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>
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
42 * if you change this list, also change bvec_alloc or things will
43 * break badly! cannot be bigger than what you can fit into an
46 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
47 static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = {
48 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
53 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
54 * IO code that does not need private memory pools.
56 struct bio_set *fs_bio_set;
57 EXPORT_SYMBOL(fs_bio_set);
60 * Our slab pool management
63 struct kmem_cache *slab;
64 unsigned int slab_ref;
65 unsigned int slab_size;
68 static DEFINE_MUTEX(bio_slab_lock);
69 static struct bio_slab *bio_slabs;
70 static unsigned int bio_slab_nr, bio_slab_max;
72 static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
74 unsigned int sz = sizeof(struct bio) + extra_size;
75 struct kmem_cache *slab = NULL;
76 struct bio_slab *bslab, *new_bio_slabs;
77 unsigned int new_bio_slab_max;
78 unsigned int i, entry = -1;
80 mutex_lock(&bio_slab_lock);
83 while (i < bio_slab_nr) {
84 bslab = &bio_slabs[i];
86 if (!bslab->slab && entry == -1)
88 else if (bslab->slab_size == sz) {
99 if (bio_slab_nr == bio_slab_max && entry == -1) {
100 new_bio_slab_max = bio_slab_max << 1;
101 new_bio_slabs = krealloc(bio_slabs,
102 new_bio_slab_max * sizeof(struct bio_slab),
106 bio_slab_max = new_bio_slab_max;
107 bio_slabs = new_bio_slabs;
110 entry = bio_slab_nr++;
112 bslab = &bio_slabs[entry];
114 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
115 slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN,
116 SLAB_HWCACHE_ALIGN, NULL);
122 bslab->slab_size = sz;
124 mutex_unlock(&bio_slab_lock);
128 static void bio_put_slab(struct bio_set *bs)
130 struct bio_slab *bslab = NULL;
133 mutex_lock(&bio_slab_lock);
135 for (i = 0; i < bio_slab_nr; i++) {
136 if (bs->bio_slab == bio_slabs[i].slab) {
137 bslab = &bio_slabs[i];
142 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
145 WARN_ON(!bslab->slab_ref);
147 if (--bslab->slab_ref)
150 kmem_cache_destroy(bslab->slab);
154 mutex_unlock(&bio_slab_lock);
157 unsigned int bvec_nr_vecs(unsigned short idx)
159 return bvec_slabs[idx].nr_vecs;
162 void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
168 BIO_BUG_ON(idx >= BVEC_POOL_NR);
170 if (idx == BVEC_POOL_MAX) {
171 mempool_free(bv, pool);
173 struct biovec_slab *bvs = bvec_slabs + idx;
175 kmem_cache_free(bvs->slab, bv);
179 struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
185 * see comment near bvec_array define!
203 case 129 ... BIO_MAX_PAGES:
211 * idx now points to the pool we want to allocate from. only the
212 * 1-vec entry pool is mempool backed.
214 if (*idx == BVEC_POOL_MAX) {
216 bvl = mempool_alloc(pool, gfp_mask);
218 struct biovec_slab *bvs = bvec_slabs + *idx;
219 gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO);
222 * Make this allocation restricted and don't dump info on
223 * allocation failures, since we'll fallback to the mempool
224 * in case of failure.
226 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
229 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM
230 * is set, retry with the 1-entry mempool
232 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
233 if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {
234 *idx = BVEC_POOL_MAX;
243 static void __bio_free(struct bio *bio)
245 bio_disassociate_task(bio);
247 if (bio_integrity(bio))
248 bio_integrity_free(bio);
251 static void bio_free(struct bio *bio)
253 struct bio_set *bs = bio->bi_pool;
259 bvec_free(bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio));
262 * If we have front padding, adjust the bio pointer before freeing
267 mempool_free(p, bs->bio_pool);
269 /* Bio was allocated by bio_kmalloc() */
274 void bio_init(struct bio *bio, struct bio_vec *table,
275 unsigned short max_vecs)
277 memset(bio, 0, sizeof(*bio));
278 atomic_set(&bio->__bi_remaining, 1);
279 atomic_set(&bio->__bi_cnt, 1);
281 bio->bi_io_vec = table;
282 bio->bi_max_vecs = max_vecs;
284 EXPORT_SYMBOL(bio_init);
287 * bio_reset - reinitialize a bio
291 * After calling bio_reset(), @bio will be in the same state as a freshly
292 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
293 * preserved are the ones that are initialized by bio_alloc_bioset(). See
294 * comment in struct bio.
296 void bio_reset(struct bio *bio)
298 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
302 memset(bio, 0, BIO_RESET_BYTES);
303 bio->bi_flags = flags;
304 atomic_set(&bio->__bi_remaining, 1);
306 EXPORT_SYMBOL(bio_reset);
308 static struct bio *__bio_chain_endio(struct bio *bio)
310 struct bio *parent = bio->bi_private;
312 if (!parent->bi_error)
313 parent->bi_error = bio->bi_error;
318 static void bio_chain_endio(struct bio *bio)
320 bio_endio(__bio_chain_endio(bio));
324 * bio_chain - chain bio completions
325 * @bio: the target bio
326 * @parent: the @bio's parent bio
328 * The caller won't have a bi_end_io called when @bio completes - instead,
329 * @parent's bi_end_io won't be called until both @parent and @bio have
330 * completed; the chained bio will also be freed when it completes.
332 * The caller must not set bi_private or bi_end_io in @bio.
334 void bio_chain(struct bio *bio, struct bio *parent)
336 BUG_ON(bio->bi_private || bio->bi_end_io);
338 bio->bi_private = parent;
339 bio->bi_end_io = bio_chain_endio;
340 bio_inc_remaining(parent);
342 EXPORT_SYMBOL(bio_chain);
344 static void bio_alloc_rescue(struct work_struct *work)
346 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
350 spin_lock(&bs->rescue_lock);
351 bio = bio_list_pop(&bs->rescue_list);
352 spin_unlock(&bs->rescue_lock);
357 generic_make_request(bio);
361 static void punt_bios_to_rescuer(struct bio_set *bs)
363 struct bio_list punt, nopunt;
367 * In order to guarantee forward progress we must punt only bios that
368 * were allocated from this bio_set; otherwise, if there was a bio on
369 * there for a stacking driver higher up in the stack, processing it
370 * could require allocating bios from this bio_set, and doing that from
371 * our own rescuer would be bad.
373 * Since bio lists are singly linked, pop them all instead of trying to
374 * remove from the middle of the list:
377 bio_list_init(&punt);
378 bio_list_init(&nopunt);
380 while ((bio = bio_list_pop(¤t->bio_list[0])))
381 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
382 current->bio_list[0] = nopunt;
384 bio_list_init(&nopunt);
385 while ((bio = bio_list_pop(¤t->bio_list[1])))
386 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
387 current->bio_list[1] = nopunt;
389 spin_lock(&bs->rescue_lock);
390 bio_list_merge(&bs->rescue_list, &punt);
391 spin_unlock(&bs->rescue_lock);
393 queue_work(bs->rescue_workqueue, &bs->rescue_work);
397 * bio_alloc_bioset - allocate a bio for I/O
398 * @gfp_mask: the GFP_ mask given to the slab allocator
399 * @nr_iovecs: number of iovecs to pre-allocate
400 * @bs: the bio_set to allocate from.
403 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
404 * backed by the @bs's mempool.
406 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will
407 * always be able to allocate a bio. This is due to the mempool guarantees.
408 * To make this work, callers must never allocate more than 1 bio at a time
409 * from this pool. Callers that need to allocate more than 1 bio must always
410 * submit the previously allocated bio for IO before attempting to allocate
411 * a new one. Failure to do so can cause deadlocks under memory pressure.
413 * Note that when running under generic_make_request() (i.e. any block
414 * driver), bios are not submitted until after you return - see the code in
415 * generic_make_request() that converts recursion into iteration, to prevent
418 * This would normally mean allocating multiple bios under
419 * generic_make_request() would be susceptible to deadlocks, but we have
420 * deadlock avoidance code that resubmits any blocked bios from a rescuer
423 * However, we do not guarantee forward progress for allocations from other
424 * mempools. Doing multiple allocations from the same mempool under
425 * generic_make_request() should be avoided - instead, use bio_set's front_pad
426 * for per bio allocations.
429 * Pointer to new bio on success, NULL on failure.
431 struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs,
434 gfp_t saved_gfp = gfp_mask;
436 unsigned inline_vecs;
437 struct bio_vec *bvl = NULL;
442 if (nr_iovecs > UIO_MAXIOV)
445 p = kmalloc(sizeof(struct bio) +
446 nr_iovecs * sizeof(struct bio_vec),
449 inline_vecs = nr_iovecs;
451 /* should not use nobvec bioset for nr_iovecs > 0 */
452 if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0))
455 * generic_make_request() converts recursion to iteration; this
456 * means if we're running beneath it, any bios we allocate and
457 * submit will not be submitted (and thus freed) until after we
460 * This exposes us to a potential deadlock if we allocate
461 * multiple bios from the same bio_set() while running
462 * underneath generic_make_request(). If we were to allocate
463 * multiple bios (say a stacking block driver that was splitting
464 * bios), we would deadlock if we exhausted the mempool's
467 * We solve this, and guarantee forward progress, with a rescuer
468 * workqueue per bio_set. If we go to allocate and there are
469 * bios on current->bio_list, we first try the allocation
470 * without __GFP_DIRECT_RECLAIM; if that fails, we punt those
471 * bios we would be blocking to the rescuer workqueue before
472 * we retry with the original gfp_flags.
475 if (current->bio_list &&
476 (!bio_list_empty(¤t->bio_list[0]) ||
477 !bio_list_empty(¤t->bio_list[1])))
478 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
480 p = mempool_alloc(bs->bio_pool, gfp_mask);
481 if (!p && gfp_mask != saved_gfp) {
482 punt_bios_to_rescuer(bs);
483 gfp_mask = saved_gfp;
484 p = mempool_alloc(bs->bio_pool, gfp_mask);
487 front_pad = bs->front_pad;
488 inline_vecs = BIO_INLINE_VECS;
495 bio_init(bio, NULL, 0);
497 if (nr_iovecs > inline_vecs) {
498 unsigned long idx = 0;
500 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
501 if (!bvl && gfp_mask != saved_gfp) {
502 punt_bios_to_rescuer(bs);
503 gfp_mask = saved_gfp;
504 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
510 bio->bi_flags |= idx << BVEC_POOL_OFFSET;
511 } else if (nr_iovecs) {
512 bvl = bio->bi_inline_vecs;
516 bio->bi_max_vecs = nr_iovecs;
517 bio->bi_io_vec = bvl;
521 mempool_free(p, bs->bio_pool);
524 EXPORT_SYMBOL(bio_alloc_bioset);
526 void zero_fill_bio(struct bio *bio)
530 struct bvec_iter iter;
532 bio_for_each_segment(bv, bio, iter) {
533 char *data = bvec_kmap_irq(&bv, &flags);
534 memset(data, 0, bv.bv_len);
535 flush_dcache_page(bv.bv_page);
536 bvec_kunmap_irq(data, &flags);
539 EXPORT_SYMBOL(zero_fill_bio);
542 * bio_put - release a reference to a bio
543 * @bio: bio to release reference to
546 * Put a reference to a &struct bio, either one you have gotten with
547 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
549 void bio_put(struct bio *bio)
551 if (!bio_flagged(bio, BIO_REFFED))
554 BIO_BUG_ON(!atomic_read(&bio->__bi_cnt));
559 if (atomic_dec_and_test(&bio->__bi_cnt))
563 EXPORT_SYMBOL(bio_put);
565 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
567 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
568 blk_recount_segments(q, bio);
570 return bio->bi_phys_segments;
572 EXPORT_SYMBOL(bio_phys_segments);
575 * __bio_clone_fast - clone a bio that shares the original bio's biovec
576 * @bio: destination bio
577 * @bio_src: bio to clone
579 * Clone a &bio. Caller will own the returned bio, but not
580 * the actual data it points to. Reference count of returned
583 * Caller must ensure that @bio_src is not freed before @bio.
585 void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
587 BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio));
590 * most users will be overriding ->bi_bdev with a new target,
591 * so we don't set nor calculate new physical/hw segment counts here
593 bio->bi_bdev = bio_src->bi_bdev;
594 bio_set_flag(bio, BIO_CLONED);
595 bio->bi_opf = bio_src->bi_opf;
596 bio->bi_iter = bio_src->bi_iter;
597 bio->bi_io_vec = bio_src->bi_io_vec;
599 bio_clone_blkcg_association(bio, bio_src);
601 EXPORT_SYMBOL(__bio_clone_fast);
604 * bio_clone_fast - clone a bio that shares the original bio's biovec
606 * @gfp_mask: allocation priority
607 * @bs: bio_set to allocate from
609 * Like __bio_clone_fast, only also allocates the returned bio
611 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
615 b = bio_alloc_bioset(gfp_mask, 0, bs);
619 __bio_clone_fast(b, bio);
621 if (bio_integrity(bio)) {
624 ret = bio_integrity_clone(b, bio, gfp_mask);
634 EXPORT_SYMBOL(bio_clone_fast);
636 static struct bio *__bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
637 struct bio_set *bs, int offset,
640 struct bvec_iter iter;
643 struct bvec_iter iter_src = bio_src->bi_iter;
645 /* for supporting partial clone */
646 if (offset || size != bio_src->bi_iter.bi_size) {
647 bio_advance_iter(bio_src, &iter_src, offset);
648 iter_src.bi_size = size;
652 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
653 * bio_src->bi_io_vec to bio->bi_io_vec.
655 * We can't do that anymore, because:
657 * - The point of cloning the biovec is to produce a bio with a biovec
658 * the caller can modify: bi_idx and bi_bvec_done should be 0.
660 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
661 * we tried to clone the whole thing bio_alloc_bioset() would fail.
662 * But the clone should succeed as long as the number of biovecs we
663 * actually need to allocate is fewer than BIO_MAX_PAGES.
665 * - Lastly, bi_vcnt should not be looked at or relied upon by code
666 * that does not own the bio - reason being drivers don't use it for
667 * iterating over the biovec anymore, so expecting it to be kept up
668 * to date (i.e. for clones that share the parent biovec) is just
669 * asking for trouble and would force extra work on
670 * __bio_clone_fast() anyways.
673 bio = bio_alloc_bioset(gfp_mask, __bio_segments(bio_src,
677 bio->bi_bdev = bio_src->bi_bdev;
678 bio->bi_opf = bio_src->bi_opf;
679 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
680 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
682 switch (bio_op(bio)) {
684 case REQ_OP_SECURE_ERASE:
685 case REQ_OP_WRITE_ZEROES:
687 case REQ_OP_WRITE_SAME:
688 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
691 __bio_for_each_segment(bv, bio_src, iter, iter_src)
692 bio->bi_io_vec[bio->bi_vcnt++] = bv;
696 if (bio_integrity(bio_src)) {
699 ret = bio_integrity_clone(bio, bio_src, gfp_mask);
706 bio_clone_blkcg_association(bio, bio_src);
712 * bio_clone_bioset - clone a bio
713 * @bio_src: bio to clone
714 * @gfp_mask: allocation priority
715 * @bs: bio_set to allocate from
717 * Clone bio. Caller will own the returned bio, but not the actual data it
718 * points to. Reference count of returned bio will be one.
720 struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask,
723 return __bio_clone_bioset(bio_src, gfp_mask, bs, 0,
724 bio_src->bi_iter.bi_size);
726 EXPORT_SYMBOL(bio_clone_bioset);
729 * bio_clone_bioset_partial - clone a partial bio
730 * @bio_src: bio to clone
731 * @gfp_mask: allocation priority
732 * @bs: bio_set to allocate from
733 * @offset: cloned starting from the offset
734 * @size: size for the cloned bio
736 * Clone bio. Caller will own the returned bio, but not the actual data it
737 * points to. Reference count of returned bio will be one.
739 struct bio *bio_clone_bioset_partial(struct bio *bio_src, gfp_t gfp_mask,
740 struct bio_set *bs, int offset,
743 return __bio_clone_bioset(bio_src, gfp_mask, bs, offset, size);
745 EXPORT_SYMBOL(bio_clone_bioset_partial);
748 * bio_add_pc_page - attempt to add page to bio
749 * @q: the target queue
750 * @bio: destination bio
752 * @len: vec entry length
753 * @offset: vec entry offset
755 * Attempt to add a page to the bio_vec maplist. This can fail for a
756 * number of reasons, such as the bio being full or target block device
757 * limitations. The target block device must allow bio's up to PAGE_SIZE,
758 * so it is always possible to add a single page to an empty bio.
760 * This should only be used by REQ_PC bios.
762 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
763 *page, unsigned int len, unsigned int offset)
765 int retried_segments = 0;
766 struct bio_vec *bvec;
769 * cloned bio must not modify vec list
771 if (unlikely(bio_flagged(bio, BIO_CLONED)))
774 if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q))
778 * For filesystems with a blocksize smaller than the pagesize
779 * we will often be called with the same page as last time and
780 * a consecutive offset. Optimize this special case.
782 if (bio->bi_vcnt > 0) {
783 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
785 if (page == prev->bv_page &&
786 offset == prev->bv_offset + prev->bv_len) {
788 bio->bi_iter.bi_size += len;
793 * If the queue doesn't support SG gaps and adding this
794 * offset would create a gap, disallow it.
796 if (bvec_gap_to_prev(q, prev, offset))
800 if (bio->bi_vcnt >= bio->bi_max_vecs)
804 * setup the new entry, we might clear it again later if we
805 * cannot add the page
807 bvec = &bio->bi_io_vec[bio->bi_vcnt];
808 bvec->bv_page = page;
810 bvec->bv_offset = offset;
812 bio->bi_phys_segments++;
813 bio->bi_iter.bi_size += len;
816 * Perform a recount if the number of segments is greater
817 * than queue_max_segments(q).
820 while (bio->bi_phys_segments > queue_max_segments(q)) {
822 if (retried_segments)
825 retried_segments = 1;
826 blk_recount_segments(q, bio);
829 /* If we may be able to merge these biovecs, force a recount */
830 if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
831 bio_clear_flag(bio, BIO_SEG_VALID);
837 bvec->bv_page = NULL;
841 bio->bi_iter.bi_size -= len;
842 blk_recount_segments(q, bio);
845 EXPORT_SYMBOL(bio_add_pc_page);
848 * bio_add_page - attempt to add page to bio
849 * @bio: destination bio
851 * @len: vec entry length
852 * @offset: vec entry offset
854 * Attempt to add a page to the bio_vec maplist. This will only fail
855 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
857 int bio_add_page(struct bio *bio, struct page *page,
858 unsigned int len, unsigned int offset)
863 * cloned bio must not modify vec list
865 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
869 * For filesystems with a blocksize smaller than the pagesize
870 * we will often be called with the same page as last time and
871 * a consecutive offset. Optimize this special case.
873 if (bio->bi_vcnt > 0) {
874 bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
876 if (page == bv->bv_page &&
877 offset == bv->bv_offset + bv->bv_len) {
883 if (bio->bi_vcnt >= bio->bi_max_vecs)
886 bv = &bio->bi_io_vec[bio->bi_vcnt];
889 bv->bv_offset = offset;
893 bio->bi_iter.bi_size += len;
896 EXPORT_SYMBOL(bio_add_page);
899 * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
900 * @bio: bio to add pages to
901 * @iter: iov iterator describing the region to be mapped
903 * Pins as many pages from *iter and appends them to @bio's bvec array. The
904 * pages will have to be released using put_page() when done.
906 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
908 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
909 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
910 struct page **pages = (struct page **)bv;
914 size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
915 if (unlikely(size <= 0))
916 return size ? size : -EFAULT;
917 nr_pages = (size + offset + PAGE_SIZE - 1) / PAGE_SIZE;
920 * Deep magic below: We need to walk the pinned pages backwards
921 * because we are abusing the space allocated for the bio_vecs
922 * for the page array. Because the bio_vecs are larger than the
923 * page pointers by definition this will always work. But it also
924 * means we can't use bio_add_page, so any changes to it's semantics
925 * need to be reflected here as well.
927 bio->bi_iter.bi_size += size;
928 bio->bi_vcnt += nr_pages;
930 diff = (nr_pages * PAGE_SIZE - offset) - size;
932 bv[nr_pages].bv_page = pages[nr_pages];
933 bv[nr_pages].bv_len = PAGE_SIZE;
934 bv[nr_pages].bv_offset = 0;
937 bv[0].bv_offset += offset;
938 bv[0].bv_len -= offset;
940 bv[bio->bi_vcnt - 1].bv_len -= diff;
942 iov_iter_advance(iter, size);
945 EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
947 struct submit_bio_ret {
948 struct completion event;
952 static void submit_bio_wait_endio(struct bio *bio)
954 struct submit_bio_ret *ret = bio->bi_private;
956 ret->error = bio->bi_error;
957 complete(&ret->event);
961 * submit_bio_wait - submit a bio, and wait until it completes
962 * @bio: The &struct bio which describes the I/O
964 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
965 * bio_endio() on failure.
967 int submit_bio_wait(struct bio *bio)
969 struct submit_bio_ret ret;
971 init_completion(&ret.event);
972 bio->bi_private = &ret;
973 bio->bi_end_io = submit_bio_wait_endio;
974 bio->bi_opf |= REQ_SYNC;
976 wait_for_completion_io(&ret.event);
980 EXPORT_SYMBOL(submit_bio_wait);
983 * bio_advance - increment/complete a bio by some number of bytes
984 * @bio: bio to advance
985 * @bytes: number of bytes to complete
987 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
988 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
989 * be updated on the last bvec as well.
991 * @bio will then represent the remaining, uncompleted portion of the io.
993 void bio_advance(struct bio *bio, unsigned bytes)
995 if (bio_integrity(bio))
996 bio_integrity_advance(bio, bytes);
998 bio_advance_iter(bio, &bio->bi_iter, bytes);
1000 EXPORT_SYMBOL(bio_advance);
1003 * bio_alloc_pages - allocates a single page for each bvec in a bio
1004 * @bio: bio to allocate pages for
1005 * @gfp_mask: flags for allocation
1007 * Allocates pages up to @bio->bi_vcnt.
1009 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
1012 int bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
1017 bio_for_each_segment_all(bv, bio, i) {
1018 bv->bv_page = alloc_page(gfp_mask);
1020 while (--bv >= bio->bi_io_vec)
1021 __free_page(bv->bv_page);
1028 EXPORT_SYMBOL(bio_alloc_pages);
1031 * bio_copy_data - copy contents of data buffers from one chain of bios to
1033 * @src: source bio list
1034 * @dst: destination bio list
1036 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
1037 * @src and @dst as linked lists of bios.
1039 * Stops when it reaches the end of either @src or @dst - that is, copies
1040 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
1042 void bio_copy_data(struct bio *dst, struct bio *src)
1044 struct bvec_iter src_iter, dst_iter;
1045 struct bio_vec src_bv, dst_bv;
1046 void *src_p, *dst_p;
1049 src_iter = src->bi_iter;
1050 dst_iter = dst->bi_iter;
1053 if (!src_iter.bi_size) {
1058 src_iter = src->bi_iter;
1061 if (!dst_iter.bi_size) {
1066 dst_iter = dst->bi_iter;
1069 src_bv = bio_iter_iovec(src, src_iter);
1070 dst_bv = bio_iter_iovec(dst, dst_iter);
1072 bytes = min(src_bv.bv_len, dst_bv.bv_len);
1074 src_p = kmap_atomic(src_bv.bv_page);
1075 dst_p = kmap_atomic(dst_bv.bv_page);
1077 memcpy(dst_p + dst_bv.bv_offset,
1078 src_p + src_bv.bv_offset,
1081 kunmap_atomic(dst_p);
1082 kunmap_atomic(src_p);
1084 bio_advance_iter(src, &src_iter, bytes);
1085 bio_advance_iter(dst, &dst_iter, bytes);
1088 EXPORT_SYMBOL(bio_copy_data);
1090 struct bio_map_data {
1092 struct iov_iter iter;
1096 static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count,
1099 if (iov_count > UIO_MAXIOV)
1102 return kmalloc(sizeof(struct bio_map_data) +
1103 sizeof(struct iovec) * iov_count, gfp_mask);
1107 * bio_copy_from_iter - copy all pages from iov_iter to bio
1108 * @bio: The &struct bio which describes the I/O as destination
1109 * @iter: iov_iter as source
1111 * Copy all pages from iov_iter to bio.
1112 * Returns 0 on success, or error on failure.
1114 static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter)
1117 struct bio_vec *bvec;
1119 bio_for_each_segment_all(bvec, bio, i) {
1122 ret = copy_page_from_iter(bvec->bv_page,
1127 if (!iov_iter_count(&iter))
1130 if (ret < bvec->bv_len)
1138 * bio_copy_to_iter - copy all pages from bio to iov_iter
1139 * @bio: The &struct bio which describes the I/O as source
1140 * @iter: iov_iter as destination
1142 * Copy all pages from bio to iov_iter.
1143 * Returns 0 on success, or error on failure.
1145 static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
1148 struct bio_vec *bvec;
1150 bio_for_each_segment_all(bvec, bio, i) {
1153 ret = copy_page_to_iter(bvec->bv_page,
1158 if (!iov_iter_count(&iter))
1161 if (ret < bvec->bv_len)
1168 void bio_free_pages(struct bio *bio)
1170 struct bio_vec *bvec;
1173 bio_for_each_segment_all(bvec, bio, i)
1174 __free_page(bvec->bv_page);
1176 EXPORT_SYMBOL(bio_free_pages);
1179 * bio_uncopy_user - finish previously mapped bio
1180 * @bio: bio being terminated
1182 * Free pages allocated from bio_copy_user_iov() and write back data
1183 * to user space in case of a read.
1185 int bio_uncopy_user(struct bio *bio)
1187 struct bio_map_data *bmd = bio->bi_private;
1190 if (!bio_flagged(bio, BIO_NULL_MAPPED)) {
1192 * if we're in a workqueue, the request is orphaned, so
1193 * don't copy into a random user address space, just free
1194 * and return -EINTR so user space doesn't expect any data.
1198 else if (bio_data_dir(bio) == READ)
1199 ret = bio_copy_to_iter(bio, bmd->iter);
1200 if (bmd->is_our_pages)
1201 bio_free_pages(bio);
1209 * bio_copy_user_iov - copy user data to bio
1210 * @q: destination block queue
1211 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1212 * @iter: iovec iterator
1213 * @gfp_mask: memory allocation flags
1215 * Prepares and returns a bio for indirect user io, bouncing data
1216 * to/from kernel pages as necessary. Must be paired with
1217 * call bio_uncopy_user() on io completion.
1219 struct bio *bio_copy_user_iov(struct request_queue *q,
1220 struct rq_map_data *map_data,
1221 const struct iov_iter *iter,
1224 struct bio_map_data *bmd;
1229 unsigned int len = iter->count;
1230 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
1232 for (i = 0; i < iter->nr_segs; i++) {
1233 unsigned long uaddr;
1235 unsigned long start;
1237 uaddr = (unsigned long) iter->iov[i].iov_base;
1238 end = (uaddr + iter->iov[i].iov_len + PAGE_SIZE - 1)
1240 start = uaddr >> PAGE_SHIFT;
1246 return ERR_PTR(-EINVAL);
1248 nr_pages += end - start;
1254 bmd = bio_alloc_map_data(iter->nr_segs, gfp_mask);
1256 return ERR_PTR(-ENOMEM);
1259 * We need to do a deep copy of the iov_iter including the iovecs.
1260 * The caller provided iov might point to an on-stack or otherwise
1263 bmd->is_our_pages = map_data ? 0 : 1;
1264 memcpy(bmd->iov, iter->iov, sizeof(struct iovec) * iter->nr_segs);
1265 iov_iter_init(&bmd->iter, iter->type, bmd->iov,
1266 iter->nr_segs, iter->count);
1269 bio = bio_kmalloc(gfp_mask, nr_pages);
1276 nr_pages = 1 << map_data->page_order;
1277 i = map_data->offset / PAGE_SIZE;
1280 unsigned int bytes = PAGE_SIZE;
1288 if (i == map_data->nr_entries * nr_pages) {
1293 page = map_data->pages[i / nr_pages];
1294 page += (i % nr_pages);
1298 page = alloc_page(q->bounce_gfp | gfp_mask);
1305 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
1318 if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
1319 (map_data && map_data->from_user)) {
1320 ret = bio_copy_from_iter(bio, *iter);
1325 bio->bi_private = bmd;
1329 bio_free_pages(bio);
1333 return ERR_PTR(ret);
1337 * bio_map_user_iov - map user iovec into bio
1338 * @q: the struct request_queue for the bio
1339 * @iter: iovec iterator
1340 * @gfp_mask: memory allocation flags
1342 * Map the user space address into a bio suitable for io to a block
1343 * device. Returns an error pointer in case of error.
1345 struct bio *bio_map_user_iov(struct request_queue *q,
1346 const struct iov_iter *iter,
1351 struct page **pages;
1358 iov_for_each(iov, i, *iter) {
1359 unsigned long uaddr = (unsigned long) iov.iov_base;
1360 unsigned long len = iov.iov_len;
1361 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1362 unsigned long start = uaddr >> PAGE_SHIFT;
1368 return ERR_PTR(-EINVAL);
1370 nr_pages += end - start;
1372 * buffer must be aligned to at least logical block size for now
1374 if (uaddr & queue_dma_alignment(q))
1375 return ERR_PTR(-EINVAL);
1379 return ERR_PTR(-EINVAL);
1381 bio = bio_kmalloc(gfp_mask, nr_pages);
1383 return ERR_PTR(-ENOMEM);
1386 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
1390 iov_for_each(iov, i, *iter) {
1391 unsigned long uaddr = (unsigned long) iov.iov_base;
1392 unsigned long len = iov.iov_len;
1393 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1394 unsigned long start = uaddr >> PAGE_SHIFT;
1395 const int local_nr_pages = end - start;
1396 const int page_limit = cur_page + local_nr_pages;
1398 ret = get_user_pages_fast(uaddr, local_nr_pages,
1399 (iter->type & WRITE) != WRITE,
1401 if (ret < local_nr_pages) {
1406 offset = offset_in_page(uaddr);
1407 for (j = cur_page; j < page_limit; j++) {
1408 unsigned int bytes = PAGE_SIZE - offset;
1419 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1429 * release the pages we didn't map into the bio, if any
1431 while (j < page_limit)
1432 put_page(pages[j++]);
1437 bio_set_flag(bio, BIO_USER_MAPPED);
1440 * subtle -- if bio_map_user_iov() ended up bouncing a bio,
1441 * it would normally disappear when its bi_end_io is run.
1442 * however, we need it for the unmap, so grab an extra
1449 for (j = 0; j < nr_pages; j++) {
1457 return ERR_PTR(ret);
1460 static void __bio_unmap_user(struct bio *bio)
1462 struct bio_vec *bvec;
1466 * make sure we dirty pages we wrote to
1468 bio_for_each_segment_all(bvec, bio, i) {
1469 if (bio_data_dir(bio) == READ)
1470 set_page_dirty_lock(bvec->bv_page);
1472 put_page(bvec->bv_page);
1479 * bio_unmap_user - unmap a bio
1480 * @bio: the bio being unmapped
1482 * Unmap a bio previously mapped by bio_map_user_iov(). Must be called from
1485 * bio_unmap_user() may sleep.
1487 void bio_unmap_user(struct bio *bio)
1489 __bio_unmap_user(bio);
1493 static void bio_map_kern_endio(struct bio *bio)
1499 * bio_map_kern - map kernel address into bio
1500 * @q: the struct request_queue for the bio
1501 * @data: pointer to buffer to map
1502 * @len: length in bytes
1503 * @gfp_mask: allocation flags for bio allocation
1505 * Map the kernel address into a bio suitable for io to a block
1506 * device. Returns an error pointer in case of error.
1508 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1511 unsigned long kaddr = (unsigned long)data;
1512 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1513 unsigned long start = kaddr >> PAGE_SHIFT;
1514 const int nr_pages = end - start;
1518 bio = bio_kmalloc(gfp_mask, nr_pages);
1520 return ERR_PTR(-ENOMEM);
1522 offset = offset_in_page(kaddr);
1523 for (i = 0; i < nr_pages; i++) {
1524 unsigned int bytes = PAGE_SIZE - offset;
1532 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1534 /* we don't support partial mappings */
1536 return ERR_PTR(-EINVAL);
1544 bio->bi_end_io = bio_map_kern_endio;
1547 EXPORT_SYMBOL(bio_map_kern);
1549 static void bio_copy_kern_endio(struct bio *bio)
1551 bio_free_pages(bio);
1555 static void bio_copy_kern_endio_read(struct bio *bio)
1557 char *p = bio->bi_private;
1558 struct bio_vec *bvec;
1561 bio_for_each_segment_all(bvec, bio, i) {
1562 memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
1566 bio_copy_kern_endio(bio);
1570 * bio_copy_kern - copy kernel address into bio
1571 * @q: the struct request_queue for the bio
1572 * @data: pointer to buffer to copy
1573 * @len: length in bytes
1574 * @gfp_mask: allocation flags for bio and page allocation
1575 * @reading: data direction is READ
1577 * copy the kernel address into a bio suitable for io to a block
1578 * device. Returns an error pointer in case of error.
1580 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1581 gfp_t gfp_mask, int reading)
1583 unsigned long kaddr = (unsigned long)data;
1584 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1585 unsigned long start = kaddr >> PAGE_SHIFT;
1594 return ERR_PTR(-EINVAL);
1596 nr_pages = end - start;
1597 bio = bio_kmalloc(gfp_mask, nr_pages);
1599 return ERR_PTR(-ENOMEM);
1603 unsigned int bytes = PAGE_SIZE;
1608 page = alloc_page(q->bounce_gfp | gfp_mask);
1613 memcpy(page_address(page), p, bytes);
1615 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
1623 bio->bi_end_io = bio_copy_kern_endio_read;
1624 bio->bi_private = data;
1626 bio->bi_end_io = bio_copy_kern_endio;
1632 bio_free_pages(bio);
1634 return ERR_PTR(-ENOMEM);
1638 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1639 * for performing direct-IO in BIOs.
1641 * The problem is that we cannot run set_page_dirty() from interrupt context
1642 * because the required locks are not interrupt-safe. So what we can do is to
1643 * mark the pages dirty _before_ performing IO. And in interrupt context,
1644 * check that the pages are still dirty. If so, fine. If not, redirty them
1645 * in process context.
1647 * We special-case compound pages here: normally this means reads into hugetlb
1648 * pages. The logic in here doesn't really work right for compound pages
1649 * because the VM does not uniformly chase down the head page in all cases.
1650 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1651 * handle them at all. So we skip compound pages here at an early stage.
1653 * Note that this code is very hard to test under normal circumstances because
1654 * direct-io pins the pages with get_user_pages(). This makes
1655 * is_page_cache_freeable return false, and the VM will not clean the pages.
1656 * But other code (eg, flusher threads) could clean the pages if they are mapped
1659 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1660 * deferred bio dirtying paths.
1664 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1666 void bio_set_pages_dirty(struct bio *bio)
1668 struct bio_vec *bvec;
1671 bio_for_each_segment_all(bvec, bio, i) {
1672 struct page *page = bvec->bv_page;
1674 if (page && !PageCompound(page))
1675 set_page_dirty_lock(page);
1679 static void bio_release_pages(struct bio *bio)
1681 struct bio_vec *bvec;
1684 bio_for_each_segment_all(bvec, bio, i) {
1685 struct page *page = bvec->bv_page;
1693 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1694 * If they are, then fine. If, however, some pages are clean then they must
1695 * have been written out during the direct-IO read. So we take another ref on
1696 * the BIO and the offending pages and re-dirty the pages in process context.
1698 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1699 * here on. It will run one put_page() against each page and will run one
1700 * bio_put() against the BIO.
1703 static void bio_dirty_fn(struct work_struct *work);
1705 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1706 static DEFINE_SPINLOCK(bio_dirty_lock);
1707 static struct bio *bio_dirty_list;
1710 * This runs in process context
1712 static void bio_dirty_fn(struct work_struct *work)
1714 unsigned long flags;
1717 spin_lock_irqsave(&bio_dirty_lock, flags);
1718 bio = bio_dirty_list;
1719 bio_dirty_list = NULL;
1720 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1723 struct bio *next = bio->bi_private;
1725 bio_set_pages_dirty(bio);
1726 bio_release_pages(bio);
1732 void bio_check_pages_dirty(struct bio *bio)
1734 struct bio_vec *bvec;
1735 int nr_clean_pages = 0;
1738 bio_for_each_segment_all(bvec, bio, i) {
1739 struct page *page = bvec->bv_page;
1741 if (PageDirty(page) || PageCompound(page)) {
1743 bvec->bv_page = NULL;
1749 if (nr_clean_pages) {
1750 unsigned long flags;
1752 spin_lock_irqsave(&bio_dirty_lock, flags);
1753 bio->bi_private = bio_dirty_list;
1754 bio_dirty_list = bio;
1755 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1756 schedule_work(&bio_dirty_work);
1762 void generic_start_io_acct(int rw, unsigned long sectors,
1763 struct hd_struct *part)
1765 int cpu = part_stat_lock();
1767 part_round_stats(cpu, part);
1768 part_stat_inc(cpu, part, ios[rw]);
1769 part_stat_add(cpu, part, sectors[rw], sectors);
1770 part_inc_in_flight(part, rw);
1774 EXPORT_SYMBOL(generic_start_io_acct);
1776 void generic_end_io_acct(int rw, struct hd_struct *part,
1777 unsigned long start_time)
1779 unsigned long duration = jiffies - start_time;
1780 int cpu = part_stat_lock();
1782 part_stat_add(cpu, part, ticks[rw], duration);
1783 part_round_stats(cpu, part);
1784 part_dec_in_flight(part, rw);
1788 EXPORT_SYMBOL(generic_end_io_acct);
1790 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1791 void bio_flush_dcache_pages(struct bio *bi)
1793 struct bio_vec bvec;
1794 struct bvec_iter iter;
1796 bio_for_each_segment(bvec, bi, iter)
1797 flush_dcache_page(bvec.bv_page);
1799 EXPORT_SYMBOL(bio_flush_dcache_pages);
1802 static inline bool bio_remaining_done(struct bio *bio)
1805 * If we're not chaining, then ->__bi_remaining is always 1 and
1806 * we always end io on the first invocation.
1808 if (!bio_flagged(bio, BIO_CHAIN))
1811 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1813 if (atomic_dec_and_test(&bio->__bi_remaining)) {
1814 bio_clear_flag(bio, BIO_CHAIN);
1822 * bio_endio - end I/O on a bio
1826 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1827 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1828 * bio unless they own it and thus know that it has an end_io function.
1830 * bio_endio() can be called several times on a bio that has been chained
1831 * using bio_chain(). The ->bi_end_io() function will only be called the
1832 * last time. At this point the BLK_TA_COMPLETE tracing event will be
1833 * generated if BIO_TRACE_COMPLETION is set.
1835 void bio_endio(struct bio *bio)
1838 if (!bio_remaining_done(bio))
1842 * Need to have a real endio function for chained bios, otherwise
1843 * various corner cases will break (like stacking block devices that
1844 * save/restore bi_end_io) - however, we want to avoid unbounded
1845 * recursion and blowing the stack. Tail call optimization would
1846 * handle this, but compiling with frame pointers also disables
1847 * gcc's sibling call optimization.
1849 if (bio->bi_end_io == bio_chain_endio) {
1850 bio = __bio_chain_endio(bio);
1854 if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
1855 trace_block_bio_complete(bdev_get_queue(bio->bi_bdev),
1856 bio, bio->bi_error);
1857 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1860 blk_throtl_bio_endio(bio);
1862 bio->bi_end_io(bio);
1864 EXPORT_SYMBOL(bio_endio);
1867 * bio_split - split a bio
1868 * @bio: bio to split
1869 * @sectors: number of sectors to split from the front of @bio
1871 * @bs: bio set to allocate from
1873 * Allocates and returns a new bio which represents @sectors from the start of
1874 * @bio, and updates @bio to represent the remaining sectors.
1876 * Unless this is a discard request the newly allocated bio will point
1877 * to @bio's bi_io_vec; it is the caller's responsibility to ensure that
1878 * @bio is not freed before the split.
1880 struct bio *bio_split(struct bio *bio, int sectors,
1881 gfp_t gfp, struct bio_set *bs)
1883 struct bio *split = NULL;
1885 BUG_ON(sectors <= 0);
1886 BUG_ON(sectors >= bio_sectors(bio));
1888 split = bio_clone_fast(bio, gfp, bs);
1892 split->bi_iter.bi_size = sectors << 9;
1894 if (bio_integrity(split))
1895 bio_integrity_trim(split, 0, sectors);
1897 bio_advance(bio, split->bi_iter.bi_size);
1899 if (bio_flagged(bio, BIO_TRACE_COMPLETION))
1900 bio_set_flag(bio, BIO_TRACE_COMPLETION);
1904 EXPORT_SYMBOL(bio_split);
1907 * bio_trim - trim a bio
1909 * @offset: number of sectors to trim from the front of @bio
1910 * @size: size we want to trim @bio to, in sectors
1912 void bio_trim(struct bio *bio, int offset, int size)
1914 /* 'bio' is a cloned bio which we need to trim to match
1915 * the given offset and size.
1919 if (offset == 0 && size == bio->bi_iter.bi_size)
1922 bio_clear_flag(bio, BIO_SEG_VALID);
1924 bio_advance(bio, offset << 9);
1926 bio->bi_iter.bi_size = size;
1928 EXPORT_SYMBOL_GPL(bio_trim);
1931 * create memory pools for biovec's in a bio_set.
1932 * use the global biovec slabs created for general use.
1934 mempool_t *biovec_create_pool(int pool_entries)
1936 struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX;
1938 return mempool_create_slab_pool(pool_entries, bp->slab);
1941 void bioset_free(struct bio_set *bs)
1943 if (bs->rescue_workqueue)
1944 destroy_workqueue(bs->rescue_workqueue);
1947 mempool_destroy(bs->bio_pool);
1950 mempool_destroy(bs->bvec_pool);
1952 bioset_integrity_free(bs);
1957 EXPORT_SYMBOL(bioset_free);
1959 static struct bio_set *__bioset_create(unsigned int pool_size,
1960 unsigned int front_pad,
1961 bool create_bvec_pool)
1963 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1966 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1970 bs->front_pad = front_pad;
1972 spin_lock_init(&bs->rescue_lock);
1973 bio_list_init(&bs->rescue_list);
1974 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1976 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1977 if (!bs->bio_slab) {
1982 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1986 if (create_bvec_pool) {
1987 bs->bvec_pool = biovec_create_pool(pool_size);
1992 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
1993 if (!bs->rescue_workqueue)
2003 * bioset_create - Create a bio_set
2004 * @pool_size: Number of bio and bio_vecs to cache in the mempool
2005 * @front_pad: Number of bytes to allocate in front of the returned bio
2008 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
2009 * to ask for a number of bytes to be allocated in front of the bio.
2010 * Front pad allocation is useful for embedding the bio inside
2011 * another structure, to avoid allocating extra data to go with the bio.
2012 * Note that the bio must be embedded at the END of that structure always,
2013 * or things will break badly.
2015 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
2017 return __bioset_create(pool_size, front_pad, true);
2019 EXPORT_SYMBOL(bioset_create);
2022 * bioset_create_nobvec - Create a bio_set without bio_vec mempool
2023 * @pool_size: Number of bio to cache in the mempool
2024 * @front_pad: Number of bytes to allocate in front of the returned bio
2027 * Same functionality as bioset_create() except that mempool is not
2028 * created for bio_vecs. Saving some memory for bio_clone_fast() users.
2030 struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad)
2032 return __bioset_create(pool_size, front_pad, false);
2034 EXPORT_SYMBOL(bioset_create_nobvec);
2036 #ifdef CONFIG_BLK_CGROUP
2039 * bio_associate_blkcg - associate a bio with the specified blkcg
2041 * @blkcg_css: css of the blkcg to associate
2043 * Associate @bio with the blkcg specified by @blkcg_css. Block layer will
2044 * treat @bio as if it were issued by a task which belongs to the blkcg.
2046 * This function takes an extra reference of @blkcg_css which will be put
2047 * when @bio is released. The caller must own @bio and is responsible for
2048 * synchronizing calls to this function.
2050 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css)
2052 if (unlikely(bio->bi_css))
2055 bio->bi_css = blkcg_css;
2058 EXPORT_SYMBOL_GPL(bio_associate_blkcg);
2061 * bio_associate_current - associate a bio with %current
2064 * Associate @bio with %current if it hasn't been associated yet. Block
2065 * layer will treat @bio as if it were issued by %current no matter which
2066 * task actually issues it.
2068 * This function takes an extra reference of @task's io_context and blkcg
2069 * which will be put when @bio is released. The caller must own @bio,
2070 * ensure %current->io_context exists, and is responsible for synchronizing
2071 * calls to this function.
2073 int bio_associate_current(struct bio *bio)
2075 struct io_context *ioc;
2080 ioc = current->io_context;
2084 get_io_context_active(ioc);
2086 bio->bi_css = task_get_css(current, io_cgrp_id);
2089 EXPORT_SYMBOL_GPL(bio_associate_current);
2092 * bio_disassociate_task - undo bio_associate_current()
2095 void bio_disassociate_task(struct bio *bio)
2098 put_io_context(bio->bi_ioc);
2102 css_put(bio->bi_css);
2108 * bio_clone_blkcg_association - clone blkcg association from src to dst bio
2109 * @dst: destination bio
2112 void bio_clone_blkcg_association(struct bio *dst, struct bio *src)
2115 WARN_ON(bio_associate_blkcg(dst, src->bi_css));
2118 #endif /* CONFIG_BLK_CGROUP */
2120 static void __init biovec_init_slabs(void)
2124 for (i = 0; i < BVEC_POOL_NR; i++) {
2126 struct biovec_slab *bvs = bvec_slabs + i;
2128 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
2133 size = bvs->nr_vecs * sizeof(struct bio_vec);
2134 bvs->slab = kmem_cache_create(bvs->name, size, 0,
2135 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
2139 static int __init init_bio(void)
2143 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
2145 panic("bio: can't allocate bios\n");
2147 bio_integrity_init();
2148 biovec_init_slabs();
2150 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
2152 panic("bio: can't allocate bios\n");
2154 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
2155 panic("bio: can't create integrity pool\n");
2159 subsys_initcall(init_bio);