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[BVEC_POOL_NR] __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)
167 BIO_BUG_ON(idx >= BVEC_POOL_NR);
169 if (idx == BVEC_POOL_MAX) {
170 mempool_free(bv, pool);
172 struct biovec_slab *bvs = bvec_slabs + idx;
174 kmem_cache_free(bvs->slab, bv);
178 struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
184 * see comment near bvec_array define!
202 case 129 ... BIO_MAX_PAGES:
210 * idx now points to the pool we want to allocate from. only the
211 * 1-vec entry pool is mempool backed.
213 if (*idx == BVEC_POOL_MAX) {
215 bvl = mempool_alloc(pool, gfp_mask);
217 struct biovec_slab *bvs = bvec_slabs + *idx;
218 gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO);
221 * Make this allocation restricted and don't dump info on
222 * allocation failures, since we'll fallback to the mempool
223 * in case of failure.
225 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
228 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM
229 * is set, retry with the 1-entry mempool
231 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
232 if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {
233 *idx = BVEC_POOL_MAX;
242 static void __bio_free(struct bio *bio)
244 bio_disassociate_task(bio);
246 if (bio_integrity(bio))
247 bio_integrity_free(bio);
250 static void bio_free(struct bio *bio)
252 struct bio_set *bs = bio->bi_pool;
258 bvec_free(bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio));
261 * If we have front padding, adjust the bio pointer before freeing
266 mempool_free(p, bs->bio_pool);
268 /* Bio was allocated by bio_kmalloc() */
273 void bio_init(struct bio *bio, struct bio_vec *table,
274 unsigned short max_vecs)
276 memset(bio, 0, sizeof(*bio));
277 atomic_set(&bio->__bi_remaining, 1);
278 atomic_set(&bio->__bi_cnt, 1);
280 bio->bi_io_vec = table;
281 bio->bi_max_vecs = max_vecs;
283 EXPORT_SYMBOL(bio_init);
286 * bio_reset - reinitialize a bio
290 * After calling bio_reset(), @bio will be in the same state as a freshly
291 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
292 * preserved are the ones that are initialized by bio_alloc_bioset(). See
293 * comment in struct bio.
295 void bio_reset(struct bio *bio)
297 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
301 memset(bio, 0, BIO_RESET_BYTES);
302 bio->bi_flags = flags;
303 atomic_set(&bio->__bi_remaining, 1);
305 EXPORT_SYMBOL(bio_reset);
307 static struct bio *__bio_chain_endio(struct bio *bio)
309 struct bio *parent = bio->bi_private;
311 if (!parent->bi_error)
312 parent->bi_error = bio->bi_error;
317 static void bio_chain_endio(struct bio *bio)
319 bio_endio(__bio_chain_endio(bio));
323 * bio_chain - chain bio completions
324 * @bio: the target bio
325 * @parent: the @bio's parent bio
327 * The caller won't have a bi_end_io called when @bio completes - instead,
328 * @parent's bi_end_io won't be called until both @parent and @bio have
329 * completed; the chained bio will also be freed when it completes.
331 * The caller must not set bi_private or bi_end_io in @bio.
333 void bio_chain(struct bio *bio, struct bio *parent)
335 BUG_ON(bio->bi_private || bio->bi_end_io);
337 bio->bi_private = parent;
338 bio->bi_end_io = bio_chain_endio;
339 bio_inc_remaining(parent);
341 EXPORT_SYMBOL(bio_chain);
343 static void bio_alloc_rescue(struct work_struct *work)
345 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
349 spin_lock(&bs->rescue_lock);
350 bio = bio_list_pop(&bs->rescue_list);
351 spin_unlock(&bs->rescue_lock);
356 generic_make_request(bio);
360 static void punt_bios_to_rescuer(struct bio_set *bs)
362 struct bio_list punt, nopunt;
366 * In order to guarantee forward progress we must punt only bios that
367 * were allocated from this bio_set; otherwise, if there was a bio on
368 * there for a stacking driver higher up in the stack, processing it
369 * could require allocating bios from this bio_set, and doing that from
370 * our own rescuer would be bad.
372 * Since bio lists are singly linked, pop them all instead of trying to
373 * remove from the middle of the list:
376 bio_list_init(&punt);
377 bio_list_init(&nopunt);
379 while ((bio = bio_list_pop(current->bio_list)))
380 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
382 *current->bio_list = nopunt;
384 spin_lock(&bs->rescue_lock);
385 bio_list_merge(&bs->rescue_list, &punt);
386 spin_unlock(&bs->rescue_lock);
388 queue_work(bs->rescue_workqueue, &bs->rescue_work);
392 * bio_alloc_bioset - allocate a bio for I/O
393 * @gfp_mask: the GFP_ mask given to the slab allocator
394 * @nr_iovecs: number of iovecs to pre-allocate
395 * @bs: the bio_set to allocate from.
398 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
399 * backed by the @bs's mempool.
401 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will
402 * always be able to allocate a bio. This is due to the mempool guarantees.
403 * To make this work, callers must never allocate more than 1 bio at a time
404 * from this pool. Callers that need to allocate more than 1 bio must always
405 * submit the previously allocated bio for IO before attempting to allocate
406 * a new one. Failure to do so can cause deadlocks under memory pressure.
408 * Note that when running under generic_make_request() (i.e. any block
409 * driver), bios are not submitted until after you return - see the code in
410 * generic_make_request() that converts recursion into iteration, to prevent
413 * This would normally mean allocating multiple bios under
414 * generic_make_request() would be susceptible to deadlocks, but we have
415 * deadlock avoidance code that resubmits any blocked bios from a rescuer
418 * However, we do not guarantee forward progress for allocations from other
419 * mempools. Doing multiple allocations from the same mempool under
420 * generic_make_request() should be avoided - instead, use bio_set's front_pad
421 * for per bio allocations.
424 * Pointer to new bio on success, NULL on failure.
426 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
428 gfp_t saved_gfp = gfp_mask;
430 unsigned inline_vecs;
431 struct bio_vec *bvl = NULL;
436 if (nr_iovecs > UIO_MAXIOV)
439 p = kmalloc(sizeof(struct bio) +
440 nr_iovecs * sizeof(struct bio_vec),
443 inline_vecs = nr_iovecs;
445 /* should not use nobvec bioset for nr_iovecs > 0 */
446 if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0))
449 * generic_make_request() converts recursion to iteration; this
450 * means if we're running beneath it, any bios we allocate and
451 * submit will not be submitted (and thus freed) until after we
454 * This exposes us to a potential deadlock if we allocate
455 * multiple bios from the same bio_set() while running
456 * underneath generic_make_request(). If we were to allocate
457 * multiple bios (say a stacking block driver that was splitting
458 * bios), we would deadlock if we exhausted the mempool's
461 * We solve this, and guarantee forward progress, with a rescuer
462 * workqueue per bio_set. If we go to allocate and there are
463 * bios on current->bio_list, we first try the allocation
464 * without __GFP_DIRECT_RECLAIM; if that fails, we punt those
465 * bios we would be blocking to the rescuer workqueue before
466 * we retry with the original gfp_flags.
469 if (current->bio_list && !bio_list_empty(current->bio_list))
470 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
472 p = mempool_alloc(bs->bio_pool, gfp_mask);
473 if (!p && gfp_mask != saved_gfp) {
474 punt_bios_to_rescuer(bs);
475 gfp_mask = saved_gfp;
476 p = mempool_alloc(bs->bio_pool, gfp_mask);
479 front_pad = bs->front_pad;
480 inline_vecs = BIO_INLINE_VECS;
487 bio_init(bio, NULL, 0);
489 if (nr_iovecs > inline_vecs) {
490 unsigned long idx = 0;
492 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
493 if (!bvl && gfp_mask != saved_gfp) {
494 punt_bios_to_rescuer(bs);
495 gfp_mask = saved_gfp;
496 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
502 bio->bi_flags |= idx << BVEC_POOL_OFFSET;
503 } else if (nr_iovecs) {
504 bvl = bio->bi_inline_vecs;
508 bio->bi_max_vecs = nr_iovecs;
509 bio->bi_io_vec = bvl;
513 mempool_free(p, bs->bio_pool);
516 EXPORT_SYMBOL(bio_alloc_bioset);
518 void zero_fill_bio(struct bio *bio)
522 struct bvec_iter iter;
524 bio_for_each_segment(bv, bio, iter) {
525 char *data = bvec_kmap_irq(&bv, &flags);
526 memset(data, 0, bv.bv_len);
527 flush_dcache_page(bv.bv_page);
528 bvec_kunmap_irq(data, &flags);
531 EXPORT_SYMBOL(zero_fill_bio);
534 * bio_put - release a reference to a bio
535 * @bio: bio to release reference to
538 * Put a reference to a &struct bio, either one you have gotten with
539 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
541 void bio_put(struct bio *bio)
543 if (!bio_flagged(bio, BIO_REFFED))
546 BIO_BUG_ON(!atomic_read(&bio->__bi_cnt));
551 if (atomic_dec_and_test(&bio->__bi_cnt))
555 EXPORT_SYMBOL(bio_put);
557 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
559 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
560 blk_recount_segments(q, bio);
562 return bio->bi_phys_segments;
564 EXPORT_SYMBOL(bio_phys_segments);
567 * __bio_clone_fast - clone a bio that shares the original bio's biovec
568 * @bio: destination bio
569 * @bio_src: bio to clone
571 * Clone a &bio. Caller will own the returned bio, but not
572 * the actual data it points to. Reference count of returned
575 * Caller must ensure that @bio_src is not freed before @bio.
577 void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
579 BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio));
582 * most users will be overriding ->bi_bdev with a new target,
583 * so we don't set nor calculate new physical/hw segment counts here
585 bio->bi_bdev = bio_src->bi_bdev;
586 bio_set_flag(bio, BIO_CLONED);
587 bio->bi_opf = bio_src->bi_opf;
588 bio->bi_iter = bio_src->bi_iter;
589 bio->bi_io_vec = bio_src->bi_io_vec;
591 bio_clone_blkcg_association(bio, bio_src);
593 EXPORT_SYMBOL(__bio_clone_fast);
596 * bio_clone_fast - clone a bio that shares the original bio's biovec
598 * @gfp_mask: allocation priority
599 * @bs: bio_set to allocate from
601 * Like __bio_clone_fast, only also allocates the returned bio
603 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
607 b = bio_alloc_bioset(gfp_mask, 0, bs);
611 __bio_clone_fast(b, bio);
613 if (bio_integrity(bio)) {
616 ret = bio_integrity_clone(b, bio, gfp_mask);
626 EXPORT_SYMBOL(bio_clone_fast);
629 * bio_clone_bioset - clone a bio
630 * @bio_src: bio to clone
631 * @gfp_mask: allocation priority
632 * @bs: bio_set to allocate from
634 * Clone bio. Caller will own the returned bio, but not the actual data it
635 * points to. Reference count of returned bio will be one.
637 struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
640 struct bvec_iter iter;
645 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
646 * bio_src->bi_io_vec to bio->bi_io_vec.
648 * We can't do that anymore, because:
650 * - The point of cloning the biovec is to produce a bio with a biovec
651 * the caller can modify: bi_idx and bi_bvec_done should be 0.
653 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
654 * we tried to clone the whole thing bio_alloc_bioset() would fail.
655 * But the clone should succeed as long as the number of biovecs we
656 * actually need to allocate is fewer than BIO_MAX_PAGES.
658 * - Lastly, bi_vcnt should not be looked at or relied upon by code
659 * that does not own the bio - reason being drivers don't use it for
660 * iterating over the biovec anymore, so expecting it to be kept up
661 * to date (i.e. for clones that share the parent biovec) is just
662 * asking for trouble and would force extra work on
663 * __bio_clone_fast() anyways.
666 bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
669 bio->bi_bdev = bio_src->bi_bdev;
670 bio->bi_opf = bio_src->bi_opf;
671 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
672 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
674 switch (bio_op(bio)) {
676 case REQ_OP_SECURE_ERASE:
678 case REQ_OP_WRITE_SAME:
679 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
682 bio_for_each_segment(bv, bio_src, iter)
683 bio->bi_io_vec[bio->bi_vcnt++] = bv;
687 if (bio_integrity(bio_src)) {
690 ret = bio_integrity_clone(bio, bio_src, gfp_mask);
697 bio_clone_blkcg_association(bio, bio_src);
701 EXPORT_SYMBOL(bio_clone_bioset);
704 * bio_add_pc_page - attempt to add page to bio
705 * @q: the target queue
706 * @bio: destination bio
708 * @len: vec entry length
709 * @offset: vec entry offset
711 * Attempt to add a page to the bio_vec maplist. This can fail for a
712 * number of reasons, such as the bio being full or target block device
713 * limitations. The target block device must allow bio's up to PAGE_SIZE,
714 * so it is always possible to add a single page to an empty bio.
716 * This should only be used by REQ_PC bios.
718 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
719 *page, unsigned int len, unsigned int offset)
721 int retried_segments = 0;
722 struct bio_vec *bvec;
725 * cloned bio must not modify vec list
727 if (unlikely(bio_flagged(bio, BIO_CLONED)))
730 if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
734 * For filesystems with a blocksize smaller than the pagesize
735 * we will often be called with the same page as last time and
736 * a consecutive offset. Optimize this special case.
738 if (bio->bi_vcnt > 0) {
739 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
741 if (page == prev->bv_page &&
742 offset == prev->bv_offset + prev->bv_len) {
744 bio->bi_iter.bi_size += len;
749 * If the queue doesn't support SG gaps and adding this
750 * offset would create a gap, disallow it.
752 if (bvec_gap_to_prev(q, prev, offset))
756 if (bio->bi_vcnt >= bio->bi_max_vecs)
760 * setup the new entry, we might clear it again later if we
761 * cannot add the page
763 bvec = &bio->bi_io_vec[bio->bi_vcnt];
764 bvec->bv_page = page;
766 bvec->bv_offset = offset;
768 bio->bi_phys_segments++;
769 bio->bi_iter.bi_size += len;
772 * Perform a recount if the number of segments is greater
773 * than queue_max_segments(q).
776 while (bio->bi_phys_segments > queue_max_segments(q)) {
778 if (retried_segments)
781 retried_segments = 1;
782 blk_recount_segments(q, bio);
785 /* If we may be able to merge these biovecs, force a recount */
786 if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
787 bio_clear_flag(bio, BIO_SEG_VALID);
793 bvec->bv_page = NULL;
797 bio->bi_iter.bi_size -= len;
798 blk_recount_segments(q, bio);
801 EXPORT_SYMBOL(bio_add_pc_page);
804 * bio_add_page - attempt to add page to bio
805 * @bio: destination bio
807 * @len: vec entry length
808 * @offset: vec entry offset
810 * Attempt to add a page to the bio_vec maplist. This will only fail
811 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
813 int bio_add_page(struct bio *bio, struct page *page,
814 unsigned int len, unsigned int offset)
819 * cloned bio must not modify vec list
821 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
825 * For filesystems with a blocksize smaller than the pagesize
826 * we will often be called with the same page as last time and
827 * a consecutive offset. Optimize this special case.
829 if (bio->bi_vcnt > 0) {
830 bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
832 if (page == bv->bv_page &&
833 offset == bv->bv_offset + bv->bv_len) {
839 if (bio->bi_vcnt >= bio->bi_max_vecs)
842 bv = &bio->bi_io_vec[bio->bi_vcnt];
845 bv->bv_offset = offset;
849 bio->bi_iter.bi_size += len;
852 EXPORT_SYMBOL(bio_add_page);
855 * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
856 * @bio: bio to add pages to
857 * @iter: iov iterator describing the region to be mapped
859 * Pins as many pages from *iter and appends them to @bio's bvec array. The
860 * pages will have to be released using put_page() when done.
862 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
864 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
865 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
866 struct page **pages = (struct page **)bv;
870 size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
871 if (unlikely(size <= 0))
872 return size ? size : -EFAULT;
873 nr_pages = (size + offset + PAGE_SIZE - 1) / PAGE_SIZE;
876 * Deep magic below: We need to walk the pinned pages backwards
877 * because we are abusing the space allocated for the bio_vecs
878 * for the page array. Because the bio_vecs are larger than the
879 * page pointers by definition this will always work. But it also
880 * means we can't use bio_add_page, so any changes to it's semantics
881 * need to be reflected here as well.
883 bio->bi_iter.bi_size += size;
884 bio->bi_vcnt += nr_pages;
886 diff = (nr_pages * PAGE_SIZE - offset) - size;
888 bv[nr_pages].bv_page = pages[nr_pages];
889 bv[nr_pages].bv_len = PAGE_SIZE;
890 bv[nr_pages].bv_offset = 0;
893 bv[0].bv_offset += offset;
894 bv[0].bv_len -= offset;
896 bv[bio->bi_vcnt - 1].bv_len -= diff;
898 iov_iter_advance(iter, size);
901 EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
903 struct submit_bio_ret {
904 struct completion event;
908 static void submit_bio_wait_endio(struct bio *bio)
910 struct submit_bio_ret *ret = bio->bi_private;
912 ret->error = bio->bi_error;
913 complete(&ret->event);
917 * submit_bio_wait - submit a bio, and wait until it completes
918 * @bio: The &struct bio which describes the I/O
920 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
921 * bio_endio() on failure.
923 int submit_bio_wait(struct bio *bio)
925 struct submit_bio_ret ret;
927 init_completion(&ret.event);
928 bio->bi_private = &ret;
929 bio->bi_end_io = submit_bio_wait_endio;
930 bio->bi_opf |= REQ_SYNC;
932 wait_for_completion_io(&ret.event);
936 EXPORT_SYMBOL(submit_bio_wait);
939 * bio_advance - increment/complete a bio by some number of bytes
940 * @bio: bio to advance
941 * @bytes: number of bytes to complete
943 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
944 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
945 * be updated on the last bvec as well.
947 * @bio will then represent the remaining, uncompleted portion of the io.
949 void bio_advance(struct bio *bio, unsigned bytes)
951 if (bio_integrity(bio))
952 bio_integrity_advance(bio, bytes);
954 bio_advance_iter(bio, &bio->bi_iter, bytes);
956 EXPORT_SYMBOL(bio_advance);
959 * bio_alloc_pages - allocates a single page for each bvec in a bio
960 * @bio: bio to allocate pages for
961 * @gfp_mask: flags for allocation
963 * Allocates pages up to @bio->bi_vcnt.
965 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
968 int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
973 bio_for_each_segment_all(bv, bio, i) {
974 bv->bv_page = alloc_page(gfp_mask);
976 while (--bv >= bio->bi_io_vec)
977 __free_page(bv->bv_page);
984 EXPORT_SYMBOL(bio_alloc_pages);
987 * bio_copy_data - copy contents of data buffers from one chain of bios to
989 * @src: source bio list
990 * @dst: destination bio list
992 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
993 * @src and @dst as linked lists of bios.
995 * Stops when it reaches the end of either @src or @dst - that is, copies
996 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
998 void bio_copy_data(struct bio *dst, struct bio *src)
1000 struct bvec_iter src_iter, dst_iter;
1001 struct bio_vec src_bv, dst_bv;
1002 void *src_p, *dst_p;
1005 src_iter = src->bi_iter;
1006 dst_iter = dst->bi_iter;
1009 if (!src_iter.bi_size) {
1014 src_iter = src->bi_iter;
1017 if (!dst_iter.bi_size) {
1022 dst_iter = dst->bi_iter;
1025 src_bv = bio_iter_iovec(src, src_iter);
1026 dst_bv = bio_iter_iovec(dst, dst_iter);
1028 bytes = min(src_bv.bv_len, dst_bv.bv_len);
1030 src_p = kmap_atomic(src_bv.bv_page);
1031 dst_p = kmap_atomic(dst_bv.bv_page);
1033 memcpy(dst_p + dst_bv.bv_offset,
1034 src_p + src_bv.bv_offset,
1037 kunmap_atomic(dst_p);
1038 kunmap_atomic(src_p);
1040 bio_advance_iter(src, &src_iter, bytes);
1041 bio_advance_iter(dst, &dst_iter, bytes);
1044 EXPORT_SYMBOL(bio_copy_data);
1046 struct bio_map_data {
1048 struct iov_iter iter;
1052 static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count,
1055 if (iov_count > UIO_MAXIOV)
1058 return kmalloc(sizeof(struct bio_map_data) +
1059 sizeof(struct iovec) * iov_count, gfp_mask);
1063 * bio_copy_from_iter - copy all pages from iov_iter to bio
1064 * @bio: The &struct bio which describes the I/O as destination
1065 * @iter: iov_iter as source
1067 * Copy all pages from iov_iter to bio.
1068 * Returns 0 on success, or error on failure.
1070 static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter)
1073 struct bio_vec *bvec;
1075 bio_for_each_segment_all(bvec, bio, i) {
1078 ret = copy_page_from_iter(bvec->bv_page,
1083 if (!iov_iter_count(&iter))
1086 if (ret < bvec->bv_len)
1094 * bio_copy_to_iter - copy all pages from bio to iov_iter
1095 * @bio: The &struct bio which describes the I/O as source
1096 * @iter: iov_iter as destination
1098 * Copy all pages from bio to iov_iter.
1099 * Returns 0 on success, or error on failure.
1101 static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
1104 struct bio_vec *bvec;
1106 bio_for_each_segment_all(bvec, bio, i) {
1109 ret = copy_page_to_iter(bvec->bv_page,
1114 if (!iov_iter_count(&iter))
1117 if (ret < bvec->bv_len)
1124 void bio_free_pages(struct bio *bio)
1126 struct bio_vec *bvec;
1129 bio_for_each_segment_all(bvec, bio, i)
1130 __free_page(bvec->bv_page);
1132 EXPORT_SYMBOL(bio_free_pages);
1135 * bio_uncopy_user - finish previously mapped bio
1136 * @bio: bio being terminated
1138 * Free pages allocated from bio_copy_user_iov() and write back data
1139 * to user space in case of a read.
1141 int bio_uncopy_user(struct bio *bio)
1143 struct bio_map_data *bmd = bio->bi_private;
1146 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1148 * if we're in a workqueue, the request is orphaned, so
1149 * don't copy into a random user address space, just free
1150 * and return -EINTR so user space doesn't expect any data.
1154 else if (bio_data_dir(bio) == READ)
1155 ret = bio_copy_to_iter(bio, bmd->iter);
1156 if (bmd->is_our_pages)
1157 bio_free_pages(bio);
1165 * bio_copy_user_iov - copy user data to bio
1166 * @q: destination block queue
1167 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1168 * @iter: iovec iterator
1169 * @gfp_mask: memory allocation flags
1171 * Prepares and returns a bio for indirect user io, bouncing data
1172 * to/from kernel pages as necessary. Must be paired with
1173 * call bio_uncopy_user() on io completion.
1175 struct bio *bio_copy_user_iov(struct request_queue *q,
1176 struct rq_map_data *map_data,
1177 const struct iov_iter *iter,
1180 struct bio_map_data *bmd;
1185 unsigned int len = iter->count;
1186 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
1188 for (i = 0; i < iter->nr_segs; i++) {
1189 unsigned long uaddr;
1191 unsigned long start;
1193 uaddr = (unsigned long) iter->iov[i].iov_base;
1194 end = (uaddr + iter->iov[i].iov_len + PAGE_SIZE - 1)
1196 start = uaddr >> PAGE_SHIFT;
1202 return ERR_PTR(-EINVAL);
1204 nr_pages += end - start;
1210 bmd = bio_alloc_map_data(iter->nr_segs, gfp_mask);
1212 return ERR_PTR(-ENOMEM);
1215 * We need to do a deep copy of the iov_iter including the iovecs.
1216 * The caller provided iov might point to an on-stack or otherwise
1219 bmd->is_our_pages = map_data ? 0 : 1;
1220 memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs);
1221 iov_iter_init(&bmd->iter, iter->type, bmd->iov,
1222 iter->nr_segs, iter->count);
1225 bio = bio_kmalloc(gfp_mask, nr_pages);
1229 if (iter->type & WRITE)
1230 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
1235 nr_pages = 1 << map_data->page_order;
1236 i = map_data->offset / PAGE_SIZE;
1239 unsigned int bytes = PAGE_SIZE;
1247 if (i == map_data->nr_entries * nr_pages) {
1252 page = map_data->pages[i / nr_pages];
1253 page += (i % nr_pages);
1257 page = alloc_page(q->bounce_gfp | gfp_mask);
1264 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1277 if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
1278 (map_data && map_data->from_user)) {
1279 ret = bio_copy_from_iter(bio, *iter);
1284 bio->bi_private = bmd;
1288 bio_free_pages(bio);
1292 return ERR_PTR(ret);
1296 * bio_map_user_iov - map user iovec into bio
1297 * @q: the struct request_queue for the bio
1298 * @iter: iovec iterator
1299 * @gfp_mask: memory allocation flags
1301 * Map the user space address into a bio suitable for io to a block
1302 * device. Returns an error pointer in case of error.
1304 struct bio *bio_map_user_iov(struct request_queue *q,
1305 const struct iov_iter *iter,
1310 struct page **pages;
1317 iov_for_each(iov, i, *iter) {
1318 unsigned long uaddr = (unsigned long) iov.iov_base;
1319 unsigned long len = iov.iov_len;
1320 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1321 unsigned long start = uaddr >> PAGE_SHIFT;
1327 return ERR_PTR(-EINVAL);
1329 nr_pages += end - start;
1331 * buffer must be aligned to at least logical block size for now
1333 if (uaddr & queue_dma_alignment(q))
1334 return ERR_PTR(-EINVAL);
1338 return ERR_PTR(-EINVAL);
1340 bio = bio_kmalloc(gfp_mask, nr_pages);
1342 return ERR_PTR(-ENOMEM);
1345 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
1349 iov_for_each(iov, i, *iter) {
1350 unsigned long uaddr = (unsigned long) iov.iov_base;
1351 unsigned long len = iov.iov_len;
1352 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1353 unsigned long start = uaddr >> PAGE_SHIFT;
1354 const int local_nr_pages = end - start;
1355 const int page_limit = cur_page + local_nr_pages;
1357 ret = get_user_pages_fast(uaddr, local_nr_pages,
1358 (iter->type & WRITE) != WRITE,
1360 if (ret < local_nr_pages) {
1365 offset = offset_in_page(uaddr);
1366 for (j = cur_page; j < page_limit; j++) {
1367 unsigned int bytes = PAGE_SIZE - offset;
1378 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1388 * release the pages we didn't map into the bio, if any
1390 while (j < page_limit)
1391 put_page(pages[j++]);
1397 * set data direction, and check if mapped pages need bouncing
1399 if (iter->type & WRITE)
1400 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
1402 bio_set_flag(bio, BIO_USER_MAPPED);
1405 * subtle -- if __bio_map_user() ended up bouncing a bio,
1406 * it would normally disappear when its bi_end_io is run.
1407 * however, we need it for the unmap, so grab an extra
1414 for (j = 0; j < nr_pages; j++) {
1422 return ERR_PTR(ret);
1425 static void __bio_unmap_user(struct bio *bio)
1427 struct bio_vec *bvec;
1431 * make sure we dirty pages we wrote to
1433 bio_for_each_segment_all(bvec, bio, i) {
1434 if (bio_data_dir(bio) == READ)
1435 set_page_dirty_lock(bvec->bv_page);
1437 put_page(bvec->bv_page);
1444 * bio_unmap_user - unmap a bio
1445 * @bio: the bio being unmapped
1447 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1448 * a process context.
1450 * bio_unmap_user() may sleep.
1452 void bio_unmap_user(struct bio *bio)
1454 __bio_unmap_user(bio);
1458 static void bio_map_kern_endio(struct bio *bio)
1464 * bio_map_kern - map kernel address into bio
1465 * @q: the struct request_queue for the bio
1466 * @data: pointer to buffer to map
1467 * @len: length in bytes
1468 * @gfp_mask: allocation flags for bio allocation
1470 * Map the kernel address into a bio suitable for io to a block
1471 * device. Returns an error pointer in case of error.
1473 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1476 unsigned long kaddr = (unsigned long)data;
1477 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1478 unsigned long start = kaddr >> PAGE_SHIFT;
1479 const int nr_pages = end - start;
1483 bio = bio_kmalloc(gfp_mask, nr_pages);
1485 return ERR_PTR(-ENOMEM);
1487 offset = offset_in_page(kaddr);
1488 for (i = 0; i < nr_pages; i++) {
1489 unsigned int bytes = PAGE_SIZE - offset;
1497 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1499 /* we don't support partial mappings */
1501 return ERR_PTR(-EINVAL);
1509 bio->bi_end_io = bio_map_kern_endio;
1512 EXPORT_SYMBOL(bio_map_kern);
1514 static void bio_copy_kern_endio(struct bio *bio)
1516 bio_free_pages(bio);
1520 static void bio_copy_kern_endio_read(struct bio *bio)
1522 char *p = bio->bi_private;
1523 struct bio_vec *bvec;
1526 bio_for_each_segment_all(bvec, bio, i) {
1527 memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
1531 bio_copy_kern_endio(bio);
1535 * bio_copy_kern - copy kernel address into bio
1536 * @q: the struct request_queue for the bio
1537 * @data: pointer to buffer to copy
1538 * @len: length in bytes
1539 * @gfp_mask: allocation flags for bio and page allocation
1540 * @reading: data direction is READ
1542 * copy the kernel address into a bio suitable for io to a block
1543 * device. Returns an error pointer in case of error.
1545 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1546 gfp_t gfp_mask, int reading)
1548 unsigned long kaddr = (unsigned long)data;
1549 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1550 unsigned long start = kaddr >> PAGE_SHIFT;
1559 return ERR_PTR(-EINVAL);
1561 nr_pages = end - start;
1562 bio = bio_kmalloc(gfp_mask, nr_pages);
1564 return ERR_PTR(-ENOMEM);
1568 unsigned int bytes = PAGE_SIZE;
1573 page = alloc_page(q->bounce_gfp | gfp_mask);
1578 memcpy(page_address(page), p, bytes);
1580 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
1588 bio->bi_end_io = bio_copy_kern_endio_read;
1589 bio->bi_private = data;
1591 bio->bi_end_io = bio_copy_kern_endio;
1592 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
1598 bio_free_pages(bio);
1600 return ERR_PTR(-ENOMEM);
1604 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1605 * for performing direct-IO in BIOs.
1607 * The problem is that we cannot run set_page_dirty() from interrupt context
1608 * because the required locks are not interrupt-safe. So what we can do is to
1609 * mark the pages dirty _before_ performing IO. And in interrupt context,
1610 * check that the pages are still dirty. If so, fine. If not, redirty them
1611 * in process context.
1613 * We special-case compound pages here: normally this means reads into hugetlb
1614 * pages. The logic in here doesn't really work right for compound pages
1615 * because the VM does not uniformly chase down the head page in all cases.
1616 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1617 * handle them at all. So we skip compound pages here at an early stage.
1619 * Note that this code is very hard to test under normal circumstances because
1620 * direct-io pins the pages with get_user_pages(). This makes
1621 * is_page_cache_freeable return false, and the VM will not clean the pages.
1622 * But other code (eg, flusher threads) could clean the pages if they are mapped
1625 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1626 * deferred bio dirtying paths.
1630 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1632 void bio_set_pages_dirty(struct bio *bio)
1634 struct bio_vec *bvec;
1637 bio_for_each_segment_all(bvec, bio, i) {
1638 struct page *page = bvec->bv_page;
1640 if (page && !PageCompound(page))
1641 set_page_dirty_lock(page);
1645 static void bio_release_pages(struct bio *bio)
1647 struct bio_vec *bvec;
1650 bio_for_each_segment_all(bvec, bio, i) {
1651 struct page *page = bvec->bv_page;
1659 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1660 * If they are, then fine. If, however, some pages are clean then they must
1661 * have been written out during the direct-IO read. So we take another ref on
1662 * the BIO and the offending pages and re-dirty the pages in process context.
1664 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1665 * here on. It will run one put_page() against each page and will run one
1666 * bio_put() against the BIO.
1669 static void bio_dirty_fn(struct work_struct *work);
1671 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1672 static DEFINE_SPINLOCK(bio_dirty_lock);
1673 static struct bio *bio_dirty_list;
1676 * This runs in process context
1678 static void bio_dirty_fn(struct work_struct *work)
1680 unsigned long flags;
1683 spin_lock_irqsave(&bio_dirty_lock, flags);
1684 bio = bio_dirty_list;
1685 bio_dirty_list = NULL;
1686 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1689 struct bio *next = bio->bi_private;
1691 bio_set_pages_dirty(bio);
1692 bio_release_pages(bio);
1698 void bio_check_pages_dirty(struct bio *bio)
1700 struct bio_vec *bvec;
1701 int nr_clean_pages = 0;
1704 bio_for_each_segment_all(bvec, bio, i) {
1705 struct page *page = bvec->bv_page;
1707 if (PageDirty(page) || PageCompound(page)) {
1709 bvec->bv_page = NULL;
1715 if (nr_clean_pages) {
1716 unsigned long flags;
1718 spin_lock_irqsave(&bio_dirty_lock, flags);
1719 bio->bi_private = bio_dirty_list;
1720 bio_dirty_list = bio;
1721 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1722 schedule_work(&bio_dirty_work);
1728 void generic_start_io_acct(int rw, unsigned long sectors,
1729 struct hd_struct *part)
1731 int cpu = part_stat_lock();
1733 part_round_stats(cpu, part);
1734 part_stat_inc(cpu, part, ios[rw]);
1735 part_stat_add(cpu, part, sectors[rw], sectors);
1736 part_inc_in_flight(part, rw);
1740 EXPORT_SYMBOL(generic_start_io_acct);
1742 void generic_end_io_acct(int rw, struct hd_struct *part,
1743 unsigned long start_time)
1745 unsigned long duration = jiffies - start_time;
1746 int cpu = part_stat_lock();
1748 part_stat_add(cpu, part, ticks[rw], duration);
1749 part_round_stats(cpu, part);
1750 part_dec_in_flight(part, rw);
1754 EXPORT_SYMBOL(generic_end_io_acct);
1756 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1757 void bio_flush_dcache_pages(struct bio *bi)
1759 struct bio_vec bvec;
1760 struct bvec_iter iter;
1762 bio_for_each_segment(bvec, bi, iter)
1763 flush_dcache_page(bvec.bv_page);
1765 EXPORT_SYMBOL(bio_flush_dcache_pages);
1768 static inline bool bio_remaining_done(struct bio *bio)
1771 * If we're not chaining, then ->__bi_remaining is always 1 and
1772 * we always end io on the first invocation.
1774 if (!bio_flagged(bio, BIO_CHAIN))
1777 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1779 if (atomic_dec_and_test(&bio->__bi_remaining)) {
1780 bio_clear_flag(bio, BIO_CHAIN);
1788 * bio_endio - end I/O on a bio
1792 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1793 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1794 * bio unless they own it and thus know that it has an end_io function.
1796 void bio_endio(struct bio *bio)
1799 if (!bio_remaining_done(bio))
1803 * Need to have a real endio function for chained bios, otherwise
1804 * various corner cases will break (like stacking block devices that
1805 * save/restore bi_end_io) - however, we want to avoid unbounded
1806 * recursion and blowing the stack. Tail call optimization would
1807 * handle this, but compiling with frame pointers also disables
1808 * gcc's sibling call optimization.
1810 if (bio->bi_end_io == bio_chain_endio) {
1811 bio = __bio_chain_endio(bio);
1816 bio->bi_end_io(bio);
1818 EXPORT_SYMBOL(bio_endio);
1821 * bio_split - split a bio
1822 * @bio: bio to split
1823 * @sectors: number of sectors to split from the front of @bio
1825 * @bs: bio set to allocate from
1827 * Allocates and returns a new bio which represents @sectors from the start of
1828 * @bio, and updates @bio to represent the remaining sectors.
1830 * Unless this is a discard request the newly allocated bio will point
1831 * to @bio's bi_io_vec; it is the caller's responsibility to ensure that
1832 * @bio is not freed before the split.
1834 struct bio *bio_split(struct bio *bio, int sectors,
1835 gfp_t gfp, struct bio_set *bs)
1837 struct bio *split = NULL;
1839 BUG_ON(sectors <= 0);
1840 BUG_ON(sectors >= bio_sectors(bio));
1843 * Discards need a mutable bio_vec to accommodate the payload
1844 * required by the DSM TRIM and UNMAP commands.
1846 if (bio_op(bio) == REQ_OP_DISCARD || bio_op(bio) == REQ_OP_SECURE_ERASE)
1847 split = bio_clone_bioset(bio, gfp, bs);
1849 split = bio_clone_fast(bio, gfp, bs);
1854 split->bi_iter.bi_size = sectors << 9;
1856 if (bio_integrity(split))
1857 bio_integrity_trim(split, 0, sectors);
1859 bio_advance(bio, split->bi_iter.bi_size);
1863 EXPORT_SYMBOL(bio_split);
1866 * bio_trim - trim a bio
1868 * @offset: number of sectors to trim from the front of @bio
1869 * @size: size we want to trim @bio to, in sectors
1871 void bio_trim(struct bio *bio, int offset, int size)
1873 /* 'bio' is a cloned bio which we need to trim to match
1874 * the given offset and size.
1878 if (offset == 0 && size == bio->bi_iter.bi_size)
1881 bio_clear_flag(bio, BIO_SEG_VALID);
1883 bio_advance(bio, offset << 9);
1885 bio->bi_iter.bi_size = size;
1887 EXPORT_SYMBOL_GPL(bio_trim);
1890 * create memory pools for biovec's in a bio_set.
1891 * use the global biovec slabs created for general use.
1893 mempool_t *biovec_create_pool(int pool_entries)
1895 struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX;
1897 return mempool_create_slab_pool(pool_entries, bp->slab);
1900 void bioset_free(struct bio_set *bs)
1902 if (bs->rescue_workqueue)
1903 destroy_workqueue(bs->rescue_workqueue);
1906 mempool_destroy(bs->bio_pool);
1909 mempool_destroy(bs->bvec_pool);
1911 bioset_integrity_free(bs);
1916 EXPORT_SYMBOL(bioset_free);
1918 static struct bio_set *__bioset_create(unsigned int pool_size,
1919 unsigned int front_pad,
1920 bool create_bvec_pool)
1922 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1925 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1929 bs->front_pad = front_pad;
1931 spin_lock_init(&bs->rescue_lock);
1932 bio_list_init(&bs->rescue_list);
1933 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1935 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1936 if (!bs->bio_slab) {
1941 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1945 if (create_bvec_pool) {
1946 bs->bvec_pool = biovec_create_pool(pool_size);
1951 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1952 if (!bs->rescue_workqueue)
1962 * bioset_create - Create a bio_set
1963 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1964 * @front_pad: Number of bytes to allocate in front of the returned bio
1967 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1968 * to ask for a number of bytes to be allocated in front of the bio.
1969 * Front pad allocation is useful for embedding the bio inside
1970 * another structure, to avoid allocating extra data to go with the bio.
1971 * Note that the bio must be embedded at the END of that structure always,
1972 * or things will break badly.
1974 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1976 return __bioset_create(pool_size, front_pad, true);
1978 EXPORT_SYMBOL(bioset_create);
1981 * bioset_create_nobvec - Create a bio_set without bio_vec mempool
1982 * @pool_size: Number of bio to cache in the mempool
1983 * @front_pad: Number of bytes to allocate in front of the returned bio
1986 * Same functionality as bioset_create() except that mempool is not
1987 * created for bio_vecs. Saving some memory for bio_clone_fast() users.
1989 struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad)
1991 return __bioset_create(pool_size, front_pad, false);
1993 EXPORT_SYMBOL(bioset_create_nobvec);
1995 #ifdef CONFIG_BLK_CGROUP
1998 * bio_associate_blkcg - associate a bio with the specified blkcg
2000 * @blkcg_css: css of the blkcg to associate
2002 * Associate @bio with the blkcg specified by @blkcg_css. Block layer will
2003 * treat @bio as if it were issued by a task which belongs to the blkcg.
2005 * This function takes an extra reference of @blkcg_css which will be put
2006 * when @bio is released. The caller must own @bio and is responsible for
2007 * synchronizing calls to this function.
2009 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
2011 if (unlikely(bio->bi_css))
2014 bio->bi_css = blkcg_css;
2017 EXPORT_SYMBOL_GPL(bio_associate_blkcg);
2020 * bio_associate_current - associate a bio with %current
2023 * Associate @bio with %current if it hasn't been associated yet. Block
2024 * layer will treat @bio as if it were issued by %current no matter which
2025 * task actually issues it.
2027 * This function takes an extra reference of @task's io_context and blkcg
2028 * which will be put when @bio is released. The caller must own @bio,
2029 * ensure %current->io_context exists, and is responsible for synchronizing
2030 * calls to this function.
2032 int bio_associate_current(struct bio *bio)
2034 struct io_context *ioc;
2039 ioc = current->io_context;
2043 get_io_context_active(ioc);
2045 bio->bi_css = task_get_css(current, io_cgrp_id);
2048 EXPORT_SYMBOL_GPL(bio_associate_current);
2051 * bio_disassociate_task - undo bio_associate_current()
2054 void bio_disassociate_task(struct bio *bio)
2057 put_io_context(bio->bi_ioc);
2061 css_put(bio->bi_css);
2067 * bio_clone_blkcg_association - clone blkcg association from src to dst bio
2068 * @dst: destination bio
2071 void bio_clone_blkcg_association(struct bio *dst, struct bio *src)
2074 WARN_ON(bio_associate_blkcg(dst, src->bi_css));
2077 #endif /* CONFIG_BLK_CGROUP */
2079 static void __init biovec_init_slabs(void)
2083 for (i = 0; i < BVEC_POOL_NR; i++) {
2085 struct biovec_slab *bvs = bvec_slabs + i;
2087 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
2092 size = bvs->nr_vecs * sizeof(struct bio_vec);
2093 bvs->slab = kmem_cache_create(bvs->name, size, 0,
2094 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2098 static int __init init_bio(void)
2102 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2104 panic("bio: can't allocate bios\n");
2106 bio_integrity_init();
2107 biovec_init_slabs();
2109 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
2111 panic("bio: can't allocate bios\n");
2113 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2114 panic("bio: can't create integrity pool\n");
2118 subsys_initcall(init_bio);