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/highmem.h>
19 #include <linux/sched/sysctl.h>
20 #include <linux/blk-crypto.h>
21 #include <linux/xarray.h>
23 #include <trace/events/block.h>
25 #include "blk-rq-qos.h"
26 #include "blk-cgroup.h"
28 #define ALLOC_CACHE_THRESHOLD 16
29 #define ALLOC_CACHE_MAX 256
31 struct bio_alloc_cache
{
32 struct bio
*free_list
;
33 struct bio
*free_list_irq
;
38 static struct biovec_slab
{
41 struct kmem_cache
*slab
;
42 } bvec_slabs
[] __read_mostly
= {
43 { .nr_vecs
= 16, .name
= "biovec-16" },
44 { .nr_vecs
= 64, .name
= "biovec-64" },
45 { .nr_vecs
= 128, .name
= "biovec-128" },
46 { .nr_vecs
= BIO_MAX_VECS
, .name
= "biovec-max" },
49 static struct biovec_slab
*biovec_slab(unsigned short nr_vecs
)
52 /* smaller bios use inline vecs */
54 return &bvec_slabs
[0];
56 return &bvec_slabs
[1];
58 return &bvec_slabs
[2];
59 case 129 ... BIO_MAX_VECS
:
60 return &bvec_slabs
[3];
68 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
69 * IO code that does not need private memory pools.
71 struct bio_set fs_bio_set
;
72 EXPORT_SYMBOL(fs_bio_set
);
75 * Our slab pool management
78 struct kmem_cache
*slab
;
79 unsigned int slab_ref
;
80 unsigned int slab_size
;
83 static DEFINE_MUTEX(bio_slab_lock
);
84 static DEFINE_XARRAY(bio_slabs
);
86 static struct bio_slab
*create_bio_slab(unsigned int size
)
88 struct bio_slab
*bslab
= kzalloc(sizeof(*bslab
), GFP_KERNEL
);
93 snprintf(bslab
->name
, sizeof(bslab
->name
), "bio-%d", size
);
94 bslab
->slab
= kmem_cache_create(bslab
->name
, size
,
95 ARCH_KMALLOC_MINALIGN
,
96 SLAB_HWCACHE_ALIGN
| SLAB_TYPESAFE_BY_RCU
, NULL
);
101 bslab
->slab_size
= size
;
103 if (!xa_err(xa_store(&bio_slabs
, size
, bslab
, GFP_KERNEL
)))
106 kmem_cache_destroy(bslab
->slab
);
113 static inline unsigned int bs_bio_slab_size(struct bio_set
*bs
)
115 return bs
->front_pad
+ sizeof(struct bio
) + bs
->back_pad
;
118 static struct kmem_cache
*bio_find_or_create_slab(struct bio_set
*bs
)
120 unsigned int size
= bs_bio_slab_size(bs
);
121 struct bio_slab
*bslab
;
123 mutex_lock(&bio_slab_lock
);
124 bslab
= xa_load(&bio_slabs
, size
);
128 bslab
= create_bio_slab(size
);
129 mutex_unlock(&bio_slab_lock
);
136 static void bio_put_slab(struct bio_set
*bs
)
138 struct bio_slab
*bslab
= NULL
;
139 unsigned int slab_size
= bs_bio_slab_size(bs
);
141 mutex_lock(&bio_slab_lock
);
143 bslab
= xa_load(&bio_slabs
, slab_size
);
144 if (WARN(!bslab
, KERN_ERR
"bio: unable to find slab!\n"))
147 WARN_ON_ONCE(bslab
->slab
!= bs
->bio_slab
);
149 WARN_ON(!bslab
->slab_ref
);
151 if (--bslab
->slab_ref
)
154 xa_erase(&bio_slabs
, slab_size
);
156 kmem_cache_destroy(bslab
->slab
);
160 mutex_unlock(&bio_slab_lock
);
163 void bvec_free(mempool_t
*pool
, struct bio_vec
*bv
, unsigned short nr_vecs
)
165 BUG_ON(nr_vecs
> BIO_MAX_VECS
);
167 if (nr_vecs
== BIO_MAX_VECS
)
168 mempool_free(bv
, pool
);
169 else if (nr_vecs
> BIO_INLINE_VECS
)
170 kmem_cache_free(biovec_slab(nr_vecs
)->slab
, bv
);
174 * Make the first allocation restricted and don't dump info on allocation
175 * failures, since we'll fall back to the mempool in case of failure.
177 static inline gfp_t
bvec_alloc_gfp(gfp_t gfp
)
179 return (gfp
& ~(__GFP_DIRECT_RECLAIM
| __GFP_IO
)) |
180 __GFP_NOMEMALLOC
| __GFP_NORETRY
| __GFP_NOWARN
;
183 struct bio_vec
*bvec_alloc(mempool_t
*pool
, unsigned short *nr_vecs
,
186 struct biovec_slab
*bvs
= biovec_slab(*nr_vecs
);
188 if (WARN_ON_ONCE(!bvs
))
192 * Upgrade the nr_vecs request to take full advantage of the allocation.
193 * We also rely on this in the bvec_free path.
195 *nr_vecs
= bvs
->nr_vecs
;
198 * Try a slab allocation first for all smaller allocations. If that
199 * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool.
200 * The mempool is sized to handle up to BIO_MAX_VECS entries.
202 if (*nr_vecs
< BIO_MAX_VECS
) {
205 bvl
= kmem_cache_alloc(bvs
->slab
, bvec_alloc_gfp(gfp_mask
));
206 if (likely(bvl
) || !(gfp_mask
& __GFP_DIRECT_RECLAIM
))
208 *nr_vecs
= BIO_MAX_VECS
;
211 return mempool_alloc(pool
, gfp_mask
);
214 void bio_uninit(struct bio
*bio
)
216 #ifdef CONFIG_BLK_CGROUP
218 blkg_put(bio
->bi_blkg
);
222 if (bio_integrity(bio
))
223 bio_integrity_free(bio
);
225 bio_crypt_free_ctx(bio
);
227 EXPORT_SYMBOL(bio_uninit
);
229 static void bio_free(struct bio
*bio
)
231 struct bio_set
*bs
= bio
->bi_pool
;
237 bvec_free(&bs
->bvec_pool
, bio
->bi_io_vec
, bio
->bi_max_vecs
);
238 mempool_free(p
- bs
->front_pad
, &bs
->bio_pool
);
242 * Users of this function have their own bio allocation. Subsequently,
243 * they must remember to pair any call to bio_init() with bio_uninit()
244 * when IO has completed, or when the bio is released.
246 void bio_init(struct bio
*bio
, struct block_device
*bdev
, struct bio_vec
*table
,
247 unsigned short max_vecs
, blk_opf_t opf
)
255 bio
->bi_iter
.bi_sector
= 0;
256 bio
->bi_iter
.bi_size
= 0;
257 bio
->bi_iter
.bi_idx
= 0;
258 bio
->bi_iter
.bi_bvec_done
= 0;
259 bio
->bi_end_io
= NULL
;
260 bio
->bi_private
= NULL
;
261 #ifdef CONFIG_BLK_CGROUP
263 bio
->bi_issue
.value
= 0;
265 bio_associate_blkg(bio
);
266 #ifdef CONFIG_BLK_CGROUP_IOCOST
267 bio
->bi_iocost_cost
= 0;
270 #ifdef CONFIG_BLK_INLINE_ENCRYPTION
271 bio
->bi_crypt_context
= NULL
;
273 #ifdef CONFIG_BLK_DEV_INTEGRITY
274 bio
->bi_integrity
= NULL
;
278 atomic_set(&bio
->__bi_remaining
, 1);
279 atomic_set(&bio
->__bi_cnt
, 1);
280 bio
->bi_cookie
= BLK_QC_T_NONE
;
282 bio
->bi_max_vecs
= max_vecs
;
283 bio
->bi_io_vec
= table
;
286 EXPORT_SYMBOL(bio_init
);
289 * bio_reset - reinitialize a bio
291 * @bdev: block device to use the bio for
292 * @opf: operation and flags for bio
295 * After calling bio_reset(), @bio will be in the same state as a freshly
296 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
297 * preserved are the ones that are initialized by bio_alloc_bioset(). See
298 * comment in struct bio.
300 void bio_reset(struct bio
*bio
, struct block_device
*bdev
, blk_opf_t opf
)
303 memset(bio
, 0, BIO_RESET_BYTES
);
304 atomic_set(&bio
->__bi_remaining
, 1);
307 bio_associate_blkg(bio
);
310 EXPORT_SYMBOL(bio_reset
);
312 static struct bio
*__bio_chain_endio(struct bio
*bio
)
314 struct bio
*parent
= bio
->bi_private
;
316 if (bio
->bi_status
&& !parent
->bi_status
)
317 parent
->bi_status
= bio
->bi_status
;
322 static void bio_chain_endio(struct bio
*bio
)
324 bio_endio(__bio_chain_endio(bio
));
328 * bio_chain - chain bio completions
329 * @bio: the target bio
330 * @parent: the parent bio of @bio
332 * The caller won't have a bi_end_io called when @bio completes - instead,
333 * @parent's bi_end_io won't be called until both @parent and @bio have
334 * completed; the chained bio will also be freed when it completes.
336 * The caller must not set bi_private or bi_end_io in @bio.
338 void bio_chain(struct bio
*bio
, struct bio
*parent
)
340 BUG_ON(bio
->bi_private
|| bio
->bi_end_io
);
342 bio
->bi_private
= parent
;
343 bio
->bi_end_io
= bio_chain_endio
;
344 bio_inc_remaining(parent
);
346 EXPORT_SYMBOL(bio_chain
);
348 struct bio
*blk_next_bio(struct bio
*bio
, struct block_device
*bdev
,
349 unsigned int nr_pages
, blk_opf_t opf
, gfp_t gfp
)
351 struct bio
*new = bio_alloc(bdev
, nr_pages
, opf
, gfp
);
360 EXPORT_SYMBOL_GPL(blk_next_bio
);
362 static void bio_alloc_rescue(struct work_struct
*work
)
364 struct bio_set
*bs
= container_of(work
, struct bio_set
, rescue_work
);
368 spin_lock(&bs
->rescue_lock
);
369 bio
= bio_list_pop(&bs
->rescue_list
);
370 spin_unlock(&bs
->rescue_lock
);
375 submit_bio_noacct(bio
);
379 static void punt_bios_to_rescuer(struct bio_set
*bs
)
381 struct bio_list punt
, nopunt
;
384 if (WARN_ON_ONCE(!bs
->rescue_workqueue
))
387 * In order to guarantee forward progress we must punt only bios that
388 * were allocated from this bio_set; otherwise, if there was a bio on
389 * there for a stacking driver higher up in the stack, processing it
390 * could require allocating bios from this bio_set, and doing that from
391 * our own rescuer would be bad.
393 * Since bio lists are singly linked, pop them all instead of trying to
394 * remove from the middle of the list:
397 bio_list_init(&punt
);
398 bio_list_init(&nopunt
);
400 while ((bio
= bio_list_pop(¤t
->bio_list
[0])))
401 bio_list_add(bio
->bi_pool
== bs
? &punt
: &nopunt
, bio
);
402 current
->bio_list
[0] = nopunt
;
404 bio_list_init(&nopunt
);
405 while ((bio
= bio_list_pop(¤t
->bio_list
[1])))
406 bio_list_add(bio
->bi_pool
== bs
? &punt
: &nopunt
, bio
);
407 current
->bio_list
[1] = nopunt
;
409 spin_lock(&bs
->rescue_lock
);
410 bio_list_merge(&bs
->rescue_list
, &punt
);
411 spin_unlock(&bs
->rescue_lock
);
413 queue_work(bs
->rescue_workqueue
, &bs
->rescue_work
);
416 static void bio_alloc_irq_cache_splice(struct bio_alloc_cache
*cache
)
420 /* cache->free_list must be empty */
421 if (WARN_ON_ONCE(cache
->free_list
))
424 local_irq_save(flags
);
425 cache
->free_list
= cache
->free_list_irq
;
426 cache
->free_list_irq
= NULL
;
427 cache
->nr
+= cache
->nr_irq
;
429 local_irq_restore(flags
);
432 static struct bio
*bio_alloc_percpu_cache(struct block_device
*bdev
,
433 unsigned short nr_vecs
, blk_opf_t opf
, gfp_t gfp
,
436 struct bio_alloc_cache
*cache
;
439 cache
= per_cpu_ptr(bs
->cache
, get_cpu());
440 if (!cache
->free_list
) {
441 if (READ_ONCE(cache
->nr_irq
) >= ALLOC_CACHE_THRESHOLD
)
442 bio_alloc_irq_cache_splice(cache
);
443 if (!cache
->free_list
) {
448 bio
= cache
->free_list
;
449 cache
->free_list
= bio
->bi_next
;
453 bio_init(bio
, bdev
, nr_vecs
? bio
->bi_inline_vecs
: NULL
, nr_vecs
, opf
);
459 * bio_alloc_bioset - allocate a bio for I/O
460 * @bdev: block device to allocate the bio for (can be %NULL)
461 * @nr_vecs: number of bvecs to pre-allocate
462 * @opf: operation and flags for bio
463 * @gfp_mask: the GFP_* mask given to the slab allocator
464 * @bs: the bio_set to allocate from.
466 * Allocate a bio from the mempools in @bs.
468 * If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to
469 * allocate a bio. This is due to the mempool guarantees. To make this work,
470 * callers must never allocate more than 1 bio at a time from the general pool.
471 * Callers that need to allocate more than 1 bio must always submit the
472 * previously allocated bio for IO before attempting to allocate a new one.
473 * Failure to do so can cause deadlocks under memory pressure.
475 * Note that when running under submit_bio_noacct() (i.e. any block driver),
476 * bios are not submitted until after you return - see the code in
477 * submit_bio_noacct() that converts recursion into iteration, to prevent
480 * This would normally mean allocating multiple bios under submit_bio_noacct()
481 * would be susceptible to deadlocks, but we have
482 * deadlock avoidance code that resubmits any blocked bios from a rescuer
485 * However, we do not guarantee forward progress for allocations from other
486 * mempools. Doing multiple allocations from the same mempool under
487 * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad
488 * for per bio allocations.
490 * Returns: Pointer to new bio on success, NULL on failure.
492 struct bio
*bio_alloc_bioset(struct block_device
*bdev
, unsigned short nr_vecs
,
493 blk_opf_t opf
, gfp_t gfp_mask
,
496 gfp_t saved_gfp
= gfp_mask
;
500 /* should not use nobvec bioset for nr_vecs > 0 */
501 if (WARN_ON_ONCE(!mempool_initialized(&bs
->bvec_pool
) && nr_vecs
> 0))
504 if (opf
& REQ_ALLOC_CACHE
) {
505 if (bs
->cache
&& nr_vecs
<= BIO_INLINE_VECS
) {
506 bio
= bio_alloc_percpu_cache(bdev
, nr_vecs
, opf
,
511 * No cached bio available, bio returned below marked with
512 * REQ_ALLOC_CACHE to particpate in per-cpu alloc cache.
515 opf
&= ~REQ_ALLOC_CACHE
;
520 * submit_bio_noacct() converts recursion to iteration; this means if
521 * we're running beneath it, any bios we allocate and submit will not be
522 * submitted (and thus freed) until after we return.
524 * This exposes us to a potential deadlock if we allocate multiple bios
525 * from the same bio_set() while running underneath submit_bio_noacct().
526 * If we were to allocate multiple bios (say a stacking block driver
527 * that was splitting bios), we would deadlock if we exhausted the
530 * We solve this, and guarantee forward progress, with a rescuer
531 * workqueue per bio_set. If we go to allocate and there are bios on
532 * current->bio_list, we first try the allocation without
533 * __GFP_DIRECT_RECLAIM; if that fails, we punt those bios we would be
534 * blocking to the rescuer workqueue before we retry with the original
537 if (current
->bio_list
&&
538 (!bio_list_empty(¤t
->bio_list
[0]) ||
539 !bio_list_empty(¤t
->bio_list
[1])) &&
540 bs
->rescue_workqueue
)
541 gfp_mask
&= ~__GFP_DIRECT_RECLAIM
;
543 p
= mempool_alloc(&bs
->bio_pool
, gfp_mask
);
544 if (!p
&& gfp_mask
!= saved_gfp
) {
545 punt_bios_to_rescuer(bs
);
546 gfp_mask
= saved_gfp
;
547 p
= mempool_alloc(&bs
->bio_pool
, gfp_mask
);
551 if (!mempool_is_saturated(&bs
->bio_pool
))
552 opf
&= ~REQ_ALLOC_CACHE
;
554 bio
= p
+ bs
->front_pad
;
555 if (nr_vecs
> BIO_INLINE_VECS
) {
556 struct bio_vec
*bvl
= NULL
;
558 bvl
= bvec_alloc(&bs
->bvec_pool
, &nr_vecs
, gfp_mask
);
559 if (!bvl
&& gfp_mask
!= saved_gfp
) {
560 punt_bios_to_rescuer(bs
);
561 gfp_mask
= saved_gfp
;
562 bvl
= bvec_alloc(&bs
->bvec_pool
, &nr_vecs
, gfp_mask
);
567 bio_init(bio
, bdev
, bvl
, nr_vecs
, opf
);
568 } else if (nr_vecs
) {
569 bio_init(bio
, bdev
, bio
->bi_inline_vecs
, BIO_INLINE_VECS
, opf
);
571 bio_init(bio
, bdev
, NULL
, 0, opf
);
578 mempool_free(p
, &bs
->bio_pool
);
581 EXPORT_SYMBOL(bio_alloc_bioset
);
584 * bio_kmalloc - kmalloc a bio
585 * @nr_vecs: number of bio_vecs to allocate
586 * @gfp_mask: the GFP_* mask given to the slab allocator
588 * Use kmalloc to allocate a bio (including bvecs). The bio must be initialized
589 * using bio_init() before use. To free a bio returned from this function use
590 * kfree() after calling bio_uninit(). A bio returned from this function can
591 * be reused by calling bio_uninit() before calling bio_init() again.
593 * Note that unlike bio_alloc() or bio_alloc_bioset() allocations from this
594 * function are not backed by a mempool can fail. Do not use this function
595 * for allocations in the file system I/O path.
597 * Returns: Pointer to new bio on success, NULL on failure.
599 struct bio
*bio_kmalloc(unsigned short nr_vecs
, gfp_t gfp_mask
)
603 if (nr_vecs
> UIO_MAXIOV
)
605 return kmalloc(struct_size(bio
, bi_inline_vecs
, nr_vecs
), gfp_mask
);
607 EXPORT_SYMBOL(bio_kmalloc
);
609 void zero_fill_bio_iter(struct bio
*bio
, struct bvec_iter start
)
612 struct bvec_iter iter
;
614 __bio_for_each_segment(bv
, bio
, iter
, start
)
617 EXPORT_SYMBOL(zero_fill_bio_iter
);
620 * bio_truncate - truncate the bio to small size of @new_size
621 * @bio: the bio to be truncated
622 * @new_size: new size for truncating the bio
625 * Truncate the bio to new size of @new_size. If bio_op(bio) is
626 * REQ_OP_READ, zero the truncated part. This function should only
627 * be used for handling corner cases, such as bio eod.
629 static void bio_truncate(struct bio
*bio
, unsigned new_size
)
632 struct bvec_iter iter
;
633 unsigned int done
= 0;
634 bool truncated
= false;
636 if (new_size
>= bio
->bi_iter
.bi_size
)
639 if (bio_op(bio
) != REQ_OP_READ
)
642 bio_for_each_segment(bv
, bio
, iter
) {
643 if (done
+ bv
.bv_len
> new_size
) {
647 offset
= new_size
- done
;
650 zero_user(bv
.bv_page
, bv
.bv_offset
+ offset
,
659 * Don't touch bvec table here and make it really immutable, since
660 * fs bio user has to retrieve all pages via bio_for_each_segment_all
661 * in its .end_bio() callback.
663 * It is enough to truncate bio by updating .bi_size since we can make
664 * correct bvec with the updated .bi_size for drivers.
666 bio
->bi_iter
.bi_size
= new_size
;
670 * guard_bio_eod - truncate a BIO to fit the block device
671 * @bio: bio to truncate
673 * This allows us to do IO even on the odd last sectors of a device, even if the
674 * block size is some multiple of the physical sector size.
676 * We'll just truncate the bio to the size of the device, and clear the end of
677 * the buffer head manually. Truly out-of-range accesses will turn into actual
678 * I/O errors, this only handles the "we need to be able to do I/O at the final
681 void guard_bio_eod(struct bio
*bio
)
683 sector_t maxsector
= bdev_nr_sectors(bio
->bi_bdev
);
689 * If the *whole* IO is past the end of the device,
690 * let it through, and the IO layer will turn it into
693 if (unlikely(bio
->bi_iter
.bi_sector
>= maxsector
))
696 maxsector
-= bio
->bi_iter
.bi_sector
;
697 if (likely((bio
->bi_iter
.bi_size
>> 9) <= maxsector
))
700 bio_truncate(bio
, maxsector
<< 9);
703 static int __bio_alloc_cache_prune(struct bio_alloc_cache
*cache
,
709 while ((bio
= cache
->free_list
) != NULL
) {
710 cache
->free_list
= bio
->bi_next
;
719 static void bio_alloc_cache_prune(struct bio_alloc_cache
*cache
,
722 nr
-= __bio_alloc_cache_prune(cache
, nr
);
723 if (!READ_ONCE(cache
->free_list
)) {
724 bio_alloc_irq_cache_splice(cache
);
725 __bio_alloc_cache_prune(cache
, nr
);
729 static int bio_cpu_dead(unsigned int cpu
, struct hlist_node
*node
)
733 bs
= hlist_entry_safe(node
, struct bio_set
, cpuhp_dead
);
735 struct bio_alloc_cache
*cache
= per_cpu_ptr(bs
->cache
, cpu
);
737 bio_alloc_cache_prune(cache
, -1U);
742 static void bio_alloc_cache_destroy(struct bio_set
*bs
)
749 cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD
, &bs
->cpuhp_dead
);
750 for_each_possible_cpu(cpu
) {
751 struct bio_alloc_cache
*cache
;
753 cache
= per_cpu_ptr(bs
->cache
, cpu
);
754 bio_alloc_cache_prune(cache
, -1U);
756 free_percpu(bs
->cache
);
760 static inline void bio_put_percpu_cache(struct bio
*bio
)
762 struct bio_alloc_cache
*cache
;
764 cache
= per_cpu_ptr(bio
->bi_pool
->cache
, get_cpu());
765 if (READ_ONCE(cache
->nr_irq
) + cache
->nr
> ALLOC_CACHE_MAX
) {
773 if ((bio
->bi_opf
& REQ_POLLED
) && !WARN_ON_ONCE(in_interrupt())) {
774 bio
->bi_next
= cache
->free_list
;
776 cache
->free_list
= bio
;
781 local_irq_save(flags
);
782 bio
->bi_next
= cache
->free_list_irq
;
783 cache
->free_list_irq
= bio
;
785 local_irq_restore(flags
);
791 * bio_put - release a reference to a bio
792 * @bio: bio to release reference to
795 * Put a reference to a &struct bio, either one you have gotten with
796 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.
798 void bio_put(struct bio
*bio
)
800 if (unlikely(bio_flagged(bio
, BIO_REFFED
))) {
801 BUG_ON(!atomic_read(&bio
->__bi_cnt
));
802 if (!atomic_dec_and_test(&bio
->__bi_cnt
))
805 if (bio
->bi_opf
& REQ_ALLOC_CACHE
)
806 bio_put_percpu_cache(bio
);
810 EXPORT_SYMBOL(bio_put
);
812 static int __bio_clone(struct bio
*bio
, struct bio
*bio_src
, gfp_t gfp
)
814 bio_set_flag(bio
, BIO_CLONED
);
815 bio
->bi_ioprio
= bio_src
->bi_ioprio
;
816 bio
->bi_iter
= bio_src
->bi_iter
;
819 if (bio
->bi_bdev
== bio_src
->bi_bdev
&&
820 bio_flagged(bio_src
, BIO_REMAPPED
))
821 bio_set_flag(bio
, BIO_REMAPPED
);
822 bio_clone_blkg_association(bio
, bio_src
);
825 if (bio_crypt_clone(bio
, bio_src
, gfp
) < 0)
827 if (bio_integrity(bio_src
) &&
828 bio_integrity_clone(bio
, bio_src
, gfp
) < 0)
834 * bio_alloc_clone - clone a bio that shares the original bio's biovec
835 * @bdev: block_device to clone onto
836 * @bio_src: bio to clone from
837 * @gfp: allocation priority
838 * @bs: bio_set to allocate from
840 * Allocate a new bio that is a clone of @bio_src. The caller owns the returned
841 * bio, but not the actual data it points to.
843 * The caller must ensure that the return bio is not freed before @bio_src.
845 struct bio
*bio_alloc_clone(struct block_device
*bdev
, struct bio
*bio_src
,
846 gfp_t gfp
, struct bio_set
*bs
)
850 bio
= bio_alloc_bioset(bdev
, 0, bio_src
->bi_opf
, gfp
, bs
);
854 if (__bio_clone(bio
, bio_src
, gfp
) < 0) {
858 bio
->bi_io_vec
= bio_src
->bi_io_vec
;
862 EXPORT_SYMBOL(bio_alloc_clone
);
865 * bio_init_clone - clone a bio that shares the original bio's biovec
866 * @bdev: block_device to clone onto
867 * @bio: bio to clone into
868 * @bio_src: bio to clone from
869 * @gfp: allocation priority
871 * Initialize a new bio in caller provided memory that is a clone of @bio_src.
872 * The caller owns the returned bio, but not the actual data it points to.
874 * The caller must ensure that @bio_src is not freed before @bio.
876 int bio_init_clone(struct block_device
*bdev
, struct bio
*bio
,
877 struct bio
*bio_src
, gfp_t gfp
)
881 bio_init(bio
, bdev
, bio_src
->bi_io_vec
, 0, bio_src
->bi_opf
);
882 ret
= __bio_clone(bio
, bio_src
, gfp
);
887 EXPORT_SYMBOL(bio_init_clone
);
890 * bio_full - check if the bio is full
892 * @len: length of one segment to be added
894 * Return true if @bio is full and one segment with @len bytes can't be
895 * added to the bio, otherwise return false
897 static inline bool bio_full(struct bio
*bio
, unsigned len
)
899 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
901 if (bio
->bi_iter
.bi_size
> UINT_MAX
- len
)
906 static bool bvec_try_merge_page(struct bio_vec
*bv
, struct page
*page
,
907 unsigned int len
, unsigned int off
, bool *same_page
)
909 size_t bv_end
= bv
->bv_offset
+ bv
->bv_len
;
910 phys_addr_t vec_end_addr
= page_to_phys(bv
->bv_page
) + bv_end
- 1;
911 phys_addr_t page_addr
= page_to_phys(page
);
913 if (vec_end_addr
+ 1 != page_addr
+ off
)
915 if (xen_domain() && !xen_biovec_phys_mergeable(bv
, page
))
917 if (!zone_device_pages_have_same_pgmap(bv
->bv_page
, page
))
920 *same_page
= ((vec_end_addr
& PAGE_MASK
) == page_addr
);
922 if (IS_ENABLED(CONFIG_KMSAN
))
924 if (bv
->bv_page
+ bv_end
/ PAGE_SIZE
!= page
+ off
/ PAGE_SIZE
)
933 * Try to merge a page into a segment, while obeying the hardware segment
934 * size limit. This is not for normal read/write bios, but for passthrough
935 * or Zone Append operations that we can't split.
937 bool bvec_try_merge_hw_page(struct request_queue
*q
, struct bio_vec
*bv
,
938 struct page
*page
, unsigned len
, unsigned offset
,
941 unsigned long mask
= queue_segment_boundary(q
);
942 phys_addr_t addr1
= page_to_phys(bv
->bv_page
) + bv
->bv_offset
;
943 phys_addr_t addr2
= page_to_phys(page
) + offset
+ len
- 1;
945 if ((addr1
| mask
) != (addr2
| mask
))
947 if (bv
->bv_len
+ len
> queue_max_segment_size(q
))
949 return bvec_try_merge_page(bv
, page
, len
, offset
, same_page
);
953 * bio_add_hw_page - attempt to add a page to a bio with hw constraints
954 * @q: the target queue
955 * @bio: destination bio
957 * @len: vec entry length
958 * @offset: vec entry offset
959 * @max_sectors: maximum number of sectors that can be added
960 * @same_page: return if the segment has been merged inside the same page
962 * Add a page to a bio while respecting the hardware max_sectors, max_segment
963 * and gap limitations.
965 int bio_add_hw_page(struct request_queue
*q
, struct bio
*bio
,
966 struct page
*page
, unsigned int len
, unsigned int offset
,
967 unsigned int max_sectors
, bool *same_page
)
969 if (WARN_ON_ONCE(bio_flagged(bio
, BIO_CLONED
)))
972 if (((bio
->bi_iter
.bi_size
+ len
) >> SECTOR_SHIFT
) > max_sectors
)
975 if (bio
->bi_vcnt
> 0) {
976 struct bio_vec
*bv
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
978 if (bvec_try_merge_hw_page(q
, bv
, page
, len
, offset
,
980 bio
->bi_iter
.bi_size
+= len
;
985 min(bio
->bi_max_vecs
, queue_max_segments(q
)))
989 * If the queue doesn't support SG gaps and adding this segment
990 * would create a gap, disallow it.
992 if (bvec_gap_to_prev(&q
->limits
, bv
, offset
))
996 bvec_set_page(&bio
->bi_io_vec
[bio
->bi_vcnt
], page
, len
, offset
);
998 bio
->bi_iter
.bi_size
+= len
;
1003 * bio_add_pc_page - attempt to add page to passthrough bio
1004 * @q: the target queue
1005 * @bio: destination bio
1006 * @page: page to add
1007 * @len: vec entry length
1008 * @offset: vec entry offset
1010 * Attempt to add a page to the bio_vec maplist. This can fail for a
1011 * number of reasons, such as the bio being full or target block device
1012 * limitations. The target block device must allow bio's up to PAGE_SIZE,
1013 * so it is always possible to add a single page to an empty bio.
1015 * This should only be used by passthrough bios.
1017 int bio_add_pc_page(struct request_queue
*q
, struct bio
*bio
,
1018 struct page
*page
, unsigned int len
, unsigned int offset
)
1020 bool same_page
= false;
1021 return bio_add_hw_page(q
, bio
, page
, len
, offset
,
1022 queue_max_hw_sectors(q
), &same_page
);
1024 EXPORT_SYMBOL(bio_add_pc_page
);
1027 * bio_add_zone_append_page - attempt to add page to zone-append bio
1028 * @bio: destination bio
1029 * @page: page to add
1030 * @len: vec entry length
1031 * @offset: vec entry offset
1033 * Attempt to add a page to the bio_vec maplist of a bio that will be submitted
1034 * for a zone-append request. This can fail for a number of reasons, such as the
1035 * bio being full or the target block device is not a zoned block device or
1036 * other limitations of the target block device. The target block device must
1037 * allow bio's up to PAGE_SIZE, so it is always possible to add a single page
1040 * Returns: number of bytes added to the bio, or 0 in case of a failure.
1042 int bio_add_zone_append_page(struct bio
*bio
, struct page
*page
,
1043 unsigned int len
, unsigned int offset
)
1045 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
1046 bool same_page
= false;
1048 if (WARN_ON_ONCE(bio_op(bio
) != REQ_OP_ZONE_APPEND
))
1051 if (WARN_ON_ONCE(!bdev_is_zoned(bio
->bi_bdev
)))
1054 return bio_add_hw_page(q
, bio
, page
, len
, offset
,
1055 queue_max_zone_append_sectors(q
), &same_page
);
1057 EXPORT_SYMBOL_GPL(bio_add_zone_append_page
);
1060 * __bio_add_page - add page(s) to a bio in a new segment
1061 * @bio: destination bio
1062 * @page: start page to add
1063 * @len: length of the data to add, may cross pages
1064 * @off: offset of the data relative to @page, may cross pages
1066 * Add the data at @page + @off to @bio as a new bvec. The caller must ensure
1067 * that @bio has space for another bvec.
1069 void __bio_add_page(struct bio
*bio
, struct page
*page
,
1070 unsigned int len
, unsigned int off
)
1072 WARN_ON_ONCE(bio_flagged(bio
, BIO_CLONED
));
1073 WARN_ON_ONCE(bio_full(bio
, len
));
1075 bvec_set_page(&bio
->bi_io_vec
[bio
->bi_vcnt
], page
, len
, off
);
1076 bio
->bi_iter
.bi_size
+= len
;
1079 EXPORT_SYMBOL_GPL(__bio_add_page
);
1082 * bio_add_page - attempt to add page(s) to bio
1083 * @bio: destination bio
1084 * @page: start page to add
1085 * @len: vec entry length, may cross pages
1086 * @offset: vec entry offset relative to @page, may cross pages
1088 * Attempt to add page(s) to the bio_vec maplist. This will only fail
1089 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
1091 int bio_add_page(struct bio
*bio
, struct page
*page
,
1092 unsigned int len
, unsigned int offset
)
1094 bool same_page
= false;
1096 if (WARN_ON_ONCE(bio_flagged(bio
, BIO_CLONED
)))
1098 if (bio
->bi_iter
.bi_size
> UINT_MAX
- len
)
1101 if (bio
->bi_vcnt
> 0 &&
1102 bvec_try_merge_page(&bio
->bi_io_vec
[bio
->bi_vcnt
- 1],
1103 page
, len
, offset
, &same_page
)) {
1104 bio
->bi_iter
.bi_size
+= len
;
1108 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
1110 __bio_add_page(bio
, page
, len
, offset
);
1113 EXPORT_SYMBOL(bio_add_page
);
1115 void bio_add_folio_nofail(struct bio
*bio
, struct folio
*folio
, size_t len
,
1118 WARN_ON_ONCE(len
> UINT_MAX
);
1119 WARN_ON_ONCE(off
> UINT_MAX
);
1120 __bio_add_page(bio
, &folio
->page
, len
, off
);
1124 * bio_add_folio - Attempt to add part of a folio to a bio.
1125 * @bio: BIO to add to.
1126 * @folio: Folio to add.
1127 * @len: How many bytes from the folio to add.
1128 * @off: First byte in this folio to add.
1130 * Filesystems that use folios can call this function instead of calling
1131 * bio_add_page() for each page in the folio. If @off is bigger than
1132 * PAGE_SIZE, this function can create a bio_vec that starts in a page
1133 * after the bv_page. BIOs do not support folios that are 4GiB or larger.
1135 * Return: Whether the addition was successful.
1137 bool bio_add_folio(struct bio
*bio
, struct folio
*folio
, size_t len
,
1140 if (len
> UINT_MAX
|| off
> UINT_MAX
)
1142 return bio_add_page(bio
, &folio
->page
, len
, off
) > 0;
1144 EXPORT_SYMBOL(bio_add_folio
);
1146 void __bio_release_pages(struct bio
*bio
, bool mark_dirty
)
1148 struct bvec_iter_all iter_all
;
1149 struct bio_vec
*bvec
;
1151 bio_for_each_segment_all(bvec
, bio
, iter_all
) {
1152 if (mark_dirty
&& !PageCompound(bvec
->bv_page
))
1153 set_page_dirty_lock(bvec
->bv_page
);
1154 bio_release_page(bio
, bvec
->bv_page
);
1157 EXPORT_SYMBOL_GPL(__bio_release_pages
);
1159 void bio_iov_bvec_set(struct bio
*bio
, struct iov_iter
*iter
)
1161 size_t size
= iov_iter_count(iter
);
1163 WARN_ON_ONCE(bio
->bi_max_vecs
);
1165 if (bio_op(bio
) == REQ_OP_ZONE_APPEND
) {
1166 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
1167 size_t max_sectors
= queue_max_zone_append_sectors(q
);
1169 size
= min(size
, max_sectors
<< SECTOR_SHIFT
);
1172 bio
->bi_vcnt
= iter
->nr_segs
;
1173 bio
->bi_io_vec
= (struct bio_vec
*)iter
->bvec
;
1174 bio
->bi_iter
.bi_bvec_done
= iter
->iov_offset
;
1175 bio
->bi_iter
.bi_size
= size
;
1176 bio_set_flag(bio
, BIO_CLONED
);
1179 static int bio_iov_add_page(struct bio
*bio
, struct page
*page
,
1180 unsigned int len
, unsigned int offset
)
1182 bool same_page
= false;
1184 if (WARN_ON_ONCE(bio
->bi_iter
.bi_size
> UINT_MAX
- len
))
1187 if (bio
->bi_vcnt
> 0 &&
1188 bvec_try_merge_page(&bio
->bi_io_vec
[bio
->bi_vcnt
- 1],
1189 page
, len
, offset
, &same_page
)) {
1190 bio
->bi_iter
.bi_size
+= len
;
1192 bio_release_page(bio
, page
);
1195 __bio_add_page(bio
, page
, len
, offset
);
1199 static int bio_iov_add_zone_append_page(struct bio
*bio
, struct page
*page
,
1200 unsigned int len
, unsigned int offset
)
1202 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
1203 bool same_page
= false;
1205 if (bio_add_hw_page(q
, bio
, page
, len
, offset
,
1206 queue_max_zone_append_sectors(q
), &same_page
) != len
)
1209 bio_release_page(bio
, page
);
1213 #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))
1216 * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
1217 * @bio: bio to add pages to
1218 * @iter: iov iterator describing the region to be mapped
1220 * Extracts pages from *iter and appends them to @bio's bvec array. The pages
1221 * will have to be cleaned up in the way indicated by the BIO_PAGE_PINNED flag.
1222 * For a multi-segment *iter, this function only adds pages from the next
1223 * non-empty segment of the iov iterator.
1225 static int __bio_iov_iter_get_pages(struct bio
*bio
, struct iov_iter
*iter
)
1227 iov_iter_extraction_t extraction_flags
= 0;
1228 unsigned short nr_pages
= bio
->bi_max_vecs
- bio
->bi_vcnt
;
1229 unsigned short entries_left
= bio
->bi_max_vecs
- bio
->bi_vcnt
;
1230 struct bio_vec
*bv
= bio
->bi_io_vec
+ bio
->bi_vcnt
;
1231 struct page
**pages
= (struct page
**)bv
;
1233 unsigned len
, i
= 0;
1238 * Move page array up in the allocated memory for the bio vecs as far as
1239 * possible so that we can start filling biovecs from the beginning
1240 * without overwriting the temporary page array.
1242 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC
< 2);
1243 pages
+= entries_left
* (PAGE_PTRS_PER_BVEC
- 1);
1245 if (bio
->bi_bdev
&& blk_queue_pci_p2pdma(bio
->bi_bdev
->bd_disk
->queue
))
1246 extraction_flags
|= ITER_ALLOW_P2PDMA
;
1249 * Each segment in the iov is required to be a block size multiple.
1250 * However, we may not be able to get the entire segment if it spans
1251 * more pages than bi_max_vecs allows, so we have to ALIGN_DOWN the
1252 * result to ensure the bio's total size is correct. The remainder of
1253 * the iov data will be picked up in the next bio iteration.
1255 size
= iov_iter_extract_pages(iter
, &pages
,
1256 UINT_MAX
- bio
->bi_iter
.bi_size
,
1257 nr_pages
, extraction_flags
, &offset
);
1258 if (unlikely(size
<= 0))
1259 return size
? size
: -EFAULT
;
1261 nr_pages
= DIV_ROUND_UP(offset
+ size
, PAGE_SIZE
);
1264 size_t trim
= size
& (bdev_logical_block_size(bio
->bi_bdev
) - 1);
1265 iov_iter_revert(iter
, trim
);
1269 if (unlikely(!size
)) {
1274 for (left
= size
, i
= 0; left
> 0; left
-= len
, i
++) {
1275 struct page
*page
= pages
[i
];
1277 len
= min_t(size_t, PAGE_SIZE
- offset
, left
);
1278 if (bio_op(bio
) == REQ_OP_ZONE_APPEND
) {
1279 ret
= bio_iov_add_zone_append_page(bio
, page
, len
,
1284 bio_iov_add_page(bio
, page
, len
, offset
);
1289 iov_iter_revert(iter
, left
);
1291 while (i
< nr_pages
)
1292 bio_release_page(bio
, pages
[i
++]);
1298 * bio_iov_iter_get_pages - add user or kernel pages to a bio
1299 * @bio: bio to add pages to
1300 * @iter: iov iterator describing the region to be added
1302 * This takes either an iterator pointing to user memory, or one pointing to
1303 * kernel pages (BVEC iterator). If we're adding user pages, we pin them and
1304 * map them into the kernel. On IO completion, the caller should put those
1305 * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided
1306 * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs
1307 * to ensure the bvecs and pages stay referenced until the submitted I/O is
1308 * completed by a call to ->ki_complete() or returns with an error other than
1309 * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF
1310 * on IO completion. If it isn't, then pages should be released.
1312 * The function tries, but does not guarantee, to pin as many pages as
1313 * fit into the bio, or are requested in @iter, whatever is smaller. If
1314 * MM encounters an error pinning the requested pages, it stops. Error
1315 * is returned only if 0 pages could be pinned.
1317 int bio_iov_iter_get_pages(struct bio
*bio
, struct iov_iter
*iter
)
1321 if (WARN_ON_ONCE(bio_flagged(bio
, BIO_CLONED
)))
1324 if (iov_iter_is_bvec(iter
)) {
1325 bio_iov_bvec_set(bio
, iter
);
1326 iov_iter_advance(iter
, bio
->bi_iter
.bi_size
);
1330 if (iov_iter_extract_will_pin(iter
))
1331 bio_set_flag(bio
, BIO_PAGE_PINNED
);
1333 ret
= __bio_iov_iter_get_pages(bio
, iter
);
1334 } while (!ret
&& iov_iter_count(iter
) && !bio_full(bio
, 0));
1336 return bio
->bi_vcnt
? 0 : ret
;
1338 EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages
);
1340 static void submit_bio_wait_endio(struct bio
*bio
)
1342 complete(bio
->bi_private
);
1346 * submit_bio_wait - submit a bio, and wait until it completes
1347 * @bio: The &struct bio which describes the I/O
1349 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
1350 * bio_endio() on failure.
1352 * WARNING: Unlike to how submit_bio() is usually used, this function does not
1353 * result in bio reference to be consumed. The caller must drop the reference
1356 int submit_bio_wait(struct bio
*bio
)
1358 DECLARE_COMPLETION_ONSTACK_MAP(done
,
1359 bio
->bi_bdev
->bd_disk
->lockdep_map
);
1360 unsigned long hang_check
;
1362 bio
->bi_private
= &done
;
1363 bio
->bi_end_io
= submit_bio_wait_endio
;
1364 bio
->bi_opf
|= REQ_SYNC
;
1367 /* Prevent hang_check timer from firing at us during very long I/O */
1368 hang_check
= sysctl_hung_task_timeout_secs
;
1370 while (!wait_for_completion_io_timeout(&done
,
1371 hang_check
* (HZ
/2)))
1374 wait_for_completion_io(&done
);
1376 return blk_status_to_errno(bio
->bi_status
);
1378 EXPORT_SYMBOL(submit_bio_wait
);
1380 void __bio_advance(struct bio
*bio
, unsigned bytes
)
1382 if (bio_integrity(bio
))
1383 bio_integrity_advance(bio
, bytes
);
1385 bio_crypt_advance(bio
, bytes
);
1386 bio_advance_iter(bio
, &bio
->bi_iter
, bytes
);
1388 EXPORT_SYMBOL(__bio_advance
);
1390 void bio_copy_data_iter(struct bio
*dst
, struct bvec_iter
*dst_iter
,
1391 struct bio
*src
, struct bvec_iter
*src_iter
)
1393 while (src_iter
->bi_size
&& dst_iter
->bi_size
) {
1394 struct bio_vec src_bv
= bio_iter_iovec(src
, *src_iter
);
1395 struct bio_vec dst_bv
= bio_iter_iovec(dst
, *dst_iter
);
1396 unsigned int bytes
= min(src_bv
.bv_len
, dst_bv
.bv_len
);
1397 void *src_buf
= bvec_kmap_local(&src_bv
);
1398 void *dst_buf
= bvec_kmap_local(&dst_bv
);
1400 memcpy(dst_buf
, src_buf
, bytes
);
1402 kunmap_local(dst_buf
);
1403 kunmap_local(src_buf
);
1405 bio_advance_iter_single(src
, src_iter
, bytes
);
1406 bio_advance_iter_single(dst
, dst_iter
, bytes
);
1409 EXPORT_SYMBOL(bio_copy_data_iter
);
1412 * bio_copy_data - copy contents of data buffers from one bio to another
1414 * @dst: destination bio
1416 * Stops when it reaches the end of either @src or @dst - that is, copies
1417 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
1419 void bio_copy_data(struct bio
*dst
, struct bio
*src
)
1421 struct bvec_iter src_iter
= src
->bi_iter
;
1422 struct bvec_iter dst_iter
= dst
->bi_iter
;
1424 bio_copy_data_iter(dst
, &dst_iter
, src
, &src_iter
);
1426 EXPORT_SYMBOL(bio_copy_data
);
1428 void bio_free_pages(struct bio
*bio
)
1430 struct bio_vec
*bvec
;
1431 struct bvec_iter_all iter_all
;
1433 bio_for_each_segment_all(bvec
, bio
, iter_all
)
1434 __free_page(bvec
->bv_page
);
1436 EXPORT_SYMBOL(bio_free_pages
);
1439 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1440 * for performing direct-IO in BIOs.
1442 * The problem is that we cannot run set_page_dirty() from interrupt context
1443 * because the required locks are not interrupt-safe. So what we can do is to
1444 * mark the pages dirty _before_ performing IO. And in interrupt context,
1445 * check that the pages are still dirty. If so, fine. If not, redirty them
1446 * in process context.
1448 * We special-case compound pages here: normally this means reads into hugetlb
1449 * pages. The logic in here doesn't really work right for compound pages
1450 * because the VM does not uniformly chase down the head page in all cases.
1451 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1452 * handle them at all. So we skip compound pages here at an early stage.
1454 * Note that this code is very hard to test under normal circumstances because
1455 * direct-io pins the pages with get_user_pages(). This makes
1456 * is_page_cache_freeable return false, and the VM will not clean the pages.
1457 * But other code (eg, flusher threads) could clean the pages if they are mapped
1460 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1461 * deferred bio dirtying paths.
1465 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1467 void bio_set_pages_dirty(struct bio
*bio
)
1469 struct bio_vec
*bvec
;
1470 struct bvec_iter_all iter_all
;
1472 bio_for_each_segment_all(bvec
, bio
, iter_all
) {
1473 if (!PageCompound(bvec
->bv_page
))
1474 set_page_dirty_lock(bvec
->bv_page
);
1477 EXPORT_SYMBOL_GPL(bio_set_pages_dirty
);
1480 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1481 * If they are, then fine. If, however, some pages are clean then they must
1482 * have been written out during the direct-IO read. So we take another ref on
1483 * the BIO and re-dirty the pages in process context.
1485 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1486 * here on. It will unpin each page and will run one bio_put() against the
1490 static void bio_dirty_fn(struct work_struct
*work
);
1492 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1493 static DEFINE_SPINLOCK(bio_dirty_lock
);
1494 static struct bio
*bio_dirty_list
;
1497 * This runs in process context
1499 static void bio_dirty_fn(struct work_struct
*work
)
1501 struct bio
*bio
, *next
;
1503 spin_lock_irq(&bio_dirty_lock
);
1504 next
= bio_dirty_list
;
1505 bio_dirty_list
= NULL
;
1506 spin_unlock_irq(&bio_dirty_lock
);
1508 while ((bio
= next
) != NULL
) {
1509 next
= bio
->bi_private
;
1511 bio_release_pages(bio
, true);
1516 void bio_check_pages_dirty(struct bio
*bio
)
1518 struct bio_vec
*bvec
;
1519 unsigned long flags
;
1520 struct bvec_iter_all iter_all
;
1522 bio_for_each_segment_all(bvec
, bio
, iter_all
) {
1523 if (!PageDirty(bvec
->bv_page
) && !PageCompound(bvec
->bv_page
))
1527 bio_release_pages(bio
, false);
1531 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1532 bio
->bi_private
= bio_dirty_list
;
1533 bio_dirty_list
= bio
;
1534 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1535 schedule_work(&bio_dirty_work
);
1537 EXPORT_SYMBOL_GPL(bio_check_pages_dirty
);
1539 static inline bool bio_remaining_done(struct bio
*bio
)
1542 * If we're not chaining, then ->__bi_remaining is always 1 and
1543 * we always end io on the first invocation.
1545 if (!bio_flagged(bio
, BIO_CHAIN
))
1548 BUG_ON(atomic_read(&bio
->__bi_remaining
) <= 0);
1550 if (atomic_dec_and_test(&bio
->__bi_remaining
)) {
1551 bio_clear_flag(bio
, BIO_CHAIN
);
1559 * bio_endio - end I/O on a bio
1563 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1564 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1565 * bio unless they own it and thus know that it has an end_io function.
1567 * bio_endio() can be called several times on a bio that has been chained
1568 * using bio_chain(). The ->bi_end_io() function will only be called the
1571 void bio_endio(struct bio
*bio
)
1574 if (!bio_remaining_done(bio
))
1576 if (!bio_integrity_endio(bio
))
1579 rq_qos_done_bio(bio
);
1581 if (bio
->bi_bdev
&& bio_flagged(bio
, BIO_TRACE_COMPLETION
)) {
1582 trace_block_bio_complete(bdev_get_queue(bio
->bi_bdev
), bio
);
1583 bio_clear_flag(bio
, BIO_TRACE_COMPLETION
);
1587 * Need to have a real endio function for chained bios, otherwise
1588 * various corner cases will break (like stacking block devices that
1589 * save/restore bi_end_io) - however, we want to avoid unbounded
1590 * recursion and blowing the stack. Tail call optimization would
1591 * handle this, but compiling with frame pointers also disables
1592 * gcc's sibling call optimization.
1594 if (bio
->bi_end_io
== bio_chain_endio
) {
1595 bio
= __bio_chain_endio(bio
);
1599 blk_throtl_bio_endio(bio
);
1600 /* release cgroup info */
1603 bio
->bi_end_io(bio
);
1605 EXPORT_SYMBOL(bio_endio
);
1608 * bio_split - split a bio
1609 * @bio: bio to split
1610 * @sectors: number of sectors to split from the front of @bio
1612 * @bs: bio set to allocate from
1614 * Allocates and returns a new bio which represents @sectors from the start of
1615 * @bio, and updates @bio to represent the remaining sectors.
1617 * Unless this is a discard request the newly allocated bio will point
1618 * to @bio's bi_io_vec. It is the caller's responsibility to ensure that
1619 * neither @bio nor @bs are freed before the split bio.
1621 struct bio
*bio_split(struct bio
*bio
, int sectors
,
1622 gfp_t gfp
, struct bio_set
*bs
)
1626 BUG_ON(sectors
<= 0);
1627 BUG_ON(sectors
>= bio_sectors(bio
));
1629 /* Zone append commands cannot be split */
1630 if (WARN_ON_ONCE(bio_op(bio
) == REQ_OP_ZONE_APPEND
))
1633 split
= bio_alloc_clone(bio
->bi_bdev
, bio
, gfp
, bs
);
1637 split
->bi_iter
.bi_size
= sectors
<< 9;
1639 if (bio_integrity(split
))
1640 bio_integrity_trim(split
);
1642 bio_advance(bio
, split
->bi_iter
.bi_size
);
1644 if (bio_flagged(bio
, BIO_TRACE_COMPLETION
))
1645 bio_set_flag(split
, BIO_TRACE_COMPLETION
);
1649 EXPORT_SYMBOL(bio_split
);
1652 * bio_trim - trim a bio
1654 * @offset: number of sectors to trim from the front of @bio
1655 * @size: size we want to trim @bio to, in sectors
1657 * This function is typically used for bios that are cloned and submitted
1658 * to the underlying device in parts.
1660 void bio_trim(struct bio
*bio
, sector_t offset
, sector_t size
)
1662 if (WARN_ON_ONCE(offset
> BIO_MAX_SECTORS
|| size
> BIO_MAX_SECTORS
||
1663 offset
+ size
> bio_sectors(bio
)))
1667 if (offset
== 0 && size
== bio
->bi_iter
.bi_size
)
1670 bio_advance(bio
, offset
<< 9);
1671 bio
->bi_iter
.bi_size
= size
;
1673 if (bio_integrity(bio
))
1674 bio_integrity_trim(bio
);
1676 EXPORT_SYMBOL_GPL(bio_trim
);
1679 * create memory pools for biovec's in a bio_set.
1680 * use the global biovec slabs created for general use.
1682 int biovec_init_pool(mempool_t
*pool
, int pool_entries
)
1684 struct biovec_slab
*bp
= bvec_slabs
+ ARRAY_SIZE(bvec_slabs
) - 1;
1686 return mempool_init_slab_pool(pool
, pool_entries
, bp
->slab
);
1690 * bioset_exit - exit a bioset initialized with bioset_init()
1692 * May be called on a zeroed but uninitialized bioset (i.e. allocated with
1695 void bioset_exit(struct bio_set
*bs
)
1697 bio_alloc_cache_destroy(bs
);
1698 if (bs
->rescue_workqueue
)
1699 destroy_workqueue(bs
->rescue_workqueue
);
1700 bs
->rescue_workqueue
= NULL
;
1702 mempool_exit(&bs
->bio_pool
);
1703 mempool_exit(&bs
->bvec_pool
);
1705 bioset_integrity_free(bs
);
1708 bs
->bio_slab
= NULL
;
1710 EXPORT_SYMBOL(bioset_exit
);
1713 * bioset_init - Initialize a bio_set
1714 * @bs: pool to initialize
1715 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1716 * @front_pad: Number of bytes to allocate in front of the returned bio
1717 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS
1718 * and %BIOSET_NEED_RESCUER
1721 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1722 * to ask for a number of bytes to be allocated in front of the bio.
1723 * Front pad allocation is useful for embedding the bio inside
1724 * another structure, to avoid allocating extra data to go with the bio.
1725 * Note that the bio must be embedded at the END of that structure always,
1726 * or things will break badly.
1727 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated
1728 * for allocating iovecs. This pool is not needed e.g. for bio_init_clone().
1729 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used
1730 * to dispatch queued requests when the mempool runs out of space.
1733 int bioset_init(struct bio_set
*bs
,
1734 unsigned int pool_size
,
1735 unsigned int front_pad
,
1738 bs
->front_pad
= front_pad
;
1739 if (flags
& BIOSET_NEED_BVECS
)
1740 bs
->back_pad
= BIO_INLINE_VECS
* sizeof(struct bio_vec
);
1744 spin_lock_init(&bs
->rescue_lock
);
1745 bio_list_init(&bs
->rescue_list
);
1746 INIT_WORK(&bs
->rescue_work
, bio_alloc_rescue
);
1748 bs
->bio_slab
= bio_find_or_create_slab(bs
);
1752 if (mempool_init_slab_pool(&bs
->bio_pool
, pool_size
, bs
->bio_slab
))
1755 if ((flags
& BIOSET_NEED_BVECS
) &&
1756 biovec_init_pool(&bs
->bvec_pool
, pool_size
))
1759 if (flags
& BIOSET_NEED_RESCUER
) {
1760 bs
->rescue_workqueue
= alloc_workqueue("bioset",
1762 if (!bs
->rescue_workqueue
)
1765 if (flags
& BIOSET_PERCPU_CACHE
) {
1766 bs
->cache
= alloc_percpu(struct bio_alloc_cache
);
1769 cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD
, &bs
->cpuhp_dead
);
1777 EXPORT_SYMBOL(bioset_init
);
1779 static int __init
init_bio(void)
1783 BUILD_BUG_ON(BIO_FLAG_LAST
> 8 * sizeof_field(struct bio
, bi_flags
));
1785 bio_integrity_init();
1787 for (i
= 0; i
< ARRAY_SIZE(bvec_slabs
); i
++) {
1788 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
1790 bvs
->slab
= kmem_cache_create(bvs
->name
,
1791 bvs
->nr_vecs
* sizeof(struct bio_vec
), 0,
1792 SLAB_HWCACHE_ALIGN
| SLAB_PANIC
, NULL
);
1795 cpuhp_setup_state_multi(CPUHP_BIO_DEAD
, "block/bio:dead", NULL
,
1798 if (bioset_init(&fs_bio_set
, BIO_POOL_SIZE
, 0,
1799 BIOSET_NEED_BVECS
| BIOSET_PERCPU_CACHE
))
1800 panic("bio: can't allocate bios\n");
1802 if (bioset_integrity_create(&fs_bio_set
, BIO_POOL_SIZE
))
1803 panic("bio: can't create integrity pool\n");
1807 subsys_initcall(init_bio
);