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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
4 */
5#include <linux/mm.h>
6#include <linux/swap.h>
7#include <linux/bio.h>
8#include <linux/blkdev.h>
9#include <linux/uio.h>
10#include <linux/iocontext.h>
11#include <linux/slab.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/export.h>
15#include <linux/mempool.h>
16#include <linux/workqueue.h>
17#include <linux/cgroup.h>
18#include <linux/highmem.h>
19#include <linux/blk-crypto.h>
20#include <linux/xarray.h>
21
22#include <trace/events/block.h>
23#include "blk.h"
24#include "blk-rq-qos.h"
25#include "blk-cgroup.h"
26
27#define ALLOC_CACHE_THRESHOLD 16
28#define ALLOC_CACHE_MAX 256
29
30struct bio_alloc_cache {
31 struct bio *free_list;
32 struct bio *free_list_irq;
33 unsigned int nr;
34 unsigned int nr_irq;
35};
36
37static struct biovec_slab {
38 int nr_vecs;
39 char *name;
40 struct kmem_cache *slab;
41} bvec_slabs[] __read_mostly = {
42 { .nr_vecs = 16, .name = "biovec-16" },
43 { .nr_vecs = 64, .name = "biovec-64" },
44 { .nr_vecs = 128, .name = "biovec-128" },
45 { .nr_vecs = BIO_MAX_VECS, .name = "biovec-max" },
46};
47
48static struct biovec_slab *biovec_slab(unsigned short nr_vecs)
49{
50 switch (nr_vecs) {
51 /* smaller bios use inline vecs */
52 case 5 ... 16:
53 return &bvec_slabs[0];
54 case 17 ... 64:
55 return &bvec_slabs[1];
56 case 65 ... 128:
57 return &bvec_slabs[2];
58 case 129 ... BIO_MAX_VECS:
59 return &bvec_slabs[3];
60 default:
61 BUG();
62 return NULL;
63 }
64}
65
66/*
67 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
68 * IO code that does not need private memory pools.
69 */
70struct bio_set fs_bio_set;
71EXPORT_SYMBOL(fs_bio_set);
72
73/*
74 * Our slab pool management
75 */
76struct bio_slab {
77 struct kmem_cache *slab;
78 unsigned int slab_ref;
79 unsigned int slab_size;
80 char name[8];
81};
82static DEFINE_MUTEX(bio_slab_lock);
83static DEFINE_XARRAY(bio_slabs);
84
85static struct bio_slab *create_bio_slab(unsigned int size)
86{
87 struct bio_slab *bslab = kzalloc(sizeof(*bslab), GFP_KERNEL);
88
89 if (!bslab)
90 return NULL;
91
92 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size);
93 bslab->slab = kmem_cache_create(bslab->name, size,
94 ARCH_KMALLOC_MINALIGN,
95 SLAB_HWCACHE_ALIGN | SLAB_TYPESAFE_BY_RCU, NULL);
96 if (!bslab->slab)
97 goto fail_alloc_slab;
98
99 bslab->slab_ref = 1;
100 bslab->slab_size = size;
101
102 if (!xa_err(xa_store(&bio_slabs, size, bslab, GFP_KERNEL)))
103 return bslab;
104
105 kmem_cache_destroy(bslab->slab);
106
107fail_alloc_slab:
108 kfree(bslab);
109 return NULL;
110}
111
112static inline unsigned int bs_bio_slab_size(struct bio_set *bs)
113{
114 return bs->front_pad + sizeof(struct bio) + bs->back_pad;
115}
116
117static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs)
118{
119 unsigned int size = bs_bio_slab_size(bs);
120 struct bio_slab *bslab;
121
122 mutex_lock(&bio_slab_lock);
123 bslab = xa_load(&bio_slabs, size);
124 if (bslab)
125 bslab->slab_ref++;
126 else
127 bslab = create_bio_slab(size);
128 mutex_unlock(&bio_slab_lock);
129
130 if (bslab)
131 return bslab->slab;
132 return NULL;
133}
134
135static void bio_put_slab(struct bio_set *bs)
136{
137 struct bio_slab *bslab = NULL;
138 unsigned int slab_size = bs_bio_slab_size(bs);
139
140 mutex_lock(&bio_slab_lock);
141
142 bslab = xa_load(&bio_slabs, slab_size);
143 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
144 goto out;
145
146 WARN_ON_ONCE(bslab->slab != bs->bio_slab);
147
148 WARN_ON(!bslab->slab_ref);
149
150 if (--bslab->slab_ref)
151 goto out;
152
153 xa_erase(&bio_slabs, slab_size);
154
155 kmem_cache_destroy(bslab->slab);
156 kfree(bslab);
157
158out:
159 mutex_unlock(&bio_slab_lock);
160}
161
162void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs)
163{
164 BUG_ON(nr_vecs > BIO_MAX_VECS);
165
166 if (nr_vecs == BIO_MAX_VECS)
167 mempool_free(bv, pool);
168 else if (nr_vecs > BIO_INLINE_VECS)
169 kmem_cache_free(biovec_slab(nr_vecs)->slab, bv);
170}
171
172/*
173 * Make the first allocation restricted and don't dump info on allocation
174 * failures, since we'll fall back to the mempool in case of failure.
175 */
176static inline gfp_t bvec_alloc_gfp(gfp_t gfp)
177{
178 return (gfp & ~(__GFP_DIRECT_RECLAIM | __GFP_IO)) |
179 __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
180}
181
182struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,
183 gfp_t gfp_mask)
184{
185 struct biovec_slab *bvs = biovec_slab(*nr_vecs);
186
187 if (WARN_ON_ONCE(!bvs))
188 return NULL;
189
190 /*
191 * Upgrade the nr_vecs request to take full advantage of the allocation.
192 * We also rely on this in the bvec_free path.
193 */
194 *nr_vecs = bvs->nr_vecs;
195
196 /*
197 * Try a slab allocation first for all smaller allocations. If that
198 * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool.
199 * The mempool is sized to handle up to BIO_MAX_VECS entries.
200 */
201 if (*nr_vecs < BIO_MAX_VECS) {
202 struct bio_vec *bvl;
203
204 bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask));
205 if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM))
206 return bvl;
207 *nr_vecs = BIO_MAX_VECS;
208 }
209
210 return mempool_alloc(pool, gfp_mask);
211}
212
213void bio_uninit(struct bio *bio)
214{
215#ifdef CONFIG_BLK_CGROUP
216 if (bio->bi_blkg) {
217 blkg_put(bio->bi_blkg);
218 bio->bi_blkg = NULL;
219 }
220#endif
221 if (bio_integrity(bio))
222 bio_integrity_free(bio);
223
224 bio_crypt_free_ctx(bio);
225}
226EXPORT_SYMBOL(bio_uninit);
227
228static void bio_free(struct bio *bio)
229{
230 struct bio_set *bs = bio->bi_pool;
231 void *p = bio;
232
233 WARN_ON_ONCE(!bs);
234
235 bio_uninit(bio);
236 bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs);
237 mempool_free(p - bs->front_pad, &bs->bio_pool);
238}
239
240/*
241 * Users of this function have their own bio allocation. Subsequently,
242 * they must remember to pair any call to bio_init() with bio_uninit()
243 * when IO has completed, or when the bio is released.
244 */
245void bio_init(struct bio *bio, struct block_device *bdev, struct bio_vec *table,
246 unsigned short max_vecs, blk_opf_t opf)
247{
248 bio->bi_next = NULL;
249 bio->bi_bdev = bdev;
250 bio->bi_opf = opf;
251 bio->bi_flags = 0;
252 bio->bi_ioprio = 0;
253 bio->bi_write_hint = 0;
254 bio->bi_status = 0;
255 bio->bi_iter.bi_sector = 0;
256 bio->bi_iter.bi_size = 0;
257 bio->bi_iter.bi_idx = 0;
258 bio->bi_iter.bi_bvec_done = 0;
259 bio->bi_end_io = NULL;
260 bio->bi_private = NULL;
261#ifdef CONFIG_BLK_CGROUP
262 bio->bi_blkg = NULL;
263 bio->bi_issue.value = 0;
264 if (bdev)
265 bio_associate_blkg(bio);
266#ifdef CONFIG_BLK_CGROUP_IOCOST
267 bio->bi_iocost_cost = 0;
268#endif
269#endif
270#ifdef CONFIG_BLK_INLINE_ENCRYPTION
271 bio->bi_crypt_context = NULL;
272#endif
273#ifdef CONFIG_BLK_DEV_INTEGRITY
274 bio->bi_integrity = NULL;
275#endif
276 bio->bi_vcnt = 0;
277
278 atomic_set(&bio->__bi_remaining, 1);
279 atomic_set(&bio->__bi_cnt, 1);
280 bio->bi_cookie = BLK_QC_T_NONE;
281
282 bio->bi_max_vecs = max_vecs;
283 bio->bi_io_vec = table;
284 bio->bi_pool = NULL;
285}
286EXPORT_SYMBOL(bio_init);
287
288/**
289 * bio_reset - reinitialize a bio
290 * @bio: bio to reset
291 * @bdev: block device to use the bio for
292 * @opf: operation and flags for bio
293 *
294 * Description:
295 * After calling bio_reset(), @bio will be in the same state as a freshly
296 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
297 * preserved are the ones that are initialized by bio_alloc_bioset(). See
298 * comment in struct bio.
299 */
300void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf)
301{
302 bio_uninit(bio);
303 memset(bio, 0, BIO_RESET_BYTES);
304 atomic_set(&bio->__bi_remaining, 1);
305 bio->bi_bdev = bdev;
306 if (bio->bi_bdev)
307 bio_associate_blkg(bio);
308 bio->bi_opf = opf;
309}
310EXPORT_SYMBOL(bio_reset);
311
312static struct bio *__bio_chain_endio(struct bio *bio)
313{
314 struct bio *parent = bio->bi_private;
315
316 if (bio->bi_status && !parent->bi_status)
317 parent->bi_status = bio->bi_status;
318 bio_put(bio);
319 return parent;
320}
321
322static void bio_chain_endio(struct bio *bio)
323{
324 bio_endio(__bio_chain_endio(bio));
325}
326
327/**
328 * bio_chain - chain bio completions
329 * @bio: the target bio
330 * @parent: the parent bio of @bio
331 *
332 * The caller won't have a bi_end_io called when @bio completes - instead,
333 * @parent's bi_end_io won't be called until both @parent and @bio have
334 * completed; the chained bio will also be freed when it completes.
335 *
336 * The caller must not set bi_private or bi_end_io in @bio.
337 */
338void bio_chain(struct bio *bio, struct bio *parent)
339{
340 BUG_ON(bio->bi_private || bio->bi_end_io);
341
342 bio->bi_private = parent;
343 bio->bi_end_io = bio_chain_endio;
344 bio_inc_remaining(parent);
345}
346EXPORT_SYMBOL(bio_chain);
347
348struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
349 unsigned int nr_pages, blk_opf_t opf, gfp_t gfp)
350{
351 struct bio *new = bio_alloc(bdev, nr_pages, opf, gfp);
352
353 if (bio) {
354 bio_chain(bio, new);
355 submit_bio(bio);
356 }
357
358 return new;
359}
360EXPORT_SYMBOL_GPL(blk_next_bio);
361
362static void bio_alloc_rescue(struct work_struct *work)
363{
364 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
365 struct bio *bio;
366
367 while (1) {
368 spin_lock(&bs->rescue_lock);
369 bio = bio_list_pop(&bs->rescue_list);
370 spin_unlock(&bs->rescue_lock);
371
372 if (!bio)
373 break;
374
375 submit_bio_noacct(bio);
376 }
377}
378
379static void punt_bios_to_rescuer(struct bio_set *bs)
380{
381 struct bio_list punt, nopunt;
382 struct bio *bio;
383
384 if (WARN_ON_ONCE(!bs->rescue_workqueue))
385 return;
386 /*
387 * In order to guarantee forward progress we must punt only bios that
388 * were allocated from this bio_set; otherwise, if there was a bio on
389 * there for a stacking driver higher up in the stack, processing it
390 * could require allocating bios from this bio_set, and doing that from
391 * our own rescuer would be bad.
392 *
393 * Since bio lists are singly linked, pop them all instead of trying to
394 * remove from the middle of the list:
395 */
396
397 bio_list_init(&punt);
398 bio_list_init(&nopunt);
399
400 while ((bio = bio_list_pop(¤t->bio_list[0])))
401 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
402 current->bio_list[0] = nopunt;
403
404 bio_list_init(&nopunt);
405 while ((bio = bio_list_pop(¤t->bio_list[1])))
406 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
407 current->bio_list[1] = nopunt;
408
409 spin_lock(&bs->rescue_lock);
410 bio_list_merge(&bs->rescue_list, &punt);
411 spin_unlock(&bs->rescue_lock);
412
413 queue_work(bs->rescue_workqueue, &bs->rescue_work);
414}
415
416static void bio_alloc_irq_cache_splice(struct bio_alloc_cache *cache)
417{
418 unsigned long flags;
419
420 /* cache->free_list must be empty */
421 if (WARN_ON_ONCE(cache->free_list))
422 return;
423
424 local_irq_save(flags);
425 cache->free_list = cache->free_list_irq;
426 cache->free_list_irq = NULL;
427 cache->nr += cache->nr_irq;
428 cache->nr_irq = 0;
429 local_irq_restore(flags);
430}
431
432static struct bio *bio_alloc_percpu_cache(struct block_device *bdev,
433 unsigned short nr_vecs, blk_opf_t opf, gfp_t gfp,
434 struct bio_set *bs)
435{
436 struct bio_alloc_cache *cache;
437 struct bio *bio;
438
439 cache = per_cpu_ptr(bs->cache, get_cpu());
440 if (!cache->free_list) {
441 if (READ_ONCE(cache->nr_irq) >= ALLOC_CACHE_THRESHOLD)
442 bio_alloc_irq_cache_splice(cache);
443 if (!cache->free_list) {
444 put_cpu();
445 return NULL;
446 }
447 }
448 bio = cache->free_list;
449 cache->free_list = bio->bi_next;
450 cache->nr--;
451 put_cpu();
452
453 bio_init(bio, bdev, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs, opf);
454 bio->bi_pool = bs;
455 return bio;
456}
457
458/**
459 * bio_alloc_bioset - allocate a bio for I/O
460 * @bdev: block device to allocate the bio for (can be %NULL)
461 * @nr_vecs: number of bvecs to pre-allocate
462 * @opf: operation and flags for bio
463 * @gfp_mask: the GFP_* mask given to the slab allocator
464 * @bs: the bio_set to allocate from.
465 *
466 * Allocate a bio from the mempools in @bs.
467 *
468 * If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to
469 * allocate a bio. This is due to the mempool guarantees. To make this work,
470 * callers must never allocate more than 1 bio at a time from the general pool.
471 * Callers that need to allocate more than 1 bio must always submit the
472 * previously allocated bio for IO before attempting to allocate a new one.
473 * Failure to do so can cause deadlocks under memory pressure.
474 *
475 * Note that when running under submit_bio_noacct() (i.e. any block driver),
476 * bios are not submitted until after you return - see the code in
477 * submit_bio_noacct() that converts recursion into iteration, to prevent
478 * stack overflows.
479 *
480 * This would normally mean allocating multiple bios under submit_bio_noacct()
481 * would be susceptible to deadlocks, but we have
482 * deadlock avoidance code that resubmits any blocked bios from a rescuer
483 * thread.
484 *
485 * However, we do not guarantee forward progress for allocations from other
486 * mempools. Doing multiple allocations from the same mempool under
487 * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad
488 * for per bio allocations.
489 *
490 * Returns: Pointer to new bio on success, NULL on failure.
491 */
492struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs,
493 blk_opf_t opf, gfp_t gfp_mask,
494 struct bio_set *bs)
495{
496 gfp_t saved_gfp = gfp_mask;
497 struct bio *bio;
498 void *p;
499
500 /* should not use nobvec bioset for nr_vecs > 0 */
501 if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && nr_vecs > 0))
502 return NULL;
503
504 if (opf & REQ_ALLOC_CACHE) {
505 if (bs->cache && nr_vecs <= BIO_INLINE_VECS) {
506 bio = bio_alloc_percpu_cache(bdev, nr_vecs, opf,
507 gfp_mask, bs);
508 if (bio)
509 return bio;
510 /*
511 * No cached bio available, bio returned below marked with
512 * REQ_ALLOC_CACHE to particpate in per-cpu alloc cache.
513 */
514 } else {
515 opf &= ~REQ_ALLOC_CACHE;
516 }
517 }
518
519 /*
520 * submit_bio_noacct() converts recursion to iteration; this means if
521 * we're running beneath it, any bios we allocate and submit will not be
522 * submitted (and thus freed) until after we return.
523 *
524 * This exposes us to a potential deadlock if we allocate multiple bios
525 * from the same bio_set() while running underneath submit_bio_noacct().
526 * If we were to allocate multiple bios (say a stacking block driver
527 * that was splitting bios), we would deadlock if we exhausted the
528 * mempool's reserve.
529 *
530 * We solve this, and guarantee forward progress, with a rescuer
531 * workqueue per bio_set. If we go to allocate and there are bios on
532 * current->bio_list, we first try the allocation without
533 * __GFP_DIRECT_RECLAIM; if that fails, we punt those bios we would be
534 * blocking to the rescuer workqueue before we retry with the original
535 * gfp_flags.
536 */
537 if (current->bio_list &&
538 (!bio_list_empty(¤t->bio_list[0]) ||
539 !bio_list_empty(¤t->bio_list[1])) &&
540 bs->rescue_workqueue)
541 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
542
543 p = mempool_alloc(&bs->bio_pool, gfp_mask);
544 if (!p && gfp_mask != saved_gfp) {
545 punt_bios_to_rescuer(bs);
546 gfp_mask = saved_gfp;
547 p = mempool_alloc(&bs->bio_pool, gfp_mask);
548 }
549 if (unlikely(!p))
550 return NULL;
551 if (!mempool_is_saturated(&bs->bio_pool))
552 opf &= ~REQ_ALLOC_CACHE;
553
554 bio = p + bs->front_pad;
555 if (nr_vecs > BIO_INLINE_VECS) {
556 struct bio_vec *bvl = NULL;
557
558 bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask);
559 if (!bvl && gfp_mask != saved_gfp) {
560 punt_bios_to_rescuer(bs);
561 gfp_mask = saved_gfp;
562 bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask);
563 }
564 if (unlikely(!bvl))
565 goto err_free;
566
567 bio_init(bio, bdev, bvl, nr_vecs, opf);
568 } else if (nr_vecs) {
569 bio_init(bio, bdev, bio->bi_inline_vecs, BIO_INLINE_VECS, opf);
570 } else {
571 bio_init(bio, bdev, NULL, 0, opf);
572 }
573
574 bio->bi_pool = bs;
575 return bio;
576
577err_free:
578 mempool_free(p, &bs->bio_pool);
579 return NULL;
580}
581EXPORT_SYMBOL(bio_alloc_bioset);
582
583/**
584 * bio_kmalloc - kmalloc a bio
585 * @nr_vecs: number of bio_vecs to allocate
586 * @gfp_mask: the GFP_* mask given to the slab allocator
587 *
588 * Use kmalloc to allocate a bio (including bvecs). The bio must be initialized
589 * using bio_init() before use. To free a bio returned from this function use
590 * kfree() after calling bio_uninit(). A bio returned from this function can
591 * be reused by calling bio_uninit() before calling bio_init() again.
592 *
593 * Note that unlike bio_alloc() or bio_alloc_bioset() allocations from this
594 * function are not backed by a mempool can fail. Do not use this function
595 * for allocations in the file system I/O path.
596 *
597 * Returns: Pointer to new bio on success, NULL on failure.
598 */
599struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask)
600{
601 struct bio *bio;
602
603 if (nr_vecs > UIO_MAXIOV)
604 return NULL;
605 return kmalloc(struct_size(bio, bi_inline_vecs, nr_vecs), gfp_mask);
606}
607EXPORT_SYMBOL(bio_kmalloc);
608
609void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
610{
611 struct bio_vec bv;
612 struct bvec_iter iter;
613
614 __bio_for_each_segment(bv, bio, iter, start)
615 memzero_bvec(&bv);
616}
617EXPORT_SYMBOL(zero_fill_bio_iter);
618
619/**
620 * bio_truncate - truncate the bio to small size of @new_size
621 * @bio: the bio to be truncated
622 * @new_size: new size for truncating the bio
623 *
624 * Description:
625 * Truncate the bio to new size of @new_size. If bio_op(bio) is
626 * REQ_OP_READ, zero the truncated part. This function should only
627 * be used for handling corner cases, such as bio eod.
628 */
629static void bio_truncate(struct bio *bio, unsigned new_size)
630{
631 struct bio_vec bv;
632 struct bvec_iter iter;
633 unsigned int done = 0;
634 bool truncated = false;
635
636 if (new_size >= bio->bi_iter.bi_size)
637 return;
638
639 if (bio_op(bio) != REQ_OP_READ)
640 goto exit;
641
642 bio_for_each_segment(bv, bio, iter) {
643 if (done + bv.bv_len > new_size) {
644 unsigned offset;
645
646 if (!truncated)
647 offset = new_size - done;
648 else
649 offset = 0;
650 zero_user(bv.bv_page, bv.bv_offset + offset,
651 bv.bv_len - offset);
652 truncated = true;
653 }
654 done += bv.bv_len;
655 }
656
657 exit:
658 /*
659 * Don't touch bvec table here and make it really immutable, since
660 * fs bio user has to retrieve all pages via bio_for_each_segment_all
661 * in its .end_bio() callback.
662 *
663 * It is enough to truncate bio by updating .bi_size since we can make
664 * correct bvec with the updated .bi_size for drivers.
665 */
666 bio->bi_iter.bi_size = new_size;
667}
668
669/**
670 * guard_bio_eod - truncate a BIO to fit the block device
671 * @bio: bio to truncate
672 *
673 * This allows us to do IO even on the odd last sectors of a device, even if the
674 * block size is some multiple of the physical sector size.
675 *
676 * We'll just truncate the bio to the size of the device, and clear the end of
677 * the buffer head manually. Truly out-of-range accesses will turn into actual
678 * I/O errors, this only handles the "we need to be able to do I/O at the final
679 * sector" case.
680 */
681void guard_bio_eod(struct bio *bio)
682{
683 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
684
685 if (!maxsector)
686 return;
687
688 /*
689 * If the *whole* IO is past the end of the device,
690 * let it through, and the IO layer will turn it into
691 * an EIO.
692 */
693 if (unlikely(bio->bi_iter.bi_sector >= maxsector))
694 return;
695
696 maxsector -= bio->bi_iter.bi_sector;
697 if (likely((bio->bi_iter.bi_size >> 9) <= maxsector))
698 return;
699
700 bio_truncate(bio, maxsector << 9);
701}
702
703static int __bio_alloc_cache_prune(struct bio_alloc_cache *cache,
704 unsigned int nr)
705{
706 unsigned int i = 0;
707 struct bio *bio;
708
709 while ((bio = cache->free_list) != NULL) {
710 cache->free_list = bio->bi_next;
711 cache->nr--;
712 bio_free(bio);
713 if (++i == nr)
714 break;
715 }
716 return i;
717}
718
719static void bio_alloc_cache_prune(struct bio_alloc_cache *cache,
720 unsigned int nr)
721{
722 nr -= __bio_alloc_cache_prune(cache, nr);
723 if (!READ_ONCE(cache->free_list)) {
724 bio_alloc_irq_cache_splice(cache);
725 __bio_alloc_cache_prune(cache, nr);
726 }
727}
728
729static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node)
730{
731 struct bio_set *bs;
732
733 bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead);
734 if (bs->cache) {
735 struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu);
736
737 bio_alloc_cache_prune(cache, -1U);
738 }
739 return 0;
740}
741
742static void bio_alloc_cache_destroy(struct bio_set *bs)
743{
744 int cpu;
745
746 if (!bs->cache)
747 return;
748
749 cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
750 for_each_possible_cpu(cpu) {
751 struct bio_alloc_cache *cache;
752
753 cache = per_cpu_ptr(bs->cache, cpu);
754 bio_alloc_cache_prune(cache, -1U);
755 }
756 free_percpu(bs->cache);
757 bs->cache = NULL;
758}
759
760static inline void bio_put_percpu_cache(struct bio *bio)
761{
762 struct bio_alloc_cache *cache;
763
764 cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu());
765 if (READ_ONCE(cache->nr_irq) + cache->nr > ALLOC_CACHE_MAX)
766 goto out_free;
767
768 if (in_task()) {
769 bio_uninit(bio);
770 bio->bi_next = cache->free_list;
771 /* Not necessary but helps not to iopoll already freed bios */
772 bio->bi_bdev = NULL;
773 cache->free_list = bio;
774 cache->nr++;
775 } else if (in_hardirq()) {
776 lockdep_assert_irqs_disabled();
777
778 bio_uninit(bio);
779 bio->bi_next = cache->free_list_irq;
780 cache->free_list_irq = bio;
781 cache->nr_irq++;
782 } else {
783 goto out_free;
784 }
785 put_cpu();
786 return;
787out_free:
788 put_cpu();
789 bio_free(bio);
790}
791
792/**
793 * bio_put - release a reference to a bio
794 * @bio: bio to release reference to
795 *
796 * Description:
797 * Put a reference to a &struct bio, either one you have gotten with
798 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.
799 **/
800void bio_put(struct bio *bio)
801{
802 if (unlikely(bio_flagged(bio, BIO_REFFED))) {
803 BUG_ON(!atomic_read(&bio->__bi_cnt));
804 if (!atomic_dec_and_test(&bio->__bi_cnt))
805 return;
806 }
807 if (bio->bi_opf & REQ_ALLOC_CACHE)
808 bio_put_percpu_cache(bio);
809 else
810 bio_free(bio);
811}
812EXPORT_SYMBOL(bio_put);
813
814static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp)
815{
816 bio_set_flag(bio, BIO_CLONED);
817 bio->bi_ioprio = bio_src->bi_ioprio;
818 bio->bi_write_hint = bio_src->bi_write_hint;
819 bio->bi_iter = bio_src->bi_iter;
820
821 if (bio->bi_bdev) {
822 if (bio->bi_bdev == bio_src->bi_bdev &&
823 bio_flagged(bio_src, BIO_REMAPPED))
824 bio_set_flag(bio, BIO_REMAPPED);
825 bio_clone_blkg_association(bio, bio_src);
826 }
827
828 if (bio_crypt_clone(bio, bio_src, gfp) < 0)
829 return -ENOMEM;
830 if (bio_integrity(bio_src) &&
831 bio_integrity_clone(bio, bio_src, gfp) < 0)
832 return -ENOMEM;
833 return 0;
834}
835
836/**
837 * bio_alloc_clone - clone a bio that shares the original bio's biovec
838 * @bdev: block_device to clone onto
839 * @bio_src: bio to clone from
840 * @gfp: allocation priority
841 * @bs: bio_set to allocate from
842 *
843 * Allocate a new bio that is a clone of @bio_src. The caller owns the returned
844 * bio, but not the actual data it points to.
845 *
846 * The caller must ensure that the return bio is not freed before @bio_src.
847 */
848struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src,
849 gfp_t gfp, struct bio_set *bs)
850{
851 struct bio *bio;
852
853 bio = bio_alloc_bioset(bdev, 0, bio_src->bi_opf, gfp, bs);
854 if (!bio)
855 return NULL;
856
857 if (__bio_clone(bio, bio_src, gfp) < 0) {
858 bio_put(bio);
859 return NULL;
860 }
861 bio->bi_io_vec = bio_src->bi_io_vec;
862
863 return bio;
864}
865EXPORT_SYMBOL(bio_alloc_clone);
866
867/**
868 * bio_init_clone - clone a bio that shares the original bio's biovec
869 * @bdev: block_device to clone onto
870 * @bio: bio to clone into
871 * @bio_src: bio to clone from
872 * @gfp: allocation priority
873 *
874 * Initialize a new bio in caller provided memory that is a clone of @bio_src.
875 * The caller owns the returned bio, but not the actual data it points to.
876 *
877 * The caller must ensure that @bio_src is not freed before @bio.
878 */
879int bio_init_clone(struct block_device *bdev, struct bio *bio,
880 struct bio *bio_src, gfp_t gfp)
881{
882 int ret;
883
884 bio_init(bio, bdev, bio_src->bi_io_vec, 0, bio_src->bi_opf);
885 ret = __bio_clone(bio, bio_src, gfp);
886 if (ret)
887 bio_uninit(bio);
888 return ret;
889}
890EXPORT_SYMBOL(bio_init_clone);
891
892/**
893 * bio_full - check if the bio is full
894 * @bio: bio to check
895 * @len: length of one segment to be added
896 *
897 * Return true if @bio is full and one segment with @len bytes can't be
898 * added to the bio, otherwise return false
899 */
900static inline bool bio_full(struct bio *bio, unsigned len)
901{
902 if (bio->bi_vcnt >= bio->bi_max_vecs)
903 return true;
904 if (bio->bi_iter.bi_size > UINT_MAX - len)
905 return true;
906 return false;
907}
908
909static bool bvec_try_merge_page(struct bio_vec *bv, struct page *page,
910 unsigned int len, unsigned int off, bool *same_page)
911{
912 size_t bv_end = bv->bv_offset + bv->bv_len;
913 phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1;
914 phys_addr_t page_addr = page_to_phys(page);
915
916 if (vec_end_addr + 1 != page_addr + off)
917 return false;
918 if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
919 return false;
920 if (!zone_device_pages_have_same_pgmap(bv->bv_page, page))
921 return false;
922
923 *same_page = ((vec_end_addr & PAGE_MASK) == page_addr);
924 if (!*same_page) {
925 if (IS_ENABLED(CONFIG_KMSAN))
926 return false;
927 if (bv->bv_page + bv_end / PAGE_SIZE != page + off / PAGE_SIZE)
928 return false;
929 }
930
931 bv->bv_len += len;
932 return true;
933}
934
935/*
936 * Try to merge a page into a segment, while obeying the hardware segment
937 * size limit. This is not for normal read/write bios, but for passthrough
938 * or Zone Append operations that we can't split.
939 */
940bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
941 struct page *page, unsigned len, unsigned offset,
942 bool *same_page)
943{
944 unsigned long mask = queue_segment_boundary(q);
945 phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset;
946 phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;
947
948 if ((addr1 | mask) != (addr2 | mask))
949 return false;
950 if (len > queue_max_segment_size(q) - bv->bv_len)
951 return false;
952 return bvec_try_merge_page(bv, page, len, offset, same_page);
953}
954
955/**
956 * bio_add_hw_page - attempt to add a page to a bio with hw constraints
957 * @q: the target queue
958 * @bio: destination bio
959 * @page: page to add
960 * @len: vec entry length
961 * @offset: vec entry offset
962 * @max_sectors: maximum number of sectors that can be added
963 * @same_page: return if the segment has been merged inside the same page
964 *
965 * Add a page to a bio while respecting the hardware max_sectors, max_segment
966 * and gap limitations.
967 */
968int bio_add_hw_page(struct request_queue *q, struct bio *bio,
969 struct page *page, unsigned int len, unsigned int offset,
970 unsigned int max_sectors, bool *same_page)
971{
972 unsigned int max_size = max_sectors << SECTOR_SHIFT;
973
974 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
975 return 0;
976
977 len = min3(len, max_size, queue_max_segment_size(q));
978 if (len > max_size - bio->bi_iter.bi_size)
979 return 0;
980
981 if (bio->bi_vcnt > 0) {
982 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
983
984 if (bvec_try_merge_hw_page(q, bv, page, len, offset,
985 same_page)) {
986 bio->bi_iter.bi_size += len;
987 return len;
988 }
989
990 if (bio->bi_vcnt >=
991 min(bio->bi_max_vecs, queue_max_segments(q)))
992 return 0;
993
994 /*
995 * If the queue doesn't support SG gaps and adding this segment
996 * would create a gap, disallow it.
997 */
998 if (bvec_gap_to_prev(&q->limits, bv, offset))
999 return 0;
1000 }
1001
1002 bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, offset);
1003 bio->bi_vcnt++;
1004 bio->bi_iter.bi_size += len;
1005 return len;
1006}
1007
1008/**
1009 * bio_add_pc_page - attempt to add page to passthrough bio
1010 * @q: the target queue
1011 * @bio: destination bio
1012 * @page: page to add
1013 * @len: vec entry length
1014 * @offset: vec entry offset
1015 *
1016 * Attempt to add a page to the bio_vec maplist. This can fail for a
1017 * number of reasons, such as the bio being full or target block device
1018 * limitations. The target block device must allow bio's up to PAGE_SIZE,
1019 * so it is always possible to add a single page to an empty bio.
1020 *
1021 * This should only be used by passthrough bios.
1022 */
1023int bio_add_pc_page(struct request_queue *q, struct bio *bio,
1024 struct page *page, unsigned int len, unsigned int offset)
1025{
1026 bool same_page = false;
1027 return bio_add_hw_page(q, bio, page, len, offset,
1028 queue_max_hw_sectors(q), &same_page);
1029}
1030EXPORT_SYMBOL(bio_add_pc_page);
1031
1032/**
1033 * bio_add_zone_append_page - attempt to add page to zone-append bio
1034 * @bio: destination bio
1035 * @page: page to add
1036 * @len: vec entry length
1037 * @offset: vec entry offset
1038 *
1039 * Attempt to add a page to the bio_vec maplist of a bio that will be submitted
1040 * for a zone-append request. This can fail for a number of reasons, such as the
1041 * bio being full or the target block device is not a zoned block device or
1042 * other limitations of the target block device. The target block device must
1043 * allow bio's up to PAGE_SIZE, so it is always possible to add a single page
1044 * to an empty bio.
1045 *
1046 * Returns: number of bytes added to the bio, or 0 in case of a failure.
1047 */
1048int bio_add_zone_append_page(struct bio *bio, struct page *page,
1049 unsigned int len, unsigned int offset)
1050{
1051 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1052 bool same_page = false;
1053
1054 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND))
1055 return 0;
1056
1057 if (WARN_ON_ONCE(!bdev_is_zoned(bio->bi_bdev)))
1058 return 0;
1059
1060 return bio_add_hw_page(q, bio, page, len, offset,
1061 queue_max_zone_append_sectors(q), &same_page);
1062}
1063EXPORT_SYMBOL_GPL(bio_add_zone_append_page);
1064
1065/**
1066 * __bio_add_page - add page(s) to a bio in a new segment
1067 * @bio: destination bio
1068 * @page: start page to add
1069 * @len: length of the data to add, may cross pages
1070 * @off: offset of the data relative to @page, may cross pages
1071 *
1072 * Add the data at @page + @off to @bio as a new bvec. The caller must ensure
1073 * that @bio has space for another bvec.
1074 */
1075void __bio_add_page(struct bio *bio, struct page *page,
1076 unsigned int len, unsigned int off)
1077{
1078 WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
1079 WARN_ON_ONCE(bio_full(bio, len));
1080
1081 bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, off);
1082 bio->bi_iter.bi_size += len;
1083 bio->bi_vcnt++;
1084}
1085EXPORT_SYMBOL_GPL(__bio_add_page);
1086
1087/**
1088 * bio_add_page - attempt to add page(s) to bio
1089 * @bio: destination bio
1090 * @page: start page to add
1091 * @len: vec entry length, may cross pages
1092 * @offset: vec entry offset relative to @page, may cross pages
1093 *
1094 * Attempt to add page(s) to the bio_vec maplist. This will only fail
1095 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
1096 */
1097int bio_add_page(struct bio *bio, struct page *page,
1098 unsigned int len, unsigned int offset)
1099{
1100 bool same_page = false;
1101
1102 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
1103 return 0;
1104 if (bio->bi_iter.bi_size > UINT_MAX - len)
1105 return 0;
1106
1107 if (bio->bi_vcnt > 0 &&
1108 bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1],
1109 page, len, offset, &same_page)) {
1110 bio->bi_iter.bi_size += len;
1111 return len;
1112 }
1113
1114 if (bio->bi_vcnt >= bio->bi_max_vecs)
1115 return 0;
1116 __bio_add_page(bio, page, len, offset);
1117 return len;
1118}
1119EXPORT_SYMBOL(bio_add_page);
1120
1121void bio_add_folio_nofail(struct bio *bio, struct folio *folio, size_t len,
1122 size_t off)
1123{
1124 WARN_ON_ONCE(len > UINT_MAX);
1125 WARN_ON_ONCE(off > UINT_MAX);
1126 __bio_add_page(bio, &folio->page, len, off);
1127}
1128
1129/**
1130 * bio_add_folio - Attempt to add part of a folio to a bio.
1131 * @bio: BIO to add to.
1132 * @folio: Folio to add.
1133 * @len: How many bytes from the folio to add.
1134 * @off: First byte in this folio to add.
1135 *
1136 * Filesystems that use folios can call this function instead of calling
1137 * bio_add_page() for each page in the folio. If @off is bigger than
1138 * PAGE_SIZE, this function can create a bio_vec that starts in a page
1139 * after the bv_page. BIOs do not support folios that are 4GiB or larger.
1140 *
1141 * Return: Whether the addition was successful.
1142 */
1143bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len,
1144 size_t off)
1145{
1146 if (len > UINT_MAX || off > UINT_MAX)
1147 return false;
1148 return bio_add_page(bio, &folio->page, len, off) > 0;
1149}
1150EXPORT_SYMBOL(bio_add_folio);
1151
1152void __bio_release_pages(struct bio *bio, bool mark_dirty)
1153{
1154 struct folio_iter fi;
1155
1156 bio_for_each_folio_all(fi, bio) {
1157 struct page *page;
1158 size_t nr_pages;
1159
1160 if (mark_dirty) {
1161 folio_lock(fi.folio);
1162 folio_mark_dirty(fi.folio);
1163 folio_unlock(fi.folio);
1164 }
1165 page = folio_page(fi.folio, fi.offset / PAGE_SIZE);
1166 nr_pages = (fi.offset + fi.length - 1) / PAGE_SIZE -
1167 fi.offset / PAGE_SIZE + 1;
1168 do {
1169 bio_release_page(bio, page++);
1170 } while (--nr_pages != 0);
1171 }
1172}
1173EXPORT_SYMBOL_GPL(__bio_release_pages);
1174
1175void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)
1176{
1177 size_t size = iov_iter_count(iter);
1178
1179 WARN_ON_ONCE(bio->bi_max_vecs);
1180
1181 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
1182 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1183 size_t max_sectors = queue_max_zone_append_sectors(q);
1184
1185 size = min(size, max_sectors << SECTOR_SHIFT);
1186 }
1187
1188 bio->bi_vcnt = iter->nr_segs;
1189 bio->bi_io_vec = (struct bio_vec *)iter->bvec;
1190 bio->bi_iter.bi_bvec_done = iter->iov_offset;
1191 bio->bi_iter.bi_size = size;
1192 bio_set_flag(bio, BIO_CLONED);
1193}
1194
1195static int bio_iov_add_page(struct bio *bio, struct page *page,
1196 unsigned int len, unsigned int offset)
1197{
1198 bool same_page = false;
1199
1200 if (WARN_ON_ONCE(bio->bi_iter.bi_size > UINT_MAX - len))
1201 return -EIO;
1202
1203 if (bio->bi_vcnt > 0 &&
1204 bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1],
1205 page, len, offset, &same_page)) {
1206 bio->bi_iter.bi_size += len;
1207 if (same_page)
1208 bio_release_page(bio, page);
1209 return 0;
1210 }
1211 __bio_add_page(bio, page, len, offset);
1212 return 0;
1213}
1214
1215static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page,
1216 unsigned int len, unsigned int offset)
1217{
1218 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1219 bool same_page = false;
1220
1221 if (bio_add_hw_page(q, bio, page, len, offset,
1222 queue_max_zone_append_sectors(q), &same_page) != len)
1223 return -EINVAL;
1224 if (same_page)
1225 bio_release_page(bio, page);
1226 return 0;
1227}
1228
1229#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
1230
1231/**
1232 * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
1233 * @bio: bio to add pages to
1234 * @iter: iov iterator describing the region to be mapped
1235 *
1236 * Extracts pages from *iter and appends them to @bio's bvec array. The pages
1237 * will have to be cleaned up in the way indicated by the BIO_PAGE_PINNED flag.
1238 * For a multi-segment *iter, this function only adds pages from the next
1239 * non-empty segment of the iov iterator.
1240 */
1241static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
1242{
1243 iov_iter_extraction_t extraction_flags = 0;
1244 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
1245 unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
1246 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
1247 struct page **pages = (struct page **)bv;
1248 ssize_t size, left;
1249 unsigned len, i = 0;
1250 size_t offset;
1251 int ret = 0;
1252
1253 /*
1254 * Move page array up in the allocated memory for the bio vecs as far as
1255 * possible so that we can start filling biovecs from the beginning
1256 * without overwriting the temporary page array.
1257 */
1258 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
1259 pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
1260
1261 if (bio->bi_bdev && blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue))
1262 extraction_flags |= ITER_ALLOW_P2PDMA;
1263
1264 /*
1265 * Each segment in the iov is required to be a block size multiple.
1266 * However, we may not be able to get the entire segment if it spans
1267 * more pages than bi_max_vecs allows, so we have to ALIGN_DOWN the
1268 * result to ensure the bio's total size is correct. The remainder of
1269 * the iov data will be picked up in the next bio iteration.
1270 */
1271 size = iov_iter_extract_pages(iter, &pages,
1272 UINT_MAX - bio->bi_iter.bi_size,
1273 nr_pages, extraction_flags, &offset);
1274 if (unlikely(size <= 0))
1275 return size ? size : -EFAULT;
1276
1277 nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE);
1278
1279 if (bio->bi_bdev) {
1280 size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1);
1281 iov_iter_revert(iter, trim);
1282 size -= trim;
1283 }
1284
1285 if (unlikely(!size)) {
1286 ret = -EFAULT;
1287 goto out;
1288 }
1289
1290 for (left = size, i = 0; left > 0; left -= len, i++) {
1291 struct page *page = pages[i];
1292
1293 len = min_t(size_t, PAGE_SIZE - offset, left);
1294 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
1295 ret = bio_iov_add_zone_append_page(bio, page, len,
1296 offset);
1297 if (ret)
1298 break;
1299 } else
1300 bio_iov_add_page(bio, page, len, offset);
1301
1302 offset = 0;
1303 }
1304
1305 iov_iter_revert(iter, left);
1306out:
1307 while (i < nr_pages)
1308 bio_release_page(bio, pages[i++]);
1309
1310 return ret;
1311}
1312
1313/**
1314 * bio_iov_iter_get_pages - add user or kernel pages to a bio
1315 * @bio: bio to add pages to
1316 * @iter: iov iterator describing the region to be added
1317 *
1318 * This takes either an iterator pointing to user memory, or one pointing to
1319 * kernel pages (BVEC iterator). If we're adding user pages, we pin them and
1320 * map them into the kernel. On IO completion, the caller should put those
1321 * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided
1322 * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs
1323 * to ensure the bvecs and pages stay referenced until the submitted I/O is
1324 * completed by a call to ->ki_complete() or returns with an error other than
1325 * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF
1326 * on IO completion. If it isn't, then pages should be released.
1327 *
1328 * The function tries, but does not guarantee, to pin as many pages as
1329 * fit into the bio, or are requested in @iter, whatever is smaller. If
1330 * MM encounters an error pinning the requested pages, it stops. Error
1331 * is returned only if 0 pages could be pinned.
1332 */
1333int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
1334{
1335 int ret = 0;
1336
1337 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
1338 return -EIO;
1339
1340 if (iov_iter_is_bvec(iter)) {
1341 bio_iov_bvec_set(bio, iter);
1342 iov_iter_advance(iter, bio->bi_iter.bi_size);
1343 return 0;
1344 }
1345
1346 if (iov_iter_extract_will_pin(iter))
1347 bio_set_flag(bio, BIO_PAGE_PINNED);
1348 do {
1349 ret = __bio_iov_iter_get_pages(bio, iter);
1350 } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));
1351
1352 return bio->bi_vcnt ? 0 : ret;
1353}
1354EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
1355
1356static void submit_bio_wait_endio(struct bio *bio)
1357{
1358 complete(bio->bi_private);
1359}
1360
1361/**
1362 * submit_bio_wait - submit a bio, and wait until it completes
1363 * @bio: The &struct bio which describes the I/O
1364 *
1365 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
1366 * bio_endio() on failure.
1367 *
1368 * WARNING: Unlike to how submit_bio() is usually used, this function does not
1369 * result in bio reference to be consumed. The caller must drop the reference
1370 * on his own.
1371 */
1372int submit_bio_wait(struct bio *bio)
1373{
1374 DECLARE_COMPLETION_ONSTACK_MAP(done,
1375 bio->bi_bdev->bd_disk->lockdep_map);
1376
1377 bio->bi_private = &done;
1378 bio->bi_end_io = submit_bio_wait_endio;
1379 bio->bi_opf |= REQ_SYNC;
1380 submit_bio(bio);
1381 blk_wait_io(&done);
1382
1383 return blk_status_to_errno(bio->bi_status);
1384}
1385EXPORT_SYMBOL(submit_bio_wait);
1386
1387void __bio_advance(struct bio *bio, unsigned bytes)
1388{
1389 if (bio_integrity(bio))
1390 bio_integrity_advance(bio, bytes);
1391
1392 bio_crypt_advance(bio, bytes);
1393 bio_advance_iter(bio, &bio->bi_iter, bytes);
1394}
1395EXPORT_SYMBOL(__bio_advance);
1396
1397void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
1398 struct bio *src, struct bvec_iter *src_iter)
1399{
1400 while (src_iter->bi_size && dst_iter->bi_size) {
1401 struct bio_vec src_bv = bio_iter_iovec(src, *src_iter);
1402 struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter);
1403 unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);
1404 void *src_buf = bvec_kmap_local(&src_bv);
1405 void *dst_buf = bvec_kmap_local(&dst_bv);
1406
1407 memcpy(dst_buf, src_buf, bytes);
1408
1409 kunmap_local(dst_buf);
1410 kunmap_local(src_buf);
1411
1412 bio_advance_iter_single(src, src_iter, bytes);
1413 bio_advance_iter_single(dst, dst_iter, bytes);
1414 }
1415}
1416EXPORT_SYMBOL(bio_copy_data_iter);
1417
1418/**
1419 * bio_copy_data - copy contents of data buffers from one bio to another
1420 * @src: source bio
1421 * @dst: destination bio
1422 *
1423 * Stops when it reaches the end of either @src or @dst - that is, copies
1424 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
1425 */
1426void bio_copy_data(struct bio *dst, struct bio *src)
1427{
1428 struct bvec_iter src_iter = src->bi_iter;
1429 struct bvec_iter dst_iter = dst->bi_iter;
1430
1431 bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
1432}
1433EXPORT_SYMBOL(bio_copy_data);
1434
1435void bio_free_pages(struct bio *bio)
1436{
1437 struct bio_vec *bvec;
1438 struct bvec_iter_all iter_all;
1439
1440 bio_for_each_segment_all(bvec, bio, iter_all)
1441 __free_page(bvec->bv_page);
1442}
1443EXPORT_SYMBOL(bio_free_pages);
1444
1445/*
1446 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1447 * for performing direct-IO in BIOs.
1448 *
1449 * The problem is that we cannot run folio_mark_dirty() from interrupt context
1450 * because the required locks are not interrupt-safe. So what we can do is to
1451 * mark the pages dirty _before_ performing IO. And in interrupt context,
1452 * check that the pages are still dirty. If so, fine. If not, redirty them
1453 * in process context.
1454 *
1455 * Note that this code is very hard to test under normal circumstances because
1456 * direct-io pins the pages with get_user_pages(). This makes
1457 * is_page_cache_freeable return false, and the VM will not clean the pages.
1458 * But other code (eg, flusher threads) could clean the pages if they are mapped
1459 * pagecache.
1460 *
1461 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1462 * deferred bio dirtying paths.
1463 */
1464
1465/*
1466 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1467 */
1468void bio_set_pages_dirty(struct bio *bio)
1469{
1470 struct folio_iter fi;
1471
1472 bio_for_each_folio_all(fi, bio) {
1473 folio_lock(fi.folio);
1474 folio_mark_dirty(fi.folio);
1475 folio_unlock(fi.folio);
1476 }
1477}
1478EXPORT_SYMBOL_GPL(bio_set_pages_dirty);
1479
1480/*
1481 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1482 * If they are, then fine. If, however, some pages are clean then they must
1483 * have been written out during the direct-IO read. So we take another ref on
1484 * the BIO and re-dirty the pages in process context.
1485 *
1486 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1487 * here on. It will unpin each page and will run one bio_put() against the
1488 * BIO.
1489 */
1490
1491static void bio_dirty_fn(struct work_struct *work);
1492
1493static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1494static DEFINE_SPINLOCK(bio_dirty_lock);
1495static struct bio *bio_dirty_list;
1496
1497/*
1498 * This runs in process context
1499 */
1500static void bio_dirty_fn(struct work_struct *work)
1501{
1502 struct bio *bio, *next;
1503
1504 spin_lock_irq(&bio_dirty_lock);
1505 next = bio_dirty_list;
1506 bio_dirty_list = NULL;
1507 spin_unlock_irq(&bio_dirty_lock);
1508
1509 while ((bio = next) != NULL) {
1510 next = bio->bi_private;
1511
1512 bio_release_pages(bio, true);
1513 bio_put(bio);
1514 }
1515}
1516
1517void bio_check_pages_dirty(struct bio *bio)
1518{
1519 struct folio_iter fi;
1520 unsigned long flags;
1521
1522 bio_for_each_folio_all(fi, bio) {
1523 if (!folio_test_dirty(fi.folio))
1524 goto defer;
1525 }
1526
1527 bio_release_pages(bio, false);
1528 bio_put(bio);
1529 return;
1530defer:
1531 spin_lock_irqsave(&bio_dirty_lock, flags);
1532 bio->bi_private = bio_dirty_list;
1533 bio_dirty_list = bio;
1534 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1535 schedule_work(&bio_dirty_work);
1536}
1537EXPORT_SYMBOL_GPL(bio_check_pages_dirty);
1538
1539static inline bool bio_remaining_done(struct bio *bio)
1540{
1541 /*
1542 * If we're not chaining, then ->__bi_remaining is always 1 and
1543 * we always end io on the first invocation.
1544 */
1545 if (!bio_flagged(bio, BIO_CHAIN))
1546 return true;
1547
1548 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1549
1550 if (atomic_dec_and_test(&bio->__bi_remaining)) {
1551 bio_clear_flag(bio, BIO_CHAIN);
1552 return true;
1553 }
1554
1555 return false;
1556}
1557
1558/**
1559 * bio_endio - end I/O on a bio
1560 * @bio: bio
1561 *
1562 * Description:
1563 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1564 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1565 * bio unless they own it and thus know that it has an end_io function.
1566 *
1567 * bio_endio() can be called several times on a bio that has been chained
1568 * using bio_chain(). The ->bi_end_io() function will only be called the
1569 * last time.
1570 **/
1571void bio_endio(struct bio *bio)
1572{
1573again:
1574 if (!bio_remaining_done(bio))
1575 return;
1576 if (!bio_integrity_endio(bio))
1577 return;
1578
1579 rq_qos_done_bio(bio);
1580
1581 if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
1582 trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio);
1583 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1584 }
1585
1586 /*
1587 * Need to have a real endio function for chained bios, otherwise
1588 * various corner cases will break (like stacking block devices that
1589 * save/restore bi_end_io) - however, we want to avoid unbounded
1590 * recursion and blowing the stack. Tail call optimization would
1591 * handle this, but compiling with frame pointers also disables
1592 * gcc's sibling call optimization.
1593 */
1594 if (bio->bi_end_io == bio_chain_endio) {
1595 bio = __bio_chain_endio(bio);
1596 goto again;
1597 }
1598
1599 blk_throtl_bio_endio(bio);
1600 /* release cgroup info */
1601 bio_uninit(bio);
1602 if (bio->bi_end_io)
1603 bio->bi_end_io(bio);
1604}
1605EXPORT_SYMBOL(bio_endio);
1606
1607/**
1608 * bio_split - split a bio
1609 * @bio: bio to split
1610 * @sectors: number of sectors to split from the front of @bio
1611 * @gfp: gfp mask
1612 * @bs: bio set to allocate from
1613 *
1614 * Allocates and returns a new bio which represents @sectors from the start of
1615 * @bio, and updates @bio to represent the remaining sectors.
1616 *
1617 * Unless this is a discard request the newly allocated bio will point
1618 * to @bio's bi_io_vec. It is the caller's responsibility to ensure that
1619 * neither @bio nor @bs are freed before the split bio.
1620 */
1621struct bio *bio_split(struct bio *bio, int sectors,
1622 gfp_t gfp, struct bio_set *bs)
1623{
1624 struct bio *split;
1625
1626 BUG_ON(sectors <= 0);
1627 BUG_ON(sectors >= bio_sectors(bio));
1628
1629 /* Zone append commands cannot be split */
1630 if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
1631 return NULL;
1632
1633 split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs);
1634 if (!split)
1635 return NULL;
1636
1637 split->bi_iter.bi_size = sectors << 9;
1638
1639 if (bio_integrity(split))
1640 bio_integrity_trim(split);
1641
1642 bio_advance(bio, split->bi_iter.bi_size);
1643
1644 if (bio_flagged(bio, BIO_TRACE_COMPLETION))
1645 bio_set_flag(split, BIO_TRACE_COMPLETION);
1646
1647 return split;
1648}
1649EXPORT_SYMBOL(bio_split);
1650
1651/**
1652 * bio_trim - trim a bio
1653 * @bio: bio to trim
1654 * @offset: number of sectors to trim from the front of @bio
1655 * @size: size we want to trim @bio to, in sectors
1656 *
1657 * This function is typically used for bios that are cloned and submitted
1658 * to the underlying device in parts.
1659 */
1660void bio_trim(struct bio *bio, sector_t offset, sector_t size)
1661{
1662 if (WARN_ON_ONCE(offset > BIO_MAX_SECTORS || size > BIO_MAX_SECTORS ||
1663 offset + size > bio_sectors(bio)))
1664 return;
1665
1666 size <<= 9;
1667 if (offset == 0 && size == bio->bi_iter.bi_size)
1668 return;
1669
1670 bio_advance(bio, offset << 9);
1671 bio->bi_iter.bi_size = size;
1672
1673 if (bio_integrity(bio))
1674 bio_integrity_trim(bio);
1675}
1676EXPORT_SYMBOL_GPL(bio_trim);
1677
1678/*
1679 * create memory pools for biovec's in a bio_set.
1680 * use the global biovec slabs created for general use.
1681 */
1682int biovec_init_pool(mempool_t *pool, int pool_entries)
1683{
1684 struct biovec_slab *bp = bvec_slabs + ARRAY_SIZE(bvec_slabs) - 1;
1685
1686 return mempool_init_slab_pool(pool, pool_entries, bp->slab);
1687}
1688
1689/*
1690 * bioset_exit - exit a bioset initialized with bioset_init()
1691 *
1692 * May be called on a zeroed but uninitialized bioset (i.e. allocated with
1693 * kzalloc()).
1694 */
1695void bioset_exit(struct bio_set *bs)
1696{
1697 bio_alloc_cache_destroy(bs);
1698 if (bs->rescue_workqueue)
1699 destroy_workqueue(bs->rescue_workqueue);
1700 bs->rescue_workqueue = NULL;
1701
1702 mempool_exit(&bs->bio_pool);
1703 mempool_exit(&bs->bvec_pool);
1704
1705 bioset_integrity_free(bs);
1706 if (bs->bio_slab)
1707 bio_put_slab(bs);
1708 bs->bio_slab = NULL;
1709}
1710EXPORT_SYMBOL(bioset_exit);
1711
1712/**
1713 * bioset_init - Initialize a bio_set
1714 * @bs: pool to initialize
1715 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1716 * @front_pad: Number of bytes to allocate in front of the returned bio
1717 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS
1718 * and %BIOSET_NEED_RESCUER
1719 *
1720 * Description:
1721 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1722 * to ask for a number of bytes to be allocated in front of the bio.
1723 * Front pad allocation is useful for embedding the bio inside
1724 * another structure, to avoid allocating extra data to go with the bio.
1725 * Note that the bio must be embedded at the END of that structure always,
1726 * or things will break badly.
1727 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated
1728 * for allocating iovecs. This pool is not needed e.g. for bio_init_clone().
1729 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used
1730 * to dispatch queued requests when the mempool runs out of space.
1731 *
1732 */
1733int bioset_init(struct bio_set *bs,
1734 unsigned int pool_size,
1735 unsigned int front_pad,
1736 int flags)
1737{
1738 bs->front_pad = front_pad;
1739 if (flags & BIOSET_NEED_BVECS)
1740 bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1741 else
1742 bs->back_pad = 0;
1743
1744 spin_lock_init(&bs->rescue_lock);
1745 bio_list_init(&bs->rescue_list);
1746 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1747
1748 bs->bio_slab = bio_find_or_create_slab(bs);
1749 if (!bs->bio_slab)
1750 return -ENOMEM;
1751
1752 if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))
1753 goto bad;
1754
1755 if ((flags & BIOSET_NEED_BVECS) &&
1756 biovec_init_pool(&bs->bvec_pool, pool_size))
1757 goto bad;
1758
1759 if (flags & BIOSET_NEED_RESCUER) {
1760 bs->rescue_workqueue = alloc_workqueue("bioset",
1761 WQ_MEM_RECLAIM, 0);
1762 if (!bs->rescue_workqueue)
1763 goto bad;
1764 }
1765 if (flags & BIOSET_PERCPU_CACHE) {
1766 bs->cache = alloc_percpu(struct bio_alloc_cache);
1767 if (!bs->cache)
1768 goto bad;
1769 cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
1770 }
1771
1772 return 0;
1773bad:
1774 bioset_exit(bs);
1775 return -ENOMEM;
1776}
1777EXPORT_SYMBOL(bioset_init);
1778
1779static int __init init_bio(void)
1780{
1781 int i;
1782
1783 BUILD_BUG_ON(BIO_FLAG_LAST > 8 * sizeof_field(struct bio, bi_flags));
1784
1785 bio_integrity_init();
1786
1787 for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) {
1788 struct biovec_slab *bvs = bvec_slabs + i;
1789
1790 bvs->slab = kmem_cache_create(bvs->name,
1791 bvs->nr_vecs * sizeof(struct bio_vec), 0,
1792 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
1793 }
1794
1795 cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL,
1796 bio_cpu_dead);
1797
1798 if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0,
1799 BIOSET_NEED_BVECS | BIOSET_PERCPU_CACHE))
1800 panic("bio: can't allocate bios\n");
1801
1802 if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE))
1803 panic("bio: can't create integrity pool\n");
1804
1805 return 0;
1806}
1807subsys_initcall(init_bio);