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#include <linux/blk-cgroup.h>
32
33#include <trace/events/block.h>
34#include "blk.h"
35#include "blk-rq-qos.h"
36
37/*
38 * Test patch to inline a certain number of bi_io_vec's inside the bio
39 * itself, to shrink a bio data allocation from two mempool calls to one
40 */
41#define BIO_INLINE_VECS 4
42
43/*
44 * if you change this list, also change bvec_alloc or things will
45 * break badly! cannot be bigger than what you can fit into an
46 * unsigned short
47 */
48#define BV(x, n) { .nr_vecs = x, .name = "biovec-"#n }
49static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = {
50 BV(1, 1), BV(4, 4), BV(16, 16), BV(64, 64), BV(128, 128), BV(BIO_MAX_PAGES, max),
51};
52#undef BV
53
54/*
55 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
56 * IO code that does not need private memory pools.
57 */
58struct bio_set fs_bio_set;
59EXPORT_SYMBOL(fs_bio_set);
60
61/*
62 * Our slab pool management
63 */
64struct bio_slab {
65 struct kmem_cache *slab;
66 unsigned int slab_ref;
67 unsigned int slab_size;
68 char name[8];
69};
70static DEFINE_MUTEX(bio_slab_lock);
71static struct bio_slab *bio_slabs;
72static unsigned int bio_slab_nr, bio_slab_max;
73
74static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
75{
76 unsigned int sz = sizeof(struct bio) + extra_size;
77 struct kmem_cache *slab = NULL;
78 struct bio_slab *bslab, *new_bio_slabs;
79 unsigned int new_bio_slab_max;
80 unsigned int i, entry = -1;
81
82 mutex_lock(&bio_slab_lock);
83
84 i = 0;
85 while (i < bio_slab_nr) {
86 bslab = &bio_slabs[i];
87
88 if (!bslab->slab && entry == -1)
89 entry = i;
90 else if (bslab->slab_size == sz) {
91 slab = bslab->slab;
92 bslab->slab_ref++;
93 break;
94 }
95 i++;
96 }
97
98 if (slab)
99 goto out_unlock;
100
101 if (bio_slab_nr == bio_slab_max && entry == -1) {
102 new_bio_slab_max = bio_slab_max << 1;
103 new_bio_slabs = krealloc(bio_slabs,
104 new_bio_slab_max * sizeof(struct bio_slab),
105 GFP_KERNEL);
106 if (!new_bio_slabs)
107 goto out_unlock;
108 bio_slab_max = new_bio_slab_max;
109 bio_slabs = new_bio_slabs;
110 }
111 if (entry == -1)
112 entry = bio_slab_nr++;
113
114 bslab = &bio_slabs[entry];
115
116 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
117 slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN,
118 SLAB_HWCACHE_ALIGN, NULL);
119 if (!slab)
120 goto out_unlock;
121
122 bslab->slab = slab;
123 bslab->slab_ref = 1;
124 bslab->slab_size = sz;
125out_unlock:
126 mutex_unlock(&bio_slab_lock);
127 return slab;
128}
129
130static void bio_put_slab(struct bio_set *bs)
131{
132 struct bio_slab *bslab = NULL;
133 unsigned int i;
134
135 mutex_lock(&bio_slab_lock);
136
137 for (i = 0; i < bio_slab_nr; i++) {
138 if (bs->bio_slab == bio_slabs[i].slab) {
139 bslab = &bio_slabs[i];
140 break;
141 }
142 }
143
144 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
145 goto out;
146
147 WARN_ON(!bslab->slab_ref);
148
149 if (--bslab->slab_ref)
150 goto out;
151
152 kmem_cache_destroy(bslab->slab);
153 bslab->slab = NULL;
154
155out:
156 mutex_unlock(&bio_slab_lock);
157}
158
159unsigned int bvec_nr_vecs(unsigned short idx)
160{
161 return bvec_slabs[--idx].nr_vecs;
162}
163
164void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
165{
166 if (!idx)
167 return;
168 idx--;
169
170 BIO_BUG_ON(idx >= BVEC_POOL_NR);
171
172 if (idx == BVEC_POOL_MAX) {
173 mempool_free(bv, pool);
174 } else {
175 struct biovec_slab *bvs = bvec_slabs + idx;
176
177 kmem_cache_free(bvs->slab, bv);
178 }
179}
180
181struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
182 mempool_t *pool)
183{
184 struct bio_vec *bvl;
185
186 /*
187 * see comment near bvec_array define!
188 */
189 switch (nr) {
190 case 1:
191 *idx = 0;
192 break;
193 case 2 ... 4:
194 *idx = 1;
195 break;
196 case 5 ... 16:
197 *idx = 2;
198 break;
199 case 17 ... 64:
200 *idx = 3;
201 break;
202 case 65 ... 128:
203 *idx = 4;
204 break;
205 case 129 ... BIO_MAX_PAGES:
206 *idx = 5;
207 break;
208 default:
209 return NULL;
210 }
211
212 /*
213 * idx now points to the pool we want to allocate from. only the
214 * 1-vec entry pool is mempool backed.
215 */
216 if (*idx == BVEC_POOL_MAX) {
217fallback:
218 bvl = mempool_alloc(pool, gfp_mask);
219 } else {
220 struct biovec_slab *bvs = bvec_slabs + *idx;
221 gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO);
222
223 /*
224 * Make this allocation restricted and don't dump info on
225 * allocation failures, since we'll fallback to the mempool
226 * in case of failure.
227 */
228 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
229
230 /*
231 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM
232 * is set, retry with the 1-entry mempool
233 */
234 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
235 if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {
236 *idx = BVEC_POOL_MAX;
237 goto fallback;
238 }
239 }
240
241 (*idx)++;
242 return bvl;
243}
244
245void bio_uninit(struct bio *bio)
246{
247 bio_disassociate_blkg(bio);
248}
249EXPORT_SYMBOL(bio_uninit);
250
251static void bio_free(struct bio *bio)
252{
253 struct bio_set *bs = bio->bi_pool;
254 void *p;
255
256 bio_uninit(bio);
257
258 if (bs) {
259 bvec_free(&bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio));
260
261 /*
262 * If we have front padding, adjust the bio pointer before freeing
263 */
264 p = bio;
265 p -= bs->front_pad;
266
267 mempool_free(p, &bs->bio_pool);
268 } else {
269 /* Bio was allocated by bio_kmalloc() */
270 kfree(bio);
271 }
272}
273
274/*
275 * Users of this function have their own bio allocation. Subsequently,
276 * they must remember to pair any call to bio_init() with bio_uninit()
277 * when IO has completed, or when the bio is released.
278 */
279void bio_init(struct bio *bio, struct bio_vec *table,
280 unsigned short max_vecs)
281{
282 memset(bio, 0, sizeof(*bio));
283 atomic_set(&bio->__bi_remaining, 1);
284 atomic_set(&bio->__bi_cnt, 1);
285
286 bio->bi_io_vec = table;
287 bio->bi_max_vecs = max_vecs;
288}
289EXPORT_SYMBOL(bio_init);
290
291/**
292 * bio_reset - reinitialize a bio
293 * @bio: bio to reset
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)
302{
303 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
304
305 bio_uninit(bio);
306
307 memset(bio, 0, BIO_RESET_BYTES);
308 bio->bi_flags = flags;
309 atomic_set(&bio->__bi_remaining, 1);
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 (!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 @bio's parent 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
349static void bio_alloc_rescue(struct work_struct *work)
350{
351 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
352 struct bio *bio;
353
354 while (1) {
355 spin_lock(&bs->rescue_lock);
356 bio = bio_list_pop(&bs->rescue_list);
357 spin_unlock(&bs->rescue_lock);
358
359 if (!bio)
360 break;
361
362 generic_make_request(bio);
363 }
364}
365
366static void punt_bios_to_rescuer(struct bio_set *bs)
367{
368 struct bio_list punt, nopunt;
369 struct bio *bio;
370
371 if (WARN_ON_ONCE(!bs->rescue_workqueue))
372 return;
373 /*
374 * In order to guarantee forward progress we must punt only bios that
375 * were allocated from this bio_set; otherwise, if there was a bio on
376 * there for a stacking driver higher up in the stack, processing it
377 * could require allocating bios from this bio_set, and doing that from
378 * our own rescuer would be bad.
379 *
380 * Since bio lists are singly linked, pop them all instead of trying to
381 * remove from the middle of the list:
382 */
383
384 bio_list_init(&punt);
385 bio_list_init(&nopunt);
386
387 while ((bio = bio_list_pop(&current->bio_list[0])))
388 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
389 current->bio_list[0] = nopunt;
390
391 bio_list_init(&nopunt);
392 while ((bio = bio_list_pop(&current->bio_list[1])))
393 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
394 current->bio_list[1] = nopunt;
395
396 spin_lock(&bs->rescue_lock);
397 bio_list_merge(&bs->rescue_list, &punt);
398 spin_unlock(&bs->rescue_lock);
399
400 queue_work(bs->rescue_workqueue, &bs->rescue_work);
401}
402
403/**
404 * bio_alloc_bioset - allocate a bio for I/O
405 * @gfp_mask: the GFP_* mask given to the slab allocator
406 * @nr_iovecs: number of iovecs to pre-allocate
407 * @bs: the bio_set to allocate from.
408 *
409 * Description:
410 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
411 * backed by the @bs's mempool.
412 *
413 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will
414 * always be able to allocate a bio. This is due to the mempool guarantees.
415 * To make this work, callers must never allocate more than 1 bio at a time
416 * from this pool. Callers that need to allocate more than 1 bio must always
417 * submit the previously allocated bio for IO before attempting to allocate
418 * a new one. Failure to do so can cause deadlocks under memory pressure.
419 *
420 * Note that when running under generic_make_request() (i.e. any block
421 * driver), bios are not submitted until after you return - see the code in
422 * generic_make_request() that converts recursion into iteration, to prevent
423 * stack overflows.
424 *
425 * This would normally mean allocating multiple bios under
426 * generic_make_request() would be susceptible to deadlocks, but we have
427 * deadlock avoidance code that resubmits any blocked bios from a rescuer
428 * thread.
429 *
430 * However, we do not guarantee forward progress for allocations from other
431 * mempools. Doing multiple allocations from the same mempool under
432 * generic_make_request() should be avoided - instead, use bio_set's front_pad
433 * for per bio allocations.
434 *
435 * RETURNS:
436 * Pointer to new bio on success, NULL on failure.
437 */
438struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs,
439 struct bio_set *bs)
440{
441 gfp_t saved_gfp = gfp_mask;
442 unsigned front_pad;
443 unsigned inline_vecs;
444 struct bio_vec *bvl = NULL;
445 struct bio *bio;
446 void *p;
447
448 if (!bs) {
449 if (nr_iovecs > UIO_MAXIOV)
450 return NULL;
451
452 p = kmalloc(sizeof(struct bio) +
453 nr_iovecs * sizeof(struct bio_vec),
454 gfp_mask);
455 front_pad = 0;
456 inline_vecs = nr_iovecs;
457 } else {
458 /* should not use nobvec bioset for nr_iovecs > 0 */
459 if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) &&
460 nr_iovecs > 0))
461 return NULL;
462 /*
463 * generic_make_request() converts recursion to iteration; this
464 * means if we're running beneath it, any bios we allocate and
465 * submit will not be submitted (and thus freed) until after we
466 * return.
467 *
468 * This exposes us to a potential deadlock if we allocate
469 * multiple bios from the same bio_set() while running
470 * underneath generic_make_request(). If we were to allocate
471 * multiple bios (say a stacking block driver that was splitting
472 * bios), we would deadlock if we exhausted the mempool's
473 * reserve.
474 *
475 * We solve this, and guarantee forward progress, with a rescuer
476 * workqueue per bio_set. If we go to allocate and there are
477 * bios on current->bio_list, we first try the allocation
478 * without __GFP_DIRECT_RECLAIM; if that fails, we punt those
479 * bios we would be blocking to the rescuer workqueue before
480 * we retry with the original gfp_flags.
481 */
482
483 if (current->bio_list &&
484 (!bio_list_empty(&current->bio_list[0]) ||
485 !bio_list_empty(&current->bio_list[1])) &&
486 bs->rescue_workqueue)
487 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
488
489 p = mempool_alloc(&bs->bio_pool, gfp_mask);
490 if (!p && gfp_mask != saved_gfp) {
491 punt_bios_to_rescuer(bs);
492 gfp_mask = saved_gfp;
493 p = mempool_alloc(&bs->bio_pool, gfp_mask);
494 }
495
496 front_pad = bs->front_pad;
497 inline_vecs = BIO_INLINE_VECS;
498 }
499
500 if (unlikely(!p))
501 return NULL;
502
503 bio = p + front_pad;
504 bio_init(bio, NULL, 0);
505
506 if (nr_iovecs > inline_vecs) {
507 unsigned long idx = 0;
508
509 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool);
510 if (!bvl && gfp_mask != saved_gfp) {
511 punt_bios_to_rescuer(bs);
512 gfp_mask = saved_gfp;
513 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool);
514 }
515
516 if (unlikely(!bvl))
517 goto err_free;
518
519 bio->bi_flags |= idx << BVEC_POOL_OFFSET;
520 } else if (nr_iovecs) {
521 bvl = bio->bi_inline_vecs;
522 }
523
524 bio->bi_pool = bs;
525 bio->bi_max_vecs = nr_iovecs;
526 bio->bi_io_vec = bvl;
527 return bio;
528
529err_free:
530 mempool_free(p, &bs->bio_pool);
531 return NULL;
532}
533EXPORT_SYMBOL(bio_alloc_bioset);
534
535void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)
536{
537 unsigned long flags;
538 struct bio_vec bv;
539 struct bvec_iter iter;
540
541 __bio_for_each_segment(bv, bio, iter, start) {
542 char *data = bvec_kmap_irq(&bv, &flags);
543 memset(data, 0, bv.bv_len);
544 flush_dcache_page(bv.bv_page);
545 bvec_kunmap_irq(data, &flags);
546 }
547}
548EXPORT_SYMBOL(zero_fill_bio_iter);
549
550/**
551 * bio_put - release a reference to a bio
552 * @bio: bio to release reference to
553 *
554 * Description:
555 * Put a reference to a &struct bio, either one you have gotten with
556 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.
557 **/
558void bio_put(struct bio *bio)
559{
560 if (!bio_flagged(bio, BIO_REFFED))
561 bio_free(bio);
562 else {
563 BIO_BUG_ON(!atomic_read(&bio->__bi_cnt));
564
565 /*
566 * last put frees it
567 */
568 if (atomic_dec_and_test(&bio->__bi_cnt))
569 bio_free(bio);
570 }
571}
572EXPORT_SYMBOL(bio_put);
573
574int bio_phys_segments(struct request_queue *q, struct bio *bio)
575{
576 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
577 blk_recount_segments(q, bio);
578
579 return bio->bi_phys_segments;
580}
581
582/**
583 * __bio_clone_fast - clone a bio that shares the original bio's biovec
584 * @bio: destination bio
585 * @bio_src: bio to clone
586 *
587 * Clone a &bio. Caller will own the returned bio, but not
588 * the actual data it points to. Reference count of returned
589 * bio will be one.
590 *
591 * Caller must ensure that @bio_src is not freed before @bio.
592 */
593void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
594{
595 BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio));
596
597 /*
598 * most users will be overriding ->bi_disk with a new target,
599 * so we don't set nor calculate new physical/hw segment counts here
600 */
601 bio->bi_disk = bio_src->bi_disk;
602 bio->bi_partno = bio_src->bi_partno;
603 bio_set_flag(bio, BIO_CLONED);
604 if (bio_flagged(bio_src, BIO_THROTTLED))
605 bio_set_flag(bio, BIO_THROTTLED);
606 bio->bi_opf = bio_src->bi_opf;
607 bio->bi_ioprio = bio_src->bi_ioprio;
608 bio->bi_write_hint = bio_src->bi_write_hint;
609 bio->bi_iter = bio_src->bi_iter;
610 bio->bi_io_vec = bio_src->bi_io_vec;
611
612 bio_clone_blkg_association(bio, bio_src);
613 blkcg_bio_issue_init(bio);
614}
615EXPORT_SYMBOL(__bio_clone_fast);
616
617/**
618 * bio_clone_fast - clone a bio that shares the original bio's biovec
619 * @bio: bio to clone
620 * @gfp_mask: allocation priority
621 * @bs: bio_set to allocate from
622 *
623 * Like __bio_clone_fast, only also allocates the returned bio
624 */
625struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
626{
627 struct bio *b;
628
629 b = bio_alloc_bioset(gfp_mask, 0, bs);
630 if (!b)
631 return NULL;
632
633 __bio_clone_fast(b, bio);
634
635 if (bio_integrity(bio)) {
636 int ret;
637
638 ret = bio_integrity_clone(b, bio, gfp_mask);
639
640 if (ret < 0) {
641 bio_put(b);
642 return NULL;
643 }
644 }
645
646 return b;
647}
648EXPORT_SYMBOL(bio_clone_fast);
649
650/**
651 * bio_add_pc_page - attempt to add page to bio
652 * @q: the target queue
653 * @bio: destination bio
654 * @page: page to add
655 * @len: vec entry length
656 * @offset: vec entry offset
657 *
658 * Attempt to add a page to the bio_vec maplist. This can fail for a
659 * number of reasons, such as the bio being full or target block device
660 * limitations. The target block device must allow bio's up to PAGE_SIZE,
661 * so it is always possible to add a single page to an empty bio.
662 *
663 * This should only be used by REQ_PC bios.
664 */
665int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
666 *page, unsigned int len, unsigned int offset)
667{
668 int retried_segments = 0;
669 struct bio_vec *bvec;
670
671 /*
672 * cloned bio must not modify vec list
673 */
674 if (unlikely(bio_flagged(bio, BIO_CLONED)))
675 return 0;
676
677 if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
678 return 0;
679
680 /*
681 * For filesystems with a blocksize smaller than the pagesize
682 * we will often be called with the same page as last time and
683 * a consecutive offset. Optimize this special case.
684 */
685 if (bio->bi_vcnt > 0) {
686 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
687
688 if (page == prev->bv_page &&
689 offset == prev->bv_offset + prev->bv_len) {
690 prev->bv_len += len;
691 bio->bi_iter.bi_size += len;
692 goto done;
693 }
694
695 /*
696 * If the queue doesn't support SG gaps and adding this
697 * offset would create a gap, disallow it.
698 */
699 if (bvec_gap_to_prev(q, prev, offset))
700 return 0;
701 }
702
703 if (bio_full(bio))
704 return 0;
705
706 /*
707 * setup the new entry, we might clear it again later if we
708 * cannot add the page
709 */
710 bvec = &bio->bi_io_vec[bio->bi_vcnt];
711 bvec->bv_page = page;
712 bvec->bv_len = len;
713 bvec->bv_offset = offset;
714 bio->bi_vcnt++;
715 bio->bi_phys_segments++;
716 bio->bi_iter.bi_size += len;
717
718 /*
719 * Perform a recount if the number of segments is greater
720 * than queue_max_segments(q).
721 */
722
723 while (bio->bi_phys_segments > queue_max_segments(q)) {
724
725 if (retried_segments)
726 goto failed;
727
728 retried_segments = 1;
729 blk_recount_segments(q, bio);
730 }
731
732 /* If we may be able to merge these biovecs, force a recount */
733 if (bio->bi_vcnt > 1 && biovec_phys_mergeable(q, bvec - 1, bvec))
734 bio_clear_flag(bio, BIO_SEG_VALID);
735
736 done:
737 return len;
738
739 failed:
740 bvec->bv_page = NULL;
741 bvec->bv_len = 0;
742 bvec->bv_offset = 0;
743 bio->bi_vcnt--;
744 bio->bi_iter.bi_size -= len;
745 blk_recount_segments(q, bio);
746 return 0;
747}
748EXPORT_SYMBOL(bio_add_pc_page);
749
750/**
751 * __bio_try_merge_page - try appending data to an existing bvec.
752 * @bio: destination bio
753 * @page: page to add
754 * @len: length of the data to add
755 * @off: offset of the data in @page
756 * @same_page: if %true only merge if the new data is in the same physical
757 * page as the last segment of the bio.
758 *
759 * Try to add the data at @page + @off to the last bvec of @bio. This is a
760 * a useful optimisation for file systems with a block size smaller than the
761 * page size.
762 *
763 * Return %true on success or %false on failure.
764 */
765bool __bio_try_merge_page(struct bio *bio, struct page *page,
766 unsigned int len, unsigned int off, bool same_page)
767{
768 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
769 return false;
770
771 if (bio->bi_vcnt > 0) {
772 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
773 phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) +
774 bv->bv_offset + bv->bv_len - 1;
775 phys_addr_t page_addr = page_to_phys(page);
776
777 if (vec_end_addr + 1 != page_addr + off)
778 return false;
779 if (same_page && (vec_end_addr & PAGE_MASK) != page_addr)
780 return false;
781
782 bv->bv_len += len;
783 bio->bi_iter.bi_size += len;
784 return true;
785 }
786 return false;
787}
788EXPORT_SYMBOL_GPL(__bio_try_merge_page);
789
790/**
791 * __bio_add_page - add page to a bio in a new segment
792 * @bio: destination bio
793 * @page: page to add
794 * @len: length of the data to add
795 * @off: offset of the data in @page
796 *
797 * Add the data at @page + @off to @bio as a new bvec. The caller must ensure
798 * that @bio has space for another bvec.
799 */
800void __bio_add_page(struct bio *bio, struct page *page,
801 unsigned int len, unsigned int off)
802{
803 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
804
805 WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
806 WARN_ON_ONCE(bio_full(bio));
807
808 bv->bv_page = page;
809 bv->bv_offset = off;
810 bv->bv_len = len;
811
812 bio->bi_iter.bi_size += len;
813 bio->bi_vcnt++;
814}
815EXPORT_SYMBOL_GPL(__bio_add_page);
816
817/**
818 * bio_add_page - attempt to add page to bio
819 * @bio: destination bio
820 * @page: page to add
821 * @len: vec entry length
822 * @offset: vec entry offset
823 *
824 * Attempt to add a page to the bio_vec maplist. This will only fail
825 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
826 */
827int bio_add_page(struct bio *bio, struct page *page,
828 unsigned int len, unsigned int offset)
829{
830 if (!__bio_try_merge_page(bio, page, len, offset, false)) {
831 if (bio_full(bio))
832 return 0;
833 __bio_add_page(bio, page, len, offset);
834 }
835 return len;
836}
837EXPORT_SYMBOL(bio_add_page);
838
839static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter)
840{
841 const struct bio_vec *bv = iter->bvec;
842 unsigned int len;
843 size_t size;
844
845 if (WARN_ON_ONCE(iter->iov_offset > bv->bv_len))
846 return -EINVAL;
847
848 len = min_t(size_t, bv->bv_len - iter->iov_offset, iter->count);
849 size = bio_add_page(bio, bv->bv_page, len,
850 bv->bv_offset + iter->iov_offset);
851 if (size == len) {
852 if (!bio_flagged(bio, BIO_NO_PAGE_REF)) {
853 struct page *page;
854 int i;
855
856 mp_bvec_for_each_page(page, bv, i)
857 get_page(page);
858 }
859
860 iov_iter_advance(iter, size);
861 return 0;
862 }
863
864 return -EINVAL;
865}
866
867#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
868
869/**
870 * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
871 * @bio: bio to add pages to
872 * @iter: iov iterator describing the region to be mapped
873 *
874 * Pins pages from *iter and appends them to @bio's bvec array. The
875 * pages will have to be released using put_page() when done.
876 * For multi-segment *iter, this function only adds pages from the
877 * the next non-empty segment of the iov iterator.
878 */
879static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
880{
881 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
882 unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
883 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
884 struct page **pages = (struct page **)bv;
885 ssize_t size, left;
886 unsigned len, i;
887 size_t offset;
888
889 /*
890 * Move page array up in the allocated memory for the bio vecs as far as
891 * possible so that we can start filling biovecs from the beginning
892 * without overwriting the temporary page array.
893 */
894 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
895 pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
896
897 size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
898 if (unlikely(size <= 0))
899 return size ? size : -EFAULT;
900
901 for (left = size, i = 0; left > 0; left -= len, i++) {
902 struct page *page = pages[i];
903
904 len = min_t(size_t, PAGE_SIZE - offset, left);
905 if (WARN_ON_ONCE(bio_add_page(bio, page, len, offset) != len))
906 return -EINVAL;
907 offset = 0;
908 }
909
910 iov_iter_advance(iter, size);
911 return 0;
912}
913
914/**
915 * bio_iov_iter_get_pages - add user or kernel pages to a bio
916 * @bio: bio to add pages to
917 * @iter: iov iterator describing the region to be added
918 *
919 * This takes either an iterator pointing to user memory, or one pointing to
920 * kernel pages (BVEC iterator). If we're adding user pages, we pin them and
921 * map them into the kernel. On IO completion, the caller should put those
922 * pages. If we're adding kernel pages, and the caller told us it's safe to
923 * do so, we just have to add the pages to the bio directly. We don't grab an
924 * extra reference to those pages (the user should already have that), and we
925 * don't put the page on IO completion. The caller needs to check if the bio is
926 * flagged BIO_NO_PAGE_REF on IO completion. If it isn't, then pages should be
927 * released.
928 *
929 * The function tries, but does not guarantee, to pin as many pages as
930 * fit into the bio, or are requested in *iter, whatever is smaller. If
931 * MM encounters an error pinning the requested pages, it stops. Error
932 * is returned only if 0 pages could be pinned.
933 */
934int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
935{
936 const bool is_bvec = iov_iter_is_bvec(iter);
937 unsigned short orig_vcnt = bio->bi_vcnt;
938
939 /*
940 * If this is a BVEC iter, then the pages are kernel pages. Don't
941 * release them on IO completion, if the caller asked us to.
942 */
943 if (is_bvec && iov_iter_bvec_no_ref(iter))
944 bio_set_flag(bio, BIO_NO_PAGE_REF);
945
946 do {
947 int ret;
948
949 if (is_bvec)
950 ret = __bio_iov_bvec_add_pages(bio, iter);
951 else
952 ret = __bio_iov_iter_get_pages(bio, iter);
953
954 if (unlikely(ret))
955 return bio->bi_vcnt > orig_vcnt ? 0 : ret;
956
957 } while (iov_iter_count(iter) && !bio_full(bio));
958
959 return 0;
960}
961
962static void submit_bio_wait_endio(struct bio *bio)
963{
964 complete(bio->bi_private);
965}
966
967/**
968 * submit_bio_wait - submit a bio, and wait until it completes
969 * @bio: The &struct bio which describes the I/O
970 *
971 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
972 * bio_endio() on failure.
973 *
974 * WARNING: Unlike to how submit_bio() is usually used, this function does not
975 * result in bio reference to be consumed. The caller must drop the reference
976 * on his own.
977 */
978int submit_bio_wait(struct bio *bio)
979{
980 DECLARE_COMPLETION_ONSTACK_MAP(done, bio->bi_disk->lockdep_map);
981
982 bio->bi_private = &done;
983 bio->bi_end_io = submit_bio_wait_endio;
984 bio->bi_opf |= REQ_SYNC;
985 submit_bio(bio);
986 wait_for_completion_io(&done);
987
988 return blk_status_to_errno(bio->bi_status);
989}
990EXPORT_SYMBOL(submit_bio_wait);
991
992/**
993 * bio_advance - increment/complete a bio by some number of bytes
994 * @bio: bio to advance
995 * @bytes: number of bytes to complete
996 *
997 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
998 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
999 * be updated on the last bvec as well.
1000 *
1001 * @bio will then represent the remaining, uncompleted portion of the io.
1002 */
1003void bio_advance(struct bio *bio, unsigned bytes)
1004{
1005 if (bio_integrity(bio))
1006 bio_integrity_advance(bio, bytes);
1007
1008 bio_advance_iter(bio, &bio->bi_iter, bytes);
1009}
1010EXPORT_SYMBOL(bio_advance);
1011
1012void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
1013 struct bio *src, struct bvec_iter *src_iter)
1014{
1015 struct bio_vec src_bv, dst_bv;
1016 void *src_p, *dst_p;
1017 unsigned bytes;
1018
1019 while (src_iter->bi_size && dst_iter->bi_size) {
1020 src_bv = bio_iter_iovec(src, *src_iter);
1021 dst_bv = bio_iter_iovec(dst, *dst_iter);
1022
1023 bytes = min(src_bv.bv_len, dst_bv.bv_len);
1024
1025 src_p = kmap_atomic(src_bv.bv_page);
1026 dst_p = kmap_atomic(dst_bv.bv_page);
1027
1028 memcpy(dst_p + dst_bv.bv_offset,
1029 src_p + src_bv.bv_offset,
1030 bytes);
1031
1032 kunmap_atomic(dst_p);
1033 kunmap_atomic(src_p);
1034
1035 flush_dcache_page(dst_bv.bv_page);
1036
1037 bio_advance_iter(src, src_iter, bytes);
1038 bio_advance_iter(dst, dst_iter, bytes);
1039 }
1040}
1041EXPORT_SYMBOL(bio_copy_data_iter);
1042
1043/**
1044 * bio_copy_data - copy contents of data buffers from one bio to another
1045 * @src: source bio
1046 * @dst: destination bio
1047 *
1048 * Stops when it reaches the end of either @src or @dst - that is, copies
1049 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
1050 */
1051void bio_copy_data(struct bio *dst, struct bio *src)
1052{
1053 struct bvec_iter src_iter = src->bi_iter;
1054 struct bvec_iter dst_iter = dst->bi_iter;
1055
1056 bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
1057}
1058EXPORT_SYMBOL(bio_copy_data);
1059
1060/**
1061 * bio_list_copy_data - copy contents of data buffers from one chain of bios to
1062 * another
1063 * @src: source bio list
1064 * @dst: destination bio list
1065 *
1066 * Stops when it reaches the end of either the @src list or @dst list - that is,
1067 * copies min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of
1068 * bios).
1069 */
1070void bio_list_copy_data(struct bio *dst, struct bio *src)
1071{
1072 struct bvec_iter src_iter = src->bi_iter;
1073 struct bvec_iter dst_iter = dst->bi_iter;
1074
1075 while (1) {
1076 if (!src_iter.bi_size) {
1077 src = src->bi_next;
1078 if (!src)
1079 break;
1080
1081 src_iter = src->bi_iter;
1082 }
1083
1084 if (!dst_iter.bi_size) {
1085 dst = dst->bi_next;
1086 if (!dst)
1087 break;
1088
1089 dst_iter = dst->bi_iter;
1090 }
1091
1092 bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
1093 }
1094}
1095EXPORT_SYMBOL(bio_list_copy_data);
1096
1097struct bio_map_data {
1098 int is_our_pages;
1099 struct iov_iter iter;
1100 struct iovec iov[];
1101};
1102
1103static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
1104 gfp_t gfp_mask)
1105{
1106 struct bio_map_data *bmd;
1107 if (data->nr_segs > UIO_MAXIOV)
1108 return NULL;
1109
1110 bmd = kmalloc(sizeof(struct bio_map_data) +
1111 sizeof(struct iovec) * data->nr_segs, gfp_mask);
1112 if (!bmd)
1113 return NULL;
1114 memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
1115 bmd->iter = *data;
1116 bmd->iter.iov = bmd->iov;
1117 return bmd;
1118}
1119
1120/**
1121 * bio_copy_from_iter - copy all pages from iov_iter to bio
1122 * @bio: The &struct bio which describes the I/O as destination
1123 * @iter: iov_iter as source
1124 *
1125 * Copy all pages from iov_iter to bio.
1126 * Returns 0 on success, or error on failure.
1127 */
1128static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
1129{
1130 int i;
1131 struct bio_vec *bvec;
1132 struct bvec_iter_all iter_all;
1133
1134 bio_for_each_segment_all(bvec, bio, i, iter_all) {
1135 ssize_t ret;
1136
1137 ret = copy_page_from_iter(bvec->bv_page,
1138 bvec->bv_offset,
1139 bvec->bv_len,
1140 iter);
1141
1142 if (!iov_iter_count(iter))
1143 break;
1144
1145 if (ret < bvec->bv_len)
1146 return -EFAULT;
1147 }
1148
1149 return 0;
1150}
1151
1152/**
1153 * bio_copy_to_iter - copy all pages from bio to iov_iter
1154 * @bio: The &struct bio which describes the I/O as source
1155 * @iter: iov_iter as destination
1156 *
1157 * Copy all pages from bio to iov_iter.
1158 * Returns 0 on success, or error on failure.
1159 */
1160static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
1161{
1162 int i;
1163 struct bio_vec *bvec;
1164 struct bvec_iter_all iter_all;
1165
1166 bio_for_each_segment_all(bvec, bio, i, iter_all) {
1167 ssize_t ret;
1168
1169 ret = copy_page_to_iter(bvec->bv_page,
1170 bvec->bv_offset,
1171 bvec->bv_len,
1172 &iter);
1173
1174 if (!iov_iter_count(&iter))
1175 break;
1176
1177 if (ret < bvec->bv_len)
1178 return -EFAULT;
1179 }
1180
1181 return 0;
1182}
1183
1184void bio_free_pages(struct bio *bio)
1185{
1186 struct bio_vec *bvec;
1187 int i;
1188 struct bvec_iter_all iter_all;
1189
1190 bio_for_each_segment_all(bvec, bio, i, iter_all)
1191 __free_page(bvec->bv_page);
1192}
1193EXPORT_SYMBOL(bio_free_pages);
1194
1195/**
1196 * bio_uncopy_user - finish previously mapped bio
1197 * @bio: bio being terminated
1198 *
1199 * Free pages allocated from bio_copy_user_iov() and write back data
1200 * to user space in case of a read.
1201 */
1202int bio_uncopy_user(struct bio *bio)
1203{
1204 struct bio_map_data *bmd = bio->bi_private;
1205 int ret = 0;
1206
1207 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1208 /*
1209 * if we're in a workqueue, the request is orphaned, so
1210 * don't copy into a random user address space, just free
1211 * and return -EINTR so user space doesn't expect any data.
1212 */
1213 if (!current->mm)
1214 ret = -EINTR;
1215 else if (bio_data_dir(bio) == READ)
1216 ret = bio_copy_to_iter(bio, bmd->iter);
1217 if (bmd->is_our_pages)
1218 bio_free_pages(bio);
1219 }
1220 kfree(bmd);
1221 bio_put(bio);
1222 return ret;
1223}
1224
1225/**
1226 * bio_copy_user_iov - copy user data to bio
1227 * @q: destination block queue
1228 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1229 * @iter: iovec iterator
1230 * @gfp_mask: memory allocation flags
1231 *
1232 * Prepares and returns a bio for indirect user io, bouncing data
1233 * to/from kernel pages as necessary. Must be paired with
1234 * call bio_uncopy_user() on io completion.
1235 */
1236struct bio *bio_copy_user_iov(struct request_queue *q,
1237 struct rq_map_data *map_data,
1238 struct iov_iter *iter,
1239 gfp_t gfp_mask)
1240{
1241 struct bio_map_data *bmd;
1242 struct page *page;
1243 struct bio *bio;
1244 int i = 0, ret;
1245 int nr_pages;
1246 unsigned int len = iter->count;
1247 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
1248
1249 bmd = bio_alloc_map_data(iter, gfp_mask);
1250 if (!bmd)
1251 return ERR_PTR(-ENOMEM);
1252
1253 /*
1254 * We need to do a deep copy of the iov_iter including the iovecs.
1255 * The caller provided iov might point to an on-stack or otherwise
1256 * shortlived one.
1257 */
1258 bmd->is_our_pages = map_data ? 0 : 1;
1259
1260 nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE);
1261 if (nr_pages > BIO_MAX_PAGES)
1262 nr_pages = BIO_MAX_PAGES;
1263
1264 ret = -ENOMEM;
1265 bio = bio_kmalloc(gfp_mask, nr_pages);
1266 if (!bio)
1267 goto out_bmd;
1268
1269 ret = 0;
1270
1271 if (map_data) {
1272 nr_pages = 1 << map_data->page_order;
1273 i = map_data->offset / PAGE_SIZE;
1274 }
1275 while (len) {
1276 unsigned int bytes = PAGE_SIZE;
1277
1278 bytes -= offset;
1279
1280 if (bytes > len)
1281 bytes = len;
1282
1283 if (map_data) {
1284 if (i == map_data->nr_entries * nr_pages) {
1285 ret = -ENOMEM;
1286 break;
1287 }
1288
1289 page = map_data->pages[i / nr_pages];
1290 page += (i % nr_pages);
1291
1292 i++;
1293 } else {
1294 page = alloc_page(q->bounce_gfp | gfp_mask);
1295 if (!page) {
1296 ret = -ENOMEM;
1297 break;
1298 }
1299 }
1300
1301 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1302 break;
1303
1304 len -= bytes;
1305 offset = 0;
1306 }
1307
1308 if (ret)
1309 goto cleanup;
1310
1311 if (map_data)
1312 map_data->offset += bio->bi_iter.bi_size;
1313
1314 /*
1315 * success
1316 */
1317 if ((iov_iter_rw(iter) == WRITE && (!map_data || !map_data->null_mapped)) ||
1318 (map_data && map_data->from_user)) {
1319 ret = bio_copy_from_iter(bio, iter);
1320 if (ret)
1321 goto cleanup;
1322 } else {
1323 if (bmd->is_our_pages)
1324 zero_fill_bio(bio);
1325 iov_iter_advance(iter, bio->bi_iter.bi_size);
1326 }
1327
1328 bio->bi_private = bmd;
1329 if (map_data && map_data->null_mapped)
1330 bio_set_flag(bio, BIO_NULL_MAPPED);
1331 return bio;
1332cleanup:
1333 if (!map_data)
1334 bio_free_pages(bio);
1335 bio_put(bio);
1336out_bmd:
1337 kfree(bmd);
1338 return ERR_PTR(ret);
1339}
1340
1341/**
1342 * bio_map_user_iov - map user iovec into bio
1343 * @q: the struct request_queue for the bio
1344 * @iter: iovec iterator
1345 * @gfp_mask: memory allocation flags
1346 *
1347 * Map the user space address into a bio suitable for io to a block
1348 * device. Returns an error pointer in case of error.
1349 */
1350struct bio *bio_map_user_iov(struct request_queue *q,
1351 struct iov_iter *iter,
1352 gfp_t gfp_mask)
1353{
1354 int j;
1355 struct bio *bio;
1356 int ret;
1357 struct bio_vec *bvec;
1358 struct bvec_iter_all iter_all;
1359
1360 if (!iov_iter_count(iter))
1361 return ERR_PTR(-EINVAL);
1362
1363 bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES));
1364 if (!bio)
1365 return ERR_PTR(-ENOMEM);
1366
1367 while (iov_iter_count(iter)) {
1368 struct page **pages;
1369 ssize_t bytes;
1370 size_t offs, added = 0;
1371 int npages;
1372
1373 bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
1374 if (unlikely(bytes <= 0)) {
1375 ret = bytes ? bytes : -EFAULT;
1376 goto out_unmap;
1377 }
1378
1379 npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
1380
1381 if (unlikely(offs & queue_dma_alignment(q))) {
1382 ret = -EINVAL;
1383 j = 0;
1384 } else {
1385 for (j = 0; j < npages; j++) {
1386 struct page *page = pages[j];
1387 unsigned int n = PAGE_SIZE - offs;
1388 unsigned short prev_bi_vcnt = bio->bi_vcnt;
1389
1390 if (n > bytes)
1391 n = bytes;
1392
1393 if (!bio_add_pc_page(q, bio, page, n, offs))
1394 break;
1395
1396 /*
1397 * check if vector was merged with previous
1398 * drop page reference if needed
1399 */
1400 if (bio->bi_vcnt == prev_bi_vcnt)
1401 put_page(page);
1402
1403 added += n;
1404 bytes -= n;
1405 offs = 0;
1406 }
1407 iov_iter_advance(iter, added);
1408 }
1409 /*
1410 * release the pages we didn't map into the bio, if any
1411 */
1412 while (j < npages)
1413 put_page(pages[j++]);
1414 kvfree(pages);
1415 /* couldn't stuff something into bio? */
1416 if (bytes)
1417 break;
1418 }
1419
1420 bio_set_flag(bio, BIO_USER_MAPPED);
1421
1422 /*
1423 * subtle -- if bio_map_user_iov() ended up bouncing a bio,
1424 * it would normally disappear when its bi_end_io is run.
1425 * however, we need it for the unmap, so grab an extra
1426 * reference to it
1427 */
1428 bio_get(bio);
1429 return bio;
1430
1431 out_unmap:
1432 bio_for_each_segment_all(bvec, bio, j, iter_all) {
1433 put_page(bvec->bv_page);
1434 }
1435 bio_put(bio);
1436 return ERR_PTR(ret);
1437}
1438
1439static void __bio_unmap_user(struct bio *bio)
1440{
1441 struct bio_vec *bvec;
1442 int i;
1443 struct bvec_iter_all iter_all;
1444
1445 /*
1446 * make sure we dirty pages we wrote to
1447 */
1448 bio_for_each_segment_all(bvec, bio, i, iter_all) {
1449 if (bio_data_dir(bio) == READ)
1450 set_page_dirty_lock(bvec->bv_page);
1451
1452 put_page(bvec->bv_page);
1453 }
1454
1455 bio_put(bio);
1456}
1457
1458/**
1459 * bio_unmap_user - unmap a bio
1460 * @bio: the bio being unmapped
1461 *
1462 * Unmap a bio previously mapped by bio_map_user_iov(). Must be called from
1463 * process context.
1464 *
1465 * bio_unmap_user() may sleep.
1466 */
1467void bio_unmap_user(struct bio *bio)
1468{
1469 __bio_unmap_user(bio);
1470 bio_put(bio);
1471}
1472
1473static void bio_map_kern_endio(struct bio *bio)
1474{
1475 bio_put(bio);
1476}
1477
1478/**
1479 * bio_map_kern - map kernel address into bio
1480 * @q: the struct request_queue for the bio
1481 * @data: pointer to buffer to map
1482 * @len: length in bytes
1483 * @gfp_mask: allocation flags for bio allocation
1484 *
1485 * Map the kernel address into a bio suitable for io to a block
1486 * device. Returns an error pointer in case of error.
1487 */
1488struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1489 gfp_t gfp_mask)
1490{
1491 unsigned long kaddr = (unsigned long)data;
1492 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1493 unsigned long start = kaddr >> PAGE_SHIFT;
1494 const int nr_pages = end - start;
1495 int offset, i;
1496 struct bio *bio;
1497
1498 bio = bio_kmalloc(gfp_mask, nr_pages);
1499 if (!bio)
1500 return ERR_PTR(-ENOMEM);
1501
1502 offset = offset_in_page(kaddr);
1503 for (i = 0; i < nr_pages; i++) {
1504 unsigned int bytes = PAGE_SIZE - offset;
1505
1506 if (len <= 0)
1507 break;
1508
1509 if (bytes > len)
1510 bytes = len;
1511
1512 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1513 offset) < bytes) {
1514 /* we don't support partial mappings */
1515 bio_put(bio);
1516 return ERR_PTR(-EINVAL);
1517 }
1518
1519 data += bytes;
1520 len -= bytes;
1521 offset = 0;
1522 }
1523
1524 bio->bi_end_io = bio_map_kern_endio;
1525 return bio;
1526}
1527EXPORT_SYMBOL(bio_map_kern);
1528
1529static void bio_copy_kern_endio(struct bio *bio)
1530{
1531 bio_free_pages(bio);
1532 bio_put(bio);
1533}
1534
1535static void bio_copy_kern_endio_read(struct bio *bio)
1536{
1537 char *p = bio->bi_private;
1538 struct bio_vec *bvec;
1539 int i;
1540 struct bvec_iter_all iter_all;
1541
1542 bio_for_each_segment_all(bvec, bio, i, iter_all) {
1543 memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
1544 p += bvec->bv_len;
1545 }
1546
1547 bio_copy_kern_endio(bio);
1548}
1549
1550/**
1551 * bio_copy_kern - copy kernel address into bio
1552 * @q: the struct request_queue for the bio
1553 * @data: pointer to buffer to copy
1554 * @len: length in bytes
1555 * @gfp_mask: allocation flags for bio and page allocation
1556 * @reading: data direction is READ
1557 *
1558 * copy the kernel address into a bio suitable for io to a block
1559 * device. Returns an error pointer in case of error.
1560 */
1561struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1562 gfp_t gfp_mask, int reading)
1563{
1564 unsigned long kaddr = (unsigned long)data;
1565 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1566 unsigned long start = kaddr >> PAGE_SHIFT;
1567 struct bio *bio;
1568 void *p = data;
1569 int nr_pages = 0;
1570
1571 /*
1572 * Overflow, abort
1573 */
1574 if (end < start)
1575 return ERR_PTR(-EINVAL);
1576
1577 nr_pages = end - start;
1578 bio = bio_kmalloc(gfp_mask, nr_pages);
1579 if (!bio)
1580 return ERR_PTR(-ENOMEM);
1581
1582 while (len) {
1583 struct page *page;
1584 unsigned int bytes = PAGE_SIZE;
1585
1586 if (bytes > len)
1587 bytes = len;
1588
1589 page = alloc_page(q->bounce_gfp | gfp_mask);
1590 if (!page)
1591 goto cleanup;
1592
1593 if (!reading)
1594 memcpy(page_address(page), p, bytes);
1595
1596 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
1597 break;
1598
1599 len -= bytes;
1600 p += bytes;
1601 }
1602
1603 if (reading) {
1604 bio->bi_end_io = bio_copy_kern_endio_read;
1605 bio->bi_private = data;
1606 } else {
1607 bio->bi_end_io = bio_copy_kern_endio;
1608 }
1609
1610 return bio;
1611
1612cleanup:
1613 bio_free_pages(bio);
1614 bio_put(bio);
1615 return ERR_PTR(-ENOMEM);
1616}
1617
1618/*
1619 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1620 * for performing direct-IO in BIOs.
1621 *
1622 * The problem is that we cannot run set_page_dirty() from interrupt context
1623 * because the required locks are not interrupt-safe. So what we can do is to
1624 * mark the pages dirty _before_ performing IO. And in interrupt context,
1625 * check that the pages are still dirty. If so, fine. If not, redirty them
1626 * in process context.
1627 *
1628 * We special-case compound pages here: normally this means reads into hugetlb
1629 * pages. The logic in here doesn't really work right for compound pages
1630 * because the VM does not uniformly chase down the head page in all cases.
1631 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1632 * handle them at all. So we skip compound pages here at an early stage.
1633 *
1634 * Note that this code is very hard to test under normal circumstances because
1635 * direct-io pins the pages with get_user_pages(). This makes
1636 * is_page_cache_freeable return false, and the VM will not clean the pages.
1637 * But other code (eg, flusher threads) could clean the pages if they are mapped
1638 * pagecache.
1639 *
1640 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1641 * deferred bio dirtying paths.
1642 */
1643
1644/*
1645 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1646 */
1647void bio_set_pages_dirty(struct bio *bio)
1648{
1649 struct bio_vec *bvec;
1650 int i;
1651 struct bvec_iter_all iter_all;
1652
1653 bio_for_each_segment_all(bvec, bio, i, iter_all) {
1654 if (!PageCompound(bvec->bv_page))
1655 set_page_dirty_lock(bvec->bv_page);
1656 }
1657}
1658
1659static void bio_release_pages(struct bio *bio)
1660{
1661 struct bio_vec *bvec;
1662 int i;
1663 struct bvec_iter_all iter_all;
1664
1665 bio_for_each_segment_all(bvec, bio, i, iter_all)
1666 put_page(bvec->bv_page);
1667}
1668
1669/*
1670 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1671 * If they are, then fine. If, however, some pages are clean then they must
1672 * have been written out during the direct-IO read. So we take another ref on
1673 * the BIO and re-dirty the pages in process context.
1674 *
1675 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1676 * here on. It will run one put_page() against each page and will run one
1677 * bio_put() against the BIO.
1678 */
1679
1680static void bio_dirty_fn(struct work_struct *work);
1681
1682static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1683static DEFINE_SPINLOCK(bio_dirty_lock);
1684static struct bio *bio_dirty_list;
1685
1686/*
1687 * This runs in process context
1688 */
1689static void bio_dirty_fn(struct work_struct *work)
1690{
1691 struct bio *bio, *next;
1692
1693 spin_lock_irq(&bio_dirty_lock);
1694 next = bio_dirty_list;
1695 bio_dirty_list = NULL;
1696 spin_unlock_irq(&bio_dirty_lock);
1697
1698 while ((bio = next) != NULL) {
1699 next = bio->bi_private;
1700
1701 bio_set_pages_dirty(bio);
1702 if (!bio_flagged(bio, BIO_NO_PAGE_REF))
1703 bio_release_pages(bio);
1704 bio_put(bio);
1705 }
1706}
1707
1708void bio_check_pages_dirty(struct bio *bio)
1709{
1710 struct bio_vec *bvec;
1711 unsigned long flags;
1712 int i;
1713 struct bvec_iter_all iter_all;
1714
1715 bio_for_each_segment_all(bvec, bio, i, iter_all) {
1716 if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page))
1717 goto defer;
1718 }
1719
1720 if (!bio_flagged(bio, BIO_NO_PAGE_REF))
1721 bio_release_pages(bio);
1722 bio_put(bio);
1723 return;
1724defer:
1725 spin_lock_irqsave(&bio_dirty_lock, flags);
1726 bio->bi_private = bio_dirty_list;
1727 bio_dirty_list = bio;
1728 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1729 schedule_work(&bio_dirty_work);
1730}
1731
1732void update_io_ticks(struct hd_struct *part, unsigned long now)
1733{
1734 unsigned long stamp;
1735again:
1736 stamp = READ_ONCE(part->stamp);
1737 if (unlikely(stamp != now)) {
1738 if (likely(cmpxchg(&part->stamp, stamp, now) == stamp)) {
1739 __part_stat_add(part, io_ticks, 1);
1740 }
1741 }
1742 if (part->partno) {
1743 part = &part_to_disk(part)->part0;
1744 goto again;
1745 }
1746}
1747
1748void generic_start_io_acct(struct request_queue *q, int op,
1749 unsigned long sectors, struct hd_struct *part)
1750{
1751 const int sgrp = op_stat_group(op);
1752
1753 part_stat_lock();
1754
1755 update_io_ticks(part, jiffies);
1756 part_stat_inc(part, ios[sgrp]);
1757 part_stat_add(part, sectors[sgrp], sectors);
1758 part_inc_in_flight(q, part, op_is_write(op));
1759
1760 part_stat_unlock();
1761}
1762EXPORT_SYMBOL(generic_start_io_acct);
1763
1764void generic_end_io_acct(struct request_queue *q, int req_op,
1765 struct hd_struct *part, unsigned long start_time)
1766{
1767 unsigned long now = jiffies;
1768 unsigned long duration = now - start_time;
1769 const int sgrp = op_stat_group(req_op);
1770
1771 part_stat_lock();
1772
1773 update_io_ticks(part, now);
1774 part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
1775 part_stat_add(part, time_in_queue, duration);
1776 part_dec_in_flight(q, part, op_is_write(req_op));
1777
1778 part_stat_unlock();
1779}
1780EXPORT_SYMBOL(generic_end_io_acct);
1781
1782#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1783void bio_flush_dcache_pages(struct bio *bi)
1784{
1785 struct bio_vec bvec;
1786 struct bvec_iter iter;
1787
1788 bio_for_each_segment(bvec, bi, iter)
1789 flush_dcache_page(bvec.bv_page);
1790}
1791EXPORT_SYMBOL(bio_flush_dcache_pages);
1792#endif
1793
1794static inline bool bio_remaining_done(struct bio *bio)
1795{
1796 /*
1797 * If we're not chaining, then ->__bi_remaining is always 1 and
1798 * we always end io on the first invocation.
1799 */
1800 if (!bio_flagged(bio, BIO_CHAIN))
1801 return true;
1802
1803 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1804
1805 if (atomic_dec_and_test(&bio->__bi_remaining)) {
1806 bio_clear_flag(bio, BIO_CHAIN);
1807 return true;
1808 }
1809
1810 return false;
1811}
1812
1813/**
1814 * bio_endio - end I/O on a bio
1815 * @bio: bio
1816 *
1817 * Description:
1818 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1819 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1820 * bio unless they own it and thus know that it has an end_io function.
1821 *
1822 * bio_endio() can be called several times on a bio that has been chained
1823 * using bio_chain(). The ->bi_end_io() function will only be called the
1824 * last time. At this point the BLK_TA_COMPLETE tracing event will be
1825 * generated if BIO_TRACE_COMPLETION is set.
1826 **/
1827void bio_endio(struct bio *bio)
1828{
1829again:
1830 if (!bio_remaining_done(bio))
1831 return;
1832 if (!bio_integrity_endio(bio))
1833 return;
1834
1835 if (bio->bi_disk)
1836 rq_qos_done_bio(bio->bi_disk->queue, bio);
1837
1838 /*
1839 * Need to have a real endio function for chained bios, otherwise
1840 * various corner cases will break (like stacking block devices that
1841 * save/restore bi_end_io) - however, we want to avoid unbounded
1842 * recursion and blowing the stack. Tail call optimization would
1843 * handle this, but compiling with frame pointers also disables
1844 * gcc's sibling call optimization.
1845 */
1846 if (bio->bi_end_io == bio_chain_endio) {
1847 bio = __bio_chain_endio(bio);
1848 goto again;
1849 }
1850
1851 if (bio->bi_disk && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
1852 trace_block_bio_complete(bio->bi_disk->queue, bio,
1853 blk_status_to_errno(bio->bi_status));
1854 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1855 }
1856
1857 blk_throtl_bio_endio(bio);
1858 /* release cgroup info */
1859 bio_uninit(bio);
1860 if (bio->bi_end_io)
1861 bio->bi_end_io(bio);
1862}
1863EXPORT_SYMBOL(bio_endio);
1864
1865/**
1866 * bio_split - split a bio
1867 * @bio: bio to split
1868 * @sectors: number of sectors to split from the front of @bio
1869 * @gfp: gfp mask
1870 * @bs: bio set to allocate from
1871 *
1872 * Allocates and returns a new bio which represents @sectors from the start of
1873 * @bio, and updates @bio to represent the remaining sectors.
1874 *
1875 * Unless this is a discard request the newly allocated bio will point
1876 * to @bio's bi_io_vec; it is the caller's responsibility to ensure that
1877 * @bio is not freed before the split.
1878 */
1879struct bio *bio_split(struct bio *bio, int sectors,
1880 gfp_t gfp, struct bio_set *bs)
1881{
1882 struct bio *split;
1883
1884 BUG_ON(sectors <= 0);
1885 BUG_ON(sectors >= bio_sectors(bio));
1886
1887 split = bio_clone_fast(bio, gfp, bs);
1888 if (!split)
1889 return NULL;
1890
1891 split->bi_iter.bi_size = sectors << 9;
1892
1893 if (bio_integrity(split))
1894 bio_integrity_trim(split);
1895
1896 bio_advance(bio, split->bi_iter.bi_size);
1897
1898 if (bio_flagged(bio, BIO_TRACE_COMPLETION))
1899 bio_set_flag(split, BIO_TRACE_COMPLETION);
1900
1901 return split;
1902}
1903EXPORT_SYMBOL(bio_split);
1904
1905/**
1906 * bio_trim - trim a bio
1907 * @bio: bio to trim
1908 * @offset: number of sectors to trim from the front of @bio
1909 * @size: size we want to trim @bio to, in sectors
1910 */
1911void bio_trim(struct bio *bio, int offset, int size)
1912{
1913 /* 'bio' is a cloned bio which we need to trim to match
1914 * the given offset and size.
1915 */
1916
1917 size <<= 9;
1918 if (offset == 0 && size == bio->bi_iter.bi_size)
1919 return;
1920
1921 bio_clear_flag(bio, BIO_SEG_VALID);
1922
1923 bio_advance(bio, offset << 9);
1924
1925 bio->bi_iter.bi_size = size;
1926
1927 if (bio_integrity(bio))
1928 bio_integrity_trim(bio);
1929
1930}
1931EXPORT_SYMBOL_GPL(bio_trim);
1932
1933/*
1934 * create memory pools for biovec's in a bio_set.
1935 * use the global biovec slabs created for general use.
1936 */
1937int biovec_init_pool(mempool_t *pool, int pool_entries)
1938{
1939 struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX;
1940
1941 return mempool_init_slab_pool(pool, pool_entries, bp->slab);
1942}
1943
1944/*
1945 * bioset_exit - exit a bioset initialized with bioset_init()
1946 *
1947 * May be called on a zeroed but uninitialized bioset (i.e. allocated with
1948 * kzalloc()).
1949 */
1950void bioset_exit(struct bio_set *bs)
1951{
1952 if (bs->rescue_workqueue)
1953 destroy_workqueue(bs->rescue_workqueue);
1954 bs->rescue_workqueue = NULL;
1955
1956 mempool_exit(&bs->bio_pool);
1957 mempool_exit(&bs->bvec_pool);
1958
1959 bioset_integrity_free(bs);
1960 if (bs->bio_slab)
1961 bio_put_slab(bs);
1962 bs->bio_slab = NULL;
1963}
1964EXPORT_SYMBOL(bioset_exit);
1965
1966/**
1967 * bioset_init - Initialize a bio_set
1968 * @bs: pool to initialize
1969 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1970 * @front_pad: Number of bytes to allocate in front of the returned bio
1971 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS
1972 * and %BIOSET_NEED_RESCUER
1973 *
1974 * Description:
1975 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1976 * to ask for a number of bytes to be allocated in front of the bio.
1977 * Front pad allocation is useful for embedding the bio inside
1978 * another structure, to avoid allocating extra data to go with the bio.
1979 * Note that the bio must be embedded at the END of that structure always,
1980 * or things will break badly.
1981 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated
1982 * for allocating iovecs. This pool is not needed e.g. for bio_clone_fast().
1983 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used to
1984 * dispatch queued requests when the mempool runs out of space.
1985 *
1986 */
1987int bioset_init(struct bio_set *bs,
1988 unsigned int pool_size,
1989 unsigned int front_pad,
1990 int flags)
1991{
1992 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1993
1994 bs->front_pad = front_pad;
1995
1996 spin_lock_init(&bs->rescue_lock);
1997 bio_list_init(&bs->rescue_list);
1998 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1999
2000 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
2001 if (!bs->bio_slab)
2002 return -ENOMEM;
2003
2004 if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))
2005 goto bad;
2006
2007 if ((flags & BIOSET_NEED_BVECS) &&
2008 biovec_init_pool(&bs->bvec_pool, pool_size))
2009 goto bad;
2010
2011 if (!(flags & BIOSET_NEED_RESCUER))
2012 return 0;
2013
2014 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
2015 if (!bs->rescue_workqueue)
2016 goto bad;
2017
2018 return 0;
2019bad:
2020 bioset_exit(bs);
2021 return -ENOMEM;
2022}
2023EXPORT_SYMBOL(bioset_init);
2024
2025/*
2026 * Initialize and setup a new bio_set, based on the settings from
2027 * another bio_set.
2028 */
2029int bioset_init_from_src(struct bio_set *bs, struct bio_set *src)
2030{
2031 int flags;
2032
2033 flags = 0;
2034 if (src->bvec_pool.min_nr)
2035 flags |= BIOSET_NEED_BVECS;
2036 if (src->rescue_workqueue)
2037 flags |= BIOSET_NEED_RESCUER;
2038
2039 return bioset_init(bs, src->bio_pool.min_nr, src->front_pad, flags);
2040}
2041EXPORT_SYMBOL(bioset_init_from_src);
2042
2043#ifdef CONFIG_BLK_CGROUP
2044
2045/**
2046 * bio_disassociate_blkg - puts back the blkg reference if associated
2047 * @bio: target bio
2048 *
2049 * Helper to disassociate the blkg from @bio if a blkg is associated.
2050 */
2051void bio_disassociate_blkg(struct bio *bio)
2052{
2053 if (bio->bi_blkg) {
2054 blkg_put(bio->bi_blkg);
2055 bio->bi_blkg = NULL;
2056 }
2057}
2058EXPORT_SYMBOL_GPL(bio_disassociate_blkg);
2059
2060/**
2061 * __bio_associate_blkg - associate a bio with the a blkg
2062 * @bio: target bio
2063 * @blkg: the blkg to associate
2064 *
2065 * This tries to associate @bio with the specified @blkg. Association failure
2066 * is handled by walking up the blkg tree. Therefore, the blkg associated can
2067 * be anything between @blkg and the root_blkg. This situation only happens
2068 * when a cgroup is dying and then the remaining bios will spill to the closest
2069 * alive blkg.
2070 *
2071 * A reference will be taken on the @blkg and will be released when @bio is
2072 * freed.
2073 */
2074static void __bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg)
2075{
2076 bio_disassociate_blkg(bio);
2077
2078 bio->bi_blkg = blkg_tryget_closest(blkg);
2079}
2080
2081/**
2082 * bio_associate_blkg_from_css - associate a bio with a specified css
2083 * @bio: target bio
2084 * @css: target css
2085 *
2086 * Associate @bio with the blkg found by combining the css's blkg and the
2087 * request_queue of the @bio. This falls back to the queue's root_blkg if
2088 * the association fails with the css.
2089 */
2090void bio_associate_blkg_from_css(struct bio *bio,
2091 struct cgroup_subsys_state *css)
2092{
2093 struct request_queue *q = bio->bi_disk->queue;
2094 struct blkcg_gq *blkg;
2095
2096 rcu_read_lock();
2097
2098 if (!css || !css->parent)
2099 blkg = q->root_blkg;
2100 else
2101 blkg = blkg_lookup_create(css_to_blkcg(css), q);
2102
2103 __bio_associate_blkg(bio, blkg);
2104
2105 rcu_read_unlock();
2106}
2107EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
2108
2109#ifdef CONFIG_MEMCG
2110/**
2111 * bio_associate_blkg_from_page - associate a bio with the page's blkg
2112 * @bio: target bio
2113 * @page: the page to lookup the blkcg from
2114 *
2115 * Associate @bio with the blkg from @page's owning memcg and the respective
2116 * request_queue. If cgroup_e_css returns %NULL, fall back to the queue's
2117 * root_blkg.
2118 */
2119void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
2120{
2121 struct cgroup_subsys_state *css;
2122
2123 if (!page->mem_cgroup)
2124 return;
2125
2126 rcu_read_lock();
2127
2128 css = cgroup_e_css(page->mem_cgroup->css.cgroup, &io_cgrp_subsys);
2129 bio_associate_blkg_from_css(bio, css);
2130
2131 rcu_read_unlock();
2132}
2133#endif /* CONFIG_MEMCG */
2134
2135/**
2136 * bio_associate_blkg - associate a bio with a blkg
2137 * @bio: target bio
2138 *
2139 * Associate @bio with the blkg found from the bio's css and request_queue.
2140 * If one is not found, bio_lookup_blkg() creates the blkg. If a blkg is
2141 * already associated, the css is reused and association redone as the
2142 * request_queue may have changed.
2143 */
2144void bio_associate_blkg(struct bio *bio)
2145{
2146 struct cgroup_subsys_state *css;
2147
2148 rcu_read_lock();
2149
2150 if (bio->bi_blkg)
2151 css = &bio_blkcg(bio)->css;
2152 else
2153 css = blkcg_css();
2154
2155 bio_associate_blkg_from_css(bio, css);
2156
2157 rcu_read_unlock();
2158}
2159EXPORT_SYMBOL_GPL(bio_associate_blkg);
2160
2161/**
2162 * bio_clone_blkg_association - clone blkg association from src to dst bio
2163 * @dst: destination bio
2164 * @src: source bio
2165 */
2166void bio_clone_blkg_association(struct bio *dst, struct bio *src)
2167{
2168 rcu_read_lock();
2169
2170 if (src->bi_blkg)
2171 __bio_associate_blkg(dst, src->bi_blkg);
2172
2173 rcu_read_unlock();
2174}
2175EXPORT_SYMBOL_GPL(bio_clone_blkg_association);
2176#endif /* CONFIG_BLK_CGROUP */
2177
2178static void __init biovec_init_slabs(void)
2179{
2180 int i;
2181
2182 for (i = 0; i < BVEC_POOL_NR; i++) {
2183 int size;
2184 struct biovec_slab *bvs = bvec_slabs + i;
2185
2186 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
2187 bvs->slab = NULL;
2188 continue;
2189 }
2190
2191 size = bvs->nr_vecs * sizeof(struct bio_vec);
2192 bvs->slab = kmem_cache_create(bvs->name, size, 0,
2193 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2194 }
2195}
2196
2197static int __init init_bio(void)
2198{
2199 bio_slab_max = 2;
2200 bio_slab_nr = 0;
2201 bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab),
2202 GFP_KERNEL);
2203 if (!bio_slabs)
2204 panic("bio: can't allocate bios\n");
2205
2206 bio_integrity_init();
2207 biovec_init_slabs();
2208
2209 if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS))
2210 panic("bio: can't allocate bios\n");
2211
2212 if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE))
2213 panic("bio: can't create integrity pool\n");
2214
2215 return 0;
2216}
2217subsys_initcall(init_bio);
2218