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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/sched/sysctl.h>
20#include <linux/blk-crypto.h>
21#include <linux/xarray.h>
22
23#include <trace/events/block.h>
24#include "blk.h"
25#include "blk-rq-qos.h"
26#include "blk-cgroup.h"
27
28#define ALLOC_CACHE_THRESHOLD 16
29#define ALLOC_CACHE_SLACK 64
30#define ALLOC_CACHE_MAX 256
31
32struct bio_alloc_cache {
33 struct bio *free_list;
34 struct bio *free_list_irq;
35 unsigned int nr;
36 unsigned int nr_irq;
37};
38
39static struct biovec_slab {
40 int nr_vecs;
41 char *name;
42 struct kmem_cache *slab;
43} bvec_slabs[] __read_mostly = {
44 { .nr_vecs = 16, .name = "biovec-16" },
45 { .nr_vecs = 64, .name = "biovec-64" },
46 { .nr_vecs = 128, .name = "biovec-128" },
47 { .nr_vecs = BIO_MAX_VECS, .name = "biovec-max" },
48};
49
50static struct biovec_slab *biovec_slab(unsigned short nr_vecs)
51{
52 switch (nr_vecs) {
53 /* smaller bios use inline vecs */
54 case 5 ... 16:
55 return &bvec_slabs[0];
56 case 17 ... 64:
57 return &bvec_slabs[1];
58 case 65 ... 128:
59 return &bvec_slabs[2];
60 case 129 ... BIO_MAX_VECS:
61 return &bvec_slabs[3];
62 default:
63 BUG();
64 return NULL;
65 }
66}
67
68/*
69 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
70 * IO code that does not need private memory pools.
71 */
72struct bio_set fs_bio_set;
73EXPORT_SYMBOL(fs_bio_set);
74
75/*
76 * Our slab pool management
77 */
78struct bio_slab {
79 struct kmem_cache *slab;
80 unsigned int slab_ref;
81 unsigned int slab_size;
82 char name[8];
83};
84static DEFINE_MUTEX(bio_slab_lock);
85static DEFINE_XARRAY(bio_slabs);
86
87static struct bio_slab *create_bio_slab(unsigned int size)
88{
89 struct bio_slab *bslab = kzalloc(sizeof(*bslab), GFP_KERNEL);
90
91 if (!bslab)
92 return NULL;
93
94 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size);
95 bslab->slab = kmem_cache_create(bslab->name, size,
96 ARCH_KMALLOC_MINALIGN,
97 SLAB_HWCACHE_ALIGN | SLAB_TYPESAFE_BY_RCU, NULL);
98 if (!bslab->slab)
99 goto fail_alloc_slab;
100
101 bslab->slab_ref = 1;
102 bslab->slab_size = size;
103
104 if (!xa_err(xa_store(&bio_slabs, size, bslab, GFP_KERNEL)))
105 return bslab;
106
107 kmem_cache_destroy(bslab->slab);
108
109fail_alloc_slab:
110 kfree(bslab);
111 return NULL;
112}
113
114static inline unsigned int bs_bio_slab_size(struct bio_set *bs)
115{
116 return bs->front_pad + sizeof(struct bio) + bs->back_pad;
117}
118
119static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs)
120{
121 unsigned int size = bs_bio_slab_size(bs);
122 struct bio_slab *bslab;
123
124 mutex_lock(&bio_slab_lock);
125 bslab = xa_load(&bio_slabs, size);
126 if (bslab)
127 bslab->slab_ref++;
128 else
129 bslab = create_bio_slab(size);
130 mutex_unlock(&bio_slab_lock);
131
132 if (bslab)
133 return bslab->slab;
134 return NULL;
135}
136
137static void bio_put_slab(struct bio_set *bs)
138{
139 struct bio_slab *bslab = NULL;
140 unsigned int slab_size = bs_bio_slab_size(bs);
141
142 mutex_lock(&bio_slab_lock);
143
144 bslab = xa_load(&bio_slabs, slab_size);
145 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
146 goto out;
147
148 WARN_ON_ONCE(bslab->slab != bs->bio_slab);
149
150 WARN_ON(!bslab->slab_ref);
151
152 if (--bslab->slab_ref)
153 goto out;
154
155 xa_erase(&bio_slabs, slab_size);
156
157 kmem_cache_destroy(bslab->slab);
158 kfree(bslab);
159
160out:
161 mutex_unlock(&bio_slab_lock);
162}
163
164void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs)
165{
166 BUG_ON(nr_vecs > BIO_MAX_VECS);
167
168 if (nr_vecs == BIO_MAX_VECS)
169 mempool_free(bv, pool);
170 else if (nr_vecs > BIO_INLINE_VECS)
171 kmem_cache_free(biovec_slab(nr_vecs)->slab, bv);
172}
173
174/*
175 * Make the first allocation restricted and don't dump info on allocation
176 * failures, since we'll fall back to the mempool in case of failure.
177 */
178static inline gfp_t bvec_alloc_gfp(gfp_t gfp)
179{
180 return (gfp & ~(__GFP_DIRECT_RECLAIM | __GFP_IO)) |
181 __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
182}
183
184struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,
185 gfp_t gfp_mask)
186{
187 struct biovec_slab *bvs = biovec_slab(*nr_vecs);
188
189 if (WARN_ON_ONCE(!bvs))
190 return NULL;
191
192 /*
193 * Upgrade the nr_vecs request to take full advantage of the allocation.
194 * We also rely on this in the bvec_free path.
195 */
196 *nr_vecs = bvs->nr_vecs;
197
198 /*
199 * Try a slab allocation first for all smaller allocations. If that
200 * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool.
201 * The mempool is sized to handle up to BIO_MAX_VECS entries.
202 */
203 if (*nr_vecs < BIO_MAX_VECS) {
204 struct bio_vec *bvl;
205
206 bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask));
207 if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM))
208 return bvl;
209 *nr_vecs = BIO_MAX_VECS;
210 }
211
212 return mempool_alloc(pool, gfp_mask);
213}
214
215void bio_uninit(struct bio *bio)
216{
217#ifdef CONFIG_BLK_CGROUP
218 if (bio->bi_blkg) {
219 blkg_put(bio->bi_blkg);
220 bio->bi_blkg = NULL;
221 }
222#endif
223 if (bio_integrity(bio))
224 bio_integrity_free(bio);
225
226 bio_crypt_free_ctx(bio);
227}
228EXPORT_SYMBOL(bio_uninit);
229
230static void bio_free(struct bio *bio)
231{
232 struct bio_set *bs = bio->bi_pool;
233 void *p = bio;
234
235 WARN_ON_ONCE(!bs);
236
237 bio_uninit(bio);
238 bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs);
239 mempool_free(p - bs->front_pad, &bs->bio_pool);
240}
241
242/*
243 * Users of this function have their own bio allocation. Subsequently,
244 * they must remember to pair any call to bio_init() with bio_uninit()
245 * when IO has completed, or when the bio is released.
246 */
247void bio_init(struct bio *bio, struct block_device *bdev, struct bio_vec *table,
248 unsigned short max_vecs, blk_opf_t opf)
249{
250 bio->bi_next = NULL;
251 bio->bi_bdev = bdev;
252 bio->bi_opf = opf;
253 bio->bi_flags = 0;
254 bio->bi_ioprio = 0;
255 bio->bi_status = 0;
256 bio->bi_iter.bi_sector = 0;
257 bio->bi_iter.bi_size = 0;
258 bio->bi_iter.bi_idx = 0;
259 bio->bi_iter.bi_bvec_done = 0;
260 bio->bi_end_io = NULL;
261 bio->bi_private = NULL;
262#ifdef CONFIG_BLK_CGROUP
263 bio->bi_blkg = NULL;
264 bio->bi_issue.value = 0;
265 if (bdev)
266 bio_associate_blkg(bio);
267#ifdef CONFIG_BLK_CGROUP_IOCOST
268 bio->bi_iocost_cost = 0;
269#endif
270#endif
271#ifdef CONFIG_BLK_INLINE_ENCRYPTION
272 bio->bi_crypt_context = NULL;
273#endif
274#ifdef CONFIG_BLK_DEV_INTEGRITY
275 bio->bi_integrity = NULL;
276#endif
277 bio->bi_vcnt = 0;
278
279 atomic_set(&bio->__bi_remaining, 1);
280 atomic_set(&bio->__bi_cnt, 1);
281 bio->bi_cookie = BLK_QC_T_NONE;
282
283 bio->bi_max_vecs = max_vecs;
284 bio->bi_io_vec = table;
285 bio->bi_pool = NULL;
286}
287EXPORT_SYMBOL(bio_init);
288
289/**
290 * bio_reset - reinitialize a bio
291 * @bio: bio to reset
292 * @bdev: block device to use the bio for
293 * @opf: operation and flags for bio
294 *
295 * Description:
296 * After calling bio_reset(), @bio will be in the same state as a freshly
297 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
298 * preserved are the ones that are initialized by bio_alloc_bioset(). See
299 * comment in struct bio.
300 */
301void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf)
302{
303 bio_uninit(bio);
304 memset(bio, 0, BIO_RESET_BYTES);
305 atomic_set(&bio->__bi_remaining, 1);
306 bio->bi_bdev = bdev;
307 if (bio->bi_bdev)
308 bio_associate_blkg(bio);
309 bio->bi_opf = opf;
310}
311EXPORT_SYMBOL(bio_reset);
312
313static struct bio *__bio_chain_endio(struct bio *bio)
314{
315 struct bio *parent = bio->bi_private;
316
317 if (bio->bi_status && !parent->bi_status)
318 parent->bi_status = bio->bi_status;
319 bio_put(bio);
320 return parent;
321}
322
323static void bio_chain_endio(struct bio *bio)
324{
325 bio_endio(__bio_chain_endio(bio));
326}
327
328/**
329 * bio_chain - chain bio completions
330 * @bio: the target bio
331 * @parent: the parent bio of @bio
332 *
333 * The caller won't have a bi_end_io called when @bio completes - instead,
334 * @parent's bi_end_io won't be called until both @parent and @bio have
335 * completed; the chained bio will also be freed when it completes.
336 *
337 * The caller must not set bi_private or bi_end_io in @bio.
338 */
339void bio_chain(struct bio *bio, struct bio *parent)
340{
341 BUG_ON(bio->bi_private || bio->bi_end_io);
342
343 bio->bi_private = parent;
344 bio->bi_end_io = bio_chain_endio;
345 bio_inc_remaining(parent);
346}
347EXPORT_SYMBOL(bio_chain);
348
349struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
350 unsigned int nr_pages, blk_opf_t opf, gfp_t gfp)
351{
352 struct bio *new = bio_alloc(bdev, nr_pages, opf, gfp);
353
354 if (bio) {
355 bio_chain(bio, new);
356 submit_bio(bio);
357 }
358
359 return new;
360}
361EXPORT_SYMBOL_GPL(blk_next_bio);
362
363static void bio_alloc_rescue(struct work_struct *work)
364{
365 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
366 struct bio *bio;
367
368 while (1) {
369 spin_lock(&bs->rescue_lock);
370 bio = bio_list_pop(&bs->rescue_list);
371 spin_unlock(&bs->rescue_lock);
372
373 if (!bio)
374 break;
375
376 submit_bio_noacct(bio);
377 }
378}
379
380static void punt_bios_to_rescuer(struct bio_set *bs)
381{
382 struct bio_list punt, nopunt;
383 struct bio *bio;
384
385 if (WARN_ON_ONCE(!bs->rescue_workqueue))
386 return;
387 /*
388 * In order to guarantee forward progress we must punt only bios that
389 * were allocated from this bio_set; otherwise, if there was a bio on
390 * there for a stacking driver higher up in the stack, processing it
391 * could require allocating bios from this bio_set, and doing that from
392 * our own rescuer would be bad.
393 *
394 * Since bio lists are singly linked, pop them all instead of trying to
395 * remove from the middle of the list:
396 */
397
398 bio_list_init(&punt);
399 bio_list_init(&nopunt);
400
401 while ((bio = bio_list_pop(¤t->bio_list[0])))
402 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
403 current->bio_list[0] = nopunt;
404
405 bio_list_init(&nopunt);
406 while ((bio = bio_list_pop(¤t->bio_list[1])))
407 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
408 current->bio_list[1] = nopunt;
409
410 spin_lock(&bs->rescue_lock);
411 bio_list_merge(&bs->rescue_list, &punt);
412 spin_unlock(&bs->rescue_lock);
413
414 queue_work(bs->rescue_workqueue, &bs->rescue_work);
415}
416
417static void bio_alloc_irq_cache_splice(struct bio_alloc_cache *cache)
418{
419 unsigned long flags;
420
421 /* cache->free_list must be empty */
422 if (WARN_ON_ONCE(cache->free_list))
423 return;
424
425 local_irq_save(flags);
426 cache->free_list = cache->free_list_irq;
427 cache->free_list_irq = NULL;
428 cache->nr += cache->nr_irq;
429 cache->nr_irq = 0;
430 local_irq_restore(flags);
431}
432
433static struct bio *bio_alloc_percpu_cache(struct block_device *bdev,
434 unsigned short nr_vecs, blk_opf_t opf, gfp_t gfp,
435 struct bio_set *bs)
436{
437 struct bio_alloc_cache *cache;
438 struct bio *bio;
439
440 cache = per_cpu_ptr(bs->cache, get_cpu());
441 if (!cache->free_list) {
442 if (READ_ONCE(cache->nr_irq) >= ALLOC_CACHE_THRESHOLD)
443 bio_alloc_irq_cache_splice(cache);
444 if (!cache->free_list) {
445 put_cpu();
446 return NULL;
447 }
448 }
449 bio = cache->free_list;
450 cache->free_list = bio->bi_next;
451 cache->nr--;
452 put_cpu();
453
454 bio_init(bio, bdev, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs, opf);
455 bio->bi_pool = bs;
456 return bio;
457}
458
459/**
460 * bio_alloc_bioset - allocate a bio for I/O
461 * @bdev: block device to allocate the bio for (can be %NULL)
462 * @nr_vecs: number of bvecs to pre-allocate
463 * @opf: operation and flags for bio
464 * @gfp_mask: the GFP_* mask given to the slab allocator
465 * @bs: the bio_set to allocate from.
466 *
467 * Allocate a bio from the mempools in @bs.
468 *
469 * If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to
470 * allocate a bio. This is due to the mempool guarantees. To make this work,
471 * callers must never allocate more than 1 bio at a time from the general pool.
472 * Callers that need to allocate more than 1 bio must always submit the
473 * previously allocated bio for IO before attempting to allocate a new one.
474 * Failure to do so can cause deadlocks under memory pressure.
475 *
476 * Note that when running under submit_bio_noacct() (i.e. any block driver),
477 * bios are not submitted until after you return - see the code in
478 * submit_bio_noacct() that converts recursion into iteration, to prevent
479 * stack overflows.
480 *
481 * This would normally mean allocating multiple bios under submit_bio_noacct()
482 * would be susceptible to deadlocks, but we have
483 * deadlock avoidance code that resubmits any blocked bios from a rescuer
484 * thread.
485 *
486 * However, we do not guarantee forward progress for allocations from other
487 * mempools. Doing multiple allocations from the same mempool under
488 * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad
489 * for per bio allocations.
490 *
491 * Returns: Pointer to new bio on success, NULL on failure.
492 */
493struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs,
494 blk_opf_t opf, gfp_t gfp_mask,
495 struct bio_set *bs)
496{
497 gfp_t saved_gfp = gfp_mask;
498 struct bio *bio;
499 void *p;
500
501 /* should not use nobvec bioset for nr_vecs > 0 */
502 if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && nr_vecs > 0))
503 return NULL;
504
505 if (opf & REQ_ALLOC_CACHE) {
506 if (bs->cache && nr_vecs <= BIO_INLINE_VECS) {
507 bio = bio_alloc_percpu_cache(bdev, nr_vecs, opf,
508 gfp_mask, bs);
509 if (bio)
510 return bio;
511 /*
512 * No cached bio available, bio returned below marked with
513 * REQ_ALLOC_CACHE to particpate in per-cpu alloc cache.
514 */
515 } else {
516 opf &= ~REQ_ALLOC_CACHE;
517 }
518 }
519
520 /*
521 * submit_bio_noacct() converts recursion to iteration; this means if
522 * we're running beneath it, any bios we allocate and submit will not be
523 * submitted (and thus freed) until after we return.
524 *
525 * This exposes us to a potential deadlock if we allocate multiple bios
526 * from the same bio_set() while running underneath submit_bio_noacct().
527 * If we were to allocate multiple bios (say a stacking block driver
528 * that was splitting bios), we would deadlock if we exhausted the
529 * mempool's reserve.
530 *
531 * We solve this, and guarantee forward progress, with a rescuer
532 * workqueue per bio_set. If we go to allocate and there are bios on
533 * current->bio_list, we first try the allocation without
534 * __GFP_DIRECT_RECLAIM; if that fails, we punt those bios we would be
535 * blocking to the rescuer workqueue before we retry with the original
536 * gfp_flags.
537 */
538 if (current->bio_list &&
539 (!bio_list_empty(¤t->bio_list[0]) ||
540 !bio_list_empty(¤t->bio_list[1])) &&
541 bs->rescue_workqueue)
542 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
543
544 p = mempool_alloc(&bs->bio_pool, gfp_mask);
545 if (!p && gfp_mask != saved_gfp) {
546 punt_bios_to_rescuer(bs);
547 gfp_mask = saved_gfp;
548 p = mempool_alloc(&bs->bio_pool, gfp_mask);
549 }
550 if (unlikely(!p))
551 return NULL;
552 if (!mempool_is_saturated(&bs->bio_pool))
553 opf &= ~REQ_ALLOC_CACHE;
554
555 bio = p + bs->front_pad;
556 if (nr_vecs > BIO_INLINE_VECS) {
557 struct bio_vec *bvl = NULL;
558
559 bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask);
560 if (!bvl && gfp_mask != saved_gfp) {
561 punt_bios_to_rescuer(bs);
562 gfp_mask = saved_gfp;
563 bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask);
564 }
565 if (unlikely(!bvl))
566 goto err_free;
567
568 bio_init(bio, bdev, bvl, nr_vecs, opf);
569 } else if (nr_vecs) {
570 bio_init(bio, bdev, bio->bi_inline_vecs, BIO_INLINE_VECS, opf);
571 } else {
572 bio_init(bio, bdev, NULL, 0, opf);
573 }
574
575 bio->bi_pool = bs;
576 return bio;
577
578err_free:
579 mempool_free(p, &bs->bio_pool);
580 return NULL;
581}
582EXPORT_SYMBOL(bio_alloc_bioset);
583
584/**
585 * bio_kmalloc - kmalloc a bio
586 * @nr_vecs: number of bio_vecs to allocate
587 * @gfp_mask: the GFP_* mask given to the slab allocator
588 *
589 * Use kmalloc to allocate a bio (including bvecs). The bio must be initialized
590 * using bio_init() before use. To free a bio returned from this function use
591 * kfree() after calling bio_uninit(). A bio returned from this function can
592 * be reused by calling bio_uninit() before calling bio_init() again.
593 *
594 * Note that unlike bio_alloc() or bio_alloc_bioset() allocations from this
595 * function are not backed by a mempool can fail. Do not use this function
596 * for allocations in the file system I/O path.
597 *
598 * Returns: Pointer to new bio on success, NULL on failure.
599 */
600struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask)
601{
602 struct bio *bio;
603
604 if (nr_vecs > UIO_MAXIOV)
605 return NULL;
606 return kmalloc(struct_size(bio, bi_inline_vecs, nr_vecs), gfp_mask);
607}
608EXPORT_SYMBOL(bio_kmalloc);
609
610void zero_fill_bio(struct bio *bio)
611{
612 struct bio_vec bv;
613 struct bvec_iter iter;
614
615 bio_for_each_segment(bv, bio, iter)
616 memzero_bvec(&bv);
617}
618EXPORT_SYMBOL(zero_fill_bio);
619
620/**
621 * bio_truncate - truncate the bio to small size of @new_size
622 * @bio: the bio to be truncated
623 * @new_size: new size for truncating the bio
624 *
625 * Description:
626 * Truncate the bio to new size of @new_size. If bio_op(bio) is
627 * REQ_OP_READ, zero the truncated part. This function should only
628 * be used for handling corner cases, such as bio eod.
629 */
630static void bio_truncate(struct bio *bio, unsigned new_size)
631{
632 struct bio_vec bv;
633 struct bvec_iter iter;
634 unsigned int done = 0;
635 bool truncated = false;
636
637 if (new_size >= bio->bi_iter.bi_size)
638 return;
639
640 if (bio_op(bio) != REQ_OP_READ)
641 goto exit;
642
643 bio_for_each_segment(bv, bio, iter) {
644 if (done + bv.bv_len > new_size) {
645 unsigned offset;
646
647 if (!truncated)
648 offset = new_size - done;
649 else
650 offset = 0;
651 zero_user(bv.bv_page, bv.bv_offset + offset,
652 bv.bv_len - offset);
653 truncated = true;
654 }
655 done += bv.bv_len;
656 }
657
658 exit:
659 /*
660 * Don't touch bvec table here and make it really immutable, since
661 * fs bio user has to retrieve all pages via bio_for_each_segment_all
662 * in its .end_bio() callback.
663 *
664 * It is enough to truncate bio by updating .bi_size since we can make
665 * correct bvec with the updated .bi_size for drivers.
666 */
667 bio->bi_iter.bi_size = new_size;
668}
669
670/**
671 * guard_bio_eod - truncate a BIO to fit the block device
672 * @bio: bio to truncate
673 *
674 * This allows us to do IO even on the odd last sectors of a device, even if the
675 * block size is some multiple of the physical sector size.
676 *
677 * We'll just truncate the bio to the size of the device, and clear the end of
678 * the buffer head manually. Truly out-of-range accesses will turn into actual
679 * I/O errors, this only handles the "we need to be able to do I/O at the final
680 * sector" case.
681 */
682void guard_bio_eod(struct bio *bio)
683{
684 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
685
686 if (!maxsector)
687 return;
688
689 /*
690 * If the *whole* IO is past the end of the device,
691 * let it through, and the IO layer will turn it into
692 * an EIO.
693 */
694 if (unlikely(bio->bi_iter.bi_sector >= maxsector))
695 return;
696
697 maxsector -= bio->bi_iter.bi_sector;
698 if (likely((bio->bi_iter.bi_size >> 9) <= maxsector))
699 return;
700
701 bio_truncate(bio, maxsector << 9);
702}
703
704static int __bio_alloc_cache_prune(struct bio_alloc_cache *cache,
705 unsigned int nr)
706{
707 unsigned int i = 0;
708 struct bio *bio;
709
710 while ((bio = cache->free_list) != NULL) {
711 cache->free_list = bio->bi_next;
712 cache->nr--;
713 bio_free(bio);
714 if (++i == nr)
715 break;
716 }
717 return i;
718}
719
720static void bio_alloc_cache_prune(struct bio_alloc_cache *cache,
721 unsigned int nr)
722{
723 nr -= __bio_alloc_cache_prune(cache, nr);
724 if (!READ_ONCE(cache->free_list)) {
725 bio_alloc_irq_cache_splice(cache);
726 __bio_alloc_cache_prune(cache, nr);
727 }
728}
729
730static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node)
731{
732 struct bio_set *bs;
733
734 bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead);
735 if (bs->cache) {
736 struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu);
737
738 bio_alloc_cache_prune(cache, -1U);
739 }
740 return 0;
741}
742
743static void bio_alloc_cache_destroy(struct bio_set *bs)
744{
745 int cpu;
746
747 if (!bs->cache)
748 return;
749
750 cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
751 for_each_possible_cpu(cpu) {
752 struct bio_alloc_cache *cache;
753
754 cache = per_cpu_ptr(bs->cache, cpu);
755 bio_alloc_cache_prune(cache, -1U);
756 }
757 free_percpu(bs->cache);
758 bs->cache = NULL;
759}
760
761static inline void bio_put_percpu_cache(struct bio *bio)
762{
763 struct bio_alloc_cache *cache;
764
765 cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu());
766 if (READ_ONCE(cache->nr_irq) + cache->nr > ALLOC_CACHE_MAX) {
767 put_cpu();
768 bio_free(bio);
769 return;
770 }
771
772 bio_uninit(bio);
773
774 if ((bio->bi_opf & REQ_POLLED) && !WARN_ON_ONCE(in_interrupt())) {
775 bio->bi_next = cache->free_list;
776 cache->free_list = bio;
777 cache->nr++;
778 } else {
779 unsigned long flags;
780
781 local_irq_save(flags);
782 bio->bi_next = cache->free_list_irq;
783 cache->free_list_irq = bio;
784 cache->nr_irq++;
785 local_irq_restore(flags);
786 }
787 put_cpu();
788}
789
790/**
791 * bio_put - release a reference to a bio
792 * @bio: bio to release reference to
793 *
794 * Description:
795 * Put a reference to a &struct bio, either one you have gotten with
796 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.
797 **/
798void bio_put(struct bio *bio)
799{
800 if (unlikely(bio_flagged(bio, BIO_REFFED))) {
801 BUG_ON(!atomic_read(&bio->__bi_cnt));
802 if (!atomic_dec_and_test(&bio->__bi_cnt))
803 return;
804 }
805 if (bio->bi_opf & REQ_ALLOC_CACHE)
806 bio_put_percpu_cache(bio);
807 else
808 bio_free(bio);
809}
810EXPORT_SYMBOL(bio_put);
811
812static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp)
813{
814 bio_set_flag(bio, BIO_CLONED);
815 bio->bi_ioprio = bio_src->bi_ioprio;
816 bio->bi_iter = bio_src->bi_iter;
817
818 if (bio->bi_bdev) {
819 if (bio->bi_bdev == bio_src->bi_bdev &&
820 bio_flagged(bio_src, BIO_REMAPPED))
821 bio_set_flag(bio, BIO_REMAPPED);
822 bio_clone_blkg_association(bio, bio_src);
823 }
824
825 if (bio_crypt_clone(bio, bio_src, gfp) < 0)
826 return -ENOMEM;
827 if (bio_integrity(bio_src) &&
828 bio_integrity_clone(bio, bio_src, gfp) < 0)
829 return -ENOMEM;
830 return 0;
831}
832
833/**
834 * bio_alloc_clone - clone a bio that shares the original bio's biovec
835 * @bdev: block_device to clone onto
836 * @bio_src: bio to clone from
837 * @gfp: allocation priority
838 * @bs: bio_set to allocate from
839 *
840 * Allocate a new bio that is a clone of @bio_src. The caller owns the returned
841 * bio, but not the actual data it points to.
842 *
843 * The caller must ensure that the return bio is not freed before @bio_src.
844 */
845struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src,
846 gfp_t gfp, struct bio_set *bs)
847{
848 struct bio *bio;
849
850 bio = bio_alloc_bioset(bdev, 0, bio_src->bi_opf, gfp, bs);
851 if (!bio)
852 return NULL;
853
854 if (__bio_clone(bio, bio_src, gfp) < 0) {
855 bio_put(bio);
856 return NULL;
857 }
858 bio->bi_io_vec = bio_src->bi_io_vec;
859
860 return bio;
861}
862EXPORT_SYMBOL(bio_alloc_clone);
863
864/**
865 * bio_init_clone - clone a bio that shares the original bio's biovec
866 * @bdev: block_device to clone onto
867 * @bio: bio to clone into
868 * @bio_src: bio to clone from
869 * @gfp: allocation priority
870 *
871 * Initialize a new bio in caller provided memory that is a clone of @bio_src.
872 * The caller owns the returned bio, but not the actual data it points to.
873 *
874 * The caller must ensure that @bio_src is not freed before @bio.
875 */
876int bio_init_clone(struct block_device *bdev, struct bio *bio,
877 struct bio *bio_src, gfp_t gfp)
878{
879 int ret;
880
881 bio_init(bio, bdev, bio_src->bi_io_vec, 0, bio_src->bi_opf);
882 ret = __bio_clone(bio, bio_src, gfp);
883 if (ret)
884 bio_uninit(bio);
885 return ret;
886}
887EXPORT_SYMBOL(bio_init_clone);
888
889/**
890 * bio_full - check if the bio is full
891 * @bio: bio to check
892 * @len: length of one segment to be added
893 *
894 * Return true if @bio is full and one segment with @len bytes can't be
895 * added to the bio, otherwise return false
896 */
897static inline bool bio_full(struct bio *bio, unsigned len)
898{
899 if (bio->bi_vcnt >= bio->bi_max_vecs)
900 return true;
901 if (bio->bi_iter.bi_size > UINT_MAX - len)
902 return true;
903 return false;
904}
905
906static inline bool page_is_mergeable(const struct bio_vec *bv,
907 struct page *page, unsigned int len, unsigned int off,
908 bool *same_page)
909{
910 size_t bv_end = bv->bv_offset + bv->bv_len;
911 phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1;
912 phys_addr_t page_addr = page_to_phys(page);
913
914 if (vec_end_addr + 1 != page_addr + off)
915 return false;
916 if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
917 return false;
918 if (!zone_device_pages_have_same_pgmap(bv->bv_page, page))
919 return false;
920
921 *same_page = ((vec_end_addr & PAGE_MASK) == page_addr);
922 if (*same_page)
923 return true;
924 else if (IS_ENABLED(CONFIG_KMSAN))
925 return false;
926 return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE);
927}
928
929/**
930 * __bio_try_merge_page - try appending data to an existing bvec.
931 * @bio: destination bio
932 * @page: start page to add
933 * @len: length of the data to add
934 * @off: offset of the data relative to @page
935 * @same_page: return if the segment has been merged inside the same page
936 *
937 * Try to add the data at @page + @off to the last bvec of @bio. This is a
938 * useful optimisation for file systems with a block size smaller than the
939 * page size.
940 *
941 * Warn if (@len, @off) crosses pages in case that @same_page is true.
942 *
943 * Return %true on success or %false on failure.
944 */
945static bool __bio_try_merge_page(struct bio *bio, struct page *page,
946 unsigned int len, unsigned int off, bool *same_page)
947{
948 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
949 return false;
950
951 if (bio->bi_vcnt > 0) {
952 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
953
954 if (page_is_mergeable(bv, page, len, off, same_page)) {
955 if (bio->bi_iter.bi_size > UINT_MAX - len) {
956 *same_page = false;
957 return false;
958 }
959 bv->bv_len += len;
960 bio->bi_iter.bi_size += len;
961 return true;
962 }
963 }
964 return false;
965}
966
967/*
968 * Try to merge a page into a segment, while obeying the hardware segment
969 * size limit. This is not for normal read/write bios, but for passthrough
970 * or Zone Append operations that we can't split.
971 */
972static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio,
973 struct page *page, unsigned len,
974 unsigned offset, bool *same_page)
975{
976 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
977 unsigned long mask = queue_segment_boundary(q);
978 phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset;
979 phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;
980
981 if ((addr1 | mask) != (addr2 | mask))
982 return false;
983 if (bv->bv_len + len > queue_max_segment_size(q))
984 return false;
985 return __bio_try_merge_page(bio, page, len, offset, same_page);
986}
987
988/**
989 * bio_add_hw_page - attempt to add a page to a bio with hw constraints
990 * @q: the target queue
991 * @bio: destination bio
992 * @page: page to add
993 * @len: vec entry length
994 * @offset: vec entry offset
995 * @max_sectors: maximum number of sectors that can be added
996 * @same_page: return if the segment has been merged inside the same page
997 *
998 * Add a page to a bio while respecting the hardware max_sectors, max_segment
999 * and gap limitations.
1000 */
1001int bio_add_hw_page(struct request_queue *q, struct bio *bio,
1002 struct page *page, unsigned int len, unsigned int offset,
1003 unsigned int max_sectors, bool *same_page)
1004{
1005 struct bio_vec *bvec;
1006
1007 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
1008 return 0;
1009
1010 if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
1011 return 0;
1012
1013 if (bio->bi_vcnt > 0) {
1014 if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page))
1015 return len;
1016
1017 /*
1018 * If the queue doesn't support SG gaps and adding this segment
1019 * would create a gap, disallow it.
1020 */
1021 bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
1022 if (bvec_gap_to_prev(&q->limits, bvec, offset))
1023 return 0;
1024 }
1025
1026 if (bio_full(bio, len))
1027 return 0;
1028
1029 if (bio->bi_vcnt >= queue_max_segments(q))
1030 return 0;
1031
1032 bvec = &bio->bi_io_vec[bio->bi_vcnt];
1033 bvec->bv_page = page;
1034 bvec->bv_len = len;
1035 bvec->bv_offset = offset;
1036 bio->bi_vcnt++;
1037 bio->bi_iter.bi_size += len;
1038 return len;
1039}
1040
1041/**
1042 * bio_add_pc_page - attempt to add page to passthrough bio
1043 * @q: the target queue
1044 * @bio: destination bio
1045 * @page: page to add
1046 * @len: vec entry length
1047 * @offset: vec entry offset
1048 *
1049 * Attempt to add a page to the bio_vec maplist. This can fail for a
1050 * number of reasons, such as the bio being full or target block device
1051 * limitations. The target block device must allow bio's up to PAGE_SIZE,
1052 * so it is always possible to add a single page to an empty bio.
1053 *
1054 * This should only be used by passthrough bios.
1055 */
1056int bio_add_pc_page(struct request_queue *q, struct bio *bio,
1057 struct page *page, unsigned int len, unsigned int offset)
1058{
1059 bool same_page = false;
1060 return bio_add_hw_page(q, bio, page, len, offset,
1061 queue_max_hw_sectors(q), &same_page);
1062}
1063EXPORT_SYMBOL(bio_add_pc_page);
1064
1065/**
1066 * bio_add_zone_append_page - attempt to add page to zone-append bio
1067 * @bio: destination bio
1068 * @page: page to add
1069 * @len: vec entry length
1070 * @offset: vec entry offset
1071 *
1072 * Attempt to add a page to the bio_vec maplist of a bio that will be submitted
1073 * for a zone-append request. This can fail for a number of reasons, such as the
1074 * bio being full or the target block device is not a zoned block device or
1075 * other limitations of the target block device. The target block device must
1076 * allow bio's up to PAGE_SIZE, so it is always possible to add a single page
1077 * to an empty bio.
1078 *
1079 * Returns: number of bytes added to the bio, or 0 in case of a failure.
1080 */
1081int bio_add_zone_append_page(struct bio *bio, struct page *page,
1082 unsigned int len, unsigned int offset)
1083{
1084 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1085 bool same_page = false;
1086
1087 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND))
1088 return 0;
1089
1090 if (WARN_ON_ONCE(!bdev_is_zoned(bio->bi_bdev)))
1091 return 0;
1092
1093 return bio_add_hw_page(q, bio, page, len, offset,
1094 queue_max_zone_append_sectors(q), &same_page);
1095}
1096EXPORT_SYMBOL_GPL(bio_add_zone_append_page);
1097
1098/**
1099 * __bio_add_page - add page(s) to a bio in a new segment
1100 * @bio: destination bio
1101 * @page: start page to add
1102 * @len: length of the data to add, may cross pages
1103 * @off: offset of the data relative to @page, may cross pages
1104 *
1105 * Add the data at @page + @off to @bio as a new bvec. The caller must ensure
1106 * that @bio has space for another bvec.
1107 */
1108void __bio_add_page(struct bio *bio, struct page *page,
1109 unsigned int len, unsigned int off)
1110{
1111 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
1112
1113 WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
1114 WARN_ON_ONCE(bio_full(bio, len));
1115
1116 bv->bv_page = page;
1117 bv->bv_offset = off;
1118 bv->bv_len = len;
1119
1120 bio->bi_iter.bi_size += len;
1121 bio->bi_vcnt++;
1122}
1123EXPORT_SYMBOL_GPL(__bio_add_page);
1124
1125/**
1126 * bio_add_page - attempt to add page(s) to bio
1127 * @bio: destination bio
1128 * @page: start page to add
1129 * @len: vec entry length, may cross pages
1130 * @offset: vec entry offset relative to @page, may cross pages
1131 *
1132 * Attempt to add page(s) to the bio_vec maplist. This will only fail
1133 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
1134 */
1135int bio_add_page(struct bio *bio, struct page *page,
1136 unsigned int len, unsigned int offset)
1137{
1138 bool same_page = false;
1139
1140 if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
1141 if (bio_full(bio, len))
1142 return 0;
1143 __bio_add_page(bio, page, len, offset);
1144 }
1145 return len;
1146}
1147EXPORT_SYMBOL(bio_add_page);
1148
1149/**
1150 * bio_add_folio - Attempt to add part of a folio to a bio.
1151 * @bio: BIO to add to.
1152 * @folio: Folio to add.
1153 * @len: How many bytes from the folio to add.
1154 * @off: First byte in this folio to add.
1155 *
1156 * Filesystems that use folios can call this function instead of calling
1157 * bio_add_page() for each page in the folio. If @off is bigger than
1158 * PAGE_SIZE, this function can create a bio_vec that starts in a page
1159 * after the bv_page. BIOs do not support folios that are 4GiB or larger.
1160 *
1161 * Return: Whether the addition was successful.
1162 */
1163bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len,
1164 size_t off)
1165{
1166 if (len > UINT_MAX || off > UINT_MAX)
1167 return false;
1168 return bio_add_page(bio, &folio->page, len, off) > 0;
1169}
1170
1171void __bio_release_pages(struct bio *bio, bool mark_dirty)
1172{
1173 struct bvec_iter_all iter_all;
1174 struct bio_vec *bvec;
1175
1176 bio_for_each_segment_all(bvec, bio, iter_all) {
1177 if (mark_dirty && !PageCompound(bvec->bv_page))
1178 set_page_dirty_lock(bvec->bv_page);
1179 put_page(bvec->bv_page);
1180 }
1181}
1182EXPORT_SYMBOL_GPL(__bio_release_pages);
1183
1184void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)
1185{
1186 size_t size = iov_iter_count(iter);
1187
1188 WARN_ON_ONCE(bio->bi_max_vecs);
1189
1190 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
1191 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1192 size_t max_sectors = queue_max_zone_append_sectors(q);
1193
1194 size = min(size, max_sectors << SECTOR_SHIFT);
1195 }
1196
1197 bio->bi_vcnt = iter->nr_segs;
1198 bio->bi_io_vec = (struct bio_vec *)iter->bvec;
1199 bio->bi_iter.bi_bvec_done = iter->iov_offset;
1200 bio->bi_iter.bi_size = size;
1201 bio_set_flag(bio, BIO_NO_PAGE_REF);
1202 bio_set_flag(bio, BIO_CLONED);
1203}
1204
1205static int bio_iov_add_page(struct bio *bio, struct page *page,
1206 unsigned int len, unsigned int offset)
1207{
1208 bool same_page = false;
1209
1210 if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
1211 __bio_add_page(bio, page, len, offset);
1212 return 0;
1213 }
1214
1215 if (same_page)
1216 put_page(page);
1217 return 0;
1218}
1219
1220static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page,
1221 unsigned int len, unsigned int offset)
1222{
1223 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1224 bool same_page = false;
1225
1226 if (bio_add_hw_page(q, bio, page, len, offset,
1227 queue_max_zone_append_sectors(q), &same_page) != len)
1228 return -EINVAL;
1229 if (same_page)
1230 put_page(page);
1231 return 0;
1232}
1233
1234#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
1235
1236/**
1237 * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
1238 * @bio: bio to add pages to
1239 * @iter: iov iterator describing the region to be mapped
1240 *
1241 * Pins pages from *iter and appends them to @bio's bvec array. The
1242 * pages will have to be released using put_page() when done.
1243 * For multi-segment *iter, this function only adds pages from the
1244 * next non-empty segment of the iov iterator.
1245 */
1246static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
1247{
1248 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
1249 unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
1250 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
1251 struct page **pages = (struct page **)bv;
1252 unsigned int gup_flags = 0;
1253 ssize_t size, left;
1254 unsigned len, i = 0;
1255 size_t offset, trim;
1256 int ret = 0;
1257
1258 /*
1259 * Move page array up in the allocated memory for the bio vecs as far as
1260 * possible so that we can start filling biovecs from the beginning
1261 * without overwriting the temporary page array.
1262 */
1263 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
1264 pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
1265
1266 if (bio->bi_bdev && blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue))
1267 gup_flags |= FOLL_PCI_P2PDMA;
1268
1269 /*
1270 * Each segment in the iov is required to be a block size multiple.
1271 * However, we may not be able to get the entire segment if it spans
1272 * more pages than bi_max_vecs allows, so we have to ALIGN_DOWN the
1273 * result to ensure the bio's total size is correct. The remainder of
1274 * the iov data will be picked up in the next bio iteration.
1275 */
1276 size = iov_iter_get_pages(iter, pages,
1277 UINT_MAX - bio->bi_iter.bi_size,
1278 nr_pages, &offset, gup_flags);
1279 if (unlikely(size <= 0))
1280 return size ? size : -EFAULT;
1281
1282 nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE);
1283
1284 trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1);
1285 iov_iter_revert(iter, trim);
1286
1287 size -= trim;
1288 if (unlikely(!size)) {
1289 ret = -EFAULT;
1290 goto out;
1291 }
1292
1293 for (left = size, i = 0; left > 0; left -= len, i++) {
1294 struct page *page = pages[i];
1295
1296 len = min_t(size_t, PAGE_SIZE - offset, left);
1297 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
1298 ret = bio_iov_add_zone_append_page(bio, page, len,
1299 offset);
1300 if (ret)
1301 break;
1302 } else
1303 bio_iov_add_page(bio, page, len, offset);
1304
1305 offset = 0;
1306 }
1307
1308 iov_iter_revert(iter, left);
1309out:
1310 while (i < nr_pages)
1311 put_page(pages[i++]);
1312
1313 return ret;
1314}
1315
1316/**
1317 * bio_iov_iter_get_pages - add user or kernel pages to a bio
1318 * @bio: bio to add pages to
1319 * @iter: iov iterator describing the region to be added
1320 *
1321 * This takes either an iterator pointing to user memory, or one pointing to
1322 * kernel pages (BVEC iterator). If we're adding user pages, we pin them and
1323 * map them into the kernel. On IO completion, the caller should put those
1324 * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided
1325 * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs
1326 * to ensure the bvecs and pages stay referenced until the submitted I/O is
1327 * completed by a call to ->ki_complete() or returns with an error other than
1328 * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF
1329 * on IO completion. If it isn't, then pages should be released.
1330 *
1331 * The function tries, but does not guarantee, to pin as many pages as
1332 * fit into the bio, or are requested in @iter, whatever is smaller. If
1333 * MM encounters an error pinning the requested pages, it stops. Error
1334 * is returned only if 0 pages could be pinned.
1335 */
1336int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
1337{
1338 int ret = 0;
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 do {
1347 ret = __bio_iov_iter_get_pages(bio, iter);
1348 } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));
1349
1350 return bio->bi_vcnt ? 0 : ret;
1351}
1352EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
1353
1354static void submit_bio_wait_endio(struct bio *bio)
1355{
1356 complete(bio->bi_private);
1357}
1358
1359/**
1360 * submit_bio_wait - submit a bio, and wait until it completes
1361 * @bio: The &struct bio which describes the I/O
1362 *
1363 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
1364 * bio_endio() on failure.
1365 *
1366 * WARNING: Unlike to how submit_bio() is usually used, this function does not
1367 * result in bio reference to be consumed. The caller must drop the reference
1368 * on his own.
1369 */
1370int submit_bio_wait(struct bio *bio)
1371{
1372 DECLARE_COMPLETION_ONSTACK_MAP(done,
1373 bio->bi_bdev->bd_disk->lockdep_map);
1374 unsigned long hang_check;
1375
1376 bio->bi_private = &done;
1377 bio->bi_end_io = submit_bio_wait_endio;
1378 bio->bi_opf |= REQ_SYNC;
1379 submit_bio(bio);
1380
1381 /* Prevent hang_check timer from firing at us during very long I/O */
1382 hang_check = sysctl_hung_task_timeout_secs;
1383 if (hang_check)
1384 while (!wait_for_completion_io_timeout(&done,
1385 hang_check * (HZ/2)))
1386 ;
1387 else
1388 wait_for_completion_io(&done);
1389
1390 return blk_status_to_errno(bio->bi_status);
1391}
1392EXPORT_SYMBOL(submit_bio_wait);
1393
1394void __bio_advance(struct bio *bio, unsigned bytes)
1395{
1396 if (bio_integrity(bio))
1397 bio_integrity_advance(bio, bytes);
1398
1399 bio_crypt_advance(bio, bytes);
1400 bio_advance_iter(bio, &bio->bi_iter, bytes);
1401}
1402EXPORT_SYMBOL(__bio_advance);
1403
1404void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
1405 struct bio *src, struct bvec_iter *src_iter)
1406{
1407 while (src_iter->bi_size && dst_iter->bi_size) {
1408 struct bio_vec src_bv = bio_iter_iovec(src, *src_iter);
1409 struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter);
1410 unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);
1411 void *src_buf = bvec_kmap_local(&src_bv);
1412 void *dst_buf = bvec_kmap_local(&dst_bv);
1413
1414 memcpy(dst_buf, src_buf, bytes);
1415
1416 kunmap_local(dst_buf);
1417 kunmap_local(src_buf);
1418
1419 bio_advance_iter_single(src, src_iter, bytes);
1420 bio_advance_iter_single(dst, dst_iter, bytes);
1421 }
1422}
1423EXPORT_SYMBOL(bio_copy_data_iter);
1424
1425/**
1426 * bio_copy_data - copy contents of data buffers from one bio to another
1427 * @src: source bio
1428 * @dst: destination bio
1429 *
1430 * Stops when it reaches the end of either @src or @dst - that is, copies
1431 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
1432 */
1433void bio_copy_data(struct bio *dst, struct bio *src)
1434{
1435 struct bvec_iter src_iter = src->bi_iter;
1436 struct bvec_iter dst_iter = dst->bi_iter;
1437
1438 bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
1439}
1440EXPORT_SYMBOL(bio_copy_data);
1441
1442void bio_free_pages(struct bio *bio)
1443{
1444 struct bio_vec *bvec;
1445 struct bvec_iter_all iter_all;
1446
1447 bio_for_each_segment_all(bvec, bio, iter_all)
1448 __free_page(bvec->bv_page);
1449}
1450EXPORT_SYMBOL(bio_free_pages);
1451
1452/*
1453 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1454 * for performing direct-IO in BIOs.
1455 *
1456 * The problem is that we cannot run set_page_dirty() from interrupt context
1457 * because the required locks are not interrupt-safe. So what we can do is to
1458 * mark the pages dirty _before_ performing IO. And in interrupt context,
1459 * check that the pages are still dirty. If so, fine. If not, redirty them
1460 * in process context.
1461 *
1462 * We special-case compound pages here: normally this means reads into hugetlb
1463 * pages. The logic in here doesn't really work right for compound pages
1464 * because the VM does not uniformly chase down the head page in all cases.
1465 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1466 * handle them at all. So we skip compound pages here at an early stage.
1467 *
1468 * Note that this code is very hard to test under normal circumstances because
1469 * direct-io pins the pages with get_user_pages(). This makes
1470 * is_page_cache_freeable return false, and the VM will not clean the pages.
1471 * But other code (eg, flusher threads) could clean the pages if they are mapped
1472 * pagecache.
1473 *
1474 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1475 * deferred bio dirtying paths.
1476 */
1477
1478/*
1479 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1480 */
1481void bio_set_pages_dirty(struct bio *bio)
1482{
1483 struct bio_vec *bvec;
1484 struct bvec_iter_all iter_all;
1485
1486 bio_for_each_segment_all(bvec, bio, iter_all) {
1487 if (!PageCompound(bvec->bv_page))
1488 set_page_dirty_lock(bvec->bv_page);
1489 }
1490}
1491
1492/*
1493 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1494 * If they are, then fine. If, however, some pages are clean then they must
1495 * have been written out during the direct-IO read. So we take another ref on
1496 * the BIO and re-dirty the pages in process context.
1497 *
1498 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1499 * here on. It will run one put_page() against each page and will run one
1500 * bio_put() against the BIO.
1501 */
1502
1503static void bio_dirty_fn(struct work_struct *work);
1504
1505static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1506static DEFINE_SPINLOCK(bio_dirty_lock);
1507static struct bio *bio_dirty_list;
1508
1509/*
1510 * This runs in process context
1511 */
1512static void bio_dirty_fn(struct work_struct *work)
1513{
1514 struct bio *bio, *next;
1515
1516 spin_lock_irq(&bio_dirty_lock);
1517 next = bio_dirty_list;
1518 bio_dirty_list = NULL;
1519 spin_unlock_irq(&bio_dirty_lock);
1520
1521 while ((bio = next) != NULL) {
1522 next = bio->bi_private;
1523
1524 bio_release_pages(bio, true);
1525 bio_put(bio);
1526 }
1527}
1528
1529void bio_check_pages_dirty(struct bio *bio)
1530{
1531 struct bio_vec *bvec;
1532 unsigned long flags;
1533 struct bvec_iter_all iter_all;
1534
1535 bio_for_each_segment_all(bvec, bio, iter_all) {
1536 if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page))
1537 goto defer;
1538 }
1539
1540 bio_release_pages(bio, false);
1541 bio_put(bio);
1542 return;
1543defer:
1544 spin_lock_irqsave(&bio_dirty_lock, flags);
1545 bio->bi_private = bio_dirty_list;
1546 bio_dirty_list = bio;
1547 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1548 schedule_work(&bio_dirty_work);
1549}
1550
1551static inline bool bio_remaining_done(struct bio *bio)
1552{
1553 /*
1554 * If we're not chaining, then ->__bi_remaining is always 1 and
1555 * we always end io on the first invocation.
1556 */
1557 if (!bio_flagged(bio, BIO_CHAIN))
1558 return true;
1559
1560 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1561
1562 if (atomic_dec_and_test(&bio->__bi_remaining)) {
1563 bio_clear_flag(bio, BIO_CHAIN);
1564 return true;
1565 }
1566
1567 return false;
1568}
1569
1570/**
1571 * bio_endio - end I/O on a bio
1572 * @bio: bio
1573 *
1574 * Description:
1575 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1576 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1577 * bio unless they own it and thus know that it has an end_io function.
1578 *
1579 * bio_endio() can be called several times on a bio that has been chained
1580 * using bio_chain(). The ->bi_end_io() function will only be called the
1581 * last time.
1582 **/
1583void bio_endio(struct bio *bio)
1584{
1585again:
1586 if (!bio_remaining_done(bio))
1587 return;
1588 if (!bio_integrity_endio(bio))
1589 return;
1590
1591 rq_qos_done_bio(bio);
1592
1593 if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
1594 trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio);
1595 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1596 }
1597
1598 /*
1599 * Need to have a real endio function for chained bios, otherwise
1600 * various corner cases will break (like stacking block devices that
1601 * save/restore bi_end_io) - however, we want to avoid unbounded
1602 * recursion and blowing the stack. Tail call optimization would
1603 * handle this, but compiling with frame pointers also disables
1604 * gcc's sibling call optimization.
1605 */
1606 if (bio->bi_end_io == bio_chain_endio) {
1607 bio = __bio_chain_endio(bio);
1608 goto again;
1609 }
1610
1611 blk_throtl_bio_endio(bio);
1612 /* release cgroup info */
1613 bio_uninit(bio);
1614 if (bio->bi_end_io)
1615 bio->bi_end_io(bio);
1616}
1617EXPORT_SYMBOL(bio_endio);
1618
1619/**
1620 * bio_split - split a bio
1621 * @bio: bio to split
1622 * @sectors: number of sectors to split from the front of @bio
1623 * @gfp: gfp mask
1624 * @bs: bio set to allocate from
1625 *
1626 * Allocates and returns a new bio which represents @sectors from the start of
1627 * @bio, and updates @bio to represent the remaining sectors.
1628 *
1629 * Unless this is a discard request the newly allocated bio will point
1630 * to @bio's bi_io_vec. It is the caller's responsibility to ensure that
1631 * neither @bio nor @bs are freed before the split bio.
1632 */
1633struct bio *bio_split(struct bio *bio, int sectors,
1634 gfp_t gfp, struct bio_set *bs)
1635{
1636 struct bio *split;
1637
1638 BUG_ON(sectors <= 0);
1639 BUG_ON(sectors >= bio_sectors(bio));
1640
1641 /* Zone append commands cannot be split */
1642 if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
1643 return NULL;
1644
1645 split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs);
1646 if (!split)
1647 return NULL;
1648
1649 split->bi_iter.bi_size = sectors << 9;
1650
1651 if (bio_integrity(split))
1652 bio_integrity_trim(split);
1653
1654 bio_advance(bio, split->bi_iter.bi_size);
1655
1656 if (bio_flagged(bio, BIO_TRACE_COMPLETION))
1657 bio_set_flag(split, BIO_TRACE_COMPLETION);
1658
1659 return split;
1660}
1661EXPORT_SYMBOL(bio_split);
1662
1663/**
1664 * bio_trim - trim a bio
1665 * @bio: bio to trim
1666 * @offset: number of sectors to trim from the front of @bio
1667 * @size: size we want to trim @bio to, in sectors
1668 *
1669 * This function is typically used for bios that are cloned and submitted
1670 * to the underlying device in parts.
1671 */
1672void bio_trim(struct bio *bio, sector_t offset, sector_t size)
1673{
1674 if (WARN_ON_ONCE(offset > BIO_MAX_SECTORS || size > BIO_MAX_SECTORS ||
1675 offset + size > bio_sectors(bio)))
1676 return;
1677
1678 size <<= 9;
1679 if (offset == 0 && size == bio->bi_iter.bi_size)
1680 return;
1681
1682 bio_advance(bio, offset << 9);
1683 bio->bi_iter.bi_size = size;
1684
1685 if (bio_integrity(bio))
1686 bio_integrity_trim(bio);
1687}
1688EXPORT_SYMBOL_GPL(bio_trim);
1689
1690/*
1691 * create memory pools for biovec's in a bio_set.
1692 * use the global biovec slabs created for general use.
1693 */
1694int biovec_init_pool(mempool_t *pool, int pool_entries)
1695{
1696 struct biovec_slab *bp = bvec_slabs + ARRAY_SIZE(bvec_slabs) - 1;
1697
1698 return mempool_init_slab_pool(pool, pool_entries, bp->slab);
1699}
1700
1701/*
1702 * bioset_exit - exit a bioset initialized with bioset_init()
1703 *
1704 * May be called on a zeroed but uninitialized bioset (i.e. allocated with
1705 * kzalloc()).
1706 */
1707void bioset_exit(struct bio_set *bs)
1708{
1709 bio_alloc_cache_destroy(bs);
1710 if (bs->rescue_workqueue)
1711 destroy_workqueue(bs->rescue_workqueue);
1712 bs->rescue_workqueue = NULL;
1713
1714 mempool_exit(&bs->bio_pool);
1715 mempool_exit(&bs->bvec_pool);
1716
1717 bioset_integrity_free(bs);
1718 if (bs->bio_slab)
1719 bio_put_slab(bs);
1720 bs->bio_slab = NULL;
1721}
1722EXPORT_SYMBOL(bioset_exit);
1723
1724/**
1725 * bioset_init - Initialize a bio_set
1726 * @bs: pool to initialize
1727 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1728 * @front_pad: Number of bytes to allocate in front of the returned bio
1729 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS
1730 * and %BIOSET_NEED_RESCUER
1731 *
1732 * Description:
1733 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1734 * to ask for a number of bytes to be allocated in front of the bio.
1735 * Front pad allocation is useful for embedding the bio inside
1736 * another structure, to avoid allocating extra data to go with the bio.
1737 * Note that the bio must be embedded at the END of that structure always,
1738 * or things will break badly.
1739 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated
1740 * for allocating iovecs. This pool is not needed e.g. for bio_init_clone().
1741 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used
1742 * to dispatch queued requests when the mempool runs out of space.
1743 *
1744 */
1745int bioset_init(struct bio_set *bs,
1746 unsigned int pool_size,
1747 unsigned int front_pad,
1748 int flags)
1749{
1750 bs->front_pad = front_pad;
1751 if (flags & BIOSET_NEED_BVECS)
1752 bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1753 else
1754 bs->back_pad = 0;
1755
1756 spin_lock_init(&bs->rescue_lock);
1757 bio_list_init(&bs->rescue_list);
1758 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1759
1760 bs->bio_slab = bio_find_or_create_slab(bs);
1761 if (!bs->bio_slab)
1762 return -ENOMEM;
1763
1764 if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))
1765 goto bad;
1766
1767 if ((flags & BIOSET_NEED_BVECS) &&
1768 biovec_init_pool(&bs->bvec_pool, pool_size))
1769 goto bad;
1770
1771 if (flags & BIOSET_NEED_RESCUER) {
1772 bs->rescue_workqueue = alloc_workqueue("bioset",
1773 WQ_MEM_RECLAIM, 0);
1774 if (!bs->rescue_workqueue)
1775 goto bad;
1776 }
1777 if (flags & BIOSET_PERCPU_CACHE) {
1778 bs->cache = alloc_percpu(struct bio_alloc_cache);
1779 if (!bs->cache)
1780 goto bad;
1781 cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
1782 }
1783
1784 return 0;
1785bad:
1786 bioset_exit(bs);
1787 return -ENOMEM;
1788}
1789EXPORT_SYMBOL(bioset_init);
1790
1791static int __init init_bio(void)
1792{
1793 int i;
1794
1795 bio_integrity_init();
1796
1797 for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) {
1798 struct biovec_slab *bvs = bvec_slabs + i;
1799
1800 bvs->slab = kmem_cache_create(bvs->name,
1801 bvs->nr_vecs * sizeof(struct bio_vec), 0,
1802 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
1803 }
1804
1805 cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL,
1806 bio_cpu_dead);
1807
1808 if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0,
1809 BIOSET_NEED_BVECS | BIOSET_PERCPU_CACHE))
1810 panic("bio: can't allocate bios\n");
1811
1812 if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE))
1813 panic("bio: can't create integrity pool\n");
1814
1815 return 0;
1816}
1817subsys_initcall(init_bio);
1/*
2 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public Licens
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
16 *
17 */
18#include <linux/mm.h>
19#include <linux/swap.h>
20#include <linux/bio.h>
21#include <linux/blkdev.h>
22#include <linux/uio.h>
23#include <linux/iocontext.h>
24#include <linux/slab.h>
25#include <linux/init.h>
26#include <linux/kernel.h>
27#include <linux/export.h>
28#include <linux/mempool.h>
29#include <linux/workqueue.h>
30#include <linux/cgroup.h>
31
32#include <trace/events/block.h>
33#include "blk.h"
34
35/*
36 * Test patch to inline a certain number of bi_io_vec's inside the bio
37 * itself, to shrink a bio data allocation from two mempool calls to one
38 */
39#define BIO_INLINE_VECS 4
40
41/*
42 * if you change this list, also change bvec_alloc or things will
43 * break badly! cannot be bigger than what you can fit into an
44 * unsigned short
45 */
46#define BV(x, n) { .nr_vecs = x, .name = "biovec-"#n }
47static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = {
48 BV(1, 1), BV(4, 4), BV(16, 16), BV(64, 64), BV(128, 128), BV(BIO_MAX_PAGES, max),
49};
50#undef BV
51
52/*
53 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
54 * IO code that does not need private memory pools.
55 */
56struct bio_set *fs_bio_set;
57EXPORT_SYMBOL(fs_bio_set);
58
59/*
60 * Our slab pool management
61 */
62struct bio_slab {
63 struct kmem_cache *slab;
64 unsigned int slab_ref;
65 unsigned int slab_size;
66 char name[8];
67};
68static DEFINE_MUTEX(bio_slab_lock);
69static struct bio_slab *bio_slabs;
70static unsigned int bio_slab_nr, bio_slab_max;
71
72static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
73{
74 unsigned int sz = sizeof(struct bio) + extra_size;
75 struct kmem_cache *slab = NULL;
76 struct bio_slab *bslab, *new_bio_slabs;
77 unsigned int new_bio_slab_max;
78 unsigned int i, entry = -1;
79
80 mutex_lock(&bio_slab_lock);
81
82 i = 0;
83 while (i < bio_slab_nr) {
84 bslab = &bio_slabs[i];
85
86 if (!bslab->slab && entry == -1)
87 entry = i;
88 else if (bslab->slab_size == sz) {
89 slab = bslab->slab;
90 bslab->slab_ref++;
91 break;
92 }
93 i++;
94 }
95
96 if (slab)
97 goto out_unlock;
98
99 if (bio_slab_nr == bio_slab_max && entry == -1) {
100 new_bio_slab_max = bio_slab_max << 1;
101 new_bio_slabs = krealloc(bio_slabs,
102 new_bio_slab_max * sizeof(struct bio_slab),
103 GFP_KERNEL);
104 if (!new_bio_slabs)
105 goto out_unlock;
106 bio_slab_max = new_bio_slab_max;
107 bio_slabs = new_bio_slabs;
108 }
109 if (entry == -1)
110 entry = bio_slab_nr++;
111
112 bslab = &bio_slabs[entry];
113
114 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
115 slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN,
116 SLAB_HWCACHE_ALIGN, NULL);
117 if (!slab)
118 goto out_unlock;
119
120 bslab->slab = slab;
121 bslab->slab_ref = 1;
122 bslab->slab_size = sz;
123out_unlock:
124 mutex_unlock(&bio_slab_lock);
125 return slab;
126}
127
128static void bio_put_slab(struct bio_set *bs)
129{
130 struct bio_slab *bslab = NULL;
131 unsigned int i;
132
133 mutex_lock(&bio_slab_lock);
134
135 for (i = 0; i < bio_slab_nr; i++) {
136 if (bs->bio_slab == bio_slabs[i].slab) {
137 bslab = &bio_slabs[i];
138 break;
139 }
140 }
141
142 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
143 goto out;
144
145 WARN_ON(!bslab->slab_ref);
146
147 if (--bslab->slab_ref)
148 goto out;
149
150 kmem_cache_destroy(bslab->slab);
151 bslab->slab = NULL;
152
153out:
154 mutex_unlock(&bio_slab_lock);
155}
156
157unsigned int bvec_nr_vecs(unsigned short idx)
158{
159 return bvec_slabs[idx].nr_vecs;
160}
161
162void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
163{
164 if (!idx)
165 return;
166 idx--;
167
168 BIO_BUG_ON(idx >= BVEC_POOL_NR);
169
170 if (idx == BVEC_POOL_MAX) {
171 mempool_free(bv, pool);
172 } else {
173 struct biovec_slab *bvs = bvec_slabs + idx;
174
175 kmem_cache_free(bvs->slab, bv);
176 }
177}
178
179struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
180 mempool_t *pool)
181{
182 struct bio_vec *bvl;
183
184 /*
185 * see comment near bvec_array define!
186 */
187 switch (nr) {
188 case 1:
189 *idx = 0;
190 break;
191 case 2 ... 4:
192 *idx = 1;
193 break;
194 case 5 ... 16:
195 *idx = 2;
196 break;
197 case 17 ... 64:
198 *idx = 3;
199 break;
200 case 65 ... 128:
201 *idx = 4;
202 break;
203 case 129 ... BIO_MAX_PAGES:
204 *idx = 5;
205 break;
206 default:
207 return NULL;
208 }
209
210 /*
211 * idx now points to the pool we want to allocate from. only the
212 * 1-vec entry pool is mempool backed.
213 */
214 if (*idx == BVEC_POOL_MAX) {
215fallback:
216 bvl = mempool_alloc(pool, gfp_mask);
217 } else {
218 struct biovec_slab *bvs = bvec_slabs + *idx;
219 gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO);
220
221 /*
222 * Make this allocation restricted and don't dump info on
223 * allocation failures, since we'll fallback to the mempool
224 * in case of failure.
225 */
226 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
227
228 /*
229 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM
230 * is set, retry with the 1-entry mempool
231 */
232 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
233 if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {
234 *idx = BVEC_POOL_MAX;
235 goto fallback;
236 }
237 }
238
239 (*idx)++;
240 return bvl;
241}
242
243void bio_uninit(struct bio *bio)
244{
245 bio_disassociate_task(bio);
246}
247EXPORT_SYMBOL(bio_uninit);
248
249static void bio_free(struct bio *bio)
250{
251 struct bio_set *bs = bio->bi_pool;
252 void *p;
253
254 bio_uninit(bio);
255
256 if (bs) {
257 bvec_free(bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio));
258
259 /*
260 * If we have front padding, adjust the bio pointer before freeing
261 */
262 p = bio;
263 p -= bs->front_pad;
264
265 mempool_free(p, bs->bio_pool);
266 } else {
267 /* Bio was allocated by bio_kmalloc() */
268 kfree(bio);
269 }
270}
271
272/*
273 * Users of this function have their own bio allocation. Subsequently,
274 * they must remember to pair any call to bio_init() with bio_uninit()
275 * when IO has completed, or when the bio is released.
276 */
277void bio_init(struct bio *bio, struct bio_vec *table,
278 unsigned short max_vecs)
279{
280 memset(bio, 0, sizeof(*bio));
281 atomic_set(&bio->__bi_remaining, 1);
282 atomic_set(&bio->__bi_cnt, 1);
283
284 bio->bi_io_vec = table;
285 bio->bi_max_vecs = max_vecs;
286}
287EXPORT_SYMBOL(bio_init);
288
289/**
290 * bio_reset - reinitialize a bio
291 * @bio: bio to reset
292 *
293 * Description:
294 * After calling bio_reset(), @bio will be in the same state as a freshly
295 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
296 * preserved are the ones that are initialized by bio_alloc_bioset(). See
297 * comment in struct bio.
298 */
299void bio_reset(struct bio *bio)
300{
301 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
302
303 bio_uninit(bio);
304
305 memset(bio, 0, BIO_RESET_BYTES);
306 bio->bi_flags = flags;
307 atomic_set(&bio->__bi_remaining, 1);
308}
309EXPORT_SYMBOL(bio_reset);
310
311static struct bio *__bio_chain_endio(struct bio *bio)
312{
313 struct bio *parent = bio->bi_private;
314
315 if (!parent->bi_status)
316 parent->bi_status = bio->bi_status;
317 bio_put(bio);
318 return parent;
319}
320
321static void bio_chain_endio(struct bio *bio)
322{
323 bio_endio(__bio_chain_endio(bio));
324}
325
326/**
327 * bio_chain - chain bio completions
328 * @bio: the target bio
329 * @parent: the @bio's parent bio
330 *
331 * The caller won't have a bi_end_io called when @bio completes - instead,
332 * @parent's bi_end_io won't be called until both @parent and @bio have
333 * completed; the chained bio will also be freed when it completes.
334 *
335 * The caller must not set bi_private or bi_end_io in @bio.
336 */
337void bio_chain(struct bio *bio, struct bio *parent)
338{
339 BUG_ON(bio->bi_private || bio->bi_end_io);
340
341 bio->bi_private = parent;
342 bio->bi_end_io = bio_chain_endio;
343 bio_inc_remaining(parent);
344}
345EXPORT_SYMBOL(bio_chain);
346
347static void bio_alloc_rescue(struct work_struct *work)
348{
349 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
350 struct bio *bio;
351
352 while (1) {
353 spin_lock(&bs->rescue_lock);
354 bio = bio_list_pop(&bs->rescue_list);
355 spin_unlock(&bs->rescue_lock);
356
357 if (!bio)
358 break;
359
360 generic_make_request(bio);
361 }
362}
363
364static void punt_bios_to_rescuer(struct bio_set *bs)
365{
366 struct bio_list punt, nopunt;
367 struct bio *bio;
368
369 if (WARN_ON_ONCE(!bs->rescue_workqueue))
370 return;
371 /*
372 * In order to guarantee forward progress we must punt only bios that
373 * were allocated from this bio_set; otherwise, if there was a bio on
374 * there for a stacking driver higher up in the stack, processing it
375 * could require allocating bios from this bio_set, and doing that from
376 * our own rescuer would be bad.
377 *
378 * Since bio lists are singly linked, pop them all instead of trying to
379 * remove from the middle of the list:
380 */
381
382 bio_list_init(&punt);
383 bio_list_init(&nopunt);
384
385 while ((bio = bio_list_pop(¤t->bio_list[0])))
386 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
387 current->bio_list[0] = nopunt;
388
389 bio_list_init(&nopunt);
390 while ((bio = bio_list_pop(¤t->bio_list[1])))
391 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
392 current->bio_list[1] = nopunt;
393
394 spin_lock(&bs->rescue_lock);
395 bio_list_merge(&bs->rescue_list, &punt);
396 spin_unlock(&bs->rescue_lock);
397
398 queue_work(bs->rescue_workqueue, &bs->rescue_work);
399}
400
401/**
402 * bio_alloc_bioset - allocate a bio for I/O
403 * @gfp_mask: the GFP_* mask given to the slab allocator
404 * @nr_iovecs: number of iovecs to pre-allocate
405 * @bs: the bio_set to allocate from.
406 *
407 * Description:
408 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
409 * backed by the @bs's mempool.
410 *
411 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will
412 * always be able to allocate a bio. This is due to the mempool guarantees.
413 * To make this work, callers must never allocate more than 1 bio at a time
414 * from this pool. Callers that need to allocate more than 1 bio must always
415 * submit the previously allocated bio for IO before attempting to allocate
416 * a new one. Failure to do so can cause deadlocks under memory pressure.
417 *
418 * Note that when running under generic_make_request() (i.e. any block
419 * driver), bios are not submitted until after you return - see the code in
420 * generic_make_request() that converts recursion into iteration, to prevent
421 * stack overflows.
422 *
423 * This would normally mean allocating multiple bios under
424 * generic_make_request() would be susceptible to deadlocks, but we have
425 * deadlock avoidance code that resubmits any blocked bios from a rescuer
426 * thread.
427 *
428 * However, we do not guarantee forward progress for allocations from other
429 * mempools. Doing multiple allocations from the same mempool under
430 * generic_make_request() should be avoided - instead, use bio_set's front_pad
431 * for per bio allocations.
432 *
433 * RETURNS:
434 * Pointer to new bio on success, NULL on failure.
435 */
436struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs,
437 struct bio_set *bs)
438{
439 gfp_t saved_gfp = gfp_mask;
440 unsigned front_pad;
441 unsigned inline_vecs;
442 struct bio_vec *bvl = NULL;
443 struct bio *bio;
444 void *p;
445
446 if (!bs) {
447 if (nr_iovecs > UIO_MAXIOV)
448 return NULL;
449
450 p = kmalloc(sizeof(struct bio) +
451 nr_iovecs * sizeof(struct bio_vec),
452 gfp_mask);
453 front_pad = 0;
454 inline_vecs = nr_iovecs;
455 } else {
456 /* should not use nobvec bioset for nr_iovecs > 0 */
457 if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0))
458 return NULL;
459 /*
460 * generic_make_request() converts recursion to iteration; this
461 * means if we're running beneath it, any bios we allocate and
462 * submit will not be submitted (and thus freed) until after we
463 * return.
464 *
465 * This exposes us to a potential deadlock if we allocate
466 * multiple bios from the same bio_set() while running
467 * underneath generic_make_request(). If we were to allocate
468 * multiple bios (say a stacking block driver that was splitting
469 * bios), we would deadlock if we exhausted the mempool's
470 * reserve.
471 *
472 * We solve this, and guarantee forward progress, with a rescuer
473 * workqueue per bio_set. If we go to allocate and there are
474 * bios on current->bio_list, we first try the allocation
475 * without __GFP_DIRECT_RECLAIM; if that fails, we punt those
476 * bios we would be blocking to the rescuer workqueue before
477 * we retry with the original gfp_flags.
478 */
479
480 if (current->bio_list &&
481 (!bio_list_empty(¤t->bio_list[0]) ||
482 !bio_list_empty(¤t->bio_list[1])) &&
483 bs->rescue_workqueue)
484 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
485
486 p = mempool_alloc(bs->bio_pool, gfp_mask);
487 if (!p && gfp_mask != saved_gfp) {
488 punt_bios_to_rescuer(bs);
489 gfp_mask = saved_gfp;
490 p = mempool_alloc(bs->bio_pool, gfp_mask);
491 }
492
493 front_pad = bs->front_pad;
494 inline_vecs = BIO_INLINE_VECS;
495 }
496
497 if (unlikely(!p))
498 return NULL;
499
500 bio = p + front_pad;
501 bio_init(bio, NULL, 0);
502
503 if (nr_iovecs > inline_vecs) {
504 unsigned long idx = 0;
505
506 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
507 if (!bvl && gfp_mask != saved_gfp) {
508 punt_bios_to_rescuer(bs);
509 gfp_mask = saved_gfp;
510 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
511 }
512
513 if (unlikely(!bvl))
514 goto err_free;
515
516 bio->bi_flags |= idx << BVEC_POOL_OFFSET;
517 } else if (nr_iovecs) {
518 bvl = bio->bi_inline_vecs;
519 }
520
521 bio->bi_pool = bs;
522 bio->bi_max_vecs = nr_iovecs;
523 bio->bi_io_vec = bvl;
524 return bio;
525
526err_free:
527 mempool_free(p, bs->bio_pool);
528 return NULL;
529}
530EXPORT_SYMBOL(bio_alloc_bioset);
531
532void zero_fill_bio(struct bio *bio)
533{
534 unsigned long flags;
535 struct bio_vec bv;
536 struct bvec_iter iter;
537
538 bio_for_each_segment(bv, bio, iter) {
539 char *data = bvec_kmap_irq(&bv, &flags);
540 memset(data, 0, bv.bv_len);
541 flush_dcache_page(bv.bv_page);
542 bvec_kunmap_irq(data, &flags);
543 }
544}
545EXPORT_SYMBOL(zero_fill_bio);
546
547/**
548 * bio_put - release a reference to a bio
549 * @bio: bio to release reference to
550 *
551 * Description:
552 * Put a reference to a &struct bio, either one you have gotten with
553 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.
554 **/
555void bio_put(struct bio *bio)
556{
557 if (!bio_flagged(bio, BIO_REFFED))
558 bio_free(bio);
559 else {
560 BIO_BUG_ON(!atomic_read(&bio->__bi_cnt));
561
562 /*
563 * last put frees it
564 */
565 if (atomic_dec_and_test(&bio->__bi_cnt))
566 bio_free(bio);
567 }
568}
569EXPORT_SYMBOL(bio_put);
570
571inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
572{
573 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
574 blk_recount_segments(q, bio);
575
576 return bio->bi_phys_segments;
577}
578EXPORT_SYMBOL(bio_phys_segments);
579
580/**
581 * __bio_clone_fast - clone a bio that shares the original bio's biovec
582 * @bio: destination bio
583 * @bio_src: bio to clone
584 *
585 * Clone a &bio. Caller will own the returned bio, but not
586 * the actual data it points to. Reference count of returned
587 * bio will be one.
588 *
589 * Caller must ensure that @bio_src is not freed before @bio.
590 */
591void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
592{
593 BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio));
594
595 /*
596 * most users will be overriding ->bi_disk with a new target,
597 * so we don't set nor calculate new physical/hw segment counts here
598 */
599 bio->bi_disk = bio_src->bi_disk;
600 bio->bi_partno = bio_src->bi_partno;
601 bio_set_flag(bio, BIO_CLONED);
602 if (bio_flagged(bio_src, BIO_THROTTLED))
603 bio_set_flag(bio, BIO_THROTTLED);
604 bio->bi_opf = bio_src->bi_opf;
605 bio->bi_write_hint = bio_src->bi_write_hint;
606 bio->bi_iter = bio_src->bi_iter;
607 bio->bi_io_vec = bio_src->bi_io_vec;
608
609 bio_clone_blkcg_association(bio, bio_src);
610}
611EXPORT_SYMBOL(__bio_clone_fast);
612
613/**
614 * bio_clone_fast - clone a bio that shares the original bio's biovec
615 * @bio: bio to clone
616 * @gfp_mask: allocation priority
617 * @bs: bio_set to allocate from
618 *
619 * Like __bio_clone_fast, only also allocates the returned bio
620 */
621struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
622{
623 struct bio *b;
624
625 b = bio_alloc_bioset(gfp_mask, 0, bs);
626 if (!b)
627 return NULL;
628
629 __bio_clone_fast(b, bio);
630
631 if (bio_integrity(bio)) {
632 int ret;
633
634 ret = bio_integrity_clone(b, bio, gfp_mask);
635
636 if (ret < 0) {
637 bio_put(b);
638 return NULL;
639 }
640 }
641
642 return b;
643}
644EXPORT_SYMBOL(bio_clone_fast);
645
646/**
647 * bio_clone_bioset - clone a bio
648 * @bio_src: bio to clone
649 * @gfp_mask: allocation priority
650 * @bs: bio_set to allocate from
651 *
652 * Clone bio. Caller will own the returned bio, but not the actual data it
653 * points to. Reference count of returned bio will be one.
654 */
655struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
656 struct bio_set *bs)
657{
658 struct bvec_iter iter;
659 struct bio_vec bv;
660 struct bio *bio;
661
662 /*
663 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
664 * bio_src->bi_io_vec to bio->bi_io_vec.
665 *
666 * We can't do that anymore, because:
667 *
668 * - The point of cloning the biovec is to produce a bio with a biovec
669 * the caller can modify: bi_idx and bi_bvec_done should be 0.
670 *
671 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
672 * we tried to clone the whole thing bio_alloc_bioset() would fail.
673 * But the clone should succeed as long as the number of biovecs we
674 * actually need to allocate is fewer than BIO_MAX_PAGES.
675 *
676 * - Lastly, bi_vcnt should not be looked at or relied upon by code
677 * that does not own the bio - reason being drivers don't use it for
678 * iterating over the biovec anymore, so expecting it to be kept up
679 * to date (i.e. for clones that share the parent biovec) is just
680 * asking for trouble and would force extra work on
681 * __bio_clone_fast() anyways.
682 */
683
684 bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
685 if (!bio)
686 return NULL;
687 bio->bi_disk = bio_src->bi_disk;
688 bio->bi_opf = bio_src->bi_opf;
689 bio->bi_write_hint = bio_src->bi_write_hint;
690 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
691 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
692
693 switch (bio_op(bio)) {
694 case REQ_OP_DISCARD:
695 case REQ_OP_SECURE_ERASE:
696 case REQ_OP_WRITE_ZEROES:
697 break;
698 case REQ_OP_WRITE_SAME:
699 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
700 break;
701 default:
702 bio_for_each_segment(bv, bio_src, iter)
703 bio->bi_io_vec[bio->bi_vcnt++] = bv;
704 break;
705 }
706
707 if (bio_integrity(bio_src)) {
708 int ret;
709
710 ret = bio_integrity_clone(bio, bio_src, gfp_mask);
711 if (ret < 0) {
712 bio_put(bio);
713 return NULL;
714 }
715 }
716
717 bio_clone_blkcg_association(bio, bio_src);
718
719 return bio;
720}
721EXPORT_SYMBOL(bio_clone_bioset);
722
723/**
724 * bio_add_pc_page - attempt to add page to bio
725 * @q: the target queue
726 * @bio: destination bio
727 * @page: page to add
728 * @len: vec entry length
729 * @offset: vec entry offset
730 *
731 * Attempt to add a page to the bio_vec maplist. This can fail for a
732 * number of reasons, such as the bio being full or target block device
733 * limitations. The target block device must allow bio's up to PAGE_SIZE,
734 * so it is always possible to add a single page to an empty bio.
735 *
736 * This should only be used by REQ_PC bios.
737 */
738int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
739 *page, unsigned int len, unsigned int offset)
740{
741 int retried_segments = 0;
742 struct bio_vec *bvec;
743
744 /*
745 * cloned bio must not modify vec list
746 */
747 if (unlikely(bio_flagged(bio, BIO_CLONED)))
748 return 0;
749
750 if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
751 return 0;
752
753 /*
754 * For filesystems with a blocksize smaller than the pagesize
755 * we will often be called with the same page as last time and
756 * a consecutive offset. Optimize this special case.
757 */
758 if (bio->bi_vcnt > 0) {
759 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
760
761 if (page == prev->bv_page &&
762 offset == prev->bv_offset + prev->bv_len) {
763 prev->bv_len += len;
764 bio->bi_iter.bi_size += len;
765 goto done;
766 }
767
768 /*
769 * If the queue doesn't support SG gaps and adding this
770 * offset would create a gap, disallow it.
771 */
772 if (bvec_gap_to_prev(q, prev, offset))
773 return 0;
774 }
775
776 if (bio->bi_vcnt >= bio->bi_max_vecs)
777 return 0;
778
779 /*
780 * setup the new entry, we might clear it again later if we
781 * cannot add the page
782 */
783 bvec = &bio->bi_io_vec[bio->bi_vcnt];
784 bvec->bv_page = page;
785 bvec->bv_len = len;
786 bvec->bv_offset = offset;
787 bio->bi_vcnt++;
788 bio->bi_phys_segments++;
789 bio->bi_iter.bi_size += len;
790
791 /*
792 * Perform a recount if the number of segments is greater
793 * than queue_max_segments(q).
794 */
795
796 while (bio->bi_phys_segments > queue_max_segments(q)) {
797
798 if (retried_segments)
799 goto failed;
800
801 retried_segments = 1;
802 blk_recount_segments(q, bio);
803 }
804
805 /* If we may be able to merge these biovecs, force a recount */
806 if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
807 bio_clear_flag(bio, BIO_SEG_VALID);
808
809 done:
810 return len;
811
812 failed:
813 bvec->bv_page = NULL;
814 bvec->bv_len = 0;
815 bvec->bv_offset = 0;
816 bio->bi_vcnt--;
817 bio->bi_iter.bi_size -= len;
818 blk_recount_segments(q, bio);
819 return 0;
820}
821EXPORT_SYMBOL(bio_add_pc_page);
822
823/**
824 * bio_add_page - attempt to add page to bio
825 * @bio: destination bio
826 * @page: page to add
827 * @len: vec entry length
828 * @offset: vec entry offset
829 *
830 * Attempt to add a page to the bio_vec maplist. This will only fail
831 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
832 */
833int bio_add_page(struct bio *bio, struct page *page,
834 unsigned int len, unsigned int offset)
835{
836 struct bio_vec *bv;
837
838 /*
839 * cloned bio must not modify vec list
840 */
841 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
842 return 0;
843
844 /*
845 * For filesystems with a blocksize smaller than the pagesize
846 * we will often be called with the same page as last time and
847 * a consecutive offset. Optimize this special case.
848 */
849 if (bio->bi_vcnt > 0) {
850 bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
851
852 if (page == bv->bv_page &&
853 offset == bv->bv_offset + bv->bv_len) {
854 bv->bv_len += len;
855 goto done;
856 }
857 }
858
859 if (bio->bi_vcnt >= bio->bi_max_vecs)
860 return 0;
861
862 bv = &bio->bi_io_vec[bio->bi_vcnt];
863 bv->bv_page = page;
864 bv->bv_len = len;
865 bv->bv_offset = offset;
866
867 bio->bi_vcnt++;
868done:
869 bio->bi_iter.bi_size += len;
870 return len;
871}
872EXPORT_SYMBOL(bio_add_page);
873
874/**
875 * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
876 * @bio: bio to add pages to
877 * @iter: iov iterator describing the region to be mapped
878 *
879 * Pins as many pages from *iter and appends them to @bio's bvec array. The
880 * pages will have to be released using put_page() when done.
881 */
882int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
883{
884 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
885 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
886 struct page **pages = (struct page **)bv;
887 size_t offset, diff;
888 ssize_t size;
889
890 size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
891 if (unlikely(size <= 0))
892 return size ? size : -EFAULT;
893 nr_pages = (size + offset + PAGE_SIZE - 1) / PAGE_SIZE;
894
895 /*
896 * Deep magic below: We need to walk the pinned pages backwards
897 * because we are abusing the space allocated for the bio_vecs
898 * for the page array. Because the bio_vecs are larger than the
899 * page pointers by definition this will always work. But it also
900 * means we can't use bio_add_page, so any changes to it's semantics
901 * need to be reflected here as well.
902 */
903 bio->bi_iter.bi_size += size;
904 bio->bi_vcnt += nr_pages;
905
906 diff = (nr_pages * PAGE_SIZE - offset) - size;
907 while (nr_pages--) {
908 bv[nr_pages].bv_page = pages[nr_pages];
909 bv[nr_pages].bv_len = PAGE_SIZE;
910 bv[nr_pages].bv_offset = 0;
911 }
912
913 bv[0].bv_offset += offset;
914 bv[0].bv_len -= offset;
915 if (diff)
916 bv[bio->bi_vcnt - 1].bv_len -= diff;
917
918 iov_iter_advance(iter, size);
919 return 0;
920}
921EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
922
923static void submit_bio_wait_endio(struct bio *bio)
924{
925 complete(bio->bi_private);
926}
927
928/**
929 * submit_bio_wait - submit a bio, and wait until it completes
930 * @bio: The &struct bio which describes the I/O
931 *
932 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
933 * bio_endio() on failure.
934 *
935 * WARNING: Unlike to how submit_bio() is usually used, this function does not
936 * result in bio reference to be consumed. The caller must drop the reference
937 * on his own.
938 */
939int submit_bio_wait(struct bio *bio)
940{
941 DECLARE_COMPLETION_ONSTACK_MAP(done, bio->bi_disk->lockdep_map);
942
943 bio->bi_private = &done;
944 bio->bi_end_io = submit_bio_wait_endio;
945 bio->bi_opf |= REQ_SYNC;
946 submit_bio(bio);
947 wait_for_completion_io(&done);
948
949 return blk_status_to_errno(bio->bi_status);
950}
951EXPORT_SYMBOL(submit_bio_wait);
952
953/**
954 * bio_advance - increment/complete a bio by some number of bytes
955 * @bio: bio to advance
956 * @bytes: number of bytes to complete
957 *
958 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
959 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
960 * be updated on the last bvec as well.
961 *
962 * @bio will then represent the remaining, uncompleted portion of the io.
963 */
964void bio_advance(struct bio *bio, unsigned bytes)
965{
966 if (bio_integrity(bio))
967 bio_integrity_advance(bio, bytes);
968
969 bio_advance_iter(bio, &bio->bi_iter, bytes);
970}
971EXPORT_SYMBOL(bio_advance);
972
973/**
974 * bio_copy_data - copy contents of data buffers from one chain of bios to
975 * another
976 * @src: source bio list
977 * @dst: destination bio list
978 *
979 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
980 * @src and @dst as linked lists of bios.
981 *
982 * Stops when it reaches the end of either @src or @dst - that is, copies
983 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
984 */
985void bio_copy_data(struct bio *dst, struct bio *src)
986{
987 struct bvec_iter src_iter, dst_iter;
988 struct bio_vec src_bv, dst_bv;
989 void *src_p, *dst_p;
990 unsigned bytes;
991
992 src_iter = src->bi_iter;
993 dst_iter = dst->bi_iter;
994
995 while (1) {
996 if (!src_iter.bi_size) {
997 src = src->bi_next;
998 if (!src)
999 break;
1000
1001 src_iter = src->bi_iter;
1002 }
1003
1004 if (!dst_iter.bi_size) {
1005 dst = dst->bi_next;
1006 if (!dst)
1007 break;
1008
1009 dst_iter = dst->bi_iter;
1010 }
1011
1012 src_bv = bio_iter_iovec(src, src_iter);
1013 dst_bv = bio_iter_iovec(dst, dst_iter);
1014
1015 bytes = min(src_bv.bv_len, dst_bv.bv_len);
1016
1017 src_p = kmap_atomic(src_bv.bv_page);
1018 dst_p = kmap_atomic(dst_bv.bv_page);
1019
1020 memcpy(dst_p + dst_bv.bv_offset,
1021 src_p + src_bv.bv_offset,
1022 bytes);
1023
1024 kunmap_atomic(dst_p);
1025 kunmap_atomic(src_p);
1026
1027 bio_advance_iter(src, &src_iter, bytes);
1028 bio_advance_iter(dst, &dst_iter, bytes);
1029 }
1030}
1031EXPORT_SYMBOL(bio_copy_data);
1032
1033struct bio_map_data {
1034 int is_our_pages;
1035 struct iov_iter iter;
1036 struct iovec iov[];
1037};
1038
1039static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
1040 gfp_t gfp_mask)
1041{
1042 struct bio_map_data *bmd;
1043 if (data->nr_segs > UIO_MAXIOV)
1044 return NULL;
1045
1046 bmd = kmalloc(sizeof(struct bio_map_data) +
1047 sizeof(struct iovec) * data->nr_segs, gfp_mask);
1048 if (!bmd)
1049 return NULL;
1050 memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
1051 bmd->iter = *data;
1052 bmd->iter.iov = bmd->iov;
1053 return bmd;
1054}
1055
1056/**
1057 * bio_copy_from_iter - copy all pages from iov_iter to bio
1058 * @bio: The &struct bio which describes the I/O as destination
1059 * @iter: iov_iter as source
1060 *
1061 * Copy all pages from iov_iter to bio.
1062 * Returns 0 on success, or error on failure.
1063 */
1064static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
1065{
1066 int i;
1067 struct bio_vec *bvec;
1068
1069 bio_for_each_segment_all(bvec, bio, i) {
1070 ssize_t ret;
1071
1072 ret = copy_page_from_iter(bvec->bv_page,
1073 bvec->bv_offset,
1074 bvec->bv_len,
1075 iter);
1076
1077 if (!iov_iter_count(iter))
1078 break;
1079
1080 if (ret < bvec->bv_len)
1081 return -EFAULT;
1082 }
1083
1084 return 0;
1085}
1086
1087/**
1088 * bio_copy_to_iter - copy all pages from bio to iov_iter
1089 * @bio: The &struct bio which describes the I/O as source
1090 * @iter: iov_iter as destination
1091 *
1092 * Copy all pages from bio to iov_iter.
1093 * Returns 0 on success, or error on failure.
1094 */
1095static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
1096{
1097 int i;
1098 struct bio_vec *bvec;
1099
1100 bio_for_each_segment_all(bvec, bio, i) {
1101 ssize_t ret;
1102
1103 ret = copy_page_to_iter(bvec->bv_page,
1104 bvec->bv_offset,
1105 bvec->bv_len,
1106 &iter);
1107
1108 if (!iov_iter_count(&iter))
1109 break;
1110
1111 if (ret < bvec->bv_len)
1112 return -EFAULT;
1113 }
1114
1115 return 0;
1116}
1117
1118void bio_free_pages(struct bio *bio)
1119{
1120 struct bio_vec *bvec;
1121 int i;
1122
1123 bio_for_each_segment_all(bvec, bio, i)
1124 __free_page(bvec->bv_page);
1125}
1126EXPORT_SYMBOL(bio_free_pages);
1127
1128/**
1129 * bio_uncopy_user - finish previously mapped bio
1130 * @bio: bio being terminated
1131 *
1132 * Free pages allocated from bio_copy_user_iov() and write back data
1133 * to user space in case of a read.
1134 */
1135int bio_uncopy_user(struct bio *bio)
1136{
1137 struct bio_map_data *bmd = bio->bi_private;
1138 int ret = 0;
1139
1140 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1141 /*
1142 * if we're in a workqueue, the request is orphaned, so
1143 * don't copy into a random user address space, just free
1144 * and return -EINTR so user space doesn't expect any data.
1145 */
1146 if (!current->mm)
1147 ret = -EINTR;
1148 else if (bio_data_dir(bio) == READ)
1149 ret = bio_copy_to_iter(bio, bmd->iter);
1150 if (bmd->is_our_pages)
1151 bio_free_pages(bio);
1152 }
1153 kfree(bmd);
1154 bio_put(bio);
1155 return ret;
1156}
1157
1158/**
1159 * bio_copy_user_iov - copy user data to bio
1160 * @q: destination block queue
1161 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1162 * @iter: iovec iterator
1163 * @gfp_mask: memory allocation flags
1164 *
1165 * Prepares and returns a bio for indirect user io, bouncing data
1166 * to/from kernel pages as necessary. Must be paired with
1167 * call bio_uncopy_user() on io completion.
1168 */
1169struct bio *bio_copy_user_iov(struct request_queue *q,
1170 struct rq_map_data *map_data,
1171 struct iov_iter *iter,
1172 gfp_t gfp_mask)
1173{
1174 struct bio_map_data *bmd;
1175 struct page *page;
1176 struct bio *bio;
1177 int i = 0, ret;
1178 int nr_pages;
1179 unsigned int len = iter->count;
1180 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
1181
1182 bmd = bio_alloc_map_data(iter, gfp_mask);
1183 if (!bmd)
1184 return ERR_PTR(-ENOMEM);
1185
1186 /*
1187 * We need to do a deep copy of the iov_iter including the iovecs.
1188 * The caller provided iov might point to an on-stack or otherwise
1189 * shortlived one.
1190 */
1191 bmd->is_our_pages = map_data ? 0 : 1;
1192
1193 nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE);
1194 if (nr_pages > BIO_MAX_PAGES)
1195 nr_pages = BIO_MAX_PAGES;
1196
1197 ret = -ENOMEM;
1198 bio = bio_kmalloc(gfp_mask, nr_pages);
1199 if (!bio)
1200 goto out_bmd;
1201
1202 ret = 0;
1203
1204 if (map_data) {
1205 nr_pages = 1 << map_data->page_order;
1206 i = map_data->offset / PAGE_SIZE;
1207 }
1208 while (len) {
1209 unsigned int bytes = PAGE_SIZE;
1210
1211 bytes -= offset;
1212
1213 if (bytes > len)
1214 bytes = len;
1215
1216 if (map_data) {
1217 if (i == map_data->nr_entries * nr_pages) {
1218 ret = -ENOMEM;
1219 break;
1220 }
1221
1222 page = map_data->pages[i / nr_pages];
1223 page += (i % nr_pages);
1224
1225 i++;
1226 } else {
1227 page = alloc_page(q->bounce_gfp | gfp_mask);
1228 if (!page) {
1229 ret = -ENOMEM;
1230 break;
1231 }
1232 }
1233
1234 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1235 break;
1236
1237 len -= bytes;
1238 offset = 0;
1239 }
1240
1241 if (ret)
1242 goto cleanup;
1243
1244 if (map_data)
1245 map_data->offset += bio->bi_iter.bi_size;
1246
1247 /*
1248 * success
1249 */
1250 if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
1251 (map_data && map_data->from_user)) {
1252 ret = bio_copy_from_iter(bio, iter);
1253 if (ret)
1254 goto cleanup;
1255 } else {
1256 iov_iter_advance(iter, bio->bi_iter.bi_size);
1257 }
1258
1259 bio->bi_private = bmd;
1260 if (map_data && map_data->null_mapped)
1261 bio_set_flag(bio, BIO_NULL_MAPPED);
1262 return bio;
1263cleanup:
1264 if (!map_data)
1265 bio_free_pages(bio);
1266 bio_put(bio);
1267out_bmd:
1268 kfree(bmd);
1269 return ERR_PTR(ret);
1270}
1271
1272/**
1273 * bio_map_user_iov - map user iovec into bio
1274 * @q: the struct request_queue for the bio
1275 * @iter: iovec iterator
1276 * @gfp_mask: memory allocation flags
1277 *
1278 * Map the user space address into a bio suitable for io to a block
1279 * device. Returns an error pointer in case of error.
1280 */
1281struct bio *bio_map_user_iov(struct request_queue *q,
1282 struct iov_iter *iter,
1283 gfp_t gfp_mask)
1284{
1285 int j;
1286 struct bio *bio;
1287 int ret;
1288 struct bio_vec *bvec;
1289
1290 if (!iov_iter_count(iter))
1291 return ERR_PTR(-EINVAL);
1292
1293 bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES));
1294 if (!bio)
1295 return ERR_PTR(-ENOMEM);
1296
1297 while (iov_iter_count(iter)) {
1298 struct page **pages;
1299 ssize_t bytes;
1300 size_t offs, added = 0;
1301 int npages;
1302
1303 bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
1304 if (unlikely(bytes <= 0)) {
1305 ret = bytes ? bytes : -EFAULT;
1306 goto out_unmap;
1307 }
1308
1309 npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
1310
1311 if (unlikely(offs & queue_dma_alignment(q))) {
1312 ret = -EINVAL;
1313 j = 0;
1314 } else {
1315 for (j = 0; j < npages; j++) {
1316 struct page *page = pages[j];
1317 unsigned int n = PAGE_SIZE - offs;
1318 unsigned short prev_bi_vcnt = bio->bi_vcnt;
1319
1320 if (n > bytes)
1321 n = bytes;
1322
1323 if (!bio_add_pc_page(q, bio, page, n, offs))
1324 break;
1325
1326 /*
1327 * check if vector was merged with previous
1328 * drop page reference if needed
1329 */
1330 if (bio->bi_vcnt == prev_bi_vcnt)
1331 put_page(page);
1332
1333 added += n;
1334 bytes -= n;
1335 offs = 0;
1336 }
1337 iov_iter_advance(iter, added);
1338 }
1339 /*
1340 * release the pages we didn't map into the bio, if any
1341 */
1342 while (j < npages)
1343 put_page(pages[j++]);
1344 kvfree(pages);
1345 /* couldn't stuff something into bio? */
1346 if (bytes)
1347 break;
1348 }
1349
1350 bio_set_flag(bio, BIO_USER_MAPPED);
1351
1352 /*
1353 * subtle -- if bio_map_user_iov() ended up bouncing a bio,
1354 * it would normally disappear when its bi_end_io is run.
1355 * however, we need it for the unmap, so grab an extra
1356 * reference to it
1357 */
1358 bio_get(bio);
1359 return bio;
1360
1361 out_unmap:
1362 bio_for_each_segment_all(bvec, bio, j) {
1363 put_page(bvec->bv_page);
1364 }
1365 bio_put(bio);
1366 return ERR_PTR(ret);
1367}
1368
1369static void __bio_unmap_user(struct bio *bio)
1370{
1371 struct bio_vec *bvec;
1372 int i;
1373
1374 /*
1375 * make sure we dirty pages we wrote to
1376 */
1377 bio_for_each_segment_all(bvec, bio, i) {
1378 if (bio_data_dir(bio) == READ)
1379 set_page_dirty_lock(bvec->bv_page);
1380
1381 put_page(bvec->bv_page);
1382 }
1383
1384 bio_put(bio);
1385}
1386
1387/**
1388 * bio_unmap_user - unmap a bio
1389 * @bio: the bio being unmapped
1390 *
1391 * Unmap a bio previously mapped by bio_map_user_iov(). Must be called from
1392 * process context.
1393 *
1394 * bio_unmap_user() may sleep.
1395 */
1396void bio_unmap_user(struct bio *bio)
1397{
1398 __bio_unmap_user(bio);
1399 bio_put(bio);
1400}
1401
1402static void bio_map_kern_endio(struct bio *bio)
1403{
1404 bio_put(bio);
1405}
1406
1407/**
1408 * bio_map_kern - map kernel address into bio
1409 * @q: the struct request_queue for the bio
1410 * @data: pointer to buffer to map
1411 * @len: length in bytes
1412 * @gfp_mask: allocation flags for bio allocation
1413 *
1414 * Map the kernel address into a bio suitable for io to a block
1415 * device. Returns an error pointer in case of error.
1416 */
1417struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1418 gfp_t gfp_mask)
1419{
1420 unsigned long kaddr = (unsigned long)data;
1421 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1422 unsigned long start = kaddr >> PAGE_SHIFT;
1423 const int nr_pages = end - start;
1424 int offset, i;
1425 struct bio *bio;
1426
1427 bio = bio_kmalloc(gfp_mask, nr_pages);
1428 if (!bio)
1429 return ERR_PTR(-ENOMEM);
1430
1431 offset = offset_in_page(kaddr);
1432 for (i = 0; i < nr_pages; i++) {
1433 unsigned int bytes = PAGE_SIZE - offset;
1434
1435 if (len <= 0)
1436 break;
1437
1438 if (bytes > len)
1439 bytes = len;
1440
1441 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1442 offset) < bytes) {
1443 /* we don't support partial mappings */
1444 bio_put(bio);
1445 return ERR_PTR(-EINVAL);
1446 }
1447
1448 data += bytes;
1449 len -= bytes;
1450 offset = 0;
1451 }
1452
1453 bio->bi_end_io = bio_map_kern_endio;
1454 return bio;
1455}
1456EXPORT_SYMBOL(bio_map_kern);
1457
1458static void bio_copy_kern_endio(struct bio *bio)
1459{
1460 bio_free_pages(bio);
1461 bio_put(bio);
1462}
1463
1464static void bio_copy_kern_endio_read(struct bio *bio)
1465{
1466 char *p = bio->bi_private;
1467 struct bio_vec *bvec;
1468 int i;
1469
1470 bio_for_each_segment_all(bvec, bio, i) {
1471 memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
1472 p += bvec->bv_len;
1473 }
1474
1475 bio_copy_kern_endio(bio);
1476}
1477
1478/**
1479 * bio_copy_kern - copy kernel address into bio
1480 * @q: the struct request_queue for the bio
1481 * @data: pointer to buffer to copy
1482 * @len: length in bytes
1483 * @gfp_mask: allocation flags for bio and page allocation
1484 * @reading: data direction is READ
1485 *
1486 * copy the kernel address into a bio suitable for io to a block
1487 * device. Returns an error pointer in case of error.
1488 */
1489struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1490 gfp_t gfp_mask, int reading)
1491{
1492 unsigned long kaddr = (unsigned long)data;
1493 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1494 unsigned long start = kaddr >> PAGE_SHIFT;
1495 struct bio *bio;
1496 void *p = data;
1497 int nr_pages = 0;
1498
1499 /*
1500 * Overflow, abort
1501 */
1502 if (end < start)
1503 return ERR_PTR(-EINVAL);
1504
1505 nr_pages = end - start;
1506 bio = bio_kmalloc(gfp_mask, nr_pages);
1507 if (!bio)
1508 return ERR_PTR(-ENOMEM);
1509
1510 while (len) {
1511 struct page *page;
1512 unsigned int bytes = PAGE_SIZE;
1513
1514 if (bytes > len)
1515 bytes = len;
1516
1517 page = alloc_page(q->bounce_gfp | gfp_mask);
1518 if (!page)
1519 goto cleanup;
1520
1521 if (!reading)
1522 memcpy(page_address(page), p, bytes);
1523
1524 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
1525 break;
1526
1527 len -= bytes;
1528 p += bytes;
1529 }
1530
1531 if (reading) {
1532 bio->bi_end_io = bio_copy_kern_endio_read;
1533 bio->bi_private = data;
1534 } else {
1535 bio->bi_end_io = bio_copy_kern_endio;
1536 }
1537
1538 return bio;
1539
1540cleanup:
1541 bio_free_pages(bio);
1542 bio_put(bio);
1543 return ERR_PTR(-ENOMEM);
1544}
1545
1546/*
1547 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1548 * for performing direct-IO in BIOs.
1549 *
1550 * The problem is that we cannot run set_page_dirty() from interrupt context
1551 * because the required locks are not interrupt-safe. So what we can do is to
1552 * mark the pages dirty _before_ performing IO. And in interrupt context,
1553 * check that the pages are still dirty. If so, fine. If not, redirty them
1554 * in process context.
1555 *
1556 * We special-case compound pages here: normally this means reads into hugetlb
1557 * pages. The logic in here doesn't really work right for compound pages
1558 * because the VM does not uniformly chase down the head page in all cases.
1559 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1560 * handle them at all. So we skip compound pages here at an early stage.
1561 *
1562 * Note that this code is very hard to test under normal circumstances because
1563 * direct-io pins the pages with get_user_pages(). This makes
1564 * is_page_cache_freeable return false, and the VM will not clean the pages.
1565 * But other code (eg, flusher threads) could clean the pages if they are mapped
1566 * pagecache.
1567 *
1568 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1569 * deferred bio dirtying paths.
1570 */
1571
1572/*
1573 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1574 */
1575void bio_set_pages_dirty(struct bio *bio)
1576{
1577 struct bio_vec *bvec;
1578 int i;
1579
1580 bio_for_each_segment_all(bvec, bio, i) {
1581 struct page *page = bvec->bv_page;
1582
1583 if (page && !PageCompound(page))
1584 set_page_dirty_lock(page);
1585 }
1586}
1587
1588static void bio_release_pages(struct bio *bio)
1589{
1590 struct bio_vec *bvec;
1591 int i;
1592
1593 bio_for_each_segment_all(bvec, bio, i) {
1594 struct page *page = bvec->bv_page;
1595
1596 if (page)
1597 put_page(page);
1598 }
1599}
1600
1601/*
1602 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1603 * If they are, then fine. If, however, some pages are clean then they must
1604 * have been written out during the direct-IO read. So we take another ref on
1605 * the BIO and the offending pages and re-dirty the pages in process context.
1606 *
1607 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1608 * here on. It will run one put_page() against each page and will run one
1609 * bio_put() against the BIO.
1610 */
1611
1612static void bio_dirty_fn(struct work_struct *work);
1613
1614static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1615static DEFINE_SPINLOCK(bio_dirty_lock);
1616static struct bio *bio_dirty_list;
1617
1618/*
1619 * This runs in process context
1620 */
1621static void bio_dirty_fn(struct work_struct *work)
1622{
1623 unsigned long flags;
1624 struct bio *bio;
1625
1626 spin_lock_irqsave(&bio_dirty_lock, flags);
1627 bio = bio_dirty_list;
1628 bio_dirty_list = NULL;
1629 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1630
1631 while (bio) {
1632 struct bio *next = bio->bi_private;
1633
1634 bio_set_pages_dirty(bio);
1635 bio_release_pages(bio);
1636 bio_put(bio);
1637 bio = next;
1638 }
1639}
1640
1641void bio_check_pages_dirty(struct bio *bio)
1642{
1643 struct bio_vec *bvec;
1644 int nr_clean_pages = 0;
1645 int i;
1646
1647 bio_for_each_segment_all(bvec, bio, i) {
1648 struct page *page = bvec->bv_page;
1649
1650 if (PageDirty(page) || PageCompound(page)) {
1651 put_page(page);
1652 bvec->bv_page = NULL;
1653 } else {
1654 nr_clean_pages++;
1655 }
1656 }
1657
1658 if (nr_clean_pages) {
1659 unsigned long flags;
1660
1661 spin_lock_irqsave(&bio_dirty_lock, flags);
1662 bio->bi_private = bio_dirty_list;
1663 bio_dirty_list = bio;
1664 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1665 schedule_work(&bio_dirty_work);
1666 } else {
1667 bio_put(bio);
1668 }
1669}
1670
1671void generic_start_io_acct(struct request_queue *q, int rw,
1672 unsigned long sectors, struct hd_struct *part)
1673{
1674 int cpu = part_stat_lock();
1675
1676 part_round_stats(q, cpu, part);
1677 part_stat_inc(cpu, part, ios[rw]);
1678 part_stat_add(cpu, part, sectors[rw], sectors);
1679 part_inc_in_flight(q, part, rw);
1680
1681 part_stat_unlock();
1682}
1683EXPORT_SYMBOL(generic_start_io_acct);
1684
1685void generic_end_io_acct(struct request_queue *q, int rw,
1686 struct hd_struct *part, unsigned long start_time)
1687{
1688 unsigned long duration = jiffies - start_time;
1689 int cpu = part_stat_lock();
1690
1691 part_stat_add(cpu, part, ticks[rw], duration);
1692 part_round_stats(q, cpu, part);
1693 part_dec_in_flight(q, part, rw);
1694
1695 part_stat_unlock();
1696}
1697EXPORT_SYMBOL(generic_end_io_acct);
1698
1699#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1700void bio_flush_dcache_pages(struct bio *bi)
1701{
1702 struct bio_vec bvec;
1703 struct bvec_iter iter;
1704
1705 bio_for_each_segment(bvec, bi, iter)
1706 flush_dcache_page(bvec.bv_page);
1707}
1708EXPORT_SYMBOL(bio_flush_dcache_pages);
1709#endif
1710
1711static inline bool bio_remaining_done(struct bio *bio)
1712{
1713 /*
1714 * If we're not chaining, then ->__bi_remaining is always 1 and
1715 * we always end io on the first invocation.
1716 */
1717 if (!bio_flagged(bio, BIO_CHAIN))
1718 return true;
1719
1720 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1721
1722 if (atomic_dec_and_test(&bio->__bi_remaining)) {
1723 bio_clear_flag(bio, BIO_CHAIN);
1724 return true;
1725 }
1726
1727 return false;
1728}
1729
1730/**
1731 * bio_endio - end I/O on a bio
1732 * @bio: bio
1733 *
1734 * Description:
1735 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1736 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1737 * bio unless they own it and thus know that it has an end_io function.
1738 *
1739 * bio_endio() can be called several times on a bio that has been chained
1740 * using bio_chain(). The ->bi_end_io() function will only be called the
1741 * last time. At this point the BLK_TA_COMPLETE tracing event will be
1742 * generated if BIO_TRACE_COMPLETION is set.
1743 **/
1744void bio_endio(struct bio *bio)
1745{
1746again:
1747 if (!bio_remaining_done(bio))
1748 return;
1749 if (!bio_integrity_endio(bio))
1750 return;
1751
1752 /*
1753 * Need to have a real endio function for chained bios, otherwise
1754 * various corner cases will break (like stacking block devices that
1755 * save/restore bi_end_io) - however, we want to avoid unbounded
1756 * recursion and blowing the stack. Tail call optimization would
1757 * handle this, but compiling with frame pointers also disables
1758 * gcc's sibling call optimization.
1759 */
1760 if (bio->bi_end_io == bio_chain_endio) {
1761 bio = __bio_chain_endio(bio);
1762 goto again;
1763 }
1764
1765 if (bio->bi_disk && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
1766 trace_block_bio_complete(bio->bi_disk->queue, bio,
1767 blk_status_to_errno(bio->bi_status));
1768 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1769 }
1770
1771 blk_throtl_bio_endio(bio);
1772 /* release cgroup info */
1773 bio_uninit(bio);
1774 if (bio->bi_end_io)
1775 bio->bi_end_io(bio);
1776}
1777EXPORT_SYMBOL(bio_endio);
1778
1779/**
1780 * bio_split - split a bio
1781 * @bio: bio to split
1782 * @sectors: number of sectors to split from the front of @bio
1783 * @gfp: gfp mask
1784 * @bs: bio set to allocate from
1785 *
1786 * Allocates and returns a new bio which represents @sectors from the start of
1787 * @bio, and updates @bio to represent the remaining sectors.
1788 *
1789 * Unless this is a discard request the newly allocated bio will point
1790 * to @bio's bi_io_vec; it is the caller's responsibility to ensure that
1791 * @bio is not freed before the split.
1792 */
1793struct bio *bio_split(struct bio *bio, int sectors,
1794 gfp_t gfp, struct bio_set *bs)
1795{
1796 struct bio *split;
1797
1798 BUG_ON(sectors <= 0);
1799 BUG_ON(sectors >= bio_sectors(bio));
1800
1801 split = bio_clone_fast(bio, gfp, bs);
1802 if (!split)
1803 return NULL;
1804
1805 split->bi_iter.bi_size = sectors << 9;
1806
1807 if (bio_integrity(split))
1808 bio_integrity_trim(split);
1809
1810 bio_advance(bio, split->bi_iter.bi_size);
1811
1812 if (bio_flagged(bio, BIO_TRACE_COMPLETION))
1813 bio_set_flag(split, BIO_TRACE_COMPLETION);
1814
1815 return split;
1816}
1817EXPORT_SYMBOL(bio_split);
1818
1819/**
1820 * bio_trim - trim a bio
1821 * @bio: bio to trim
1822 * @offset: number of sectors to trim from the front of @bio
1823 * @size: size we want to trim @bio to, in sectors
1824 */
1825void bio_trim(struct bio *bio, int offset, int size)
1826{
1827 /* 'bio' is a cloned bio which we need to trim to match
1828 * the given offset and size.
1829 */
1830
1831 size <<= 9;
1832 if (offset == 0 && size == bio->bi_iter.bi_size)
1833 return;
1834
1835 bio_clear_flag(bio, BIO_SEG_VALID);
1836
1837 bio_advance(bio, offset << 9);
1838
1839 bio->bi_iter.bi_size = size;
1840
1841 if (bio_integrity(bio))
1842 bio_integrity_trim(bio);
1843
1844}
1845EXPORT_SYMBOL_GPL(bio_trim);
1846
1847/*
1848 * create memory pools for biovec's in a bio_set.
1849 * use the global biovec slabs created for general use.
1850 */
1851mempool_t *biovec_create_pool(int pool_entries)
1852{
1853 struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX;
1854
1855 return mempool_create_slab_pool(pool_entries, bp->slab);
1856}
1857
1858void bioset_free(struct bio_set *bs)
1859{
1860 if (bs->rescue_workqueue)
1861 destroy_workqueue(bs->rescue_workqueue);
1862
1863 mempool_destroy(bs->bio_pool);
1864 mempool_destroy(bs->bvec_pool);
1865
1866 bioset_integrity_free(bs);
1867 bio_put_slab(bs);
1868
1869 kfree(bs);
1870}
1871EXPORT_SYMBOL(bioset_free);
1872
1873/**
1874 * bioset_create - Create a bio_set
1875 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1876 * @front_pad: Number of bytes to allocate in front of the returned bio
1877 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS
1878 * and %BIOSET_NEED_RESCUER
1879 *
1880 * Description:
1881 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1882 * to ask for a number of bytes to be allocated in front of the bio.
1883 * Front pad allocation is useful for embedding the bio inside
1884 * another structure, to avoid allocating extra data to go with the bio.
1885 * Note that the bio must be embedded at the END of that structure always,
1886 * or things will break badly.
1887 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated
1888 * for allocating iovecs. This pool is not needed e.g. for bio_clone_fast().
1889 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used to
1890 * dispatch queued requests when the mempool runs out of space.
1891 *
1892 */
1893struct bio_set *bioset_create(unsigned int pool_size,
1894 unsigned int front_pad,
1895 int flags)
1896{
1897 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1898 struct bio_set *bs;
1899
1900 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1901 if (!bs)
1902 return NULL;
1903
1904 bs->front_pad = front_pad;
1905
1906 spin_lock_init(&bs->rescue_lock);
1907 bio_list_init(&bs->rescue_list);
1908 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1909
1910 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1911 if (!bs->bio_slab) {
1912 kfree(bs);
1913 return NULL;
1914 }
1915
1916 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1917 if (!bs->bio_pool)
1918 goto bad;
1919
1920 if (flags & BIOSET_NEED_BVECS) {
1921 bs->bvec_pool = biovec_create_pool(pool_size);
1922 if (!bs->bvec_pool)
1923 goto bad;
1924 }
1925
1926 if (!(flags & BIOSET_NEED_RESCUER))
1927 return bs;
1928
1929 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1930 if (!bs->rescue_workqueue)
1931 goto bad;
1932
1933 return bs;
1934bad:
1935 bioset_free(bs);
1936 return NULL;
1937}
1938EXPORT_SYMBOL(bioset_create);
1939
1940#ifdef CONFIG_BLK_CGROUP
1941
1942/**
1943 * bio_associate_blkcg - associate a bio with the specified blkcg
1944 * @bio: target bio
1945 * @blkcg_css: css of the blkcg to associate
1946 *
1947 * Associate @bio with the blkcg specified by @blkcg_css. Block layer will
1948 * treat @bio as if it were issued by a task which belongs to the blkcg.
1949 *
1950 * This function takes an extra reference of @blkcg_css which will be put
1951 * when @bio is released. The caller must own @bio and is responsible for
1952 * synchronizing calls to this function.
1953 */
1954int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
1955{
1956 if (unlikely(bio->bi_css))
1957 return -EBUSY;
1958 css_get(blkcg_css);
1959 bio->bi_css = blkcg_css;
1960 return 0;
1961}
1962EXPORT_SYMBOL_GPL(bio_associate_blkcg);
1963
1964/**
1965 * bio_disassociate_task - undo bio_associate_current()
1966 * @bio: target bio
1967 */
1968void bio_disassociate_task(struct bio *bio)
1969{
1970 if (bio->bi_ioc) {
1971 put_io_context(bio->bi_ioc);
1972 bio->bi_ioc = NULL;
1973 }
1974 if (bio->bi_css) {
1975 css_put(bio->bi_css);
1976 bio->bi_css = NULL;
1977 }
1978}
1979
1980/**
1981 * bio_clone_blkcg_association - clone blkcg association from src to dst bio
1982 * @dst: destination bio
1983 * @src: source bio
1984 */
1985void bio_clone_blkcg_association(struct bio *dst, struct bio *src)
1986{
1987 if (src->bi_css)
1988 WARN_ON(bio_associate_blkcg(dst, src->bi_css));
1989}
1990EXPORT_SYMBOL_GPL(bio_clone_blkcg_association);
1991#endif /* CONFIG_BLK_CGROUP */
1992
1993static void __init biovec_init_slabs(void)
1994{
1995 int i;
1996
1997 for (i = 0; i < BVEC_POOL_NR; i++) {
1998 int size;
1999 struct biovec_slab *bvs = bvec_slabs + i;
2000
2001 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
2002 bvs->slab = NULL;
2003 continue;
2004 }
2005
2006 size = bvs->nr_vecs * sizeof(struct bio_vec);
2007 bvs->slab = kmem_cache_create(bvs->name, size, 0,
2008 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2009 }
2010}
2011
2012static int __init init_bio(void)
2013{
2014 bio_slab_max = 2;
2015 bio_slab_nr = 0;
2016 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2017 if (!bio_slabs)
2018 panic("bio: can't allocate bios\n");
2019
2020 bio_integrity_init();
2021 biovec_init_slabs();
2022
2023 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
2024 if (!fs_bio_set)
2025 panic("bio: can't allocate bios\n");
2026
2027 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2028 panic("bio: can't create integrity pool\n");
2029
2030 return 0;
2031}
2032subsys_initcall(init_bio);