep->random_seq);
1209 cachep->random_seq = NULL;
1210}
1211#endif /* CONFIG_SLAB_FREELIST_RANDOM */
1212
1213#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
1214#ifdef CONFIG_SLAB
1215#define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR)
1216#else
1217#define SLABINFO_RIGHTS S_IRUSR
1218#endif
1219
1220static void print_slabinfo_header(struct seq_file *m)
1221{
1222 /*
1223 * Output format version, so at least we can change it
1224 * without _too_ many complaints.
1225 */
1226#ifdef CONFIG_DEBUG_SLAB
1227 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
1228#else
1229 seq_puts(m, "slabinfo - version: 2.1\n");
1230#endif
1231 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
1232 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
1233 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
1234#ifdef CONFIG_DEBUG_SLAB
1235 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
1236 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
1237#endif
1238 seq_putc(m, '\n');
1239}
1240
1241void *slab_start(struct seq_file *m, loff_t *pos)
1242{
1243 mutex_lock(&slab_mutex);
1244 return seq_list_start(&slab_root_caches, *pos);
1245}
1246
1247void *slab_next(struct seq_file *m, void *p, loff_t *pos)
1248{
1249 return seq_list_next(p, &slab_root_caches, pos);
1250}
1251
1252void slab_stop(struct seq_file *m, void *p)
1253{
1254 mutex_unlock(&slab_mutex);
1255}
1256
1257static void
1258memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
1259{
1260 struct kmem_cache *c;
1261 struct slabinfo sinfo;
1262
1263 if (!is_root_cache(s))
1264 return;
1265
1266 for_each_memcg_cache(c, s) {
1267 memset(&sinfo, 0, sizeof(sinfo));
1268 get_slabinfo(c, &sinfo);
1269
1270 info->active_slabs += sinfo.active_slabs;
1271 info->num_slabs += sinfo.num_slabs;
1272 info->shared_avail += sinfo.shared_avail;
1273 info->active_objs += sinfo.active_objs;
1274 info->num_objs += sinfo.num_objs;
1275 }
1276}
1277
1278static void cache_show(struct kmem_cache *s, struct seq_file *m)
1279{
1280 struct slabinfo sinfo;
1281
1282 memset(&sinfo, 0, sizeof(sinfo));
1283 get_slabinfo(s, &sinfo);
1284
1285 memcg_accumulate_slabinfo(s, &sinfo);
1286
1287 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
1288 cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
1289 sinfo.objects_per_slab, (1 << sinfo.cache_order));
1290
1291 seq_printf(m, " : tunables %4u %4u %4u",
1292 sinfo.limit, sinfo.batchcount, sinfo.shared);
1293 seq_printf(m, " : slabdata %6lu %6lu %6lu",
1294 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
1295 slabinfo_show_stats(m, s);
1296 seq_putc(m, '\n');
1297}
1298
1299static int slab_show(struct seq_file *m, void *p)
1300{
1301 struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node);
1302
1303 if (p == slab_root_caches.next)
1304 print_slabinfo_header(m);
1305 cache_show(s, m);
1306 return 0;
1307}
1308
1309void dump_unreclaimable_slab(void)
1310{
1311 struct kmem_cache *s, *s2;
1312 struct slabinfo sinfo;
1313
1314 /*
1315 * Here acquiring slab_mutex is risky since we don't prefer to get
1316 * sleep in oom path. But, without mutex hold, it may introduce a
1317 * risk of crash.
1318 * Use mutex_trylock to protect the list traverse, dump nothing
1319 * without acquiring the mutex.
1320 */
1321 if (!mutex_trylock(&slab_mutex)) {
1322 pr_warn("excessive unreclaimable slab but cannot dump stats\n");
1323 return;
1324 }
1325
1326 pr_info("Unreclaimable slab info:\n");
1327 pr_info("Name Used Total\n");
1328
1329 list_for_each_entry_safe(s, s2, &slab_caches, list) {
1330 if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT))
1331 continue;
1332
1333 get_slabinfo(s, &sinfo);
1334
1335 if (sinfo.num_objs > 0)
1336 pr_info("%-17s %10luKB %10luKB\n", cache_name(s),
1337 (sinfo.active_objs * s->size) / 1024,
1338 (sinfo.num_objs * s->size) / 1024);
1339 }
1340 mutex_unlock(&slab_mutex);
1341}
1342
1343#if defined(CONFIG_MEMCG)
1344void *memcg_slab_start(struct seq_file *m, loff_t *pos)
1345{
1346 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
1347
1348 mutex_lock(&slab_mutex);
1349 return seq_list_start(&memcg->kmem_caches, *pos);
1350}
1351
1352void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos)
1353{
1354 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
1355
1356 return seq_list_next(p, &memcg->kmem_caches, pos);
1357}
1358
1359void memcg_slab_stop(struct seq_file *m, void *p)
1360{
1361 mutex_unlock(&slab_mutex);
1362}
1363
1364int memcg_slab_show(struct seq_file *m, void *p)
1365{
1366 struct kmem_cache *s = list_entry(p, struct kmem_cache,
1367 memcg_params.kmem_caches_node);
1368 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
1369
1370 if (p == memcg->kmem_caches.next)
1371 print_slabinfo_header(m);
1372 cache_show(s, m);
1373 return 0;
1374}
1375#endif
1376
1377/*
1378 * slabinfo_op - iterator that generates /proc/slabinfo
1379 *
1380 * Output layout:
1381 * cache-name
1382 * num-active-objs
1383 * total-objs
1384 * object size
1385 * num-active-slabs
1386 * total-slabs
1387 * num-pages-per-slab
1388 * + further values on SMP and with statistics enabled
1389 */
1390static const struct seq_operations slabinfo_op = {
1391 .start = slab_start,
1392 .next = slab_next,
1393 .stop = slab_stop,
1394 .show = slab_show,
1395};
1396
1397static int slabinfo_open(struct inode *inode, struct file *file)
1398{
1399 return seq_open(file, &slabinfo_op);
1400}
1401
1402static const struct file_operations proc_slabinfo_operations = {
1403 .open = slabinfo_open,
1404 .read = seq_read,
1405 .write = slabinfo_write,
1406 .llseek = seq_lseek,
1407 .release = seq_release,
1408};
1409
1410static int __init slab_proc_init(void)
1411{
1412 proc_create("slabinfo", SLABINFO_RIGHTS, NULL,
1413 &proc_slabinfo_operations);
1414 return 0;
1415}
1416module_init(slab_proc_init);
1417#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
1418
1419static __always_inline void *__do_krealloc(const void *p, size_t new_size,
1420 gfp_t flags)
1421{
1422 void *ret;
1423 size_t ks = 0;
1424
1425 if (p)
1426 ks = ksize(p);
1427
1428 if (ks >= new_size) {
1429 kasan_krealloc((void *)p, new_size, flags);
1430 return (void *)p;
1431 }
1432
1433 ret = kmalloc_track_caller(new_size, flags);
1434 if (ret && p)
1435 memcpy(ret, p, ks);
1436
1437 return ret;
1438}
1439
1440/**
1441 * __krealloc - like krealloc() but don't free @p.
1442 * @p: object to reallocate memory for.
1443 * @new_size: how many bytes of memory are required.
1444 * @flags: the type of memory to allocate.
1445 *
1446 * This function is like krealloc() except it never frees the originally
1447 * allocated buffer. Use this if you don't want to free the buffer immediately
1448 * like, for example, with RCU.
1449 */
1450void *__krealloc(const void *p, size_t new_size, gfp_t flags)
1451{
1452 if (unlikely(!new_size))
1453 return ZERO_SIZE_PTR;
1454
1455 return __do_krealloc(p, new_size, flags);
1456
1457}
1458EXPORT_SYMBOL(__krealloc);
1459
1460/**
1461 * krealloc - reallocate memory. The contents will remain unchanged.
1462 * @p: object to reallocate memory for.
1463 * @new_size: how many bytes of memory are required.
1464 * @flags: the type of memory to allocate.
1465 *
1466 * The contents of the object pointed to are preserved up to the
1467 * lesser of the new and old sizes. If @p is %NULL, krealloc()
1468 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
1469 * %NULL pointer, the object pointed to is freed.
1470 */
1471void *krealloc(const void *p, size_t new_size, gfp_t flags)
1472{
1473 void *ret;
1474
1475 if (unlikely(!new_size)) {
1476 kfree(p);
1477 return ZERO_SIZE_PTR;
1478 }
1479
1480 ret = __do_krealloc(p, new_size, flags);
1481 if (ret && p != ret)
1482 kfree(p);
1483
1484 return ret;
1485}
1486EXPORT_SYMBOL(krealloc);
1487
1488/**
1489 * kzfree - like kfree but zero memory
1490 * @p: object to free memory of
1491 *
1492 * The memory of the object @p points to is zeroed before freed.
1493 * If @p is %NULL, kzfree() does nothing.
1494 *
1495 * Note: this function zeroes the whole allocated buffer which can be a good
1496 * deal bigger than the requested buffer size passed to kmalloc(). So be
1497 * careful when using this function in performance sensitive code.
1498 */
1499void kzfree(const void *p)
1500{
1501 size_t ks;
1502 void *mem = (void *)p;
1503
1504 if (unlikely(ZERO_OR_NULL_PTR(mem)))
1505 return;
1506 ks = ksize(mem);
1507 memset(mem, 0, ks);
1508 kfree(mem);
1509}
1510EXPORT_SYMBOL(kzfree);
1511
1512/* Tracepoints definitions. */
1513EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1514EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1515EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
1516EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
1517EXPORT_TRACEPOINT_SYMBOL(kfree);
1518EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1519
1520int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
1521{
1522 if (__should_failslab(s, gfpflags))
1523 return -ENOMEM;
1524 return 0;
1525}
1526ALLOW_ERROR_INJECTION(should_failslab, ERRNO);