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/iocontext.h>
23 #include <linux/slab.h>
24 #include <linux/init.h>
25 #include <linux/kernel.h>
26 #include <linux/export.h>
27 #include <linux/mempool.h>
28 #include <linux/workqueue.h>
29 #include <linux/cgroup.h>
30 #include <scsi/sg.h> /* for struct sg_iovec */
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
40 static mempool_t *bio_split_pool __read_mostly;
43 * if you change this list, also change bvec_alloc or things will
44 * break badly! cannot be bigger than what you can fit into an
47 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
48 static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
49 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
54 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
55 * IO code that does not need private memory pools.
57 struct bio_set *fs_bio_set;
58 EXPORT_SYMBOL(fs_bio_set);
61 * Our slab pool management
64 struct kmem_cache *slab;
65 unsigned int slab_ref;
66 unsigned int slab_size;
69 static DEFINE_MUTEX(bio_slab_lock);
70 static struct bio_slab *bio_slabs;
71 static unsigned int bio_slab_nr, bio_slab_max;
73 static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
75 unsigned int sz = sizeof(struct bio) + extra_size;
76 struct kmem_cache *slab = NULL;
77 struct bio_slab *bslab, *new_bio_slabs;
78 unsigned int new_bio_slab_max;
79 unsigned int i, entry = -1;
81 mutex_lock(&bio_slab_lock);
84 while (i < bio_slab_nr) {
85 bslab = &bio_slabs[i];
87 if (!bslab->slab && entry == -1)
89 else if (bslab->slab_size == sz) {
100 if (bio_slab_nr == bio_slab_max && entry == -1) {
101 new_bio_slab_max = bio_slab_max << 1;
102 new_bio_slabs = krealloc(bio_slabs,
103 new_bio_slab_max * sizeof(struct bio_slab),
107 bio_slab_max = new_bio_slab_max;
108 bio_slabs = new_bio_slabs;
111 entry = bio_slab_nr++;
113 bslab = &bio_slabs[entry];
115 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
116 slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
120 printk(KERN_INFO "bio: create slab <%s> at %d\n", bslab->name, entry);
123 bslab->slab_size = sz;
125 mutex_unlock(&bio_slab_lock);
129 static void bio_put_slab(struct bio_set *bs)
131 struct bio_slab *bslab = NULL;
134 mutex_lock(&bio_slab_lock);
136 for (i = 0; i < bio_slab_nr; i++) {
137 if (bs->bio_slab == bio_slabs[i].slab) {
138 bslab = &bio_slabs[i];
143 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
146 WARN_ON(!bslab->slab_ref);
148 if (--bslab->slab_ref)
151 kmem_cache_destroy(bslab->slab);
155 mutex_unlock(&bio_slab_lock);
158 unsigned int bvec_nr_vecs(unsigned short idx)
160 return bvec_slabs[idx].nr_vecs;
163 void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
165 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
167 if (idx == BIOVEC_MAX_IDX)
168 mempool_free(bv, pool);
170 struct biovec_slab *bvs = bvec_slabs + idx;
172 kmem_cache_free(bvs->slab, bv);
176 struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
182 * see comment near bvec_array define!
200 case 129 ... BIO_MAX_PAGES:
208 * idx now points to the pool we want to allocate from. only the
209 * 1-vec entry pool is mempool backed.
211 if (*idx == BIOVEC_MAX_IDX) {
213 bvl = mempool_alloc(pool, gfp_mask);
215 struct biovec_slab *bvs = bvec_slabs + *idx;
216 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
219 * Make this allocation restricted and don't dump info on
220 * allocation failures, since we'll fallback to the mempool
221 * in case of failure.
223 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
226 * Try a slab allocation. If this fails and __GFP_WAIT
227 * is set, retry with the 1-entry mempool
229 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
230 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
231 *idx = BIOVEC_MAX_IDX;
239 static void __bio_free(struct bio *bio)
241 bio_disassociate_task(bio);
243 if (bio_integrity(bio))
244 bio_integrity_free(bio);
247 static void bio_free(struct bio *bio)
249 struct bio_set *bs = bio->bi_pool;
255 if (bio_flagged(bio, BIO_OWNS_VEC))
256 bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
259 * If we have front padding, adjust the bio pointer before freeing
264 mempool_free(p, bs->bio_pool);
266 /* Bio was allocated by bio_kmalloc() */
271 void bio_init(struct bio *bio)
273 memset(bio, 0, sizeof(*bio));
274 bio->bi_flags = 1 << BIO_UPTODATE;
275 atomic_set(&bio->bi_cnt, 1);
277 EXPORT_SYMBOL(bio_init);
280 * bio_reset - reinitialize a bio
284 * After calling bio_reset(), @bio will be in the same state as a freshly
285 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
286 * preserved are the ones that are initialized by bio_alloc_bioset(). See
287 * comment in struct bio.
289 void bio_reset(struct bio *bio)
291 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
295 memset(bio, 0, BIO_RESET_BYTES);
296 bio->bi_flags = flags|(1 << BIO_UPTODATE);
298 EXPORT_SYMBOL(bio_reset);
300 static void bio_alloc_rescue(struct work_struct *work)
302 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
306 spin_lock(&bs->rescue_lock);
307 bio = bio_list_pop(&bs->rescue_list);
308 spin_unlock(&bs->rescue_lock);
313 generic_make_request(bio);
317 static void punt_bios_to_rescuer(struct bio_set *bs)
319 struct bio_list punt, nopunt;
323 * In order to guarantee forward progress we must punt only bios that
324 * were allocated from this bio_set; otherwise, if there was a bio on
325 * there for a stacking driver higher up in the stack, processing it
326 * could require allocating bios from this bio_set, and doing that from
327 * our own rescuer would be bad.
329 * Since bio lists are singly linked, pop them all instead of trying to
330 * remove from the middle of the list:
333 bio_list_init(&punt);
334 bio_list_init(&nopunt);
336 while ((bio = bio_list_pop(current->bio_list)))
337 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
339 *current->bio_list = nopunt;
341 spin_lock(&bs->rescue_lock);
342 bio_list_merge(&bs->rescue_list, &punt);
343 spin_unlock(&bs->rescue_lock);
345 queue_work(bs->rescue_workqueue, &bs->rescue_work);
349 * bio_alloc_bioset - allocate a bio for I/O
350 * @gfp_mask: the GFP_ mask given to the slab allocator
351 * @nr_iovecs: number of iovecs to pre-allocate
352 * @bs: the bio_set to allocate from.
355 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
356 * backed by the @bs's mempool.
358 * When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
359 * able to allocate a bio. This is due to the mempool guarantees. To make this
360 * work, callers must never allocate more than 1 bio at a time from this pool.
361 * Callers that need to allocate more than 1 bio must always submit the
362 * previously allocated bio for IO before attempting to allocate a new one.
363 * Failure to do so can cause deadlocks under memory pressure.
365 * Note that when running under generic_make_request() (i.e. any block
366 * driver), bios are not submitted until after you return - see the code in
367 * generic_make_request() that converts recursion into iteration, to prevent
370 * This would normally mean allocating multiple bios under
371 * generic_make_request() would be susceptible to deadlocks, but we have
372 * deadlock avoidance code that resubmits any blocked bios from a rescuer
375 * However, we do not guarantee forward progress for allocations from other
376 * mempools. Doing multiple allocations from the same mempool under
377 * generic_make_request() should be avoided - instead, use bio_set's front_pad
378 * for per bio allocations.
381 * Pointer to new bio on success, NULL on failure.
383 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
385 gfp_t saved_gfp = gfp_mask;
387 unsigned inline_vecs;
388 unsigned long idx = BIO_POOL_NONE;
389 struct bio_vec *bvl = NULL;
394 if (nr_iovecs > UIO_MAXIOV)
397 p = kmalloc(sizeof(struct bio) +
398 nr_iovecs * sizeof(struct bio_vec),
401 inline_vecs = nr_iovecs;
404 * generic_make_request() converts recursion to iteration; this
405 * means if we're running beneath it, any bios we allocate and
406 * submit will not be submitted (and thus freed) until after we
409 * This exposes us to a potential deadlock if we allocate
410 * multiple bios from the same bio_set() while running
411 * underneath generic_make_request(). If we were to allocate
412 * multiple bios (say a stacking block driver that was splitting
413 * bios), we would deadlock if we exhausted the mempool's
416 * We solve this, and guarantee forward progress, with a rescuer
417 * workqueue per bio_set. If we go to allocate and there are
418 * bios on current->bio_list, we first try the allocation
419 * without __GFP_WAIT; if that fails, we punt those bios we
420 * would be blocking to the rescuer workqueue before we retry
421 * with the original gfp_flags.
424 if (current->bio_list && !bio_list_empty(current->bio_list))
425 gfp_mask &= ~__GFP_WAIT;
427 p = mempool_alloc(bs->bio_pool, gfp_mask);
428 if (!p && gfp_mask != saved_gfp) {
429 punt_bios_to_rescuer(bs);
430 gfp_mask = saved_gfp;
431 p = mempool_alloc(bs->bio_pool, gfp_mask);
434 front_pad = bs->front_pad;
435 inline_vecs = BIO_INLINE_VECS;
444 if (nr_iovecs > inline_vecs) {
445 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
446 if (!bvl && gfp_mask != saved_gfp) {
447 punt_bios_to_rescuer(bs);
448 gfp_mask = saved_gfp;
449 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
455 bio->bi_flags |= 1 << BIO_OWNS_VEC;
456 } else if (nr_iovecs) {
457 bvl = bio->bi_inline_vecs;
461 bio->bi_flags |= idx << BIO_POOL_OFFSET;
462 bio->bi_max_vecs = nr_iovecs;
463 bio->bi_io_vec = bvl;
467 mempool_free(p, bs->bio_pool);
470 EXPORT_SYMBOL(bio_alloc_bioset);
472 void zero_fill_bio(struct bio *bio)
478 bio_for_each_segment(bv, bio, i) {
479 char *data = bvec_kmap_irq(bv, &flags);
480 memset(data, 0, bv->bv_len);
481 flush_dcache_page(bv->bv_page);
482 bvec_kunmap_irq(data, &flags);
485 EXPORT_SYMBOL(zero_fill_bio);
488 * bio_put - release a reference to a bio
489 * @bio: bio to release reference to
492 * Put a reference to a &struct bio, either one you have gotten with
493 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
495 void bio_put(struct bio *bio)
497 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
502 if (atomic_dec_and_test(&bio->bi_cnt))
505 EXPORT_SYMBOL(bio_put);
507 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
509 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
510 blk_recount_segments(q, bio);
512 return bio->bi_phys_segments;
514 EXPORT_SYMBOL(bio_phys_segments);
517 * __bio_clone - clone a bio
518 * @bio: destination bio
519 * @bio_src: bio to clone
521 * Clone a &bio. Caller will own the returned bio, but not
522 * the actual data it points to. Reference count of returned
525 void __bio_clone(struct bio *bio, struct bio *bio_src)
527 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
528 bio_src->bi_max_vecs * sizeof(struct bio_vec));
531 * most users will be overriding ->bi_bdev with a new target,
532 * so we don't set nor calculate new physical/hw segment counts here
534 bio->bi_sector = bio_src->bi_sector;
535 bio->bi_bdev = bio_src->bi_bdev;
536 bio->bi_flags |= 1 << BIO_CLONED;
537 bio->bi_rw = bio_src->bi_rw;
538 bio->bi_vcnt = bio_src->bi_vcnt;
539 bio->bi_size = bio_src->bi_size;
540 bio->bi_idx = bio_src->bi_idx;
542 EXPORT_SYMBOL(__bio_clone);
545 * bio_clone_bioset - clone a bio
547 * @gfp_mask: allocation priority
548 * @bs: bio_set to allocate from
550 * Like __bio_clone, only also allocates the returned bio
552 struct bio *bio_clone_bioset(struct bio *bio, gfp_t gfp_mask,
557 b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, bs);
563 if (bio_integrity(bio)) {
566 ret = bio_integrity_clone(b, bio, gfp_mask);
576 EXPORT_SYMBOL(bio_clone_bioset);
579 * bio_get_nr_vecs - return approx number of vecs
582 * Return the approximate number of pages we can send to this target.
583 * There's no guarantee that you will be able to fit this number of pages
584 * into a bio, it does not account for dynamic restrictions that vary
587 int bio_get_nr_vecs(struct block_device *bdev)
589 struct request_queue *q = bdev_get_queue(bdev);
592 nr_pages = min_t(unsigned,
593 queue_max_segments(q),
594 queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
596 return min_t(unsigned, nr_pages, BIO_MAX_PAGES);
599 EXPORT_SYMBOL(bio_get_nr_vecs);
601 static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
602 *page, unsigned int len, unsigned int offset,
603 unsigned short max_sectors)
605 int retried_segments = 0;
606 struct bio_vec *bvec;
609 * cloned bio must not modify vec list
611 if (unlikely(bio_flagged(bio, BIO_CLONED)))
614 if (((bio->bi_size + len) >> 9) > max_sectors)
618 * For filesystems with a blocksize smaller than the pagesize
619 * we will often be called with the same page as last time and
620 * a consecutive offset. Optimize this special case.
622 if (bio->bi_vcnt > 0) {
623 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
625 if (page == prev->bv_page &&
626 offset == prev->bv_offset + prev->bv_len) {
627 unsigned int prev_bv_len = prev->bv_len;
630 if (q->merge_bvec_fn) {
631 struct bvec_merge_data bvm = {
632 /* prev_bvec is already charged in
633 bi_size, discharge it in order to
634 simulate merging updated prev_bvec
636 .bi_bdev = bio->bi_bdev,
637 .bi_sector = bio->bi_sector,
638 .bi_size = bio->bi_size - prev_bv_len,
642 if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
652 if (bio->bi_vcnt >= bio->bi_max_vecs)
656 * we might lose a segment or two here, but rather that than
657 * make this too complex.
660 while (bio->bi_phys_segments >= queue_max_segments(q)) {
662 if (retried_segments)
665 retried_segments = 1;
666 blk_recount_segments(q, bio);
670 * setup the new entry, we might clear it again later if we
671 * cannot add the page
673 bvec = &bio->bi_io_vec[bio->bi_vcnt];
674 bvec->bv_page = page;
676 bvec->bv_offset = offset;
679 * if queue has other restrictions (eg varying max sector size
680 * depending on offset), it can specify a merge_bvec_fn in the
681 * queue to get further control
683 if (q->merge_bvec_fn) {
684 struct bvec_merge_data bvm = {
685 .bi_bdev = bio->bi_bdev,
686 .bi_sector = bio->bi_sector,
687 .bi_size = bio->bi_size,
692 * merge_bvec_fn() returns number of bytes it can accept
695 if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
696 bvec->bv_page = NULL;
703 /* If we may be able to merge these biovecs, force a recount */
704 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
705 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
708 bio->bi_phys_segments++;
715 * bio_add_pc_page - attempt to add page to bio
716 * @q: the target queue
717 * @bio: destination bio
719 * @len: vec entry length
720 * @offset: vec entry offset
722 * Attempt to add a page to the bio_vec maplist. This can fail for a
723 * number of reasons, such as the bio being full or target block device
724 * limitations. The target block device must allow bio's up to PAGE_SIZE,
725 * so it is always possible to add a single page to an empty bio.
727 * This should only be used by REQ_PC bios.
729 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
730 unsigned int len, unsigned int offset)
732 return __bio_add_page(q, bio, page, len, offset,
733 queue_max_hw_sectors(q));
735 EXPORT_SYMBOL(bio_add_pc_page);
738 * bio_add_page - attempt to add page to bio
739 * @bio: destination bio
741 * @len: vec entry length
742 * @offset: vec entry offset
744 * Attempt to add a page to the bio_vec maplist. This can fail for a
745 * number of reasons, such as the bio being full or target block device
746 * limitations. The target block device must allow bio's up to PAGE_SIZE,
747 * so it is always possible to add a single page to an empty bio.
749 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
752 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
753 return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
755 EXPORT_SYMBOL(bio_add_page);
757 struct submit_bio_ret {
758 struct completion event;
762 static void submit_bio_wait_endio(struct bio *bio, int error)
764 struct submit_bio_ret *ret = bio->bi_private;
767 complete(&ret->event);
771 * submit_bio_wait - submit a bio, and wait until it completes
772 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
773 * @bio: The &struct bio which describes the I/O
775 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
776 * bio_endio() on failure.
778 int submit_bio_wait(int rw, struct bio *bio)
780 struct submit_bio_ret ret;
783 init_completion(&ret.event);
784 bio->bi_private = &ret;
785 bio->bi_end_io = submit_bio_wait_endio;
787 wait_for_completion(&ret.event);
791 EXPORT_SYMBOL(submit_bio_wait);
794 * bio_advance - increment/complete a bio by some number of bytes
795 * @bio: bio to advance
796 * @bytes: number of bytes to complete
798 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
799 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
800 * be updated on the last bvec as well.
802 * @bio will then represent the remaining, uncompleted portion of the io.
804 void bio_advance(struct bio *bio, unsigned bytes)
806 if (bio_integrity(bio))
807 bio_integrity_advance(bio, bytes);
809 bio->bi_sector += bytes >> 9;
810 bio->bi_size -= bytes;
812 if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
816 if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
817 WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
818 bio->bi_idx, bio->bi_vcnt);
822 if (bytes >= bio_iovec(bio)->bv_len) {
823 bytes -= bio_iovec(bio)->bv_len;
826 bio_iovec(bio)->bv_len -= bytes;
827 bio_iovec(bio)->bv_offset += bytes;
832 EXPORT_SYMBOL(bio_advance);
835 * bio_alloc_pages - allocates a single page for each bvec in a bio
836 * @bio: bio to allocate pages for
837 * @gfp_mask: flags for allocation
839 * Allocates pages up to @bio->bi_vcnt.
841 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
844 int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
849 bio_for_each_segment_all(bv, bio, i) {
850 bv->bv_page = alloc_page(gfp_mask);
852 while (--bv >= bio->bi_io_vec)
853 __free_page(bv->bv_page);
860 EXPORT_SYMBOL(bio_alloc_pages);
863 * bio_copy_data - copy contents of data buffers from one chain of bios to
865 * @src: source bio list
866 * @dst: destination bio list
868 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
869 * @src and @dst as linked lists of bios.
871 * Stops when it reaches the end of either @src or @dst - that is, copies
872 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
874 void bio_copy_data(struct bio *dst, struct bio *src)
876 struct bio_vec *src_bv, *dst_bv;
877 unsigned src_offset, dst_offset, bytes;
880 src_bv = bio_iovec(src);
881 dst_bv = bio_iovec(dst);
883 src_offset = src_bv->bv_offset;
884 dst_offset = dst_bv->bv_offset;
887 if (src_offset == src_bv->bv_offset + src_bv->bv_len) {
889 if (src_bv == bio_iovec_idx(src, src->bi_vcnt)) {
894 src_bv = bio_iovec(src);
897 src_offset = src_bv->bv_offset;
900 if (dst_offset == dst_bv->bv_offset + dst_bv->bv_len) {
902 if (dst_bv == bio_iovec_idx(dst, dst->bi_vcnt)) {
907 dst_bv = bio_iovec(dst);
910 dst_offset = dst_bv->bv_offset;
913 bytes = min(dst_bv->bv_offset + dst_bv->bv_len - dst_offset,
914 src_bv->bv_offset + src_bv->bv_len - src_offset);
916 src_p = kmap_atomic(src_bv->bv_page);
917 dst_p = kmap_atomic(dst_bv->bv_page);
919 memcpy(dst_p + dst_bv->bv_offset,
920 src_p + src_bv->bv_offset,
923 kunmap_atomic(dst_p);
924 kunmap_atomic(src_p);
930 EXPORT_SYMBOL(bio_copy_data);
932 struct bio_map_data {
933 struct bio_vec *iovecs;
934 struct sg_iovec *sgvecs;
939 static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
940 struct sg_iovec *iov, int iov_count,
943 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
944 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
945 bmd->nr_sgvecs = iov_count;
946 bmd->is_our_pages = is_our_pages;
947 bio->bi_private = bmd;
950 static void bio_free_map_data(struct bio_map_data *bmd)
957 static struct bio_map_data *bio_alloc_map_data(int nr_segs,
958 unsigned int iov_count,
961 struct bio_map_data *bmd;
963 if (iov_count > UIO_MAXIOV)
966 bmd = kmalloc(sizeof(*bmd), gfp_mask);
970 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
976 bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
985 static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
986 struct sg_iovec *iov, int iov_count,
987 int to_user, int from_user, int do_free_page)
990 struct bio_vec *bvec;
992 unsigned int iov_off = 0;
994 bio_for_each_segment_all(bvec, bio, i) {
995 char *bv_addr = page_address(bvec->bv_page);
996 unsigned int bv_len = iovecs[i].bv_len;
998 while (bv_len && iov_idx < iov_count) {
1000 char __user *iov_addr;
1002 bytes = min_t(unsigned int,
1003 iov[iov_idx].iov_len - iov_off, bv_len);
1004 iov_addr = iov[iov_idx].iov_base + iov_off;
1008 ret = copy_to_user(iov_addr, bv_addr,
1012 ret = copy_from_user(bv_addr, iov_addr,
1024 if (iov[iov_idx].iov_len == iov_off) {
1031 __free_page(bvec->bv_page);
1038 * bio_uncopy_user - finish previously mapped bio
1039 * @bio: bio being terminated
1041 * Free pages allocated from bio_copy_user() and write back data
1042 * to user space in case of a read.
1044 int bio_uncopy_user(struct bio *bio)
1046 struct bio_map_data *bmd = bio->bi_private;
1049 if (!bio_flagged(bio, BIO_NULL_MAPPED))
1050 ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
1051 bmd->nr_sgvecs, bio_data_dir(bio) == READ,
1052 0, bmd->is_our_pages);
1053 bio_free_map_data(bmd);
1057 EXPORT_SYMBOL(bio_uncopy_user);
1060 * bio_copy_user_iov - copy user data to bio
1061 * @q: destination block queue
1062 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1064 * @iov_count: number of elements in the iovec
1065 * @write_to_vm: bool indicating writing to pages or not
1066 * @gfp_mask: memory allocation flags
1068 * Prepares and returns a bio for indirect user io, bouncing data
1069 * to/from kernel pages as necessary. Must be paired with
1070 * call bio_uncopy_user() on io completion.
1072 struct bio *bio_copy_user_iov(struct request_queue *q,
1073 struct rq_map_data *map_data,
1074 struct sg_iovec *iov, int iov_count,
1075 int write_to_vm, gfp_t gfp_mask)
1077 struct bio_map_data *bmd;
1078 struct bio_vec *bvec;
1083 unsigned int len = 0;
1084 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
1086 for (i = 0; i < iov_count; i++) {
1087 unsigned long uaddr;
1089 unsigned long start;
1091 uaddr = (unsigned long)iov[i].iov_base;
1092 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1093 start = uaddr >> PAGE_SHIFT;
1099 return ERR_PTR(-EINVAL);
1101 nr_pages += end - start;
1102 len += iov[i].iov_len;
1108 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
1110 return ERR_PTR(-ENOMEM);
1113 bio = bio_kmalloc(gfp_mask, nr_pages);
1118 bio->bi_rw |= REQ_WRITE;
1123 nr_pages = 1 << map_data->page_order;
1124 i = map_data->offset / PAGE_SIZE;
1127 unsigned int bytes = PAGE_SIZE;
1135 if (i == map_data->nr_entries * nr_pages) {
1140 page = map_data->pages[i / nr_pages];
1141 page += (i % nr_pages);
1145 page = alloc_page(q->bounce_gfp | gfp_mask);
1152 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1165 if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
1166 (map_data && map_data->from_user)) {
1167 ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
1172 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
1176 bio_for_each_segment_all(bvec, bio, i)
1177 __free_page(bvec->bv_page);
1181 bio_free_map_data(bmd);
1182 return ERR_PTR(ret);
1186 * bio_copy_user - copy user data to bio
1187 * @q: destination block queue
1188 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1189 * @uaddr: start of user address
1190 * @len: length in bytes
1191 * @write_to_vm: bool indicating writing to pages or not
1192 * @gfp_mask: memory allocation flags
1194 * Prepares and returns a bio for indirect user io, bouncing data
1195 * to/from kernel pages as necessary. Must be paired with
1196 * call bio_uncopy_user() on io completion.
1198 struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
1199 unsigned long uaddr, unsigned int len,
1200 int write_to_vm, gfp_t gfp_mask)
1202 struct sg_iovec iov;
1204 iov.iov_base = (void __user *)uaddr;
1207 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
1209 EXPORT_SYMBOL(bio_copy_user);
1211 static struct bio *__bio_map_user_iov(struct request_queue *q,
1212 struct block_device *bdev,
1213 struct sg_iovec *iov, int iov_count,
1214 int write_to_vm, gfp_t gfp_mask)
1218 struct page **pages;
1223 for (i = 0; i < iov_count; i++) {
1224 unsigned long uaddr = (unsigned long)iov[i].iov_base;
1225 unsigned long len = iov[i].iov_len;
1226 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1227 unsigned long start = uaddr >> PAGE_SHIFT;
1233 return ERR_PTR(-EINVAL);
1235 nr_pages += end - start;
1237 * buffer must be aligned to at least hardsector size for now
1239 if (uaddr & queue_dma_alignment(q))
1240 return ERR_PTR(-EINVAL);
1244 return ERR_PTR(-EINVAL);
1246 bio = bio_kmalloc(gfp_mask, nr_pages);
1248 return ERR_PTR(-ENOMEM);
1251 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
1255 for (i = 0; i < iov_count; i++) {
1256 unsigned long uaddr = (unsigned long)iov[i].iov_base;
1257 unsigned long len = iov[i].iov_len;
1258 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1259 unsigned long start = uaddr >> PAGE_SHIFT;
1260 const int local_nr_pages = end - start;
1261 const int page_limit = cur_page + local_nr_pages;
1263 ret = get_user_pages_fast(uaddr, local_nr_pages,
1264 write_to_vm, &pages[cur_page]);
1265 if (ret < local_nr_pages) {
1270 offset = uaddr & ~PAGE_MASK;
1271 for (j = cur_page; j < page_limit; j++) {
1272 unsigned int bytes = PAGE_SIZE - offset;
1283 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1293 * release the pages we didn't map into the bio, if any
1295 while (j < page_limit)
1296 page_cache_release(pages[j++]);
1302 * set data direction, and check if mapped pages need bouncing
1305 bio->bi_rw |= REQ_WRITE;
1307 bio->bi_bdev = bdev;
1308 bio->bi_flags |= (1 << BIO_USER_MAPPED);
1312 for (i = 0; i < nr_pages; i++) {
1315 page_cache_release(pages[i]);
1320 return ERR_PTR(ret);
1324 * bio_map_user - map user address into bio
1325 * @q: the struct request_queue for the bio
1326 * @bdev: destination block device
1327 * @uaddr: start of user address
1328 * @len: length in bytes
1329 * @write_to_vm: bool indicating writing to pages or not
1330 * @gfp_mask: memory allocation flags
1332 * Map the user space address into a bio suitable for io to a block
1333 * device. Returns an error pointer in case of error.
1335 struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1336 unsigned long uaddr, unsigned int len, int write_to_vm,
1339 struct sg_iovec iov;
1341 iov.iov_base = (void __user *)uaddr;
1344 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1346 EXPORT_SYMBOL(bio_map_user);
1349 * bio_map_user_iov - map user sg_iovec table into bio
1350 * @q: the struct request_queue for the bio
1351 * @bdev: destination block device
1353 * @iov_count: number of elements in the iovec
1354 * @write_to_vm: bool indicating writing to pages or not
1355 * @gfp_mask: memory allocation flags
1357 * Map the user space address into a bio suitable for io to a block
1358 * device. Returns an error pointer in case of error.
1360 struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1361 struct sg_iovec *iov, int iov_count,
1362 int write_to_vm, gfp_t gfp_mask)
1366 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
1372 * subtle -- if __bio_map_user() ended up bouncing a bio,
1373 * it would normally disappear when its bi_end_io is run.
1374 * however, we need it for the unmap, so grab an extra
1382 static void __bio_unmap_user(struct bio *bio)
1384 struct bio_vec *bvec;
1388 * make sure we dirty pages we wrote to
1390 bio_for_each_segment_all(bvec, bio, i) {
1391 if (bio_data_dir(bio) == READ)
1392 set_page_dirty_lock(bvec->bv_page);
1394 page_cache_release(bvec->bv_page);
1401 * bio_unmap_user - unmap a bio
1402 * @bio: the bio being unmapped
1404 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1405 * a process context.
1407 * bio_unmap_user() may sleep.
1409 void bio_unmap_user(struct bio *bio)
1411 __bio_unmap_user(bio);
1414 EXPORT_SYMBOL(bio_unmap_user);
1416 static void bio_map_kern_endio(struct bio *bio, int err)
1421 static struct bio *__bio_map_kern(struct request_queue *q, void *data,
1422 unsigned int len, gfp_t gfp_mask)
1424 unsigned long kaddr = (unsigned long)data;
1425 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1426 unsigned long start = kaddr >> PAGE_SHIFT;
1427 const int nr_pages = end - start;
1431 bio = bio_kmalloc(gfp_mask, nr_pages);
1433 return ERR_PTR(-ENOMEM);
1435 offset = offset_in_page(kaddr);
1436 for (i = 0; i < nr_pages; i++) {
1437 unsigned int bytes = PAGE_SIZE - offset;
1445 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1454 bio->bi_end_io = bio_map_kern_endio;
1459 * bio_map_kern - map kernel address into bio
1460 * @q: the struct request_queue for the bio
1461 * @data: pointer to buffer to map
1462 * @len: length in bytes
1463 * @gfp_mask: allocation flags for bio allocation
1465 * Map the kernel address into a bio suitable for io to a block
1466 * device. Returns an error pointer in case of error.
1468 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1473 bio = __bio_map_kern(q, data, len, gfp_mask);
1477 if (bio->bi_size == len)
1481 * Don't support partial mappings.
1484 return ERR_PTR(-EINVAL);
1486 EXPORT_SYMBOL(bio_map_kern);
1488 static void bio_copy_kern_endio(struct bio *bio, int err)
1490 struct bio_vec *bvec;
1491 const int read = bio_data_dir(bio) == READ;
1492 struct bio_map_data *bmd = bio->bi_private;
1494 char *p = bmd->sgvecs[0].iov_base;
1496 bio_for_each_segment_all(bvec, bio, i) {
1497 char *addr = page_address(bvec->bv_page);
1498 int len = bmd->iovecs[i].bv_len;
1501 memcpy(p, addr, len);
1503 __free_page(bvec->bv_page);
1507 bio_free_map_data(bmd);
1512 * bio_copy_kern - copy kernel address into bio
1513 * @q: the struct request_queue for the bio
1514 * @data: pointer to buffer to copy
1515 * @len: length in bytes
1516 * @gfp_mask: allocation flags for bio and page allocation
1517 * @reading: data direction is READ
1519 * copy the kernel address into a bio suitable for io to a block
1520 * device. Returns an error pointer in case of error.
1522 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1523 gfp_t gfp_mask, int reading)
1526 struct bio_vec *bvec;
1529 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
1536 bio_for_each_segment_all(bvec, bio, i) {
1537 char *addr = page_address(bvec->bv_page);
1539 memcpy(addr, p, bvec->bv_len);
1544 bio->bi_end_io = bio_copy_kern_endio;
1548 EXPORT_SYMBOL(bio_copy_kern);
1551 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1552 * for performing direct-IO in BIOs.
1554 * The problem is that we cannot run set_page_dirty() from interrupt context
1555 * because the required locks are not interrupt-safe. So what we can do is to
1556 * mark the pages dirty _before_ performing IO. And in interrupt context,
1557 * check that the pages are still dirty. If so, fine. If not, redirty them
1558 * in process context.
1560 * We special-case compound pages here: normally this means reads into hugetlb
1561 * pages. The logic in here doesn't really work right for compound pages
1562 * because the VM does not uniformly chase down the head page in all cases.
1563 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1564 * handle them at all. So we skip compound pages here at an early stage.
1566 * Note that this code is very hard to test under normal circumstances because
1567 * direct-io pins the pages with get_user_pages(). This makes
1568 * is_page_cache_freeable return false, and the VM will not clean the pages.
1569 * But other code (eg, flusher threads) could clean the pages if they are mapped
1572 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1573 * deferred bio dirtying paths.
1577 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1579 void bio_set_pages_dirty(struct bio *bio)
1581 struct bio_vec *bvec;
1584 bio_for_each_segment_all(bvec, bio, i) {
1585 struct page *page = bvec->bv_page;
1587 if (page && !PageCompound(page))
1588 set_page_dirty_lock(page);
1592 static void bio_release_pages(struct bio *bio)
1594 struct bio_vec *bvec;
1597 bio_for_each_segment_all(bvec, bio, i) {
1598 struct page *page = bvec->bv_page;
1606 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1607 * If they are, then fine. If, however, some pages are clean then they must
1608 * have been written out during the direct-IO read. So we take another ref on
1609 * the BIO and the offending pages and re-dirty the pages in process context.
1611 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1612 * here on. It will run one page_cache_release() against each page and will
1613 * run one bio_put() against the BIO.
1616 static void bio_dirty_fn(struct work_struct *work);
1618 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1619 static DEFINE_SPINLOCK(bio_dirty_lock);
1620 static struct bio *bio_dirty_list;
1623 * This runs in process context
1625 static void bio_dirty_fn(struct work_struct *work)
1627 unsigned long flags;
1630 spin_lock_irqsave(&bio_dirty_lock, flags);
1631 bio = bio_dirty_list;
1632 bio_dirty_list = NULL;
1633 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1636 struct bio *next = bio->bi_private;
1638 bio_set_pages_dirty(bio);
1639 bio_release_pages(bio);
1645 void bio_check_pages_dirty(struct bio *bio)
1647 struct bio_vec *bvec;
1648 int nr_clean_pages = 0;
1651 bio_for_each_segment_all(bvec, bio, i) {
1652 struct page *page = bvec->bv_page;
1654 if (PageDirty(page) || PageCompound(page)) {
1655 page_cache_release(page);
1656 bvec->bv_page = NULL;
1662 if (nr_clean_pages) {
1663 unsigned long flags;
1665 spin_lock_irqsave(&bio_dirty_lock, flags);
1666 bio->bi_private = bio_dirty_list;
1667 bio_dirty_list = bio;
1668 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1669 schedule_work(&bio_dirty_work);
1675 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1676 void bio_flush_dcache_pages(struct bio *bi)
1679 struct bio_vec *bvec;
1681 bio_for_each_segment(bvec, bi, i)
1682 flush_dcache_page(bvec->bv_page);
1684 EXPORT_SYMBOL(bio_flush_dcache_pages);
1688 * bio_endio - end I/O on a bio
1690 * @error: error, if any
1693 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1694 * preferred way to end I/O on a bio, it takes care of clearing
1695 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1696 * established -Exxxx (-EIO, for instance) error values in case
1697 * something went wrong. No one should call bi_end_io() directly on a
1698 * bio unless they own it and thus know that it has an end_io
1701 void bio_endio(struct bio *bio, int error)
1704 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1705 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1708 trace_block_bio_complete(bio, error);
1711 bio->bi_end_io(bio, error);
1713 EXPORT_SYMBOL(bio_endio);
1715 void bio_pair_release(struct bio_pair *bp)
1717 if (atomic_dec_and_test(&bp->cnt)) {
1718 struct bio *master = bp->bio1.bi_private;
1720 bio_endio(master, bp->error);
1721 mempool_free(bp, bp->bio2.bi_private);
1724 EXPORT_SYMBOL(bio_pair_release);
1726 static void bio_pair_end_1(struct bio *bi, int err)
1728 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1733 bio_pair_release(bp);
1736 static void bio_pair_end_2(struct bio *bi, int err)
1738 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1743 bio_pair_release(bp);
1747 * split a bio - only worry about a bio with a single page in its iovec
1749 struct bio_pair *bio_split(struct bio *bi, int first_sectors)
1751 struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
1756 trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1757 bi->bi_sector + first_sectors);
1759 BUG_ON(bio_segments(bi) > 1);
1760 atomic_set(&bp->cnt, 3);
1764 bp->bio2.bi_sector += first_sectors;
1765 bp->bio2.bi_size -= first_sectors << 9;
1766 bp->bio1.bi_size = first_sectors << 9;
1768 if (bi->bi_vcnt != 0) {
1769 bp->bv1 = *bio_iovec(bi);
1770 bp->bv2 = *bio_iovec(bi);
1772 if (bio_is_rw(bi)) {
1773 bp->bv2.bv_offset += first_sectors << 9;
1774 bp->bv2.bv_len -= first_sectors << 9;
1775 bp->bv1.bv_len = first_sectors << 9;
1778 bp->bio1.bi_io_vec = &bp->bv1;
1779 bp->bio2.bi_io_vec = &bp->bv2;
1781 bp->bio1.bi_max_vecs = 1;
1782 bp->bio2.bi_max_vecs = 1;
1785 bp->bio1.bi_end_io = bio_pair_end_1;
1786 bp->bio2.bi_end_io = bio_pair_end_2;
1788 bp->bio1.bi_private = bi;
1789 bp->bio2.bi_private = bio_split_pool;
1791 if (bio_integrity(bi))
1792 bio_integrity_split(bi, bp, first_sectors);
1796 EXPORT_SYMBOL(bio_split);
1799 * bio_sector_offset - Find hardware sector offset in bio
1800 * @bio: bio to inspect
1801 * @index: bio_vec index
1802 * @offset: offset in bv_page
1804 * Return the number of hardware sectors between beginning of bio
1805 * and an end point indicated by a bio_vec index and an offset
1806 * within that vector's page.
1808 sector_t bio_sector_offset(struct bio *bio, unsigned short index,
1809 unsigned int offset)
1811 unsigned int sector_sz;
1816 sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1819 if (index >= bio->bi_idx)
1820 index = bio->bi_vcnt - 1;
1822 bio_for_each_segment_all(bv, bio, i) {
1824 if (offset > bv->bv_offset)
1825 sectors += (offset - bv->bv_offset) / sector_sz;
1829 sectors += bv->bv_len / sector_sz;
1834 EXPORT_SYMBOL(bio_sector_offset);
1837 * create memory pools for biovec's in a bio_set.
1838 * use the global biovec slabs created for general use.
1840 mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
1842 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
1844 return mempool_create_slab_pool(pool_entries, bp->slab);
1847 void bioset_free(struct bio_set *bs)
1849 if (bs->rescue_workqueue)
1850 destroy_workqueue(bs->rescue_workqueue);
1853 mempool_destroy(bs->bio_pool);
1856 mempool_destroy(bs->bvec_pool);
1858 bioset_integrity_free(bs);
1863 EXPORT_SYMBOL(bioset_free);
1866 * bioset_create - Create a bio_set
1867 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1868 * @front_pad: Number of bytes to allocate in front of the returned bio
1871 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1872 * to ask for a number of bytes to be allocated in front of the bio.
1873 * Front pad allocation is useful for embedding the bio inside
1874 * another structure, to avoid allocating extra data to go with the bio.
1875 * Note that the bio must be embedded at the END of that structure always,
1876 * or things will break badly.
1878 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1880 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1883 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1887 bs->front_pad = front_pad;
1889 spin_lock_init(&bs->rescue_lock);
1890 bio_list_init(&bs->rescue_list);
1891 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1893 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1894 if (!bs->bio_slab) {
1899 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1903 bs->bvec_pool = biovec_create_pool(bs, pool_size);
1907 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1908 if (!bs->rescue_workqueue)
1916 EXPORT_SYMBOL(bioset_create);
1918 #ifdef CONFIG_BLK_CGROUP
1920 * bio_associate_current - associate a bio with %current
1923 * Associate @bio with %current if it hasn't been associated yet. Block
1924 * layer will treat @bio as if it were issued by %current no matter which
1925 * task actually issues it.
1927 * This function takes an extra reference of @task's io_context and blkcg
1928 * which will be put when @bio is released. The caller must own @bio,
1929 * ensure %current->io_context exists, and is responsible for synchronizing
1930 * calls to this function.
1932 int bio_associate_current(struct bio *bio)
1934 struct io_context *ioc;
1935 struct cgroup_subsys_state *css;
1940 ioc = current->io_context;
1944 /* acquire active ref on @ioc and associate */
1945 get_io_context_active(ioc);
1948 /* associate blkcg if exists */
1950 css = task_subsys_state(current, blkio_subsys_id);
1951 if (css && css_tryget(css))
1959 * bio_disassociate_task - undo bio_associate_current()
1962 void bio_disassociate_task(struct bio *bio)
1965 put_io_context(bio->bi_ioc);
1969 css_put(bio->bi_css);
1974 #endif /* CONFIG_BLK_CGROUP */
1976 static void __init biovec_init_slabs(void)
1980 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1982 struct biovec_slab *bvs = bvec_slabs + i;
1984 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
1989 size = bvs->nr_vecs * sizeof(struct bio_vec);
1990 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1991 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1995 static int __init init_bio(void)
1999 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2001 panic("bio: can't allocate bios\n");
2003 bio_integrity_init();
2004 biovec_init_slabs();
2006 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
2008 panic("bio: can't allocate bios\n");
2010 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2011 panic("bio: can't create integrity pool\n");
2013 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
2014 sizeof(struct bio_pair));
2015 if (!bio_split_pool)
2016 panic("bio: can't create split pool\n");
2020 subsys_initcall(init_bio);