1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
6 #include <linux/swap.h>
8 #include <linux/blkdev.h>
10 #include <linux/iocontext.h>
11 #include <linux/slab.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/export.h>
15 #include <linux/mempool.h>
16 #include <linux/workqueue.h>
17 #include <linux/cgroup.h>
18 #include <linux/blk-cgroup.h>
19 #include <linux/highmem.h>
20 #include <linux/sched/sysctl.h>
21 #include <linux/blk-crypto.h>
22 #include <linux/xarray.h>
24 #include <trace/events/block.h>
26 #include "blk-rq-qos.h"
28 struct bio_alloc_cache {
29 struct bio *free_list;
33 static struct biovec_slab {
36 struct kmem_cache *slab;
37 } bvec_slabs[] __read_mostly = {
38 { .nr_vecs = 16, .name = "biovec-16" },
39 { .nr_vecs = 64, .name = "biovec-64" },
40 { .nr_vecs = 128, .name = "biovec-128" },
41 { .nr_vecs = BIO_MAX_VECS, .name = "biovec-max" },
44 static struct biovec_slab *biovec_slab(unsigned short nr_vecs)
47 /* smaller bios use inline vecs */
49 return &bvec_slabs[0];
51 return &bvec_slabs[1];
53 return &bvec_slabs[2];
54 case 129 ... BIO_MAX_VECS:
55 return &bvec_slabs[3];
63 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
64 * IO code that does not need private memory pools.
66 struct bio_set fs_bio_set;
67 EXPORT_SYMBOL(fs_bio_set);
70 * Our slab pool management
73 struct kmem_cache *slab;
74 unsigned int slab_ref;
75 unsigned int slab_size;
78 static DEFINE_MUTEX(bio_slab_lock);
79 static DEFINE_XARRAY(bio_slabs);
81 static struct bio_slab *create_bio_slab(unsigned int size)
83 struct bio_slab *bslab = kzalloc(sizeof(*bslab), GFP_KERNEL);
88 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size);
89 bslab->slab = kmem_cache_create(bslab->name, size,
90 ARCH_KMALLOC_MINALIGN,
91 SLAB_HWCACHE_ALIGN | SLAB_TYPESAFE_BY_RCU, NULL);
96 bslab->slab_size = size;
98 if (!xa_err(xa_store(&bio_slabs, size, bslab, GFP_KERNEL)))
101 kmem_cache_destroy(bslab->slab);
108 static inline unsigned int bs_bio_slab_size(struct bio_set *bs)
110 return bs->front_pad + sizeof(struct bio) + bs->back_pad;
113 static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs)
115 unsigned int size = bs_bio_slab_size(bs);
116 struct bio_slab *bslab;
118 mutex_lock(&bio_slab_lock);
119 bslab = xa_load(&bio_slabs, size);
123 bslab = create_bio_slab(size);
124 mutex_unlock(&bio_slab_lock);
131 static void bio_put_slab(struct bio_set *bs)
133 struct bio_slab *bslab = NULL;
134 unsigned int slab_size = bs_bio_slab_size(bs);
136 mutex_lock(&bio_slab_lock);
138 bslab = xa_load(&bio_slabs, slab_size);
139 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
142 WARN_ON_ONCE(bslab->slab != bs->bio_slab);
144 WARN_ON(!bslab->slab_ref);
146 if (--bslab->slab_ref)
149 xa_erase(&bio_slabs, slab_size);
151 kmem_cache_destroy(bslab->slab);
155 mutex_unlock(&bio_slab_lock);
158 void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs)
160 BUG_ON(nr_vecs > BIO_MAX_VECS);
162 if (nr_vecs == BIO_MAX_VECS)
163 mempool_free(bv, pool);
164 else if (nr_vecs > BIO_INLINE_VECS)
165 kmem_cache_free(biovec_slab(nr_vecs)->slab, bv);
169 * Make the first allocation restricted and don't dump info on allocation
170 * failures, since we'll fall back to the mempool in case of failure.
172 static inline gfp_t bvec_alloc_gfp(gfp_t gfp)
174 return (gfp & ~(__GFP_DIRECT_RECLAIM | __GFP_IO)) |
175 __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
178 struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,
181 struct biovec_slab *bvs = biovec_slab(*nr_vecs);
183 if (WARN_ON_ONCE(!bvs))
187 * Upgrade the nr_vecs request to take full advantage of the allocation.
188 * We also rely on this in the bvec_free path.
190 *nr_vecs = bvs->nr_vecs;
193 * Try a slab allocation first for all smaller allocations. If that
194 * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool.
195 * The mempool is sized to handle up to BIO_MAX_VECS entries.
197 if (*nr_vecs < BIO_MAX_VECS) {
200 bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask));
201 if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM))
203 *nr_vecs = BIO_MAX_VECS;
206 return mempool_alloc(pool, gfp_mask);
209 void bio_uninit(struct bio *bio)
211 #ifdef CONFIG_BLK_CGROUP
213 blkg_put(bio->bi_blkg);
217 if (bio_integrity(bio))
218 bio_integrity_free(bio);
220 bio_crypt_free_ctx(bio);
222 EXPORT_SYMBOL(bio_uninit);
224 static void bio_free(struct bio *bio)
226 struct bio_set *bs = bio->bi_pool;
232 bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs);
235 * If we have front padding, adjust the bio pointer before freeing
240 mempool_free(p, &bs->bio_pool);
242 /* Bio was allocated by bio_kmalloc() */
248 * Users of this function have their own bio allocation. Subsequently,
249 * they must remember to pair any call to bio_init() with bio_uninit()
250 * when IO has completed, or when the bio is released.
252 void bio_init(struct bio *bio, struct bio_vec *table,
253 unsigned short max_vecs)
260 bio->bi_write_hint = 0;
262 bio->bi_iter.bi_sector = 0;
263 bio->bi_iter.bi_size = 0;
264 bio->bi_iter.bi_idx = 0;
265 bio->bi_iter.bi_bvec_done = 0;
266 bio->bi_end_io = NULL;
267 bio->bi_private = NULL;
268 #ifdef CONFIG_BLK_CGROUP
270 bio->bi_issue.value = 0;
271 #ifdef CONFIG_BLK_CGROUP_IOCOST
272 bio->bi_iocost_cost = 0;
275 #ifdef CONFIG_BLK_INLINE_ENCRYPTION
276 bio->bi_crypt_context = NULL;
278 #ifdef CONFIG_BLK_DEV_INTEGRITY
279 bio->bi_integrity = NULL;
283 atomic_set(&bio->__bi_remaining, 1);
284 atomic_set(&bio->__bi_cnt, 1);
285 bio->bi_cookie = BLK_QC_T_NONE;
287 bio->bi_max_vecs = max_vecs;
288 bio->bi_io_vec = table;
291 EXPORT_SYMBOL(bio_init);
294 * bio_reset - reinitialize a bio
298 * After calling bio_reset(), @bio will be in the same state as a freshly
299 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
300 * preserved are the ones that are initialized by bio_alloc_bioset(). See
301 * comment in struct bio.
303 void bio_reset(struct bio *bio)
306 memset(bio, 0, BIO_RESET_BYTES);
307 atomic_set(&bio->__bi_remaining, 1);
309 EXPORT_SYMBOL(bio_reset);
311 static struct bio *__bio_chain_endio(struct bio *bio)
313 struct bio *parent = bio->bi_private;
315 if (bio->bi_status && !parent->bi_status)
316 parent->bi_status = bio->bi_status;
321 static void bio_chain_endio(struct bio *bio)
323 bio_endio(__bio_chain_endio(bio));
327 * bio_chain - chain bio completions
328 * @bio: the target bio
329 * @parent: the parent bio of @bio
331 * The caller won't have a bi_end_io called when @bio completes - instead,
332 * @parent's bi_end_io won't be called until both @parent and @bio have
333 * completed; the chained bio will also be freed when it completes.
335 * The caller must not set bi_private or bi_end_io in @bio.
337 void bio_chain(struct bio *bio, struct bio *parent)
339 BUG_ON(bio->bi_private || bio->bi_end_io);
341 bio->bi_private = parent;
342 bio->bi_end_io = bio_chain_endio;
343 bio_inc_remaining(parent);
345 EXPORT_SYMBOL(bio_chain);
347 static void bio_alloc_rescue(struct work_struct *work)
349 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);
353 spin_lock(&bs->rescue_lock);
354 bio = bio_list_pop(&bs->rescue_list);
355 spin_unlock(&bs->rescue_lock);
360 submit_bio_noacct(bio);
364 static void punt_bios_to_rescuer(struct bio_set *bs)
366 struct bio_list punt, nopunt;
369 if (WARN_ON_ONCE(!bs->rescue_workqueue))
372 * In order to guarantee forward progress we must punt only bios that
373 * were allocated from this bio_set; otherwise, if there was a bio on
374 * there for a stacking driver higher up in the stack, processing it
375 * could require allocating bios from this bio_set, and doing that from
376 * our own rescuer would be bad.
378 * Since bio lists are singly linked, pop them all instead of trying to
379 * remove from the middle of the list:
382 bio_list_init(&punt);
383 bio_list_init(&nopunt);
385 while ((bio = bio_list_pop(¤t->bio_list[0])))
386 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
387 current->bio_list[0] = nopunt;
389 bio_list_init(&nopunt);
390 while ((bio = bio_list_pop(¤t->bio_list[1])))
391 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);
392 current->bio_list[1] = nopunt;
394 spin_lock(&bs->rescue_lock);
395 bio_list_merge(&bs->rescue_list, &punt);
396 spin_unlock(&bs->rescue_lock);
398 queue_work(bs->rescue_workqueue, &bs->rescue_work);
402 * bio_alloc_bioset - allocate a bio for I/O
403 * @gfp_mask: the GFP_* mask given to the slab allocator
404 * @nr_iovecs: number of iovecs to pre-allocate
405 * @bs: the bio_set to allocate from.
407 * Allocate a bio from the mempools in @bs.
409 * If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to
410 * allocate a bio. This is due to the mempool guarantees. To make this work,
411 * callers must never allocate more than 1 bio at a time from the general pool.
412 * Callers that need to allocate more than 1 bio must always submit the
413 * previously allocated bio for IO before attempting to allocate a new one.
414 * Failure to do so can cause deadlocks under memory pressure.
416 * Note that when running under submit_bio_noacct() (i.e. any block driver),
417 * bios are not submitted until after you return - see the code in
418 * submit_bio_noacct() that converts recursion into iteration, to prevent
421 * This would normally mean allocating multiple bios under submit_bio_noacct()
422 * would be susceptible to deadlocks, but we have
423 * deadlock avoidance code that resubmits any blocked bios from a rescuer
426 * However, we do not guarantee forward progress for allocations from other
427 * mempools. Doing multiple allocations from the same mempool under
428 * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad
429 * for per bio allocations.
431 * Returns: Pointer to new bio on success, NULL on failure.
433 struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned short nr_iovecs,
436 gfp_t saved_gfp = gfp_mask;
440 /* should not use nobvec bioset for nr_iovecs > 0 */
441 if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && nr_iovecs > 0))
445 * submit_bio_noacct() converts recursion to iteration; this means if
446 * we're running beneath it, any bios we allocate and submit will not be
447 * submitted (and thus freed) until after we return.
449 * This exposes us to a potential deadlock if we allocate multiple bios
450 * from the same bio_set() while running underneath submit_bio_noacct().
451 * If we were to allocate multiple bios (say a stacking block driver
452 * that was splitting bios), we would deadlock if we exhausted the
455 * We solve this, and guarantee forward progress, with a rescuer
456 * workqueue per bio_set. If we go to allocate and there are bios on
457 * current->bio_list, we first try the allocation without
458 * __GFP_DIRECT_RECLAIM; if that fails, we punt those bios we would be
459 * blocking to the rescuer workqueue before we retry with the original
462 if (current->bio_list &&
463 (!bio_list_empty(¤t->bio_list[0]) ||
464 !bio_list_empty(¤t->bio_list[1])) &&
465 bs->rescue_workqueue)
466 gfp_mask &= ~__GFP_DIRECT_RECLAIM;
468 p = mempool_alloc(&bs->bio_pool, gfp_mask);
469 if (!p && gfp_mask != saved_gfp) {
470 punt_bios_to_rescuer(bs);
471 gfp_mask = saved_gfp;
472 p = mempool_alloc(&bs->bio_pool, gfp_mask);
477 bio = p + bs->front_pad;
478 if (nr_iovecs > BIO_INLINE_VECS) {
479 struct bio_vec *bvl = NULL;
481 bvl = bvec_alloc(&bs->bvec_pool, &nr_iovecs, gfp_mask);
482 if (!bvl && gfp_mask != saved_gfp) {
483 punt_bios_to_rescuer(bs);
484 gfp_mask = saved_gfp;
485 bvl = bvec_alloc(&bs->bvec_pool, &nr_iovecs, gfp_mask);
490 bio_init(bio, bvl, nr_iovecs);
491 } else if (nr_iovecs) {
492 bio_init(bio, bio->bi_inline_vecs, BIO_INLINE_VECS);
494 bio_init(bio, NULL, 0);
501 mempool_free(p, &bs->bio_pool);
504 EXPORT_SYMBOL(bio_alloc_bioset);
507 * bio_kmalloc - kmalloc a bio for I/O
508 * @gfp_mask: the GFP_* mask given to the slab allocator
509 * @nr_iovecs: number of iovecs to pre-allocate
511 * Use kmalloc to allocate and initialize a bio.
513 * Returns: Pointer to new bio on success, NULL on failure.
515 struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs)
519 if (nr_iovecs > UIO_MAXIOV)
522 bio = kmalloc(struct_size(bio, bi_inline_vecs, nr_iovecs), gfp_mask);
525 bio_init(bio, nr_iovecs ? bio->bi_inline_vecs : NULL, nr_iovecs);
529 EXPORT_SYMBOL(bio_kmalloc);
531 void zero_fill_bio(struct bio *bio)
534 struct bvec_iter iter;
536 bio_for_each_segment(bv, bio, iter)
539 EXPORT_SYMBOL(zero_fill_bio);
542 * bio_truncate - truncate the bio to small size of @new_size
543 * @bio: the bio to be truncated
544 * @new_size: new size for truncating the bio
547 * Truncate the bio to new size of @new_size. If bio_op(bio) is
548 * REQ_OP_READ, zero the truncated part. This function should only
549 * be used for handling corner cases, such as bio eod.
551 static void bio_truncate(struct bio *bio, unsigned new_size)
554 struct bvec_iter iter;
555 unsigned int done = 0;
556 bool truncated = false;
558 if (new_size >= bio->bi_iter.bi_size)
561 if (bio_op(bio) != REQ_OP_READ)
564 bio_for_each_segment(bv, bio, iter) {
565 if (done + bv.bv_len > new_size) {
569 offset = new_size - done;
572 zero_user(bv.bv_page, offset, bv.bv_len - offset);
580 * Don't touch bvec table here and make it really immutable, since
581 * fs bio user has to retrieve all pages via bio_for_each_segment_all
582 * in its .end_bio() callback.
584 * It is enough to truncate bio by updating .bi_size since we can make
585 * correct bvec with the updated .bi_size for drivers.
587 bio->bi_iter.bi_size = new_size;
591 * guard_bio_eod - truncate a BIO to fit the block device
592 * @bio: bio to truncate
594 * This allows us to do IO even on the odd last sectors of a device, even if the
595 * block size is some multiple of the physical sector size.
597 * We'll just truncate the bio to the size of the device, and clear the end of
598 * the buffer head manually. Truly out-of-range accesses will turn into actual
599 * I/O errors, this only handles the "we need to be able to do I/O at the final
602 void guard_bio_eod(struct bio *bio)
604 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);
610 * If the *whole* IO is past the end of the device,
611 * let it through, and the IO layer will turn it into
614 if (unlikely(bio->bi_iter.bi_sector >= maxsector))
617 maxsector -= bio->bi_iter.bi_sector;
618 if (likely((bio->bi_iter.bi_size >> 9) <= maxsector))
621 bio_truncate(bio, maxsector << 9);
624 #define ALLOC_CACHE_MAX 512
625 #define ALLOC_CACHE_SLACK 64
627 static void bio_alloc_cache_prune(struct bio_alloc_cache *cache,
633 while ((bio = cache->free_list) != NULL) {
634 cache->free_list = bio->bi_next;
642 static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node)
646 bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead);
648 struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu);
650 bio_alloc_cache_prune(cache, -1U);
655 static void bio_alloc_cache_destroy(struct bio_set *bs)
662 cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
663 for_each_possible_cpu(cpu) {
664 struct bio_alloc_cache *cache;
666 cache = per_cpu_ptr(bs->cache, cpu);
667 bio_alloc_cache_prune(cache, -1U);
669 free_percpu(bs->cache);
673 * bio_put - release a reference to a bio
674 * @bio: bio to release reference to
677 * Put a reference to a &struct bio, either one you have gotten with
678 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.
680 void bio_put(struct bio *bio)
682 if (unlikely(bio_flagged(bio, BIO_REFFED))) {
683 BUG_ON(!atomic_read(&bio->__bi_cnt));
684 if (!atomic_dec_and_test(&bio->__bi_cnt))
688 if (bio_flagged(bio, BIO_PERCPU_CACHE)) {
689 struct bio_alloc_cache *cache;
692 cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu());
693 bio->bi_next = cache->free_list;
694 cache->free_list = bio;
695 if (++cache->nr > ALLOC_CACHE_MAX + ALLOC_CACHE_SLACK)
696 bio_alloc_cache_prune(cache, ALLOC_CACHE_SLACK);
702 EXPORT_SYMBOL(bio_put);
705 * __bio_clone_fast - clone a bio that shares the original bio's biovec
706 * @bio: destination bio
707 * @bio_src: bio to clone
709 * Clone a &bio. Caller will own the returned bio, but not
710 * the actual data it points to. Reference count of returned
713 * Caller must ensure that @bio_src is not freed before @bio.
715 void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
717 WARN_ON_ONCE(bio->bi_pool && bio->bi_max_vecs);
720 * most users will be overriding ->bi_bdev with a new target,
721 * so we don't set nor calculate new physical/hw segment counts here
723 bio->bi_bdev = bio_src->bi_bdev;
724 bio_set_flag(bio, BIO_CLONED);
725 if (bio_flagged(bio_src, BIO_THROTTLED))
726 bio_set_flag(bio, BIO_THROTTLED);
727 if (bio_flagged(bio_src, BIO_REMAPPED))
728 bio_set_flag(bio, BIO_REMAPPED);
729 bio->bi_opf = bio_src->bi_opf;
730 bio->bi_ioprio = bio_src->bi_ioprio;
731 bio->bi_write_hint = bio_src->bi_write_hint;
732 bio->bi_iter = bio_src->bi_iter;
733 bio->bi_io_vec = bio_src->bi_io_vec;
735 bio_clone_blkg_association(bio, bio_src);
736 blkcg_bio_issue_init(bio);
738 EXPORT_SYMBOL(__bio_clone_fast);
741 * bio_clone_fast - clone a bio that shares the original bio's biovec
743 * @gfp_mask: allocation priority
744 * @bs: bio_set to allocate from
746 * Like __bio_clone_fast, only also allocates the returned bio
748 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
752 b = bio_alloc_bioset(gfp_mask, 0, bs);
756 __bio_clone_fast(b, bio);
758 if (bio_crypt_clone(b, bio, gfp_mask) < 0)
761 if (bio_integrity(bio) &&
762 bio_integrity_clone(b, bio, gfp_mask) < 0)
771 EXPORT_SYMBOL(bio_clone_fast);
773 const char *bio_devname(struct bio *bio, char *buf)
775 return bdevname(bio->bi_bdev, buf);
777 EXPORT_SYMBOL(bio_devname);
780 * bio_full - check if the bio is full
782 * @len: length of one segment to be added
784 * Return true if @bio is full and one segment with @len bytes can't be
785 * added to the bio, otherwise return false
787 static inline bool bio_full(struct bio *bio, unsigned len)
789 if (bio->bi_vcnt >= bio->bi_max_vecs)
791 if (bio->bi_iter.bi_size > UINT_MAX - len)
796 static inline bool page_is_mergeable(const struct bio_vec *bv,
797 struct page *page, unsigned int len, unsigned int off,
800 size_t bv_end = bv->bv_offset + bv->bv_len;
801 phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1;
802 phys_addr_t page_addr = page_to_phys(page);
804 if (vec_end_addr + 1 != page_addr + off)
806 if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
809 *same_page = ((vec_end_addr & PAGE_MASK) == page_addr);
812 return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE);
816 * __bio_try_merge_page - try appending data to an existing bvec.
817 * @bio: destination bio
818 * @page: start page to add
819 * @len: length of the data to add
820 * @off: offset of the data relative to @page
821 * @same_page: return if the segment has been merged inside the same page
823 * Try to add the data at @page + @off to the last bvec of @bio. This is a
824 * useful optimisation for file systems with a block size smaller than the
827 * Warn if (@len, @off) crosses pages in case that @same_page is true.
829 * Return %true on success or %false on failure.
831 static bool __bio_try_merge_page(struct bio *bio, struct page *page,
832 unsigned int len, unsigned int off, bool *same_page)
834 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
837 if (bio->bi_vcnt > 0) {
838 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
840 if (page_is_mergeable(bv, page, len, off, same_page)) {
841 if (bio->bi_iter.bi_size > UINT_MAX - len) {
846 bio->bi_iter.bi_size += len;
854 * Try to merge a page into a segment, while obeying the hardware segment
855 * size limit. This is not for normal read/write bios, but for passthrough
856 * or Zone Append operations that we can't split.
858 static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio,
859 struct page *page, unsigned len,
860 unsigned offset, bool *same_page)
862 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
863 unsigned long mask = queue_segment_boundary(q);
864 phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset;
865 phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;
867 if ((addr1 | mask) != (addr2 | mask))
869 if (bv->bv_len + len > queue_max_segment_size(q))
871 return __bio_try_merge_page(bio, page, len, offset, same_page);
875 * bio_add_hw_page - attempt to add a page to a bio with hw constraints
876 * @q: the target queue
877 * @bio: destination bio
879 * @len: vec entry length
880 * @offset: vec entry offset
881 * @max_sectors: maximum number of sectors that can be added
882 * @same_page: return if the segment has been merged inside the same page
884 * Add a page to a bio while respecting the hardware max_sectors, max_segment
885 * and gap limitations.
887 int bio_add_hw_page(struct request_queue *q, struct bio *bio,
888 struct page *page, unsigned int len, unsigned int offset,
889 unsigned int max_sectors, bool *same_page)
891 struct bio_vec *bvec;
893 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
896 if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors)
899 if (bio->bi_vcnt > 0) {
900 if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page))
904 * If the queue doesn't support SG gaps and adding this segment
905 * would create a gap, disallow it.
907 bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
908 if (bvec_gap_to_prev(q, bvec, offset))
912 if (bio_full(bio, len))
915 if (bio->bi_vcnt >= queue_max_segments(q))
918 bvec = &bio->bi_io_vec[bio->bi_vcnt];
919 bvec->bv_page = page;
921 bvec->bv_offset = offset;
923 bio->bi_iter.bi_size += len;
928 * bio_add_pc_page - attempt to add page to passthrough bio
929 * @q: the target queue
930 * @bio: destination bio
932 * @len: vec entry length
933 * @offset: vec entry offset
935 * Attempt to add a page to the bio_vec maplist. This can fail for a
936 * number of reasons, such as the bio being full or target block device
937 * limitations. The target block device must allow bio's up to PAGE_SIZE,
938 * so it is always possible to add a single page to an empty bio.
940 * This should only be used by passthrough bios.
942 int bio_add_pc_page(struct request_queue *q, struct bio *bio,
943 struct page *page, unsigned int len, unsigned int offset)
945 bool same_page = false;
946 return bio_add_hw_page(q, bio, page, len, offset,
947 queue_max_hw_sectors(q), &same_page);
949 EXPORT_SYMBOL(bio_add_pc_page);
952 * bio_add_zone_append_page - attempt to add page to zone-append bio
953 * @bio: destination bio
955 * @len: vec entry length
956 * @offset: vec entry offset
958 * Attempt to add a page to the bio_vec maplist of a bio that will be submitted
959 * for a zone-append request. This can fail for a number of reasons, such as the
960 * bio being full or the target block device is not a zoned block device or
961 * other limitations of the target block device. The target block device must
962 * allow bio's up to PAGE_SIZE, so it is always possible to add a single page
965 * Returns: number of bytes added to the bio, or 0 in case of a failure.
967 int bio_add_zone_append_page(struct bio *bio, struct page *page,
968 unsigned int len, unsigned int offset)
970 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
971 bool same_page = false;
973 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND))
976 if (WARN_ON_ONCE(!blk_queue_is_zoned(q)))
979 return bio_add_hw_page(q, bio, page, len, offset,
980 queue_max_zone_append_sectors(q), &same_page);
982 EXPORT_SYMBOL_GPL(bio_add_zone_append_page);
985 * __bio_add_page - add page(s) to a bio in a new segment
986 * @bio: destination bio
987 * @page: start page to add
988 * @len: length of the data to add, may cross pages
989 * @off: offset of the data relative to @page, may cross pages
991 * Add the data at @page + @off to @bio as a new bvec. The caller must ensure
992 * that @bio has space for another bvec.
994 void __bio_add_page(struct bio *bio, struct page *page,
995 unsigned int len, unsigned int off)
997 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
999 WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
1000 WARN_ON_ONCE(bio_full(bio, len));
1003 bv->bv_offset = off;
1006 bio->bi_iter.bi_size += len;
1009 if (!bio_flagged(bio, BIO_WORKINGSET) && unlikely(PageWorkingset(page)))
1010 bio_set_flag(bio, BIO_WORKINGSET);
1012 EXPORT_SYMBOL_GPL(__bio_add_page);
1015 * bio_add_page - attempt to add page(s) to bio
1016 * @bio: destination bio
1017 * @page: start page to add
1018 * @len: vec entry length, may cross pages
1019 * @offset: vec entry offset relative to @page, may cross pages
1021 * Attempt to add page(s) to the bio_vec maplist. This will only fail
1022 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
1024 int bio_add_page(struct bio *bio, struct page *page,
1025 unsigned int len, unsigned int offset)
1027 bool same_page = false;
1029 if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
1030 if (bio_full(bio, len))
1032 __bio_add_page(bio, page, len, offset);
1036 EXPORT_SYMBOL(bio_add_page);
1039 * bio_add_folio - Attempt to add part of a folio to a bio.
1040 * @bio: BIO to add to.
1041 * @folio: Folio to add.
1042 * @len: How many bytes from the folio to add.
1043 * @off: First byte in this folio to add.
1045 * Filesystems that use folios can call this function instead of calling
1046 * bio_add_page() for each page in the folio. If @off is bigger than
1047 * PAGE_SIZE, this function can create a bio_vec that starts in a page
1048 * after the bv_page. BIOs do not support folios that are 4GiB or larger.
1050 * Return: Whether the addition was successful.
1052 bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len,
1055 if (len > UINT_MAX || off > UINT_MAX)
1057 return bio_add_page(bio, &folio->page, len, off) > 0;
1060 void __bio_release_pages(struct bio *bio, bool mark_dirty)
1062 struct bvec_iter_all iter_all;
1063 struct bio_vec *bvec;
1065 bio_for_each_segment_all(bvec, bio, iter_all) {
1066 if (mark_dirty && !PageCompound(bvec->bv_page))
1067 set_page_dirty_lock(bvec->bv_page);
1068 put_page(bvec->bv_page);
1071 EXPORT_SYMBOL_GPL(__bio_release_pages);
1073 void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)
1075 size_t size = iov_iter_count(iter);
1077 WARN_ON_ONCE(bio->bi_max_vecs);
1079 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
1080 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1081 size_t max_sectors = queue_max_zone_append_sectors(q);
1083 size = min(size, max_sectors << SECTOR_SHIFT);
1086 bio->bi_vcnt = iter->nr_segs;
1087 bio->bi_io_vec = (struct bio_vec *)iter->bvec;
1088 bio->bi_iter.bi_bvec_done = iter->iov_offset;
1089 bio->bi_iter.bi_size = size;
1090 bio_set_flag(bio, BIO_NO_PAGE_REF);
1091 bio_set_flag(bio, BIO_CLONED);
1094 static void bio_put_pages(struct page **pages, size_t size, size_t off)
1096 size_t i, nr = DIV_ROUND_UP(size + (off & ~PAGE_MASK), PAGE_SIZE);
1098 for (i = 0; i < nr; i++)
1102 #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
1105 * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
1106 * @bio: bio to add pages to
1107 * @iter: iov iterator describing the region to be mapped
1109 * Pins pages from *iter and appends them to @bio's bvec array. The
1110 * pages will have to be released using put_page() when done.
1111 * For multi-segment *iter, this function only adds pages from the
1112 * next non-empty segment of the iov iterator.
1114 static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
1116 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
1117 unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
1118 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
1119 struct page **pages = (struct page **)bv;
1120 bool same_page = false;
1126 * Move page array up in the allocated memory for the bio vecs as far as
1127 * possible so that we can start filling biovecs from the beginning
1128 * without overwriting the temporary page array.
1130 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
1131 pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
1133 size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
1134 if (unlikely(size <= 0))
1135 return size ? size : -EFAULT;
1137 for (left = size, i = 0; left > 0; left -= len, i++) {
1138 struct page *page = pages[i];
1140 len = min_t(size_t, PAGE_SIZE - offset, left);
1142 if (__bio_try_merge_page(bio, page, len, offset, &same_page)) {
1146 if (WARN_ON_ONCE(bio_full(bio, len))) {
1147 bio_put_pages(pages + i, left, offset);
1150 __bio_add_page(bio, page, len, offset);
1155 iov_iter_advance(iter, size);
1159 static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)
1161 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
1162 unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
1163 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
1164 unsigned int max_append_sectors = queue_max_zone_append_sectors(q);
1165 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
1166 struct page **pages = (struct page **)bv;
1172 if (WARN_ON_ONCE(!max_append_sectors))
1176 * Move page array up in the allocated memory for the bio vecs as far as
1177 * possible so that we can start filling biovecs from the beginning
1178 * without overwriting the temporary page array.
1180 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
1181 pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
1183 size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset);
1184 if (unlikely(size <= 0))
1185 return size ? size : -EFAULT;
1187 for (left = size, i = 0; left > 0; left -= len, i++) {
1188 struct page *page = pages[i];
1189 bool same_page = false;
1191 len = min_t(size_t, PAGE_SIZE - offset, left);
1192 if (bio_add_hw_page(q, bio, page, len, offset,
1193 max_append_sectors, &same_page) != len) {
1194 bio_put_pages(pages + i, left, offset);
1203 iov_iter_advance(iter, size - left);
1208 * bio_iov_iter_get_pages - add user or kernel pages to a bio
1209 * @bio: bio to add pages to
1210 * @iter: iov iterator describing the region to be added
1212 * This takes either an iterator pointing to user memory, or one pointing to
1213 * kernel pages (BVEC iterator). If we're adding user pages, we pin them and
1214 * map them into the kernel. On IO completion, the caller should put those
1215 * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided
1216 * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs
1217 * to ensure the bvecs and pages stay referenced until the submitted I/O is
1218 * completed by a call to ->ki_complete() or returns with an error other than
1219 * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF
1220 * on IO completion. If it isn't, then pages should be released.
1222 * The function tries, but does not guarantee, to pin as many pages as
1223 * fit into the bio, or are requested in @iter, whatever is smaller. If
1224 * MM encounters an error pinning the requested pages, it stops. Error
1225 * is returned only if 0 pages could be pinned.
1227 * It's intended for direct IO, so doesn't do PSI tracking, the caller is
1228 * responsible for setting BIO_WORKINGSET if necessary.
1230 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
1234 if (iov_iter_is_bvec(iter)) {
1235 bio_iov_bvec_set(bio, iter);
1236 iov_iter_advance(iter, bio->bi_iter.bi_size);
1241 if (bio_op(bio) == REQ_OP_ZONE_APPEND)
1242 ret = __bio_iov_append_get_pages(bio, iter);
1244 ret = __bio_iov_iter_get_pages(bio, iter);
1245 } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));
1247 /* don't account direct I/O as memory stall */
1248 bio_clear_flag(bio, BIO_WORKINGSET);
1249 return bio->bi_vcnt ? 0 : ret;
1251 EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);
1253 static void submit_bio_wait_endio(struct bio *bio)
1255 complete(bio->bi_private);
1259 * submit_bio_wait - submit a bio, and wait until it completes
1260 * @bio: The &struct bio which describes the I/O
1262 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
1263 * bio_endio() on failure.
1265 * WARNING: Unlike to how submit_bio() is usually used, this function does not
1266 * result in bio reference to be consumed. The caller must drop the reference
1269 int submit_bio_wait(struct bio *bio)
1271 DECLARE_COMPLETION_ONSTACK_MAP(done,
1272 bio->bi_bdev->bd_disk->lockdep_map);
1273 unsigned long hang_check;
1275 bio->bi_private = &done;
1276 bio->bi_end_io = submit_bio_wait_endio;
1277 bio->bi_opf |= REQ_SYNC;
1280 /* Prevent hang_check timer from firing at us during very long I/O */
1281 hang_check = sysctl_hung_task_timeout_secs;
1283 while (!wait_for_completion_io_timeout(&done,
1284 hang_check * (HZ/2)))
1287 wait_for_completion_io(&done);
1289 return blk_status_to_errno(bio->bi_status);
1291 EXPORT_SYMBOL(submit_bio_wait);
1293 void __bio_advance(struct bio *bio, unsigned bytes)
1295 if (bio_integrity(bio))
1296 bio_integrity_advance(bio, bytes);
1298 bio_crypt_advance(bio, bytes);
1299 bio_advance_iter(bio, &bio->bi_iter, bytes);
1301 EXPORT_SYMBOL(__bio_advance);
1303 void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
1304 struct bio *src, struct bvec_iter *src_iter)
1306 while (src_iter->bi_size && dst_iter->bi_size) {
1307 struct bio_vec src_bv = bio_iter_iovec(src, *src_iter);
1308 struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter);
1309 unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);
1312 src_buf = bvec_kmap_local(&src_bv);
1313 memcpy_to_bvec(&dst_bv, src_buf);
1314 kunmap_local(src_buf);
1316 bio_advance_iter_single(src, src_iter, bytes);
1317 bio_advance_iter_single(dst, dst_iter, bytes);
1320 EXPORT_SYMBOL(bio_copy_data_iter);
1323 * bio_copy_data - copy contents of data buffers from one bio to another
1325 * @dst: destination bio
1327 * Stops when it reaches the end of either @src or @dst - that is, copies
1328 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
1330 void bio_copy_data(struct bio *dst, struct bio *src)
1332 struct bvec_iter src_iter = src->bi_iter;
1333 struct bvec_iter dst_iter = dst->bi_iter;
1335 bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
1337 EXPORT_SYMBOL(bio_copy_data);
1339 void bio_free_pages(struct bio *bio)
1341 struct bio_vec *bvec;
1342 struct bvec_iter_all iter_all;
1344 bio_for_each_segment_all(bvec, bio, iter_all)
1345 __free_page(bvec->bv_page);
1347 EXPORT_SYMBOL(bio_free_pages);
1350 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1351 * for performing direct-IO in BIOs.
1353 * The problem is that we cannot run set_page_dirty() from interrupt context
1354 * because the required locks are not interrupt-safe. So what we can do is to
1355 * mark the pages dirty _before_ performing IO. And in interrupt context,
1356 * check that the pages are still dirty. If so, fine. If not, redirty them
1357 * in process context.
1359 * We special-case compound pages here: normally this means reads into hugetlb
1360 * pages. The logic in here doesn't really work right for compound pages
1361 * because the VM does not uniformly chase down the head page in all cases.
1362 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1363 * handle them at all. So we skip compound pages here at an early stage.
1365 * Note that this code is very hard to test under normal circumstances because
1366 * direct-io pins the pages with get_user_pages(). This makes
1367 * is_page_cache_freeable return false, and the VM will not clean the pages.
1368 * But other code (eg, flusher threads) could clean the pages if they are mapped
1371 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1372 * deferred bio dirtying paths.
1376 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1378 void bio_set_pages_dirty(struct bio *bio)
1380 struct bio_vec *bvec;
1381 struct bvec_iter_all iter_all;
1383 bio_for_each_segment_all(bvec, bio, iter_all) {
1384 if (!PageCompound(bvec->bv_page))
1385 set_page_dirty_lock(bvec->bv_page);
1390 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1391 * If they are, then fine. If, however, some pages are clean then they must
1392 * have been written out during the direct-IO read. So we take another ref on
1393 * the BIO and re-dirty the pages in process context.
1395 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1396 * here on. It will run one put_page() against each page and will run one
1397 * bio_put() against the BIO.
1400 static void bio_dirty_fn(struct work_struct *work);
1402 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1403 static DEFINE_SPINLOCK(bio_dirty_lock);
1404 static struct bio *bio_dirty_list;
1407 * This runs in process context
1409 static void bio_dirty_fn(struct work_struct *work)
1411 struct bio *bio, *next;
1413 spin_lock_irq(&bio_dirty_lock);
1414 next = bio_dirty_list;
1415 bio_dirty_list = NULL;
1416 spin_unlock_irq(&bio_dirty_lock);
1418 while ((bio = next) != NULL) {
1419 next = bio->bi_private;
1421 bio_release_pages(bio, true);
1426 void bio_check_pages_dirty(struct bio *bio)
1428 struct bio_vec *bvec;
1429 unsigned long flags;
1430 struct bvec_iter_all iter_all;
1432 bio_for_each_segment_all(bvec, bio, iter_all) {
1433 if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page))
1437 bio_release_pages(bio, false);
1441 spin_lock_irqsave(&bio_dirty_lock, flags);
1442 bio->bi_private = bio_dirty_list;
1443 bio_dirty_list = bio;
1444 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1445 schedule_work(&bio_dirty_work);
1448 static inline bool bio_remaining_done(struct bio *bio)
1451 * If we're not chaining, then ->__bi_remaining is always 1 and
1452 * we always end io on the first invocation.
1454 if (!bio_flagged(bio, BIO_CHAIN))
1457 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);
1459 if (atomic_dec_and_test(&bio->__bi_remaining)) {
1460 bio_clear_flag(bio, BIO_CHAIN);
1468 * bio_endio - end I/O on a bio
1472 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1473 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1474 * bio unless they own it and thus know that it has an end_io function.
1476 * bio_endio() can be called several times on a bio that has been chained
1477 * using bio_chain(). The ->bi_end_io() function will only be called the
1480 void bio_endio(struct bio *bio)
1483 if (!bio_remaining_done(bio))
1485 if (!bio_integrity_endio(bio))
1488 if (bio->bi_bdev && bio_flagged(bio, BIO_TRACKED))
1489 rq_qos_done_bio(bdev_get_queue(bio->bi_bdev), bio);
1491 if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {
1492 trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio);
1493 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
1497 * Need to have a real endio function for chained bios, otherwise
1498 * various corner cases will break (like stacking block devices that
1499 * save/restore bi_end_io) - however, we want to avoid unbounded
1500 * recursion and blowing the stack. Tail call optimization would
1501 * handle this, but compiling with frame pointers also disables
1502 * gcc's sibling call optimization.
1504 if (bio->bi_end_io == bio_chain_endio) {
1505 bio = __bio_chain_endio(bio);
1509 blk_throtl_bio_endio(bio);
1510 /* release cgroup info */
1513 bio->bi_end_io(bio);
1515 EXPORT_SYMBOL(bio_endio);
1518 * bio_split - split a bio
1519 * @bio: bio to split
1520 * @sectors: number of sectors to split from the front of @bio
1522 * @bs: bio set to allocate from
1524 * Allocates and returns a new bio which represents @sectors from the start of
1525 * @bio, and updates @bio to represent the remaining sectors.
1527 * Unless this is a discard request the newly allocated bio will point
1528 * to @bio's bi_io_vec. It is the caller's responsibility to ensure that
1529 * neither @bio nor @bs are freed before the split bio.
1531 struct bio *bio_split(struct bio *bio, int sectors,
1532 gfp_t gfp, struct bio_set *bs)
1536 BUG_ON(sectors <= 0);
1537 BUG_ON(sectors >= bio_sectors(bio));
1539 /* Zone append commands cannot be split */
1540 if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
1543 split = bio_clone_fast(bio, gfp, bs);
1547 split->bi_iter.bi_size = sectors << 9;
1549 if (bio_integrity(split))
1550 bio_integrity_trim(split);
1552 bio_advance(bio, split->bi_iter.bi_size);
1554 if (bio_flagged(bio, BIO_TRACE_COMPLETION))
1555 bio_set_flag(split, BIO_TRACE_COMPLETION);
1559 EXPORT_SYMBOL(bio_split);
1562 * bio_trim - trim a bio
1564 * @offset: number of sectors to trim from the front of @bio
1565 * @size: size we want to trim @bio to, in sectors
1567 * This function is typically used for bios that are cloned and submitted
1568 * to the underlying device in parts.
1570 void bio_trim(struct bio *bio, sector_t offset, sector_t size)
1572 if (WARN_ON_ONCE(offset > BIO_MAX_SECTORS || size > BIO_MAX_SECTORS ||
1573 offset + size > bio->bi_iter.bi_size))
1577 if (offset == 0 && size == bio->bi_iter.bi_size)
1580 bio_advance(bio, offset << 9);
1581 bio->bi_iter.bi_size = size;
1583 if (bio_integrity(bio))
1584 bio_integrity_trim(bio);
1586 EXPORT_SYMBOL_GPL(bio_trim);
1589 * create memory pools for biovec's in a bio_set.
1590 * use the global biovec slabs created for general use.
1592 int biovec_init_pool(mempool_t *pool, int pool_entries)
1594 struct biovec_slab *bp = bvec_slabs + ARRAY_SIZE(bvec_slabs) - 1;
1596 return mempool_init_slab_pool(pool, pool_entries, bp->slab);
1600 * bioset_exit - exit a bioset initialized with bioset_init()
1602 * May be called on a zeroed but uninitialized bioset (i.e. allocated with
1605 void bioset_exit(struct bio_set *bs)
1607 bio_alloc_cache_destroy(bs);
1608 if (bs->rescue_workqueue)
1609 destroy_workqueue(bs->rescue_workqueue);
1610 bs->rescue_workqueue = NULL;
1612 mempool_exit(&bs->bio_pool);
1613 mempool_exit(&bs->bvec_pool);
1615 bioset_integrity_free(bs);
1618 bs->bio_slab = NULL;
1620 EXPORT_SYMBOL(bioset_exit);
1623 * bioset_init - Initialize a bio_set
1624 * @bs: pool to initialize
1625 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1626 * @front_pad: Number of bytes to allocate in front of the returned bio
1627 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS
1628 * and %BIOSET_NEED_RESCUER
1631 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1632 * to ask for a number of bytes to be allocated in front of the bio.
1633 * Front pad allocation is useful for embedding the bio inside
1634 * another structure, to avoid allocating extra data to go with the bio.
1635 * Note that the bio must be embedded at the END of that structure always,
1636 * or things will break badly.
1637 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated
1638 * for allocating iovecs. This pool is not needed e.g. for bio_clone_fast().
1639 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used to
1640 * dispatch queued requests when the mempool runs out of space.
1643 int bioset_init(struct bio_set *bs,
1644 unsigned int pool_size,
1645 unsigned int front_pad,
1648 bs->front_pad = front_pad;
1649 if (flags & BIOSET_NEED_BVECS)
1650 bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1654 spin_lock_init(&bs->rescue_lock);
1655 bio_list_init(&bs->rescue_list);
1656 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
1658 bs->bio_slab = bio_find_or_create_slab(bs);
1662 if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))
1665 if ((flags & BIOSET_NEED_BVECS) &&
1666 biovec_init_pool(&bs->bvec_pool, pool_size))
1669 if (flags & BIOSET_NEED_RESCUER) {
1670 bs->rescue_workqueue = alloc_workqueue("bioset",
1672 if (!bs->rescue_workqueue)
1675 if (flags & BIOSET_PERCPU_CACHE) {
1676 bs->cache = alloc_percpu(struct bio_alloc_cache);
1679 cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
1687 EXPORT_SYMBOL(bioset_init);
1690 * Initialize and setup a new bio_set, based on the settings from
1693 int bioset_init_from_src(struct bio_set *bs, struct bio_set *src)
1698 if (src->bvec_pool.min_nr)
1699 flags |= BIOSET_NEED_BVECS;
1700 if (src->rescue_workqueue)
1701 flags |= BIOSET_NEED_RESCUER;
1703 return bioset_init(bs, src->bio_pool.min_nr, src->front_pad, flags);
1705 EXPORT_SYMBOL(bioset_init_from_src);
1708 * bio_alloc_kiocb - Allocate a bio from bio_set based on kiocb
1709 * @kiocb: kiocb describing the IO
1710 * @nr_vecs: number of iovecs to pre-allocate
1711 * @bs: bio_set to allocate from
1714 * Like @bio_alloc_bioset, but pass in the kiocb. The kiocb is only
1715 * used to check if we should dip into the per-cpu bio_set allocation
1716 * cache. The allocation uses GFP_KERNEL internally. On return, the
1717 * bio is marked BIO_PERCPU_CACHEABLE, and the final put of the bio
1718 * MUST be done from process context, not hard/soft IRQ.
1721 struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
1724 struct bio_alloc_cache *cache;
1727 if (!(kiocb->ki_flags & IOCB_ALLOC_CACHE) || nr_vecs > BIO_INLINE_VECS)
1728 return bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
1730 cache = per_cpu_ptr(bs->cache, get_cpu());
1731 if (cache->free_list) {
1732 bio = cache->free_list;
1733 cache->free_list = bio->bi_next;
1736 bio_init(bio, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs);
1738 bio_set_flag(bio, BIO_PERCPU_CACHE);
1742 bio = bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
1743 bio_set_flag(bio, BIO_PERCPU_CACHE);
1746 EXPORT_SYMBOL_GPL(bio_alloc_kiocb);
1748 static int __init init_bio(void)
1752 bio_integrity_init();
1754 for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) {
1755 struct biovec_slab *bvs = bvec_slabs + i;
1757 bvs->slab = kmem_cache_create(bvs->name,
1758 bvs->nr_vecs * sizeof(struct bio_vec), 0,
1759 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
1762 cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL,
1765 if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS))
1766 panic("bio: can't allocate bios\n");
1768 if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE))
1769 panic("bio: can't create integrity pool\n");
1773 subsys_initcall(init_bio);