2 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
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.
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.
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-
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>
32 #include <trace/events/block.h>
35 * Test patch to inline a certain number of bi_io_vec's inside the bio
36 * itself, to shrink a bio data allocation from two mempool calls to one
38 #define BIO_INLINE_VECS 4
41 * if you change this list, also change bvec_alloc or things will
42 * break badly! cannot be bigger than what you can fit into an
45 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
46 static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
47 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
52 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
53 * IO code that does not need private memory pools.
55 struct bio_set *fs_bio_set;
56 EXPORT_SYMBOL(fs_bio_set);
59 * Our slab pool management
62 struct kmem_cache *slab;
63 unsigned int slab_ref;
64 unsigned int slab_size;
67 static DEFINE_MUTEX(bio_slab_lock);
68 static struct bio_slab *bio_slabs;
69 static unsigned int bio_slab_nr, bio_slab_max;
71 static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
73 unsigned int sz = sizeof(struct bio) + extra_size;
74 struct kmem_cache *slab = NULL;
75 struct bio_slab *bslab, *new_bio_slabs;
76 unsigned int new_bio_slab_max;
77 unsigned int i, entry = -1;
79 mutex_lock(&bio_slab_lock);
82 while (i < bio_slab_nr) {
83 bslab = &bio_slabs[i];
85 if (!bslab->slab && entry == -1)
87 else if (bslab->slab_size == sz) {
98 if (bio_slab_nr == bio_slab_max && entry == -1) {
99 new_bio_slab_max = bio_slab_max << 1;
100 new_bio_slabs = krealloc(bio_slabs,
101 new_bio_slab_max * sizeof(struct bio_slab),
105 bio_slab_max = new_bio_slab_max;
106 bio_slabs = new_bio_slabs;
109 entry = bio_slab_nr++;
111 bslab = &bio_slabs[entry];
113 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
114 slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN,
115 SLAB_HWCACHE_ALIGN, NULL);
121 bslab->slab_size = sz;
123 mutex_unlock(&bio_slab_lock);
127 static void bio_put_slab(struct bio_set *bs)
129 struct bio_slab *bslab = NULL;
132 mutex_lock(&bio_slab_lock);
134 for (i = 0; i < bio_slab_nr; i++) {
135 if (bs->bio_slab == bio_slabs[i].slab) {
136 bslab = &bio_slabs[i];
141 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
144 WARN_ON(!bslab->slab_ref);
146 if (--bslab->slab_ref)
149 kmem_cache_destroy(bslab->slab);
153 mutex_unlock(&bio_slab_lock);
156 unsigned int bvec_nr_vecs(unsigned short idx)
158 return bvec_slabs[idx].nr_vecs;
161 void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
163 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
165 if (idx == BIOVEC_MAX_IDX)
166 mempool_free(bv, pool);
168 struct biovec_slab *bvs = bvec_slabs + idx;
170 kmem_cache_free(bvs->slab, bv);
174 struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
180 * see comment near bvec_array define!
198 case 129 ... BIO_MAX_PAGES:
206 * idx now points to the pool we want to allocate from. only the
207 * 1-vec entry pool is mempool backed.
209 if (*idx == BIOVEC_MAX_IDX) {
211 bvl = mempool_alloc(pool, gfp_mask);
213 struct biovec_slab *bvs = bvec_slabs + *idx;
214 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
217 * Make this allocation restricted and don't dump info on
218 * allocation failures, since we'll fallback to the mempool
219 * in case of failure.
221 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
224 * Try a slab allocation. If this fails and __GFP_WAIT
225 * is set, retry with the 1-entry mempool
227 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
228 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
229 *idx = BIOVEC_MAX_IDX;
237 static void __bio_free(struct bio *bio)
239 bio_disassociate_task(bio);
241 if (bio_integrity(bio))
242 bio_integrity_free(bio);
245 static void bio_free(struct bio *bio)
247 struct bio_set *bs = bio->bi_pool;
253 if (bio_flagged(bio, BIO_OWNS_VEC))
254 bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
257 * If we have front padding, adjust the bio pointer before freeing
262 mempool_free(p, bs->bio_pool);
264 /* Bio was allocated by bio_kmalloc() */
269 void bio_init(struct bio *bio)
271 memset(bio, 0, sizeof(*bio));
272 bio->bi_flags = 1 << BIO_UPTODATE;
273 atomic_set(&bio->bi_remaining, 1);
274 atomic_set(&bio->bi_cnt, 1);
276 EXPORT_SYMBOL(bio_init);
279 * bio_reset - reinitialize a bio
283 * After calling bio_reset(), @bio will be in the same state as a freshly
284 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
285 * preserved are the ones that are initialized by bio_alloc_bioset(). See
286 * comment in struct bio.
288 void bio_reset(struct bio *bio)
290 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
294 memset(bio, 0, BIO_RESET_BYTES);
295 bio->bi_flags = flags|(1 << BIO_UPTODATE);
296 atomic_set(&bio->bi_remaining, 1);
298 EXPORT_SYMBOL(bio_reset);
300 static void bio_chain_endio(struct bio *bio, int error)
302 bio_endio(bio->bi_private, error);
307 * bio_chain - chain bio completions
308 * @bio: the target bio
309 * @parent: the @bio's parent bio
311 * The caller won't have a bi_end_io called when @bio completes - instead,
312 * @parent's bi_end_io won't be called until both @parent and @bio have
313 * completed; the chained bio will also be freed when it completes.
315 * The caller must not set bi_private or bi_end_io in @bio.
317 void bio_chain(struct bio *bio, struct bio *parent)
319 BUG_ON(bio->bi_private || bio->bi_end_io);
321 bio->bi_private = parent;
322 bio->bi_end_io = bio_chain_endio;
323 atomic_inc(&parent->bi_remaining);
325 EXPORT_SYMBOL(bio_chain);
327 static void bio_alloc_rescue(struct work_struct *work)
329 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
333 spin_lock(&bs->rescue_lock);
334 bio = bio_list_pop(&bs->rescue_list);
335 spin_unlock(&bs->rescue_lock);
340 generic_make_request(bio);
344 static void punt_bios_to_rescuer(struct bio_set *bs)
346 struct bio_list punt, nopunt;
350 * In order to guarantee forward progress we must punt only bios that
351 * were allocated from this bio_set; otherwise, if there was a bio on
352 * there for a stacking driver higher up in the stack, processing it
353 * could require allocating bios from this bio_set, and doing that from
354 * our own rescuer would be bad.
356 * Since bio lists are singly linked, pop them all instead of trying to
357 * remove from the middle of the list:
360 bio_list_init(&punt);
361 bio_list_init(&nopunt);
363 while ((bio = bio_list_pop(current->bio_list)))
364 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
366 *current->bio_list = nopunt;
368 spin_lock(&bs->rescue_lock);
369 bio_list_merge(&bs->rescue_list, &punt);
370 spin_unlock(&bs->rescue_lock);
372 queue_work(bs->rescue_workqueue, &bs->rescue_work);
376 * bio_alloc_bioset - allocate a bio for I/O
377 * @gfp_mask: the GFP_ mask given to the slab allocator
378 * @nr_iovecs: number of iovecs to pre-allocate
379 * @bs: the bio_set to allocate from.
382 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
383 * backed by the @bs's mempool.
385 * When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
386 * able to allocate a bio. This is due to the mempool guarantees. To make this
387 * work, callers must never allocate more than 1 bio at a time from this pool.
388 * Callers that need to allocate more than 1 bio must always submit the
389 * previously allocated bio for IO before attempting to allocate a new one.
390 * Failure to do so can cause deadlocks under memory pressure.
392 * Note that when running under generic_make_request() (i.e. any block
393 * driver), bios are not submitted until after you return - see the code in
394 * generic_make_request() that converts recursion into iteration, to prevent
397 * This would normally mean allocating multiple bios under
398 * generic_make_request() would be susceptible to deadlocks, but we have
399 * deadlock avoidance code that resubmits any blocked bios from a rescuer
402 * However, we do not guarantee forward progress for allocations from other
403 * mempools. Doing multiple allocations from the same mempool under
404 * generic_make_request() should be avoided - instead, use bio_set's front_pad
405 * for per bio allocations.
408 * Pointer to new bio on success, NULL on failure.
410 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
412 gfp_t saved_gfp = gfp_mask;
414 unsigned inline_vecs;
415 unsigned long idx = BIO_POOL_NONE;
416 struct bio_vec *bvl = NULL;
421 if (nr_iovecs > UIO_MAXIOV)
424 p = kmalloc(sizeof(struct bio) +
425 nr_iovecs * sizeof(struct bio_vec),
428 inline_vecs = nr_iovecs;
430 /* should not use nobvec bioset for nr_iovecs > 0 */
431 if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0))
434 * generic_make_request() converts recursion to iteration; this
435 * means if we're running beneath it, any bios we allocate and
436 * submit will not be submitted (and thus freed) until after we
439 * This exposes us to a potential deadlock if we allocate
440 * multiple bios from the same bio_set() while running
441 * underneath generic_make_request(). If we were to allocate
442 * multiple bios (say a stacking block driver that was splitting
443 * bios), we would deadlock if we exhausted the mempool's
446 * We solve this, and guarantee forward progress, with a rescuer
447 * workqueue per bio_set. If we go to allocate and there are
448 * bios on current->bio_list, we first try the allocation
449 * without __GFP_WAIT; if that fails, we punt those bios we
450 * would be blocking to the rescuer workqueue before we retry
451 * with the original gfp_flags.
454 if (current->bio_list && !bio_list_empty(current->bio_list))
455 gfp_mask &= ~__GFP_WAIT;
457 p = mempool_alloc(bs->bio_pool, gfp_mask);
458 if (!p && gfp_mask != saved_gfp) {
459 punt_bios_to_rescuer(bs);
460 gfp_mask = saved_gfp;
461 p = mempool_alloc(bs->bio_pool, gfp_mask);
464 front_pad = bs->front_pad;
465 inline_vecs = BIO_INLINE_VECS;
474 if (nr_iovecs > inline_vecs) {
475 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
476 if (!bvl && gfp_mask != saved_gfp) {
477 punt_bios_to_rescuer(bs);
478 gfp_mask = saved_gfp;
479 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
485 bio->bi_flags |= 1 << BIO_OWNS_VEC;
486 } else if (nr_iovecs) {
487 bvl = bio->bi_inline_vecs;
491 bio->bi_flags |= idx << BIO_POOL_OFFSET;
492 bio->bi_max_vecs = nr_iovecs;
493 bio->bi_io_vec = bvl;
497 mempool_free(p, bs->bio_pool);
500 EXPORT_SYMBOL(bio_alloc_bioset);
502 void zero_fill_bio(struct bio *bio)
506 struct bvec_iter iter;
508 bio_for_each_segment(bv, bio, iter) {
509 char *data = bvec_kmap_irq(&bv, &flags);
510 memset(data, 0, bv.bv_len);
511 flush_dcache_page(bv.bv_page);
512 bvec_kunmap_irq(data, &flags);
515 EXPORT_SYMBOL(zero_fill_bio);
518 * bio_put - release a reference to a bio
519 * @bio: bio to release reference to
522 * Put a reference to a &struct bio, either one you have gotten with
523 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
525 void bio_put(struct bio *bio)
527 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
532 if (atomic_dec_and_test(&bio->bi_cnt))
535 EXPORT_SYMBOL(bio_put);
537 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
539 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
540 blk_recount_segments(q, bio);
542 return bio->bi_phys_segments;
544 EXPORT_SYMBOL(bio_phys_segments);
547 * __bio_clone_fast - clone a bio that shares the original bio's biovec
548 * @bio: destination bio
549 * @bio_src: bio to clone
551 * Clone a &bio. Caller will own the returned bio, but not
552 * the actual data it points to. Reference count of returned
555 * Caller must ensure that @bio_src is not freed before @bio.
557 void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
559 BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE);
562 * most users will be overriding ->bi_bdev with a new target,
563 * so we don't set nor calculate new physical/hw segment counts here
565 bio->bi_bdev = bio_src->bi_bdev;
566 bio->bi_flags |= 1 << BIO_CLONED;
567 bio->bi_rw = bio_src->bi_rw;
568 bio->bi_iter = bio_src->bi_iter;
569 bio->bi_io_vec = bio_src->bi_io_vec;
571 EXPORT_SYMBOL(__bio_clone_fast);
574 * bio_clone_fast - clone a bio that shares the original bio's biovec
576 * @gfp_mask: allocation priority
577 * @bs: bio_set to allocate from
579 * Like __bio_clone_fast, only also allocates the returned bio
581 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
585 b = bio_alloc_bioset(gfp_mask, 0, bs);
589 __bio_clone_fast(b, bio);
591 if (bio_integrity(bio)) {
594 ret = bio_integrity_clone(b, bio, gfp_mask);
604 EXPORT_SYMBOL(bio_clone_fast);
607 * bio_clone_bioset - clone a bio
608 * @bio_src: bio to clone
609 * @gfp_mask: allocation priority
610 * @bs: bio_set to allocate from
612 * Clone bio. Caller will own the returned bio, but not the actual data it
613 * points to. Reference count of returned bio will be one.
615 struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
618 struct bvec_iter iter;
623 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
624 * bio_src->bi_io_vec to bio->bi_io_vec.
626 * We can't do that anymore, because:
628 * - The point of cloning the biovec is to produce a bio with a biovec
629 * the caller can modify: bi_idx and bi_bvec_done should be 0.
631 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
632 * we tried to clone the whole thing bio_alloc_bioset() would fail.
633 * But the clone should succeed as long as the number of biovecs we
634 * actually need to allocate is fewer than BIO_MAX_PAGES.
636 * - Lastly, bi_vcnt should not be looked at or relied upon by code
637 * that does not own the bio - reason being drivers don't use it for
638 * iterating over the biovec anymore, so expecting it to be kept up
639 * to date (i.e. for clones that share the parent biovec) is just
640 * asking for trouble and would force extra work on
641 * __bio_clone_fast() anyways.
644 bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
648 bio->bi_bdev = bio_src->bi_bdev;
649 bio->bi_rw = bio_src->bi_rw;
650 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
651 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
653 if (bio->bi_rw & REQ_DISCARD)
654 goto integrity_clone;
656 if (bio->bi_rw & REQ_WRITE_SAME) {
657 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
658 goto integrity_clone;
661 bio_for_each_segment(bv, bio_src, iter)
662 bio->bi_io_vec[bio->bi_vcnt++] = bv;
665 if (bio_integrity(bio_src)) {
668 ret = bio_integrity_clone(bio, bio_src, gfp_mask);
677 EXPORT_SYMBOL(bio_clone_bioset);
680 * bio_get_nr_vecs - return approx number of vecs
683 * Return the approximate number of pages we can send to this target.
684 * There's no guarantee that you will be able to fit this number of pages
685 * into a bio, it does not account for dynamic restrictions that vary
688 int bio_get_nr_vecs(struct block_device *bdev)
690 struct request_queue *q = bdev_get_queue(bdev);
693 nr_pages = min_t(unsigned,
694 queue_max_segments(q),
695 queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
697 return min_t(unsigned, nr_pages, BIO_MAX_PAGES);
700 EXPORT_SYMBOL(bio_get_nr_vecs);
702 static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
703 *page, unsigned int len, unsigned int offset,
704 unsigned int max_sectors)
706 int retried_segments = 0;
707 struct bio_vec *bvec;
710 * cloned bio must not modify vec list
712 if (unlikely(bio_flagged(bio, BIO_CLONED)))
715 if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
719 * For filesystems with a blocksize smaller than the pagesize
720 * we will often be called with the same page as last time and
721 * a consecutive offset. Optimize this special case.
723 if (bio->bi_vcnt > 0) {
724 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
726 if (page == prev->bv_page &&
727 offset == prev->bv_offset + prev->bv_len) {
728 unsigned int prev_bv_len = prev->bv_len;
731 if (q->merge_bvec_fn) {
732 struct bvec_merge_data bvm = {
733 /* prev_bvec is already charged in
734 bi_size, discharge it in order to
735 simulate merging updated prev_bvec
737 .bi_bdev = bio->bi_bdev,
738 .bi_sector = bio->bi_iter.bi_sector,
739 .bi_size = bio->bi_iter.bi_size -
744 if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
750 bio->bi_iter.bi_size += len;
755 * If the queue doesn't support SG gaps and adding this
756 * offset would create a gap, disallow it.
758 if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) &&
759 bvec_gap_to_prev(prev, offset))
763 if (bio->bi_vcnt >= bio->bi_max_vecs)
767 * setup the new entry, we might clear it again later if we
768 * cannot add the page
770 bvec = &bio->bi_io_vec[bio->bi_vcnt];
771 bvec->bv_page = page;
773 bvec->bv_offset = offset;
775 bio->bi_phys_segments++;
776 bio->bi_iter.bi_size += len;
779 * Perform a recount if the number of segments is greater
780 * than queue_max_segments(q).
783 while (bio->bi_phys_segments > queue_max_segments(q)) {
785 if (retried_segments)
788 retried_segments = 1;
789 blk_recount_segments(q, bio);
793 * if queue has other restrictions (eg varying max sector size
794 * depending on offset), it can specify a merge_bvec_fn in the
795 * queue to get further control
797 if (q->merge_bvec_fn) {
798 struct bvec_merge_data bvm = {
799 .bi_bdev = bio->bi_bdev,
800 .bi_sector = bio->bi_iter.bi_sector,
801 .bi_size = bio->bi_iter.bi_size - len,
806 * merge_bvec_fn() returns number of bytes it can accept
809 if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len)
813 /* If we may be able to merge these biovecs, force a recount */
814 if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
815 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
821 bvec->bv_page = NULL;
825 bio->bi_iter.bi_size -= len;
826 blk_recount_segments(q, bio);
831 * bio_add_pc_page - attempt to add page to bio
832 * @q: the target queue
833 * @bio: destination bio
835 * @len: vec entry length
836 * @offset: vec entry offset
838 * Attempt to add a page to the bio_vec maplist. This can fail for a
839 * number of reasons, such as the bio being full or target block device
840 * limitations. The target block device must allow bio's up to PAGE_SIZE,
841 * so it is always possible to add a single page to an empty bio.
843 * This should only be used by REQ_PC bios.
845 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
846 unsigned int len, unsigned int offset)
848 return __bio_add_page(q, bio, page, len, offset,
849 queue_max_hw_sectors(q));
851 EXPORT_SYMBOL(bio_add_pc_page);
854 * bio_add_page - attempt to add page to bio
855 * @bio: destination bio
857 * @len: vec entry length
858 * @offset: vec entry offset
860 * Attempt to add a page to the bio_vec maplist. This can fail for a
861 * number of reasons, such as the bio being full or target block device
862 * limitations. The target block device must allow bio's up to PAGE_SIZE,
863 * so it is always possible to add a single page to an empty bio.
865 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
868 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
869 unsigned int max_sectors;
871 max_sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector);
872 if ((max_sectors < (len >> 9)) && !bio->bi_iter.bi_size)
873 max_sectors = len >> 9;
875 return __bio_add_page(q, bio, page, len, offset, max_sectors);
877 EXPORT_SYMBOL(bio_add_page);
879 struct submit_bio_ret {
880 struct completion event;
884 static void submit_bio_wait_endio(struct bio *bio, int error)
886 struct submit_bio_ret *ret = bio->bi_private;
889 complete(&ret->event);
893 * submit_bio_wait - submit a bio, and wait until it completes
894 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
895 * @bio: The &struct bio which describes the I/O
897 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
898 * bio_endio() on failure.
900 int submit_bio_wait(int rw, struct bio *bio)
902 struct submit_bio_ret ret;
905 init_completion(&ret.event);
906 bio->bi_private = &ret;
907 bio->bi_end_io = submit_bio_wait_endio;
909 wait_for_completion(&ret.event);
913 EXPORT_SYMBOL(submit_bio_wait);
916 * bio_advance - increment/complete a bio by some number of bytes
917 * @bio: bio to advance
918 * @bytes: number of bytes to complete
920 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
921 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
922 * be updated on the last bvec as well.
924 * @bio will then represent the remaining, uncompleted portion of the io.
926 void bio_advance(struct bio *bio, unsigned bytes)
928 if (bio_integrity(bio))
929 bio_integrity_advance(bio, bytes);
931 bio_advance_iter(bio, &bio->bi_iter, bytes);
933 EXPORT_SYMBOL(bio_advance);
936 * bio_alloc_pages - allocates a single page for each bvec in a bio
937 * @bio: bio to allocate pages for
938 * @gfp_mask: flags for allocation
940 * Allocates pages up to @bio->bi_vcnt.
942 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
945 int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
950 bio_for_each_segment_all(bv, bio, i) {
951 bv->bv_page = alloc_page(gfp_mask);
953 while (--bv >= bio->bi_io_vec)
954 __free_page(bv->bv_page);
961 EXPORT_SYMBOL(bio_alloc_pages);
964 * bio_copy_data - copy contents of data buffers from one chain of bios to
966 * @src: source bio list
967 * @dst: destination bio list
969 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
970 * @src and @dst as linked lists of bios.
972 * Stops when it reaches the end of either @src or @dst - that is, copies
973 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
975 void bio_copy_data(struct bio *dst, struct bio *src)
977 struct bvec_iter src_iter, dst_iter;
978 struct bio_vec src_bv, dst_bv;
982 src_iter = src->bi_iter;
983 dst_iter = dst->bi_iter;
986 if (!src_iter.bi_size) {
991 src_iter = src->bi_iter;
994 if (!dst_iter.bi_size) {
999 dst_iter = dst->bi_iter;
1002 src_bv = bio_iter_iovec(src, src_iter);
1003 dst_bv = bio_iter_iovec(dst, dst_iter);
1005 bytes = min(src_bv.bv_len, dst_bv.bv_len);
1007 src_p = kmap_atomic(src_bv.bv_page);
1008 dst_p = kmap_atomic(dst_bv.bv_page);
1010 memcpy(dst_p + dst_bv.bv_offset,
1011 src_p + src_bv.bv_offset,
1014 kunmap_atomic(dst_p);
1015 kunmap_atomic(src_p);
1017 bio_advance_iter(src, &src_iter, bytes);
1018 bio_advance_iter(dst, &dst_iter, bytes);
1021 EXPORT_SYMBOL(bio_copy_data);
1023 struct bio_map_data {
1025 struct iov_iter iter;
1029 static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count,
1032 if (iov_count > UIO_MAXIOV)
1035 return kmalloc(sizeof(struct bio_map_data) +
1036 sizeof(struct iovec) * iov_count, gfp_mask);
1040 * bio_copy_from_iter - copy all pages from iov_iter to bio
1041 * @bio: The &struct bio which describes the I/O as destination
1042 * @iter: iov_iter as source
1044 * Copy all pages from iov_iter to bio.
1045 * Returns 0 on success, or error on failure.
1047 static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter)
1050 struct bio_vec *bvec;
1052 bio_for_each_segment_all(bvec, bio, i) {
1055 ret = copy_page_from_iter(bvec->bv_page,
1060 if (!iov_iter_count(&iter))
1063 if (ret < bvec->bv_len)
1071 * bio_copy_to_iter - copy all pages from bio to iov_iter
1072 * @bio: The &struct bio which describes the I/O as source
1073 * @iter: iov_iter as destination
1075 * Copy all pages from bio to iov_iter.
1076 * Returns 0 on success, or error on failure.
1078 static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
1081 struct bio_vec *bvec;
1083 bio_for_each_segment_all(bvec, bio, i) {
1086 ret = copy_page_to_iter(bvec->bv_page,
1091 if (!iov_iter_count(&iter))
1094 if (ret < bvec->bv_len)
1101 static void bio_free_pages(struct bio *bio)
1103 struct bio_vec *bvec;
1106 bio_for_each_segment_all(bvec, bio, i)
1107 __free_page(bvec->bv_page);
1111 * bio_uncopy_user - finish previously mapped bio
1112 * @bio: bio being terminated
1114 * Free pages allocated from bio_copy_user_iov() and write back data
1115 * to user space in case of a read.
1117 int bio_uncopy_user(struct bio *bio)
1119 struct bio_map_data *bmd = bio->bi_private;
1122 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1124 * if we're in a workqueue, the request is orphaned, so
1125 * don't copy into a random user address space, just free.
1127 if (current->mm && bio_data_dir(bio) == READ)
1128 ret = bio_copy_to_iter(bio, bmd->iter);
1129 if (bmd->is_our_pages)
1130 bio_free_pages(bio);
1136 EXPORT_SYMBOL(bio_uncopy_user);
1139 * bio_copy_user_iov - copy user data to bio
1140 * @q: destination block queue
1141 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1142 * @iter: iovec iterator
1143 * @gfp_mask: memory allocation flags
1145 * Prepares and returns a bio for indirect user io, bouncing data
1146 * to/from kernel pages as necessary. Must be paired with
1147 * call bio_uncopy_user() on io completion.
1149 struct bio *bio_copy_user_iov(struct request_queue *q,
1150 struct rq_map_data *map_data,
1151 const struct iov_iter *iter,
1154 struct bio_map_data *bmd;
1159 unsigned int len = iter->count;
1160 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
1162 for (i = 0; i < iter->nr_segs; i++) {
1163 unsigned long uaddr;
1165 unsigned long start;
1167 uaddr = (unsigned long) iter->iov[i].iov_base;
1168 end = (uaddr + iter->iov[i].iov_len + PAGE_SIZE - 1)
1170 start = uaddr >> PAGE_SHIFT;
1176 return ERR_PTR(-EINVAL);
1178 nr_pages += end - start;
1184 bmd = bio_alloc_map_data(iter->nr_segs, gfp_mask);
1186 return ERR_PTR(-ENOMEM);
1189 * We need to do a deep copy of the iov_iter including the iovecs.
1190 * The caller provided iov might point to an on-stack or otherwise
1193 bmd->is_our_pages = map_data ? 0 : 1;
1194 memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs);
1195 iov_iter_init(&bmd->iter, iter->type, bmd->iov,
1196 iter->nr_segs, iter->count);
1199 bio = bio_kmalloc(gfp_mask, nr_pages);
1203 if (iter->type & WRITE)
1204 bio->bi_rw |= REQ_WRITE;
1209 nr_pages = 1 << map_data->page_order;
1210 i = map_data->offset / PAGE_SIZE;
1213 unsigned int bytes = PAGE_SIZE;
1221 if (i == map_data->nr_entries * nr_pages) {
1226 page = map_data->pages[i / nr_pages];
1227 page += (i % nr_pages);
1231 page = alloc_page(q->bounce_gfp | gfp_mask);
1238 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1251 if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
1252 (map_data && map_data->from_user)) {
1253 ret = bio_copy_from_iter(bio, *iter);
1258 bio->bi_private = bmd;
1262 bio_free_pages(bio);
1266 return ERR_PTR(ret);
1270 * bio_map_user_iov - map user iovec into bio
1271 * @q: the struct request_queue for the bio
1272 * @iter: iovec iterator
1273 * @gfp_mask: memory allocation flags
1275 * Map the user space address into a bio suitable for io to a block
1276 * device. Returns an error pointer in case of error.
1278 struct bio *bio_map_user_iov(struct request_queue *q,
1279 const struct iov_iter *iter,
1284 struct page **pages;
1291 iov_for_each(iov, i, *iter) {
1292 unsigned long uaddr = (unsigned long) iov.iov_base;
1293 unsigned long len = iov.iov_len;
1294 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1295 unsigned long start = uaddr >> PAGE_SHIFT;
1301 return ERR_PTR(-EINVAL);
1303 nr_pages += end - start;
1305 * buffer must be aligned to at least hardsector size for now
1307 if (uaddr & queue_dma_alignment(q))
1308 return ERR_PTR(-EINVAL);
1312 return ERR_PTR(-EINVAL);
1314 bio = bio_kmalloc(gfp_mask, nr_pages);
1316 return ERR_PTR(-ENOMEM);
1319 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
1323 iov_for_each(iov, i, *iter) {
1324 unsigned long uaddr = (unsigned long) iov.iov_base;
1325 unsigned long len = iov.iov_len;
1326 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1327 unsigned long start = uaddr >> PAGE_SHIFT;
1328 const int local_nr_pages = end - start;
1329 const int page_limit = cur_page + local_nr_pages;
1331 ret = get_user_pages_fast(uaddr, local_nr_pages,
1332 (iter->type & WRITE) != WRITE,
1334 if (ret < local_nr_pages) {
1339 offset = uaddr & ~PAGE_MASK;
1340 for (j = cur_page; j < page_limit; j++) {
1341 unsigned int bytes = PAGE_SIZE - offset;
1352 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1362 * release the pages we didn't map into the bio, if any
1364 while (j < page_limit)
1365 page_cache_release(pages[j++]);
1371 * set data direction, and check if mapped pages need bouncing
1373 if (iter->type & WRITE)
1374 bio->bi_rw |= REQ_WRITE;
1376 bio->bi_flags |= (1 << BIO_USER_MAPPED);
1379 * subtle -- if __bio_map_user() ended up bouncing a bio,
1380 * it would normally disappear when its bi_end_io is run.
1381 * however, we need it for the unmap, so grab an extra
1388 for (j = 0; j < nr_pages; j++) {
1391 page_cache_release(pages[j]);
1396 return ERR_PTR(ret);
1399 static void __bio_unmap_user(struct bio *bio)
1401 struct bio_vec *bvec;
1405 * make sure we dirty pages we wrote to
1407 bio_for_each_segment_all(bvec, bio, i) {
1408 if (bio_data_dir(bio) == READ)
1409 set_page_dirty_lock(bvec->bv_page);
1411 page_cache_release(bvec->bv_page);
1418 * bio_unmap_user - unmap a bio
1419 * @bio: the bio being unmapped
1421 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1422 * a process context.
1424 * bio_unmap_user() may sleep.
1426 void bio_unmap_user(struct bio *bio)
1428 __bio_unmap_user(bio);
1431 EXPORT_SYMBOL(bio_unmap_user);
1433 static void bio_map_kern_endio(struct bio *bio, int err)
1439 * bio_map_kern - map kernel address into bio
1440 * @q: the struct request_queue for the bio
1441 * @data: pointer to buffer to map
1442 * @len: length in bytes
1443 * @gfp_mask: allocation flags for bio allocation
1445 * Map the kernel address into a bio suitable for io to a block
1446 * device. Returns an error pointer in case of error.
1448 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1451 unsigned long kaddr = (unsigned long)data;
1452 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1453 unsigned long start = kaddr >> PAGE_SHIFT;
1454 const int nr_pages = end - start;
1458 bio = bio_kmalloc(gfp_mask, nr_pages);
1460 return ERR_PTR(-ENOMEM);
1462 offset = offset_in_page(kaddr);
1463 for (i = 0; i < nr_pages; i++) {
1464 unsigned int bytes = PAGE_SIZE - offset;
1472 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1474 /* we don't support partial mappings */
1476 return ERR_PTR(-EINVAL);
1484 bio->bi_end_io = bio_map_kern_endio;
1487 EXPORT_SYMBOL(bio_map_kern);
1489 static void bio_copy_kern_endio(struct bio *bio, int err)
1491 bio_free_pages(bio);
1495 static void bio_copy_kern_endio_read(struct bio *bio, int err)
1497 char *p = bio->bi_private;
1498 struct bio_vec *bvec;
1501 bio_for_each_segment_all(bvec, bio, i) {
1502 memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
1506 bio_copy_kern_endio(bio, err);
1510 * bio_copy_kern - copy kernel address into bio
1511 * @q: the struct request_queue for the bio
1512 * @data: pointer to buffer to copy
1513 * @len: length in bytes
1514 * @gfp_mask: allocation flags for bio and page allocation
1515 * @reading: data direction is READ
1517 * copy the kernel address into a bio suitable for io to a block
1518 * device. Returns an error pointer in case of error.
1520 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1521 gfp_t gfp_mask, int reading)
1523 unsigned long kaddr = (unsigned long)data;
1524 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1525 unsigned long start = kaddr >> PAGE_SHIFT;
1534 return ERR_PTR(-EINVAL);
1536 nr_pages = end - start;
1537 bio = bio_kmalloc(gfp_mask, nr_pages);
1539 return ERR_PTR(-ENOMEM);
1543 unsigned int bytes = PAGE_SIZE;
1548 page = alloc_page(q->bounce_gfp | gfp_mask);
1553 memcpy(page_address(page), p, bytes);
1555 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
1563 bio->bi_end_io = bio_copy_kern_endio_read;
1564 bio->bi_private = data;
1566 bio->bi_end_io = bio_copy_kern_endio;
1567 bio->bi_rw |= REQ_WRITE;
1573 bio_free_pages(bio);
1575 return ERR_PTR(-ENOMEM);
1577 EXPORT_SYMBOL(bio_copy_kern);
1580 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1581 * for performing direct-IO in BIOs.
1583 * The problem is that we cannot run set_page_dirty() from interrupt context
1584 * because the required locks are not interrupt-safe. So what we can do is to
1585 * mark the pages dirty _before_ performing IO. And in interrupt context,
1586 * check that the pages are still dirty. If so, fine. If not, redirty them
1587 * in process context.
1589 * We special-case compound pages here: normally this means reads into hugetlb
1590 * pages. The logic in here doesn't really work right for compound pages
1591 * because the VM does not uniformly chase down the head page in all cases.
1592 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1593 * handle them at all. So we skip compound pages here at an early stage.
1595 * Note that this code is very hard to test under normal circumstances because
1596 * direct-io pins the pages with get_user_pages(). This makes
1597 * is_page_cache_freeable return false, and the VM will not clean the pages.
1598 * But other code (eg, flusher threads) could clean the pages if they are mapped
1601 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1602 * deferred bio dirtying paths.
1606 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1608 void bio_set_pages_dirty(struct bio *bio)
1610 struct bio_vec *bvec;
1613 bio_for_each_segment_all(bvec, bio, i) {
1614 struct page *page = bvec->bv_page;
1616 if (page && !PageCompound(page))
1617 set_page_dirty_lock(page);
1621 static void bio_release_pages(struct bio *bio)
1623 struct bio_vec *bvec;
1626 bio_for_each_segment_all(bvec, bio, i) {
1627 struct page *page = bvec->bv_page;
1635 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1636 * If they are, then fine. If, however, some pages are clean then they must
1637 * have been written out during the direct-IO read. So we take another ref on
1638 * the BIO and the offending pages and re-dirty the pages in process context.
1640 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1641 * here on. It will run one page_cache_release() against each page and will
1642 * run one bio_put() against the BIO.
1645 static void bio_dirty_fn(struct work_struct *work);
1647 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1648 static DEFINE_SPINLOCK(bio_dirty_lock);
1649 static struct bio *bio_dirty_list;
1652 * This runs in process context
1654 static void bio_dirty_fn(struct work_struct *work)
1656 unsigned long flags;
1659 spin_lock_irqsave(&bio_dirty_lock, flags);
1660 bio = bio_dirty_list;
1661 bio_dirty_list = NULL;
1662 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1665 struct bio *next = bio->bi_private;
1667 bio_set_pages_dirty(bio);
1668 bio_release_pages(bio);
1674 void bio_check_pages_dirty(struct bio *bio)
1676 struct bio_vec *bvec;
1677 int nr_clean_pages = 0;
1680 bio_for_each_segment_all(bvec, bio, i) {
1681 struct page *page = bvec->bv_page;
1683 if (PageDirty(page) || PageCompound(page)) {
1684 page_cache_release(page);
1685 bvec->bv_page = NULL;
1691 if (nr_clean_pages) {
1692 unsigned long flags;
1694 spin_lock_irqsave(&bio_dirty_lock, flags);
1695 bio->bi_private = bio_dirty_list;
1696 bio_dirty_list = bio;
1697 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1698 schedule_work(&bio_dirty_work);
1704 void generic_start_io_acct(int rw, unsigned long sectors,
1705 struct hd_struct *part)
1707 int cpu = part_stat_lock();
1709 part_round_stats(cpu, part);
1710 part_stat_inc(cpu, part, ios[rw]);
1711 part_stat_add(cpu, part, sectors[rw], sectors);
1712 part_inc_in_flight(part, rw);
1716 EXPORT_SYMBOL(generic_start_io_acct);
1718 void generic_end_io_acct(int rw, struct hd_struct *part,
1719 unsigned long start_time)
1721 unsigned long duration = jiffies - start_time;
1722 int cpu = part_stat_lock();
1724 part_stat_add(cpu, part, ticks[rw], duration);
1725 part_round_stats(cpu, part);
1726 part_dec_in_flight(part, rw);
1730 EXPORT_SYMBOL(generic_end_io_acct);
1732 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1733 void bio_flush_dcache_pages(struct bio *bi)
1735 struct bio_vec bvec;
1736 struct bvec_iter iter;
1738 bio_for_each_segment(bvec, bi, iter)
1739 flush_dcache_page(bvec.bv_page);
1741 EXPORT_SYMBOL(bio_flush_dcache_pages);
1745 * bio_endio - end I/O on a bio
1747 * @error: error, if any
1750 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1751 * preferred way to end I/O on a bio, it takes care of clearing
1752 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1753 * established -Exxxx (-EIO, for instance) error values in case
1754 * something went wrong. No one should call bi_end_io() directly on a
1755 * bio unless they own it and thus know that it has an end_io
1758 void bio_endio(struct bio *bio, int error)
1761 BUG_ON(atomic_read(&bio->bi_remaining) <= 0);
1764 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1765 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1768 if (!atomic_dec_and_test(&bio->bi_remaining))
1772 * Need to have a real endio function for chained bios,
1773 * otherwise various corner cases will break (like stacking
1774 * block devices that save/restore bi_end_io) - however, we want
1775 * to avoid unbounded recursion and blowing the stack. Tail call
1776 * optimization would handle this, but compiling with frame
1777 * pointers also disables gcc's sibling call optimization.
1779 if (bio->bi_end_io == bio_chain_endio) {
1780 struct bio *parent = bio->bi_private;
1785 bio->bi_end_io(bio, error);
1790 EXPORT_SYMBOL(bio_endio);
1793 * bio_endio_nodec - end I/O on a bio, without decrementing bi_remaining
1795 * @error: error, if any
1797 * For code that has saved and restored bi_end_io; thing hard before using this
1798 * function, probably you should've cloned the entire bio.
1800 void bio_endio_nodec(struct bio *bio, int error)
1802 atomic_inc(&bio->bi_remaining);
1803 bio_endio(bio, error);
1805 EXPORT_SYMBOL(bio_endio_nodec);
1808 * bio_split - split a bio
1809 * @bio: bio to split
1810 * @sectors: number of sectors to split from the front of @bio
1812 * @bs: bio set to allocate from
1814 * Allocates and returns a new bio which represents @sectors from the start of
1815 * @bio, and updates @bio to represent the remaining sectors.
1817 * The newly allocated bio will point to @bio's bi_io_vec; it is the caller's
1818 * responsibility to ensure that @bio is not freed before the split.
1820 struct bio *bio_split(struct bio *bio, int sectors,
1821 gfp_t gfp, struct bio_set *bs)
1823 struct bio *split = NULL;
1825 BUG_ON(sectors <= 0);
1826 BUG_ON(sectors >= bio_sectors(bio));
1828 split = bio_clone_fast(bio, gfp, bs);
1832 split->bi_iter.bi_size = sectors << 9;
1834 if (bio_integrity(split))
1835 bio_integrity_trim(split, 0, sectors);
1837 bio_advance(bio, split->bi_iter.bi_size);
1841 EXPORT_SYMBOL(bio_split);
1844 * bio_trim - trim a bio
1846 * @offset: number of sectors to trim from the front of @bio
1847 * @size: size we want to trim @bio to, in sectors
1849 void bio_trim(struct bio *bio, int offset, int size)
1851 /* 'bio' is a cloned bio which we need to trim to match
1852 * the given offset and size.
1856 if (offset == 0 && size == bio->bi_iter.bi_size)
1859 clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1861 bio_advance(bio, offset << 9);
1863 bio->bi_iter.bi_size = size;
1865 EXPORT_SYMBOL_GPL(bio_trim);
1868 * create memory pools for biovec's in a bio_set.
1869 * use the global biovec slabs created for general use.
1871 mempool_t *biovec_create_pool(int pool_entries)
1873 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
1875 return mempool_create_slab_pool(pool_entries, bp->slab);
1878 void bioset_free(struct bio_set *bs)
1880 if (bs->rescue_workqueue)
1881 destroy_workqueue(bs->rescue_workqueue);
1884 mempool_destroy(bs->bio_pool);
1887 mempool_destroy(bs->bvec_pool);
1889 bioset_integrity_free(bs);
1894 EXPORT_SYMBOL(bioset_free);
1896 static struct bio_set *__bioset_create(unsigned int pool_size,
1897 unsigned int front_pad,
1898 bool create_bvec_pool)
1900 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1903 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1907 bs->front_pad = front_pad;
1909 spin_lock_init(&bs->rescue_lock);
1910 bio_list_init(&bs->rescue_list);
1911 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1913 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1914 if (!bs->bio_slab) {
1919 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1923 if (create_bvec_pool) {
1924 bs->bvec_pool = biovec_create_pool(pool_size);
1929 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1930 if (!bs->rescue_workqueue)
1940 * bioset_create - Create a bio_set
1941 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1942 * @front_pad: Number of bytes to allocate in front of the returned bio
1945 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1946 * to ask for a number of bytes to be allocated in front of the bio.
1947 * Front pad allocation is useful for embedding the bio inside
1948 * another structure, to avoid allocating extra data to go with the bio.
1949 * Note that the bio must be embedded at the END of that structure always,
1950 * or things will break badly.
1952 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1954 return __bioset_create(pool_size, front_pad, true);
1956 EXPORT_SYMBOL(bioset_create);
1959 * bioset_create_nobvec - Create a bio_set without bio_vec mempool
1960 * @pool_size: Number of bio to cache in the mempool
1961 * @front_pad: Number of bytes to allocate in front of the returned bio
1964 * Same functionality as bioset_create() except that mempool is not
1965 * created for bio_vecs. Saving some memory for bio_clone_fast() users.
1967 struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad)
1969 return __bioset_create(pool_size, front_pad, false);
1971 EXPORT_SYMBOL(bioset_create_nobvec);
1973 #ifdef CONFIG_BLK_CGROUP
1975 * bio_associate_current - associate a bio with %current
1978 * Associate @bio with %current if it hasn't been associated yet. Block
1979 * layer will treat @bio as if it were issued by %current no matter which
1980 * task actually issues it.
1982 * This function takes an extra reference of @task's io_context and blkcg
1983 * which will be put when @bio is released. The caller must own @bio,
1984 * ensure %current->io_context exists, and is responsible for synchronizing
1985 * calls to this function.
1987 int bio_associate_current(struct bio *bio)
1989 struct io_context *ioc;
1990 struct cgroup_subsys_state *css;
1995 ioc = current->io_context;
1999 /* acquire active ref on @ioc and associate */
2000 get_io_context_active(ioc);
2003 /* associate blkcg if exists */
2005 css = task_css(current, blkio_cgrp_id);
2006 if (css && css_tryget_online(css))
2014 * bio_disassociate_task - undo bio_associate_current()
2017 void bio_disassociate_task(struct bio *bio)
2020 put_io_context(bio->bi_ioc);
2024 css_put(bio->bi_css);
2029 #endif /* CONFIG_BLK_CGROUP */
2031 static void __init biovec_init_slabs(void)
2035 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
2037 struct biovec_slab *bvs = bvec_slabs + i;
2039 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
2044 size = bvs->nr_vecs * sizeof(struct bio_vec);
2045 bvs->slab = kmem_cache_create(bvs->name, size, 0,
2046 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2050 static int __init init_bio(void)
2054 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2056 panic("bio: can't allocate bios\n");
2058 bio_integrity_init();
2059 biovec_init_slabs();
2061 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
2063 panic("bio: can't allocate bios\n");
2065 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2066 panic("bio: can't create integrity pool\n");
2070 subsys_initcall(init_bio);