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>
31 #include <scsi/sg.h> /* for struct sg_iovec */
33 #include <trace/events/block.h>
36 * Test patch to inline a certain number of bi_io_vec's inside the bio
37 * itself, to shrink a bio data allocation from two mempool calls to one
39 #define BIO_INLINE_VECS 4
41 static mempool_t *bio_split_pool __read_mostly;
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
48 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
49 static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
50 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
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.
58 struct bio_set *fs_bio_set;
59 EXPORT_SYMBOL(fs_bio_set);
62 * Our slab pool management
65 struct kmem_cache *slab;
66 unsigned int slab_ref;
67 unsigned int slab_size;
70 static DEFINE_MUTEX(bio_slab_lock);
71 static struct bio_slab *bio_slabs;
72 static unsigned int bio_slab_nr, bio_slab_max;
74 static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
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;
82 mutex_lock(&bio_slab_lock);
85 while (i < bio_slab_nr) {
86 bslab = &bio_slabs[i];
88 if (!bslab->slab && entry == -1)
90 else if (bslab->slab_size == sz) {
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),
108 bio_slab_max = new_bio_slab_max;
109 bio_slabs = new_bio_slabs;
112 entry = bio_slab_nr++;
114 bslab = &bio_slabs[entry];
116 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
117 slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
121 printk(KERN_INFO "bio: create slab <%s> at %d\n", bslab->name, entry);
124 bslab->slab_size = sz;
126 mutex_unlock(&bio_slab_lock);
130 static void bio_put_slab(struct bio_set *bs)
132 struct bio_slab *bslab = NULL;
135 mutex_lock(&bio_slab_lock);
137 for (i = 0; i < bio_slab_nr; i++) {
138 if (bs->bio_slab == bio_slabs[i].slab) {
139 bslab = &bio_slabs[i];
144 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
147 WARN_ON(!bslab->slab_ref);
149 if (--bslab->slab_ref)
152 kmem_cache_destroy(bslab->slab);
156 mutex_unlock(&bio_slab_lock);
159 unsigned int bvec_nr_vecs(unsigned short idx)
161 return bvec_slabs[idx].nr_vecs;
164 void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
166 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
168 if (idx == BIOVEC_MAX_IDX)
169 mempool_free(bv, pool);
171 struct biovec_slab *bvs = bvec_slabs + idx;
173 kmem_cache_free(bvs->slab, bv);
177 struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
183 * see comment near bvec_array define!
201 case 129 ... BIO_MAX_PAGES:
209 * idx now points to the pool we want to allocate from. only the
210 * 1-vec entry pool is mempool backed.
212 if (*idx == BIOVEC_MAX_IDX) {
214 bvl = mempool_alloc(pool, gfp_mask);
216 struct biovec_slab *bvs = bvec_slabs + *idx;
217 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
220 * Make this allocation restricted and don't dump info on
221 * allocation failures, since we'll fallback to the mempool
222 * in case of failure.
224 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
227 * Try a slab allocation. If this fails and __GFP_WAIT
228 * is set, retry with the 1-entry mempool
230 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
231 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
232 *idx = BIOVEC_MAX_IDX;
240 static void __bio_free(struct bio *bio)
242 bio_disassociate_task(bio);
244 if (bio_integrity(bio))
245 bio_integrity_free(bio);
248 static void bio_free(struct bio *bio)
250 struct bio_set *bs = bio->bi_pool;
256 if (bio_flagged(bio, BIO_OWNS_VEC))
257 bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
260 * If we have front padding, adjust the bio pointer before freeing
265 mempool_free(p, bs->bio_pool);
267 /* Bio was allocated by bio_kmalloc() */
272 void bio_init(struct bio *bio)
274 memset(bio, 0, sizeof(*bio));
275 bio->bi_flags = 1 << BIO_UPTODATE;
276 atomic_set(&bio->bi_cnt, 1);
278 EXPORT_SYMBOL(bio_init);
281 * bio_reset - reinitialize a bio
285 * After calling bio_reset(), @bio will be in the same state as a freshly
286 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
287 * preserved are the ones that are initialized by bio_alloc_bioset(). See
288 * comment in struct bio.
290 void bio_reset(struct bio *bio)
292 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
296 memset(bio, 0, BIO_RESET_BYTES);
297 bio->bi_flags = flags|(1 << BIO_UPTODATE);
299 EXPORT_SYMBOL(bio_reset);
301 static void bio_alloc_rescue(struct work_struct *work)
303 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
307 spin_lock(&bs->rescue_lock);
308 bio = bio_list_pop(&bs->rescue_list);
309 spin_unlock(&bs->rescue_lock);
314 generic_make_request(bio);
318 static void punt_bios_to_rescuer(struct bio_set *bs)
320 struct bio_list punt, nopunt;
324 * In order to guarantee forward progress we must punt only bios that
325 * were allocated from this bio_set; otherwise, if there was a bio on
326 * there for a stacking driver higher up in the stack, processing it
327 * could require allocating bios from this bio_set, and doing that from
328 * our own rescuer would be bad.
330 * Since bio lists are singly linked, pop them all instead of trying to
331 * remove from the middle of the list:
334 bio_list_init(&punt);
335 bio_list_init(&nopunt);
337 while ((bio = bio_list_pop(current->bio_list)))
338 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
340 *current->bio_list = nopunt;
342 spin_lock(&bs->rescue_lock);
343 bio_list_merge(&bs->rescue_list, &punt);
344 spin_unlock(&bs->rescue_lock);
346 queue_work(bs->rescue_workqueue, &bs->rescue_work);
350 * bio_alloc_bioset - allocate a bio for I/O
351 * @gfp_mask: the GFP_ mask given to the slab allocator
352 * @nr_iovecs: number of iovecs to pre-allocate
353 * @bs: the bio_set to allocate from.
356 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
357 * backed by the @bs's mempool.
359 * When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
360 * able to allocate a bio. This is due to the mempool guarantees. To make this
361 * work, callers must never allocate more than 1 bio at a time from this pool.
362 * Callers that need to allocate more than 1 bio must always submit the
363 * previously allocated bio for IO before attempting to allocate a new one.
364 * Failure to do so can cause deadlocks under memory pressure.
366 * Note that when running under generic_make_request() (i.e. any block
367 * driver), bios are not submitted until after you return - see the code in
368 * generic_make_request() that converts recursion into iteration, to prevent
371 * This would normally mean allocating multiple bios under
372 * generic_make_request() would be susceptible to deadlocks, but we have
373 * deadlock avoidance code that resubmits any blocked bios from a rescuer
376 * However, we do not guarantee forward progress for allocations from other
377 * mempools. Doing multiple allocations from the same mempool under
378 * generic_make_request() should be avoided - instead, use bio_set's front_pad
379 * for per bio allocations.
382 * Pointer to new bio on success, NULL on failure.
384 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
386 gfp_t saved_gfp = gfp_mask;
388 unsigned inline_vecs;
389 unsigned long idx = BIO_POOL_NONE;
390 struct bio_vec *bvl = NULL;
395 if (nr_iovecs > UIO_MAXIOV)
398 p = kmalloc(sizeof(struct bio) +
399 nr_iovecs * sizeof(struct bio_vec),
402 inline_vecs = nr_iovecs;
405 * generic_make_request() converts recursion to iteration; this
406 * means if we're running beneath it, any bios we allocate and
407 * submit will not be submitted (and thus freed) until after we
410 * This exposes us to a potential deadlock if we allocate
411 * multiple bios from the same bio_set() while running
412 * underneath generic_make_request(). If we were to allocate
413 * multiple bios (say a stacking block driver that was splitting
414 * bios), we would deadlock if we exhausted the mempool's
417 * We solve this, and guarantee forward progress, with a rescuer
418 * workqueue per bio_set. If we go to allocate and there are
419 * bios on current->bio_list, we first try the allocation
420 * without __GFP_WAIT; if that fails, we punt those bios we
421 * would be blocking to the rescuer workqueue before we retry
422 * with the original gfp_flags.
425 if (current->bio_list && !bio_list_empty(current->bio_list))
426 gfp_mask &= ~__GFP_WAIT;
428 p = mempool_alloc(bs->bio_pool, gfp_mask);
429 if (!p && gfp_mask != saved_gfp) {
430 punt_bios_to_rescuer(bs);
431 gfp_mask = saved_gfp;
432 p = mempool_alloc(bs->bio_pool, gfp_mask);
435 front_pad = bs->front_pad;
436 inline_vecs = BIO_INLINE_VECS;
445 if (nr_iovecs > inline_vecs) {
446 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
447 if (!bvl && gfp_mask != saved_gfp) {
448 punt_bios_to_rescuer(bs);
449 gfp_mask = saved_gfp;
450 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
456 bio->bi_flags |= 1 << BIO_OWNS_VEC;
457 } else if (nr_iovecs) {
458 bvl = bio->bi_inline_vecs;
462 bio->bi_flags |= idx << BIO_POOL_OFFSET;
463 bio->bi_max_vecs = nr_iovecs;
464 bio->bi_io_vec = bvl;
468 mempool_free(p, bs->bio_pool);
471 EXPORT_SYMBOL(bio_alloc_bioset);
473 void zero_fill_bio(struct bio *bio)
477 struct bvec_iter iter;
479 bio_for_each_segment(bv, bio, iter) {
480 char *data = bvec_kmap_irq(&bv, &flags);
481 memset(data, 0, bv.bv_len);
482 flush_dcache_page(bv.bv_page);
483 bvec_kunmap_irq(data, &flags);
486 EXPORT_SYMBOL(zero_fill_bio);
489 * bio_put - release a reference to a bio
490 * @bio: bio to release reference to
493 * Put a reference to a &struct bio, either one you have gotten with
494 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
496 void bio_put(struct bio *bio)
498 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
503 if (atomic_dec_and_test(&bio->bi_cnt))
506 EXPORT_SYMBOL(bio_put);
508 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
510 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
511 blk_recount_segments(q, bio);
513 return bio->bi_phys_segments;
515 EXPORT_SYMBOL(bio_phys_segments);
518 * __bio_clone_fast - clone a bio that shares the original bio's biovec
519 * @bio: destination bio
520 * @bio_src: bio to clone
522 * Clone a &bio. Caller will own the returned bio, but not
523 * the actual data it points to. Reference count of returned
526 * Caller must ensure that @bio_src is not freed before @bio.
528 void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
530 BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE);
533 * most users will be overriding ->bi_bdev with a new target,
534 * so we don't set nor calculate new physical/hw segment counts here
536 bio->bi_bdev = bio_src->bi_bdev;
537 bio->bi_flags |= 1 << BIO_CLONED;
538 bio->bi_rw = bio_src->bi_rw;
539 bio->bi_iter = bio_src->bi_iter;
540 bio->bi_io_vec = bio_src->bi_io_vec;
542 EXPORT_SYMBOL(__bio_clone_fast);
545 * bio_clone_fast - clone a bio that shares the original bio's biovec
547 * @gfp_mask: allocation priority
548 * @bs: bio_set to allocate from
550 * Like __bio_clone_fast, only also allocates the returned bio
552 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
556 b = bio_alloc_bioset(gfp_mask, 0, bs);
560 __bio_clone_fast(b, bio);
562 if (bio_integrity(bio)) {
565 ret = bio_integrity_clone(b, bio, gfp_mask);
575 EXPORT_SYMBOL(bio_clone_fast);
578 * bio_clone_bioset - clone a bio
579 * @bio_src: bio to clone
580 * @gfp_mask: allocation priority
581 * @bs: bio_set to allocate from
583 * Clone bio. Caller will own the returned bio, but not the actual data it
584 * points to. Reference count of returned bio will be one.
586 struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
589 unsigned nr_iovecs = 0;
590 struct bvec_iter iter;
595 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
596 * bio_src->bi_io_vec to bio->bi_io_vec.
598 * We can't do that anymore, because:
600 * - The point of cloning the biovec is to produce a bio with a biovec
601 * the caller can modify: bi_idx and bi_bvec_done should be 0.
603 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
604 * we tried to clone the whole thing bio_alloc_bioset() would fail.
605 * But the clone should succeed as long as the number of biovecs we
606 * actually need to allocate is fewer than BIO_MAX_PAGES.
608 * - Lastly, bi_vcnt should not be looked at or relied upon by code
609 * that does not own the bio - reason being drivers don't use it for
610 * iterating over the biovec anymore, so expecting it to be kept up
611 * to date (i.e. for clones that share the parent biovec) is just
612 * asking for trouble and would force extra work on
613 * __bio_clone_fast() anyways.
616 bio_for_each_segment(bv, bio_src, iter)
619 bio = bio_alloc_bioset(gfp_mask, nr_iovecs, bs);
623 bio->bi_bdev = bio_src->bi_bdev;
624 bio->bi_rw = bio_src->bi_rw;
625 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
626 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
628 bio_for_each_segment(bv, bio_src, iter)
629 bio->bi_io_vec[bio->bi_vcnt++] = bv;
631 if (bio_integrity(bio_src)) {
634 ret = bio_integrity_clone(bio, bio_src, gfp_mask);
643 EXPORT_SYMBOL(bio_clone_bioset);
646 * bio_get_nr_vecs - return approx number of vecs
649 * Return the approximate number of pages we can send to this target.
650 * There's no guarantee that you will be able to fit this number of pages
651 * into a bio, it does not account for dynamic restrictions that vary
654 int bio_get_nr_vecs(struct block_device *bdev)
656 struct request_queue *q = bdev_get_queue(bdev);
659 nr_pages = min_t(unsigned,
660 queue_max_segments(q),
661 queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
663 return min_t(unsigned, nr_pages, BIO_MAX_PAGES);
666 EXPORT_SYMBOL(bio_get_nr_vecs);
668 static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
669 *page, unsigned int len, unsigned int offset,
670 unsigned int max_sectors)
672 int retried_segments = 0;
673 struct bio_vec *bvec;
676 * cloned bio must not modify vec list
678 if (unlikely(bio_flagged(bio, BIO_CLONED)))
681 if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
685 * For filesystems with a blocksize smaller than the pagesize
686 * we will often be called with the same page as last time and
687 * a consecutive offset. Optimize this special case.
689 if (bio->bi_vcnt > 0) {
690 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
692 if (page == prev->bv_page &&
693 offset == prev->bv_offset + prev->bv_len) {
694 unsigned int prev_bv_len = prev->bv_len;
697 if (q->merge_bvec_fn) {
698 struct bvec_merge_data bvm = {
699 /* prev_bvec is already charged in
700 bi_size, discharge it in order to
701 simulate merging updated prev_bvec
703 .bi_bdev = bio->bi_bdev,
704 .bi_sector = bio->bi_iter.bi_sector,
705 .bi_size = bio->bi_iter.bi_size -
710 if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
720 if (bio->bi_vcnt >= bio->bi_max_vecs)
724 * we might lose a segment or two here, but rather that than
725 * make this too complex.
728 while (bio->bi_phys_segments >= queue_max_segments(q)) {
730 if (retried_segments)
733 retried_segments = 1;
734 blk_recount_segments(q, bio);
738 * setup the new entry, we might clear it again later if we
739 * cannot add the page
741 bvec = &bio->bi_io_vec[bio->bi_vcnt];
742 bvec->bv_page = page;
744 bvec->bv_offset = offset;
747 * if queue has other restrictions (eg varying max sector size
748 * depending on offset), it can specify a merge_bvec_fn in the
749 * queue to get further control
751 if (q->merge_bvec_fn) {
752 struct bvec_merge_data bvm = {
753 .bi_bdev = bio->bi_bdev,
754 .bi_sector = bio->bi_iter.bi_sector,
755 .bi_size = bio->bi_iter.bi_size,
760 * merge_bvec_fn() returns number of bytes it can accept
763 if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
764 bvec->bv_page = NULL;
771 /* If we may be able to merge these biovecs, force a recount */
772 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
773 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
776 bio->bi_phys_segments++;
778 bio->bi_iter.bi_size += len;
783 * bio_add_pc_page - attempt to add page to bio
784 * @q: the target queue
785 * @bio: destination bio
787 * @len: vec entry length
788 * @offset: vec entry offset
790 * Attempt to add a page to the bio_vec maplist. This can fail for a
791 * number of reasons, such as the bio being full or target block device
792 * limitations. The target block device must allow bio's up to PAGE_SIZE,
793 * so it is always possible to add a single page to an empty bio.
795 * This should only be used by REQ_PC bios.
797 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
798 unsigned int len, unsigned int offset)
800 return __bio_add_page(q, bio, page, len, offset,
801 queue_max_hw_sectors(q));
803 EXPORT_SYMBOL(bio_add_pc_page);
806 * bio_add_page - attempt to add page to bio
807 * @bio: destination bio
809 * @len: vec entry length
810 * @offset: vec entry offset
812 * Attempt to add a page to the bio_vec maplist. This can fail for a
813 * number of reasons, such as the bio being full or target block device
814 * limitations. The target block device must allow bio's up to PAGE_SIZE,
815 * so it is always possible to add a single page to an empty bio.
817 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
820 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
821 return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
823 EXPORT_SYMBOL(bio_add_page);
825 struct submit_bio_ret {
826 struct completion event;
830 static void submit_bio_wait_endio(struct bio *bio, int error)
832 struct submit_bio_ret *ret = bio->bi_private;
835 complete(&ret->event);
839 * submit_bio_wait - submit a bio, and wait until it completes
840 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
841 * @bio: The &struct bio which describes the I/O
843 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
844 * bio_endio() on failure.
846 int submit_bio_wait(int rw, struct bio *bio)
848 struct submit_bio_ret ret;
851 init_completion(&ret.event);
852 bio->bi_private = &ret;
853 bio->bi_end_io = submit_bio_wait_endio;
855 wait_for_completion(&ret.event);
859 EXPORT_SYMBOL(submit_bio_wait);
862 * bio_advance - increment/complete a bio by some number of bytes
863 * @bio: bio to advance
864 * @bytes: number of bytes to complete
866 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
867 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
868 * be updated on the last bvec as well.
870 * @bio will then represent the remaining, uncompleted portion of the io.
872 void bio_advance(struct bio *bio, unsigned bytes)
874 if (bio_integrity(bio))
875 bio_integrity_advance(bio, bytes);
877 bio_advance_iter(bio, &bio->bi_iter, bytes);
879 EXPORT_SYMBOL(bio_advance);
882 * bio_alloc_pages - allocates a single page for each bvec in a bio
883 * @bio: bio to allocate pages for
884 * @gfp_mask: flags for allocation
886 * Allocates pages up to @bio->bi_vcnt.
888 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
891 int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
896 bio_for_each_segment_all(bv, bio, i) {
897 bv->bv_page = alloc_page(gfp_mask);
899 while (--bv >= bio->bi_io_vec)
900 __free_page(bv->bv_page);
907 EXPORT_SYMBOL(bio_alloc_pages);
910 * bio_copy_data - copy contents of data buffers from one chain of bios to
912 * @src: source bio list
913 * @dst: destination bio list
915 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
916 * @src and @dst as linked lists of bios.
918 * Stops when it reaches the end of either @src or @dst - that is, copies
919 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
921 void bio_copy_data(struct bio *dst, struct bio *src)
923 struct bvec_iter src_iter, dst_iter;
924 struct bio_vec src_bv, dst_bv;
928 src_iter = src->bi_iter;
929 dst_iter = dst->bi_iter;
932 if (!src_iter.bi_size) {
937 src_iter = src->bi_iter;
940 if (!dst_iter.bi_size) {
945 dst_iter = dst->bi_iter;
948 src_bv = bio_iter_iovec(src, src_iter);
949 dst_bv = bio_iter_iovec(dst, dst_iter);
951 bytes = min(src_bv.bv_len, dst_bv.bv_len);
953 src_p = kmap_atomic(src_bv.bv_page);
954 dst_p = kmap_atomic(dst_bv.bv_page);
956 memcpy(dst_p + dst_bv.bv_offset,
957 src_p + src_bv.bv_offset,
960 kunmap_atomic(dst_p);
961 kunmap_atomic(src_p);
963 bio_advance_iter(src, &src_iter, bytes);
964 bio_advance_iter(dst, &dst_iter, bytes);
967 EXPORT_SYMBOL(bio_copy_data);
969 struct bio_map_data {
972 struct sg_iovec sgvecs[];
975 static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
976 struct sg_iovec *iov, int iov_count,
979 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
980 bmd->nr_sgvecs = iov_count;
981 bmd->is_our_pages = is_our_pages;
982 bio->bi_private = bmd;
985 static struct bio_map_data *bio_alloc_map_data(int nr_segs,
986 unsigned int iov_count,
989 if (iov_count > UIO_MAXIOV)
992 return kmalloc(sizeof(struct bio_map_data) +
993 sizeof(struct sg_iovec) * iov_count, gfp_mask);
996 static int __bio_copy_iov(struct bio *bio, struct sg_iovec *iov, int iov_count,
997 int to_user, int from_user, int do_free_page)
1000 struct bio_vec *bvec;
1002 unsigned int iov_off = 0;
1004 bio_for_each_segment_all(bvec, bio, i) {
1005 char *bv_addr = page_address(bvec->bv_page);
1006 unsigned int bv_len = bvec->bv_len;
1008 while (bv_len && iov_idx < iov_count) {
1010 char __user *iov_addr;
1012 bytes = min_t(unsigned int,
1013 iov[iov_idx].iov_len - iov_off, bv_len);
1014 iov_addr = iov[iov_idx].iov_base + iov_off;
1018 ret = copy_to_user(iov_addr, bv_addr,
1022 ret = copy_from_user(bv_addr, iov_addr,
1034 if (iov[iov_idx].iov_len == iov_off) {
1041 __free_page(bvec->bv_page);
1048 * bio_uncopy_user - finish previously mapped bio
1049 * @bio: bio being terminated
1051 * Free pages allocated from bio_copy_user() and write back data
1052 * to user space in case of a read.
1054 int bio_uncopy_user(struct bio *bio)
1056 struct bio_map_data *bmd = bio->bi_private;
1057 struct bio_vec *bvec;
1060 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1062 * if we're in a workqueue, the request is orphaned, so
1063 * don't copy into a random user address space, just free.
1066 ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs,
1067 bio_data_dir(bio) == READ,
1068 0, bmd->is_our_pages);
1069 else if (bmd->is_our_pages)
1070 bio_for_each_segment_all(bvec, bio, i)
1071 __free_page(bvec->bv_page);
1077 EXPORT_SYMBOL(bio_uncopy_user);
1080 * bio_copy_user_iov - copy user data to bio
1081 * @q: destination block queue
1082 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1084 * @iov_count: number of elements in the iovec
1085 * @write_to_vm: bool indicating writing to pages or not
1086 * @gfp_mask: memory allocation flags
1088 * Prepares and returns a bio for indirect user io, bouncing data
1089 * to/from kernel pages as necessary. Must be paired with
1090 * call bio_uncopy_user() on io completion.
1092 struct bio *bio_copy_user_iov(struct request_queue *q,
1093 struct rq_map_data *map_data,
1094 struct sg_iovec *iov, int iov_count,
1095 int write_to_vm, gfp_t gfp_mask)
1097 struct bio_map_data *bmd;
1098 struct bio_vec *bvec;
1103 unsigned int len = 0;
1104 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
1106 for (i = 0; i < iov_count; i++) {
1107 unsigned long uaddr;
1109 unsigned long start;
1111 uaddr = (unsigned long)iov[i].iov_base;
1112 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1113 start = uaddr >> PAGE_SHIFT;
1119 return ERR_PTR(-EINVAL);
1121 nr_pages += end - start;
1122 len += iov[i].iov_len;
1128 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
1130 return ERR_PTR(-ENOMEM);
1133 bio = bio_kmalloc(gfp_mask, nr_pages);
1138 bio->bi_rw |= REQ_WRITE;
1143 nr_pages = 1 << map_data->page_order;
1144 i = map_data->offset / PAGE_SIZE;
1147 unsigned int bytes = PAGE_SIZE;
1155 if (i == map_data->nr_entries * nr_pages) {
1160 page = map_data->pages[i / nr_pages];
1161 page += (i % nr_pages);
1165 page = alloc_page(q->bounce_gfp | gfp_mask);
1172 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1185 if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
1186 (map_data && map_data->from_user)) {
1187 ret = __bio_copy_iov(bio, iov, iov_count, 0, 1, 0);
1192 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
1196 bio_for_each_segment_all(bvec, bio, i)
1197 __free_page(bvec->bv_page);
1202 return ERR_PTR(ret);
1206 * bio_copy_user - copy user data to bio
1207 * @q: destination block queue
1208 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1209 * @uaddr: start of user address
1210 * @len: length in bytes
1211 * @write_to_vm: bool indicating writing to pages or not
1212 * @gfp_mask: memory allocation flags
1214 * Prepares and returns a bio for indirect user io, bouncing data
1215 * to/from kernel pages as necessary. Must be paired with
1216 * call bio_uncopy_user() on io completion.
1218 struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
1219 unsigned long uaddr, unsigned int len,
1220 int write_to_vm, gfp_t gfp_mask)
1222 struct sg_iovec iov;
1224 iov.iov_base = (void __user *)uaddr;
1227 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
1229 EXPORT_SYMBOL(bio_copy_user);
1231 static struct bio *__bio_map_user_iov(struct request_queue *q,
1232 struct block_device *bdev,
1233 struct sg_iovec *iov, int iov_count,
1234 int write_to_vm, gfp_t gfp_mask)
1238 struct page **pages;
1243 for (i = 0; i < iov_count; i++) {
1244 unsigned long uaddr = (unsigned long)iov[i].iov_base;
1245 unsigned long len = iov[i].iov_len;
1246 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1247 unsigned long start = uaddr >> PAGE_SHIFT;
1253 return ERR_PTR(-EINVAL);
1255 nr_pages += end - start;
1257 * buffer must be aligned to at least hardsector size for now
1259 if (uaddr & queue_dma_alignment(q))
1260 return ERR_PTR(-EINVAL);
1264 return ERR_PTR(-EINVAL);
1266 bio = bio_kmalloc(gfp_mask, nr_pages);
1268 return ERR_PTR(-ENOMEM);
1271 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
1275 for (i = 0; i < iov_count; i++) {
1276 unsigned long uaddr = (unsigned long)iov[i].iov_base;
1277 unsigned long len = iov[i].iov_len;
1278 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1279 unsigned long start = uaddr >> PAGE_SHIFT;
1280 const int local_nr_pages = end - start;
1281 const int page_limit = cur_page + local_nr_pages;
1283 ret = get_user_pages_fast(uaddr, local_nr_pages,
1284 write_to_vm, &pages[cur_page]);
1285 if (ret < local_nr_pages) {
1290 offset = uaddr & ~PAGE_MASK;
1291 for (j = cur_page; j < page_limit; j++) {
1292 unsigned int bytes = PAGE_SIZE - offset;
1303 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1313 * release the pages we didn't map into the bio, if any
1315 while (j < page_limit)
1316 page_cache_release(pages[j++]);
1322 * set data direction, and check if mapped pages need bouncing
1325 bio->bi_rw |= REQ_WRITE;
1327 bio->bi_bdev = bdev;
1328 bio->bi_flags |= (1 << BIO_USER_MAPPED);
1332 for (i = 0; i < nr_pages; i++) {
1335 page_cache_release(pages[i]);
1340 return ERR_PTR(ret);
1344 * bio_map_user - map user address into bio
1345 * @q: the struct request_queue for the bio
1346 * @bdev: destination block device
1347 * @uaddr: start of user address
1348 * @len: length in bytes
1349 * @write_to_vm: bool indicating writing to pages or not
1350 * @gfp_mask: memory allocation flags
1352 * Map the user space address into a bio suitable for io to a block
1353 * device. Returns an error pointer in case of error.
1355 struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1356 unsigned long uaddr, unsigned int len, int write_to_vm,
1359 struct sg_iovec iov;
1361 iov.iov_base = (void __user *)uaddr;
1364 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1366 EXPORT_SYMBOL(bio_map_user);
1369 * bio_map_user_iov - map user sg_iovec table into bio
1370 * @q: the struct request_queue for the bio
1371 * @bdev: destination block device
1373 * @iov_count: number of elements in the iovec
1374 * @write_to_vm: bool indicating writing to pages or not
1375 * @gfp_mask: memory allocation flags
1377 * Map the user space address into a bio suitable for io to a block
1378 * device. Returns an error pointer in case of error.
1380 struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1381 struct sg_iovec *iov, int iov_count,
1382 int write_to_vm, gfp_t gfp_mask)
1386 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
1392 * subtle -- if __bio_map_user() ended up bouncing a bio,
1393 * it would normally disappear when its bi_end_io is run.
1394 * however, we need it for the unmap, so grab an extra
1402 static void __bio_unmap_user(struct bio *bio)
1404 struct bio_vec *bvec;
1408 * make sure we dirty pages we wrote to
1410 bio_for_each_segment_all(bvec, bio, i) {
1411 if (bio_data_dir(bio) == READ)
1412 set_page_dirty_lock(bvec->bv_page);
1414 page_cache_release(bvec->bv_page);
1421 * bio_unmap_user - unmap a bio
1422 * @bio: the bio being unmapped
1424 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1425 * a process context.
1427 * bio_unmap_user() may sleep.
1429 void bio_unmap_user(struct bio *bio)
1431 __bio_unmap_user(bio);
1434 EXPORT_SYMBOL(bio_unmap_user);
1436 static void bio_map_kern_endio(struct bio *bio, int err)
1441 static struct bio *__bio_map_kern(struct request_queue *q, void *data,
1442 unsigned int len, gfp_t gfp_mask)
1444 unsigned long kaddr = (unsigned long)data;
1445 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1446 unsigned long start = kaddr >> PAGE_SHIFT;
1447 const int nr_pages = end - start;
1451 bio = bio_kmalloc(gfp_mask, nr_pages);
1453 return ERR_PTR(-ENOMEM);
1455 offset = offset_in_page(kaddr);
1456 for (i = 0; i < nr_pages; i++) {
1457 unsigned int bytes = PAGE_SIZE - offset;
1465 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1474 bio->bi_end_io = bio_map_kern_endio;
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
1485 * Map the kernel address into a bio suitable for io to a block
1486 * device. Returns an error pointer in case of error.
1488 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1493 bio = __bio_map_kern(q, data, len, gfp_mask);
1497 if (bio->bi_iter.bi_size == len)
1501 * Don't support partial mappings.
1504 return ERR_PTR(-EINVAL);
1506 EXPORT_SYMBOL(bio_map_kern);
1508 static void bio_copy_kern_endio(struct bio *bio, int err)
1510 struct bio_vec *bvec;
1511 const int read = bio_data_dir(bio) == READ;
1512 struct bio_map_data *bmd = bio->bi_private;
1514 char *p = bmd->sgvecs[0].iov_base;
1516 bio_for_each_segment_all(bvec, bio, i) {
1517 char *addr = page_address(bvec->bv_page);
1520 memcpy(p, addr, bvec->bv_len);
1522 __free_page(bvec->bv_page);
1531 * bio_copy_kern - copy kernel address into bio
1532 * @q: the struct request_queue for the bio
1533 * @data: pointer to buffer to copy
1534 * @len: length in bytes
1535 * @gfp_mask: allocation flags for bio and page allocation
1536 * @reading: data direction is READ
1538 * copy the kernel address into a bio suitable for io to a block
1539 * device. Returns an error pointer in case of error.
1541 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1542 gfp_t gfp_mask, int reading)
1545 struct bio_vec *bvec;
1548 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
1555 bio_for_each_segment_all(bvec, bio, i) {
1556 char *addr = page_address(bvec->bv_page);
1558 memcpy(addr, p, bvec->bv_len);
1563 bio->bi_end_io = bio_copy_kern_endio;
1567 EXPORT_SYMBOL(bio_copy_kern);
1570 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1571 * for performing direct-IO in BIOs.
1573 * The problem is that we cannot run set_page_dirty() from interrupt context
1574 * because the required locks are not interrupt-safe. So what we can do is to
1575 * mark the pages dirty _before_ performing IO. And in interrupt context,
1576 * check that the pages are still dirty. If so, fine. If not, redirty them
1577 * in process context.
1579 * We special-case compound pages here: normally this means reads into hugetlb
1580 * pages. The logic in here doesn't really work right for compound pages
1581 * because the VM does not uniformly chase down the head page in all cases.
1582 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1583 * handle them at all. So we skip compound pages here at an early stage.
1585 * Note that this code is very hard to test under normal circumstances because
1586 * direct-io pins the pages with get_user_pages(). This makes
1587 * is_page_cache_freeable return false, and the VM will not clean the pages.
1588 * But other code (eg, flusher threads) could clean the pages if they are mapped
1591 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1592 * deferred bio dirtying paths.
1596 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1598 void bio_set_pages_dirty(struct bio *bio)
1600 struct bio_vec *bvec;
1603 bio_for_each_segment_all(bvec, bio, i) {
1604 struct page *page = bvec->bv_page;
1606 if (page && !PageCompound(page))
1607 set_page_dirty_lock(page);
1611 static void bio_release_pages(struct bio *bio)
1613 struct bio_vec *bvec;
1616 bio_for_each_segment_all(bvec, bio, i) {
1617 struct page *page = bvec->bv_page;
1625 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1626 * If they are, then fine. If, however, some pages are clean then they must
1627 * have been written out during the direct-IO read. So we take another ref on
1628 * the BIO and the offending pages and re-dirty the pages in process context.
1630 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1631 * here on. It will run one page_cache_release() against each page and will
1632 * run one bio_put() against the BIO.
1635 static void bio_dirty_fn(struct work_struct *work);
1637 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1638 static DEFINE_SPINLOCK(bio_dirty_lock);
1639 static struct bio *bio_dirty_list;
1642 * This runs in process context
1644 static void bio_dirty_fn(struct work_struct *work)
1646 unsigned long flags;
1649 spin_lock_irqsave(&bio_dirty_lock, flags);
1650 bio = bio_dirty_list;
1651 bio_dirty_list = NULL;
1652 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1655 struct bio *next = bio->bi_private;
1657 bio_set_pages_dirty(bio);
1658 bio_release_pages(bio);
1664 void bio_check_pages_dirty(struct bio *bio)
1666 struct bio_vec *bvec;
1667 int nr_clean_pages = 0;
1670 bio_for_each_segment_all(bvec, bio, i) {
1671 struct page *page = bvec->bv_page;
1673 if (PageDirty(page) || PageCompound(page)) {
1674 page_cache_release(page);
1675 bvec->bv_page = NULL;
1681 if (nr_clean_pages) {
1682 unsigned long flags;
1684 spin_lock_irqsave(&bio_dirty_lock, flags);
1685 bio->bi_private = bio_dirty_list;
1686 bio_dirty_list = bio;
1687 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1688 schedule_work(&bio_dirty_work);
1694 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1695 void bio_flush_dcache_pages(struct bio *bi)
1697 struct bio_vec bvec;
1698 struct bvec_iter iter;
1700 bio_for_each_segment(bvec, bi, iter)
1701 flush_dcache_page(bvec.bv_page);
1703 EXPORT_SYMBOL(bio_flush_dcache_pages);
1707 * bio_endio - end I/O on a bio
1709 * @error: error, if any
1712 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1713 * preferred way to end I/O on a bio, it takes care of clearing
1714 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1715 * established -Exxxx (-EIO, for instance) error values in case
1716 * something went wrong. No one should call bi_end_io() directly on a
1717 * bio unless they own it and thus know that it has an end_io
1720 void bio_endio(struct bio *bio, int error)
1723 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1724 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1728 bio->bi_end_io(bio, error);
1730 EXPORT_SYMBOL(bio_endio);
1732 void bio_pair_release(struct bio_pair *bp)
1734 if (atomic_dec_and_test(&bp->cnt)) {
1735 struct bio *master = bp->bio1.bi_private;
1737 bio_endio(master, bp->error);
1738 mempool_free(bp, bp->bio2.bi_private);
1741 EXPORT_SYMBOL(bio_pair_release);
1743 static void bio_pair_end_1(struct bio *bi, int err)
1745 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1750 bio_pair_release(bp);
1753 static void bio_pair_end_2(struct bio *bi, int err)
1755 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1760 bio_pair_release(bp);
1764 * split a bio - only worry about a bio with a single page in its iovec
1766 struct bio_pair *bio_split(struct bio *bi, int first_sectors)
1768 struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
1773 trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1774 bi->bi_iter.bi_sector + first_sectors);
1776 BUG_ON(bio_multiple_segments(bi));
1777 atomic_set(&bp->cnt, 3);
1781 bp->bio2.bi_iter.bi_sector += first_sectors;
1782 bp->bio2.bi_iter.bi_size -= first_sectors << 9;
1783 bp->bio1.bi_iter.bi_size = first_sectors << 9;
1785 if (bi->bi_vcnt != 0) {
1786 bp->bv1 = bio_iovec(bi);
1787 bp->bv2 = bio_iovec(bi);
1789 if (bio_is_rw(bi)) {
1790 bp->bv2.bv_offset += first_sectors << 9;
1791 bp->bv2.bv_len -= first_sectors << 9;
1792 bp->bv1.bv_len = first_sectors << 9;
1795 bp->bio1.bi_io_vec = &bp->bv1;
1796 bp->bio2.bi_io_vec = &bp->bv2;
1798 bp->bio1.bi_max_vecs = 1;
1799 bp->bio2.bi_max_vecs = 1;
1802 bp->bio1.bi_end_io = bio_pair_end_1;
1803 bp->bio2.bi_end_io = bio_pair_end_2;
1805 bp->bio1.bi_private = bi;
1806 bp->bio2.bi_private = bio_split_pool;
1808 if (bio_integrity(bi))
1809 bio_integrity_split(bi, bp, first_sectors);
1813 EXPORT_SYMBOL(bio_split);
1816 * bio_trim - trim a bio
1818 * @offset: number of sectors to trim from the front of @bio
1819 * @size: size we want to trim @bio to, in sectors
1821 void bio_trim(struct bio *bio, int offset, int size)
1823 /* 'bio' is a cloned bio which we need to trim to match
1824 * the given offset and size.
1828 if (offset == 0 && size == bio->bi_iter.bi_size)
1831 clear_bit(BIO_SEG_VALID, &bio->bi_flags);
1833 bio_advance(bio, offset << 9);
1835 bio->bi_iter.bi_size = size;
1837 EXPORT_SYMBOL_GPL(bio_trim);
1840 * create memory pools for biovec's in a bio_set.
1841 * use the global biovec slabs created for general use.
1843 mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
1845 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
1847 return mempool_create_slab_pool(pool_entries, bp->slab);
1850 void bioset_free(struct bio_set *bs)
1852 if (bs->rescue_workqueue)
1853 destroy_workqueue(bs->rescue_workqueue);
1856 mempool_destroy(bs->bio_pool);
1859 mempool_destroy(bs->bvec_pool);
1861 bioset_integrity_free(bs);
1866 EXPORT_SYMBOL(bioset_free);
1869 * bioset_create - Create a bio_set
1870 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1871 * @front_pad: Number of bytes to allocate in front of the returned bio
1874 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1875 * to ask for a number of bytes to be allocated in front of the bio.
1876 * Front pad allocation is useful for embedding the bio inside
1877 * another structure, to avoid allocating extra data to go with the bio.
1878 * Note that the bio must be embedded at the END of that structure always,
1879 * or things will break badly.
1881 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1883 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1886 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1890 bs->front_pad = front_pad;
1892 spin_lock_init(&bs->rescue_lock);
1893 bio_list_init(&bs->rescue_list);
1894 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1896 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1897 if (!bs->bio_slab) {
1902 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1906 bs->bvec_pool = biovec_create_pool(bs, pool_size);
1910 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1911 if (!bs->rescue_workqueue)
1919 EXPORT_SYMBOL(bioset_create);
1921 #ifdef CONFIG_BLK_CGROUP
1923 * bio_associate_current - associate a bio with %current
1926 * Associate @bio with %current if it hasn't been associated yet. Block
1927 * layer will treat @bio as if it were issued by %current no matter which
1928 * task actually issues it.
1930 * This function takes an extra reference of @task's io_context and blkcg
1931 * which will be put when @bio is released. The caller must own @bio,
1932 * ensure %current->io_context exists, and is responsible for synchronizing
1933 * calls to this function.
1935 int bio_associate_current(struct bio *bio)
1937 struct io_context *ioc;
1938 struct cgroup_subsys_state *css;
1943 ioc = current->io_context;
1947 /* acquire active ref on @ioc and associate */
1948 get_io_context_active(ioc);
1951 /* associate blkcg if exists */
1953 css = task_css(current, blkio_subsys_id);
1954 if (css && css_tryget(css))
1962 * bio_disassociate_task - undo bio_associate_current()
1965 void bio_disassociate_task(struct bio *bio)
1968 put_io_context(bio->bi_ioc);
1972 css_put(bio->bi_css);
1977 #endif /* CONFIG_BLK_CGROUP */
1979 static void __init biovec_init_slabs(void)
1983 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1985 struct biovec_slab *bvs = bvec_slabs + i;
1987 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
1992 size = bvs->nr_vecs * sizeof(struct bio_vec);
1993 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1994 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1998 static int __init init_bio(void)
2002 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2004 panic("bio: can't allocate bios\n");
2006 bio_integrity_init();
2007 biovec_init_slabs();
2009 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
2011 panic("bio: can't allocate bios\n");
2013 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2014 panic("bio: can't create integrity pool\n");
2016 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
2017 sizeof(struct bio_pair));
2018 if (!bio_split_pool)
2019 panic("bio: can't create split pool\n");
2023 subsys_initcall(init_bio);