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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - block/bio.c
2 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public Licens
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
19 #include <linux/swap.h>
20 #include <linux/bio.h>
21 #include <linux/blkdev.h>
22 #include <linux/uio.h>
23 #include <linux/iocontext.h>
24 #include <linux/slab.h>
25 #include <linux/init.h>
26 #include <linux/kernel.h>
27 #include <linux/export.h>
28 #include <linux/mempool.h>
29 #include <linux/workqueue.h>
30 #include <linux/cgroup.h>
32 #include <trace/events/block.h>
35 * Test patch to inline a certain number of bi_io_vec's inside the bio
36 * itself, to shrink a bio data allocation from two mempool calls to one
38 #define BIO_INLINE_VECS 4
41 * if you change this list, also change bvec_alloc or things will
42 * break badly! cannot be bigger than what you can fit into an
45 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
46 static struct biovec_slab bvec_slabs
[BVEC_POOL_NR
] __read_mostly
= {
47 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES
),
52 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
53 * IO code that does not need private memory pools.
55 struct bio_set
*fs_bio_set
;
56 EXPORT_SYMBOL(fs_bio_set
);
59 * Our slab pool management
62 struct kmem_cache
*slab
;
63 unsigned int slab_ref
;
64 unsigned int slab_size
;
67 static DEFINE_MUTEX(bio_slab_lock
);
68 static struct bio_slab
*bio_slabs
;
69 static unsigned int bio_slab_nr
, bio_slab_max
;
71 static struct kmem_cache
*bio_find_or_create_slab(unsigned int extra_size
)
73 unsigned int sz
= sizeof(struct bio
) + extra_size
;
74 struct kmem_cache
*slab
= NULL
;
75 struct bio_slab
*bslab
, *new_bio_slabs
;
76 unsigned int new_bio_slab_max
;
77 unsigned int i
, entry
= -1;
79 mutex_lock(&bio_slab_lock
);
82 while (i
< bio_slab_nr
) {
83 bslab
= &bio_slabs
[i
];
85 if (!bslab
->slab
&& entry
== -1)
87 else if (bslab
->slab_size
== sz
) {
98 if (bio_slab_nr
== bio_slab_max
&& entry
== -1) {
99 new_bio_slab_max
= bio_slab_max
<< 1;
100 new_bio_slabs
= krealloc(bio_slabs
,
101 new_bio_slab_max
* sizeof(struct bio_slab
),
105 bio_slab_max
= new_bio_slab_max
;
106 bio_slabs
= new_bio_slabs
;
109 entry
= bio_slab_nr
++;
111 bslab
= &bio_slabs
[entry
];
113 snprintf(bslab
->name
, sizeof(bslab
->name
), "bio-%d", entry
);
114 slab
= kmem_cache_create(bslab
->name
, sz
, ARCH_KMALLOC_MINALIGN
,
115 SLAB_HWCACHE_ALIGN
, NULL
);
121 bslab
->slab_size
= sz
;
123 mutex_unlock(&bio_slab_lock
);
127 static void bio_put_slab(struct bio_set
*bs
)
129 struct bio_slab
*bslab
= NULL
;
132 mutex_lock(&bio_slab_lock
);
134 for (i
= 0; i
< bio_slab_nr
; i
++) {
135 if (bs
->bio_slab
== bio_slabs
[i
].slab
) {
136 bslab
= &bio_slabs
[i
];
141 if (WARN(!bslab
, KERN_ERR
"bio: unable to find slab!\n"))
144 WARN_ON(!bslab
->slab_ref
);
146 if (--bslab
->slab_ref
)
149 kmem_cache_destroy(bslab
->slab
);
153 mutex_unlock(&bio_slab_lock
);
156 unsigned int bvec_nr_vecs(unsigned short idx
)
158 return bvec_slabs
[idx
].nr_vecs
;
161 void bvec_free(mempool_t
*pool
, struct bio_vec
*bv
, unsigned int idx
)
167 BIO_BUG_ON(idx
>= BVEC_POOL_NR
);
169 if (idx
== BVEC_POOL_MAX
) {
170 mempool_free(bv
, pool
);
172 struct biovec_slab
*bvs
= bvec_slabs
+ idx
;
174 kmem_cache_free(bvs
->slab
, bv
);
178 struct bio_vec
*bvec_alloc(gfp_t gfp_mask
, int nr
, unsigned long *idx
,
184 * see comment near bvec_array define!
202 case 129 ... BIO_MAX_PAGES
:
210 * idx now points to the pool we want to allocate from. only the
211 * 1-vec entry pool is mempool backed.
213 if (*idx
== BVEC_POOL_MAX
) {
215 bvl
= mempool_alloc(pool
, gfp_mask
);
217 struct biovec_slab
*bvs
= bvec_slabs
+ *idx
;
218 gfp_t __gfp_mask
= gfp_mask
& ~(__GFP_DIRECT_RECLAIM
| __GFP_IO
);
221 * Make this allocation restricted and don't dump info on
222 * allocation failures, since we'll fallback to the mempool
223 * in case of failure.
225 __gfp_mask
|= __GFP_NOMEMALLOC
| __GFP_NORETRY
| __GFP_NOWARN
;
228 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM
229 * is set, retry with the 1-entry mempool
231 bvl
= kmem_cache_alloc(bvs
->slab
, __gfp_mask
);
232 if (unlikely(!bvl
&& (gfp_mask
& __GFP_DIRECT_RECLAIM
))) {
233 *idx
= BVEC_POOL_MAX
;
242 static void __bio_free(struct bio
*bio
)
244 bio_disassociate_task(bio
);
246 if (bio_integrity(bio
))
247 bio_integrity_free(bio
);
250 static void bio_free(struct bio
*bio
)
252 struct bio_set
*bs
= bio
->bi_pool
;
258 bvec_free(bs
->bvec_pool
, bio
->bi_io_vec
, BVEC_POOL_IDX(bio
));
261 * If we have front padding, adjust the bio pointer before freeing
266 mempool_free(p
, bs
->bio_pool
);
268 /* Bio was allocated by bio_kmalloc() */
273 void bio_init(struct bio
*bio
)
275 memset(bio
, 0, sizeof(*bio
));
276 atomic_set(&bio
->__bi_remaining
, 1);
277 atomic_set(&bio
->__bi_cnt
, 1);
279 EXPORT_SYMBOL(bio_init
);
282 * bio_reset - reinitialize a bio
286 * After calling bio_reset(), @bio will be in the same state as a freshly
287 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
288 * preserved are the ones that are initialized by bio_alloc_bioset(). See
289 * comment in struct bio.
291 void bio_reset(struct bio
*bio
)
293 unsigned long flags
= bio
->bi_flags
& (~0UL << BIO_RESET_BITS
);
297 memset(bio
, 0, BIO_RESET_BYTES
);
298 bio
->bi_flags
= flags
;
299 atomic_set(&bio
->__bi_remaining
, 1);
301 EXPORT_SYMBOL(bio_reset
);
303 static struct bio
*__bio_chain_endio(struct bio
*bio
)
305 struct bio
*parent
= bio
->bi_private
;
307 if (!parent
->bi_error
)
308 parent
->bi_error
= bio
->bi_error
;
313 static void bio_chain_endio(struct bio
*bio
)
315 bio_endio(__bio_chain_endio(bio
));
319 * bio_chain - chain bio completions
320 * @bio: the target bio
321 * @parent: the @bio's parent bio
323 * The caller won't have a bi_end_io called when @bio completes - instead,
324 * @parent's bi_end_io won't be called until both @parent and @bio have
325 * completed; the chained bio will also be freed when it completes.
327 * The caller must not set bi_private or bi_end_io in @bio.
329 void bio_chain(struct bio
*bio
, struct bio
*parent
)
331 BUG_ON(bio
->bi_private
|| bio
->bi_end_io
);
333 bio
->bi_private
= parent
;
334 bio
->bi_end_io
= bio_chain_endio
;
335 bio_inc_remaining(parent
);
337 EXPORT_SYMBOL(bio_chain
);
339 static void bio_alloc_rescue(struct work_struct
*work
)
341 struct bio_set
*bs
= container_of(work
, struct bio_set
, rescue_work
);
345 spin_lock(&bs
->rescue_lock
);
346 bio
= bio_list_pop(&bs
->rescue_list
);
347 spin_unlock(&bs
->rescue_lock
);
352 generic_make_request(bio
);
356 static void punt_bios_to_rescuer(struct bio_set
*bs
)
358 struct bio_list punt
, nopunt
;
362 * In order to guarantee forward progress we must punt only bios that
363 * were allocated from this bio_set; otherwise, if there was a bio on
364 * there for a stacking driver higher up in the stack, processing it
365 * could require allocating bios from this bio_set, and doing that from
366 * our own rescuer would be bad.
368 * Since bio lists are singly linked, pop them all instead of trying to
369 * remove from the middle of the list:
372 bio_list_init(&punt
);
373 bio_list_init(&nopunt
);
375 while ((bio
= bio_list_pop(current
->bio_list
)))
376 bio_list_add(bio
->bi_pool
== bs
? &punt
: &nopunt
, bio
);
378 *current
->bio_list
= nopunt
;
380 spin_lock(&bs
->rescue_lock
);
381 bio_list_merge(&bs
->rescue_list
, &punt
);
382 spin_unlock(&bs
->rescue_lock
);
384 queue_work(bs
->rescue_workqueue
, &bs
->rescue_work
);
388 * bio_alloc_bioset - allocate a bio for I/O
389 * @gfp_mask: the GFP_ mask given to the slab allocator
390 * @nr_iovecs: number of iovecs to pre-allocate
391 * @bs: the bio_set to allocate from.
394 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
395 * backed by the @bs's mempool.
397 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will
398 * always be able to allocate a bio. This is due to the mempool guarantees.
399 * To make this work, callers must never allocate more than 1 bio at a time
400 * from this pool. Callers that need to allocate more than 1 bio must always
401 * submit the previously allocated bio for IO before attempting to allocate
402 * a new one. Failure to do so can cause deadlocks under memory pressure.
404 * Note that when running under generic_make_request() (i.e. any block
405 * driver), bios are not submitted until after you return - see the code in
406 * generic_make_request() that converts recursion into iteration, to prevent
409 * This would normally mean allocating multiple bios under
410 * generic_make_request() would be susceptible to deadlocks, but we have
411 * deadlock avoidance code that resubmits any blocked bios from a rescuer
414 * However, we do not guarantee forward progress for allocations from other
415 * mempools. Doing multiple allocations from the same mempool under
416 * generic_make_request() should be avoided - instead, use bio_set's front_pad
417 * for per bio allocations.
420 * Pointer to new bio on success, NULL on failure.
422 struct bio
*bio_alloc_bioset(gfp_t gfp_mask
, int nr_iovecs
, struct bio_set
*bs
)
424 gfp_t saved_gfp
= gfp_mask
;
426 unsigned inline_vecs
;
427 struct bio_vec
*bvl
= NULL
;
432 if (nr_iovecs
> UIO_MAXIOV
)
435 p
= kmalloc(sizeof(struct bio
) +
436 nr_iovecs
* sizeof(struct bio_vec
),
439 inline_vecs
= nr_iovecs
;
441 /* should not use nobvec bioset for nr_iovecs > 0 */
442 if (WARN_ON_ONCE(!bs
->bvec_pool
&& nr_iovecs
> 0))
445 * generic_make_request() converts recursion to iteration; this
446 * means if we're running beneath it, any bios we allocate and
447 * submit will not be submitted (and thus freed) until after we
450 * This exposes us to a potential deadlock if we allocate
451 * multiple bios from the same bio_set() while running
452 * underneath generic_make_request(). If we were to allocate
453 * multiple bios (say a stacking block driver that was splitting
454 * bios), we would deadlock if we exhausted the mempool's
457 * We solve this, and guarantee forward progress, with a rescuer
458 * workqueue per bio_set. If we go to allocate and there are
459 * bios on current->bio_list, we first try the allocation
460 * without __GFP_DIRECT_RECLAIM; if that fails, we punt those
461 * bios we would be blocking to the rescuer workqueue before
462 * we retry with the original gfp_flags.
465 if (current
->bio_list
&& !bio_list_empty(current
->bio_list
))
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
);
475 front_pad
= bs
->front_pad
;
476 inline_vecs
= BIO_INLINE_VECS
;
485 if (nr_iovecs
> inline_vecs
) {
486 unsigned long idx
= 0;
488 bvl
= bvec_alloc(gfp_mask
, nr_iovecs
, &idx
, bs
->bvec_pool
);
489 if (!bvl
&& gfp_mask
!= saved_gfp
) {
490 punt_bios_to_rescuer(bs
);
491 gfp_mask
= saved_gfp
;
492 bvl
= bvec_alloc(gfp_mask
, nr_iovecs
, &idx
, bs
->bvec_pool
);
498 bio
->bi_flags
|= idx
<< BVEC_POOL_OFFSET
;
499 } else if (nr_iovecs
) {
500 bvl
= bio
->bi_inline_vecs
;
504 bio
->bi_max_vecs
= nr_iovecs
;
505 bio
->bi_io_vec
= bvl
;
509 mempool_free(p
, bs
->bio_pool
);
512 EXPORT_SYMBOL(bio_alloc_bioset
);
514 void zero_fill_bio(struct bio
*bio
)
518 struct bvec_iter iter
;
520 bio_for_each_segment(bv
, bio
, iter
) {
521 char *data
= bvec_kmap_irq(&bv
, &flags
);
522 memset(data
, 0, bv
.bv_len
);
523 flush_dcache_page(bv
.bv_page
);
524 bvec_kunmap_irq(data
, &flags
);
527 EXPORT_SYMBOL(zero_fill_bio
);
530 * bio_put - release a reference to a bio
531 * @bio: bio to release reference to
534 * Put a reference to a &struct bio, either one you have gotten with
535 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
537 void bio_put(struct bio
*bio
)
539 if (!bio_flagged(bio
, BIO_REFFED
))
542 BIO_BUG_ON(!atomic_read(&bio
->__bi_cnt
));
547 if (atomic_dec_and_test(&bio
->__bi_cnt
))
551 EXPORT_SYMBOL(bio_put
);
553 inline int bio_phys_segments(struct request_queue
*q
, struct bio
*bio
)
555 if (unlikely(!bio_flagged(bio
, BIO_SEG_VALID
)))
556 blk_recount_segments(q
, bio
);
558 return bio
->bi_phys_segments
;
560 EXPORT_SYMBOL(bio_phys_segments
);
563 * __bio_clone_fast - clone a bio that shares the original bio's biovec
564 * @bio: destination bio
565 * @bio_src: bio to clone
567 * Clone a &bio. Caller will own the returned bio, but not
568 * the actual data it points to. Reference count of returned
571 * Caller must ensure that @bio_src is not freed before @bio.
573 void __bio_clone_fast(struct bio
*bio
, struct bio
*bio_src
)
575 BUG_ON(bio
->bi_pool
&& BVEC_POOL_IDX(bio
));
578 * most users will be overriding ->bi_bdev with a new target,
579 * so we don't set nor calculate new physical/hw segment counts here
581 bio
->bi_bdev
= bio_src
->bi_bdev
;
582 bio_set_flag(bio
, BIO_CLONED
);
583 bio
->bi_opf
= bio_src
->bi_opf
;
584 bio
->bi_iter
= bio_src
->bi_iter
;
585 bio
->bi_io_vec
= bio_src
->bi_io_vec
;
587 bio_clone_blkcg_association(bio
, bio_src
);
589 EXPORT_SYMBOL(__bio_clone_fast
);
592 * bio_clone_fast - clone a bio that shares the original bio's biovec
594 * @gfp_mask: allocation priority
595 * @bs: bio_set to allocate from
597 * Like __bio_clone_fast, only also allocates the returned bio
599 struct bio
*bio_clone_fast(struct bio
*bio
, gfp_t gfp_mask
, struct bio_set
*bs
)
603 b
= bio_alloc_bioset(gfp_mask
, 0, bs
);
607 __bio_clone_fast(b
, bio
);
609 if (bio_integrity(bio
)) {
612 ret
= bio_integrity_clone(b
, bio
, gfp_mask
);
622 EXPORT_SYMBOL(bio_clone_fast
);
625 * bio_clone_bioset - clone a bio
626 * @bio_src: bio to clone
627 * @gfp_mask: allocation priority
628 * @bs: bio_set to allocate from
630 * Clone bio. Caller will own the returned bio, but not the actual data it
631 * points to. Reference count of returned bio will be one.
633 struct bio
*bio_clone_bioset(struct bio
*bio_src
, gfp_t gfp_mask
,
636 struct bvec_iter iter
;
641 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
642 * bio_src->bi_io_vec to bio->bi_io_vec.
644 * We can't do that anymore, because:
646 * - The point of cloning the biovec is to produce a bio with a biovec
647 * the caller can modify: bi_idx and bi_bvec_done should be 0.
649 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
650 * we tried to clone the whole thing bio_alloc_bioset() would fail.
651 * But the clone should succeed as long as the number of biovecs we
652 * actually need to allocate is fewer than BIO_MAX_PAGES.
654 * - Lastly, bi_vcnt should not be looked at or relied upon by code
655 * that does not own the bio - reason being drivers don't use it for
656 * iterating over the biovec anymore, so expecting it to be kept up
657 * to date (i.e. for clones that share the parent biovec) is just
658 * asking for trouble and would force extra work on
659 * __bio_clone_fast() anyways.
662 bio
= bio_alloc_bioset(gfp_mask
, bio_segments(bio_src
), bs
);
665 bio
->bi_bdev
= bio_src
->bi_bdev
;
666 bio
->bi_opf
= bio_src
->bi_opf
;
667 bio
->bi_iter
.bi_sector
= bio_src
->bi_iter
.bi_sector
;
668 bio
->bi_iter
.bi_size
= bio_src
->bi_iter
.bi_size
;
670 switch (bio_op(bio
)) {
672 case REQ_OP_SECURE_ERASE
:
674 case REQ_OP_WRITE_SAME
:
675 bio
->bi_io_vec
[bio
->bi_vcnt
++] = bio_src
->bi_io_vec
[0];
678 bio_for_each_segment(bv
, bio_src
, iter
)
679 bio
->bi_io_vec
[bio
->bi_vcnt
++] = bv
;
683 if (bio_integrity(bio_src
)) {
686 ret
= bio_integrity_clone(bio
, bio_src
, gfp_mask
);
693 bio_clone_blkcg_association(bio
, bio_src
);
697 EXPORT_SYMBOL(bio_clone_bioset
);
700 * bio_add_pc_page - attempt to add page to bio
701 * @q: the target queue
702 * @bio: destination bio
704 * @len: vec entry length
705 * @offset: vec entry offset
707 * Attempt to add a page to the bio_vec maplist. This can fail for a
708 * number of reasons, such as the bio being full or target block device
709 * limitations. The target block device must allow bio's up to PAGE_SIZE,
710 * so it is always possible to add a single page to an empty bio.
712 * This should only be used by REQ_PC bios.
714 int bio_add_pc_page(struct request_queue
*q
, struct bio
*bio
, struct page
715 *page
, unsigned int len
, unsigned int offset
)
717 int retried_segments
= 0;
718 struct bio_vec
*bvec
;
721 * cloned bio must not modify vec list
723 if (unlikely(bio_flagged(bio
, BIO_CLONED
)))
726 if (((bio
->bi_iter
.bi_size
+ len
) >> 9) > queue_max_hw_sectors(q
))
730 * For filesystems with a blocksize smaller than the pagesize
731 * we will often be called with the same page as last time and
732 * a consecutive offset. Optimize this special case.
734 if (bio
->bi_vcnt
> 0) {
735 struct bio_vec
*prev
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
737 if (page
== prev
->bv_page
&&
738 offset
== prev
->bv_offset
+ prev
->bv_len
) {
740 bio
->bi_iter
.bi_size
+= len
;
745 * If the queue doesn't support SG gaps and adding this
746 * offset would create a gap, disallow it.
748 if (bvec_gap_to_prev(q
, prev
, offset
))
752 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
756 * setup the new entry, we might clear it again later if we
757 * cannot add the page
759 bvec
= &bio
->bi_io_vec
[bio
->bi_vcnt
];
760 bvec
->bv_page
= page
;
762 bvec
->bv_offset
= offset
;
764 bio
->bi_phys_segments
++;
765 bio
->bi_iter
.bi_size
+= len
;
768 * Perform a recount if the number of segments is greater
769 * than queue_max_segments(q).
772 while (bio
->bi_phys_segments
> queue_max_segments(q
)) {
774 if (retried_segments
)
777 retried_segments
= 1;
778 blk_recount_segments(q
, bio
);
781 /* If we may be able to merge these biovecs, force a recount */
782 if (bio
->bi_vcnt
> 1 && (BIOVEC_PHYS_MERGEABLE(bvec
-1, bvec
)))
783 bio_clear_flag(bio
, BIO_SEG_VALID
);
789 bvec
->bv_page
= NULL
;
793 bio
->bi_iter
.bi_size
-= len
;
794 blk_recount_segments(q
, bio
);
797 EXPORT_SYMBOL(bio_add_pc_page
);
800 * bio_add_page - attempt to add page to bio
801 * @bio: destination bio
803 * @len: vec entry length
804 * @offset: vec entry offset
806 * Attempt to add a page to the bio_vec maplist. This will only fail
807 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.
809 int bio_add_page(struct bio
*bio
, struct page
*page
,
810 unsigned int len
, unsigned int offset
)
815 * cloned bio must not modify vec list
817 if (WARN_ON_ONCE(bio_flagged(bio
, BIO_CLONED
)))
821 * For filesystems with a blocksize smaller than the pagesize
822 * we will often be called with the same page as last time and
823 * a consecutive offset. Optimize this special case.
825 if (bio
->bi_vcnt
> 0) {
826 bv
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
828 if (page
== bv
->bv_page
&&
829 offset
== bv
->bv_offset
+ bv
->bv_len
) {
835 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
838 bv
= &bio
->bi_io_vec
[bio
->bi_vcnt
];
841 bv
->bv_offset
= offset
;
845 bio
->bi_iter
.bi_size
+= len
;
848 EXPORT_SYMBOL(bio_add_page
);
850 struct submit_bio_ret
{
851 struct completion event
;
855 static void submit_bio_wait_endio(struct bio
*bio
)
857 struct submit_bio_ret
*ret
= bio
->bi_private
;
859 ret
->error
= bio
->bi_error
;
860 complete(&ret
->event
);
864 * submit_bio_wait - submit a bio, and wait until it completes
865 * @bio: The &struct bio which describes the I/O
867 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
868 * bio_endio() on failure.
870 int submit_bio_wait(struct bio
*bio
)
872 struct submit_bio_ret ret
;
874 init_completion(&ret
.event
);
875 bio
->bi_private
= &ret
;
876 bio
->bi_end_io
= submit_bio_wait_endio
;
877 bio
->bi_opf
|= REQ_SYNC
;
879 wait_for_completion_io(&ret
.event
);
883 EXPORT_SYMBOL(submit_bio_wait
);
886 * bio_advance - increment/complete a bio by some number of bytes
887 * @bio: bio to advance
888 * @bytes: number of bytes to complete
890 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
891 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
892 * be updated on the last bvec as well.
894 * @bio will then represent the remaining, uncompleted portion of the io.
896 void bio_advance(struct bio
*bio
, unsigned bytes
)
898 if (bio_integrity(bio
))
899 bio_integrity_advance(bio
, bytes
);
901 bio_advance_iter(bio
, &bio
->bi_iter
, bytes
);
903 EXPORT_SYMBOL(bio_advance
);
906 * bio_alloc_pages - allocates a single page for each bvec in a bio
907 * @bio: bio to allocate pages for
908 * @gfp_mask: flags for allocation
910 * Allocates pages up to @bio->bi_vcnt.
912 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
915 int bio_alloc_pages(struct bio
*bio
, gfp_t gfp_mask
)
920 bio_for_each_segment_all(bv
, bio
, i
) {
921 bv
->bv_page
= alloc_page(gfp_mask
);
923 while (--bv
>= bio
->bi_io_vec
)
924 __free_page(bv
->bv_page
);
931 EXPORT_SYMBOL(bio_alloc_pages
);
934 * bio_copy_data - copy contents of data buffers from one chain of bios to
936 * @src: source bio list
937 * @dst: destination bio list
939 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
940 * @src and @dst as linked lists of bios.
942 * Stops when it reaches the end of either @src or @dst - that is, copies
943 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
945 void bio_copy_data(struct bio
*dst
, struct bio
*src
)
947 struct bvec_iter src_iter
, dst_iter
;
948 struct bio_vec src_bv
, dst_bv
;
952 src_iter
= src
->bi_iter
;
953 dst_iter
= dst
->bi_iter
;
956 if (!src_iter
.bi_size
) {
961 src_iter
= src
->bi_iter
;
964 if (!dst_iter
.bi_size
) {
969 dst_iter
= dst
->bi_iter
;
972 src_bv
= bio_iter_iovec(src
, src_iter
);
973 dst_bv
= bio_iter_iovec(dst
, dst_iter
);
975 bytes
= min(src_bv
.bv_len
, dst_bv
.bv_len
);
977 src_p
= kmap_atomic(src_bv
.bv_page
);
978 dst_p
= kmap_atomic(dst_bv
.bv_page
);
980 memcpy(dst_p
+ dst_bv
.bv_offset
,
981 src_p
+ src_bv
.bv_offset
,
984 kunmap_atomic(dst_p
);
985 kunmap_atomic(src_p
);
987 bio_advance_iter(src
, &src_iter
, bytes
);
988 bio_advance_iter(dst
, &dst_iter
, bytes
);
991 EXPORT_SYMBOL(bio_copy_data
);
993 struct bio_map_data
{
995 struct iov_iter iter
;
999 static struct bio_map_data
*bio_alloc_map_data(unsigned int iov_count
,
1002 if (iov_count
> UIO_MAXIOV
)
1005 return kmalloc(sizeof(struct bio_map_data
) +
1006 sizeof(struct iovec
) * iov_count
, gfp_mask
);
1010 * bio_copy_from_iter - copy all pages from iov_iter to bio
1011 * @bio: The &struct bio which describes the I/O as destination
1012 * @iter: iov_iter as source
1014 * Copy all pages from iov_iter to bio.
1015 * Returns 0 on success, or error on failure.
1017 static int bio_copy_from_iter(struct bio
*bio
, struct iov_iter iter
)
1020 struct bio_vec
*bvec
;
1022 bio_for_each_segment_all(bvec
, bio
, i
) {
1025 ret
= copy_page_from_iter(bvec
->bv_page
,
1030 if (!iov_iter_count(&iter
))
1033 if (ret
< bvec
->bv_len
)
1041 * bio_copy_to_iter - copy all pages from bio to iov_iter
1042 * @bio: The &struct bio which describes the I/O as source
1043 * @iter: iov_iter as destination
1045 * Copy all pages from bio to iov_iter.
1046 * Returns 0 on success, or error on failure.
1048 static int bio_copy_to_iter(struct bio
*bio
, struct iov_iter iter
)
1051 struct bio_vec
*bvec
;
1053 bio_for_each_segment_all(bvec
, bio
, i
) {
1056 ret
= copy_page_to_iter(bvec
->bv_page
,
1061 if (!iov_iter_count(&iter
))
1064 if (ret
< bvec
->bv_len
)
1071 void bio_free_pages(struct bio
*bio
)
1073 struct bio_vec
*bvec
;
1076 bio_for_each_segment_all(bvec
, bio
, i
)
1077 __free_page(bvec
->bv_page
);
1079 EXPORT_SYMBOL(bio_free_pages
);
1082 * bio_uncopy_user - finish previously mapped bio
1083 * @bio: bio being terminated
1085 * Free pages allocated from bio_copy_user_iov() and write back data
1086 * to user space in case of a read.
1088 int bio_uncopy_user(struct bio
*bio
)
1090 struct bio_map_data
*bmd
= bio
->bi_private
;
1093 if (!bio_flagged(bio
, BIO_NULL_MAPPED
)) {
1095 * if we're in a workqueue, the request is orphaned, so
1096 * don't copy into a random user address space, just free
1097 * and return -EINTR so user space doesn't expect any data.
1101 else if (bio_data_dir(bio
) == READ
)
1102 ret
= bio_copy_to_iter(bio
, bmd
->iter
);
1103 if (bmd
->is_our_pages
)
1104 bio_free_pages(bio
);
1112 * bio_copy_user_iov - copy user data to bio
1113 * @q: destination block queue
1114 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1115 * @iter: iovec iterator
1116 * @gfp_mask: memory allocation flags
1118 * Prepares and returns a bio for indirect user io, bouncing data
1119 * to/from kernel pages as necessary. Must be paired with
1120 * call bio_uncopy_user() on io completion.
1122 struct bio
*bio_copy_user_iov(struct request_queue
*q
,
1123 struct rq_map_data
*map_data
,
1124 const struct iov_iter
*iter
,
1127 struct bio_map_data
*bmd
;
1132 unsigned int len
= iter
->count
;
1133 unsigned int offset
= map_data
? offset_in_page(map_data
->offset
) : 0;
1135 for (i
= 0; i
< iter
->nr_segs
; i
++) {
1136 unsigned long uaddr
;
1138 unsigned long start
;
1140 uaddr
= (unsigned long) iter
->iov
[i
].iov_base
;
1141 end
= (uaddr
+ iter
->iov
[i
].iov_len
+ PAGE_SIZE
- 1)
1143 start
= uaddr
>> PAGE_SHIFT
;
1149 return ERR_PTR(-EINVAL
);
1151 nr_pages
+= end
- start
;
1157 bmd
= bio_alloc_map_data(iter
->nr_segs
, gfp_mask
);
1159 return ERR_PTR(-ENOMEM
);
1162 * We need to do a deep copy of the iov_iter including the iovecs.
1163 * The caller provided iov might point to an on-stack or otherwise
1166 bmd
->is_our_pages
= map_data
? 0 : 1;
1167 memcpy(bmd
->iov
, iter
->iov
, sizeof(struct iovec
) * iter
->nr_segs
);
1168 iov_iter_init(&bmd
->iter
, iter
->type
, bmd
->iov
,
1169 iter
->nr_segs
, iter
->count
);
1172 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1176 if (iter
->type
& WRITE
)
1177 bio_set_op_attrs(bio
, REQ_OP_WRITE
, 0);
1182 nr_pages
= 1 << map_data
->page_order
;
1183 i
= map_data
->offset
/ PAGE_SIZE
;
1186 unsigned int bytes
= PAGE_SIZE
;
1194 if (i
== map_data
->nr_entries
* nr_pages
) {
1199 page
= map_data
->pages
[i
/ nr_pages
];
1200 page
+= (i
% nr_pages
);
1204 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
1211 if (bio_add_pc_page(q
, bio
, page
, bytes
, offset
) < bytes
)
1224 if (((iter
->type
& WRITE
) && (!map_data
|| !map_data
->null_mapped
)) ||
1225 (map_data
&& map_data
->from_user
)) {
1226 ret
= bio_copy_from_iter(bio
, *iter
);
1231 bio
->bi_private
= bmd
;
1235 bio_free_pages(bio
);
1239 return ERR_PTR(ret
);
1243 * bio_map_user_iov - map user iovec into bio
1244 * @q: the struct request_queue for the bio
1245 * @iter: iovec iterator
1246 * @gfp_mask: memory allocation flags
1248 * Map the user space address into a bio suitable for io to a block
1249 * device. Returns an error pointer in case of error.
1251 struct bio
*bio_map_user_iov(struct request_queue
*q
,
1252 const struct iov_iter
*iter
,
1257 struct page
**pages
;
1264 iov_for_each(iov
, i
, *iter
) {
1265 unsigned long uaddr
= (unsigned long) iov
.iov_base
;
1266 unsigned long len
= iov
.iov_len
;
1267 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1268 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1274 return ERR_PTR(-EINVAL
);
1276 nr_pages
+= end
- start
;
1278 * buffer must be aligned to at least logical block size for now
1280 if (uaddr
& queue_dma_alignment(q
))
1281 return ERR_PTR(-EINVAL
);
1285 return ERR_PTR(-EINVAL
);
1287 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1289 return ERR_PTR(-ENOMEM
);
1292 pages
= kcalloc(nr_pages
, sizeof(struct page
*), gfp_mask
);
1296 iov_for_each(iov
, i
, *iter
) {
1297 unsigned long uaddr
= (unsigned long) iov
.iov_base
;
1298 unsigned long len
= iov
.iov_len
;
1299 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1300 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1301 const int local_nr_pages
= end
- start
;
1302 const int page_limit
= cur_page
+ local_nr_pages
;
1304 ret
= get_user_pages_fast(uaddr
, local_nr_pages
,
1305 (iter
->type
& WRITE
) != WRITE
,
1307 if (ret
< local_nr_pages
) {
1312 offset
= offset_in_page(uaddr
);
1313 for (j
= cur_page
; j
< page_limit
; j
++) {
1314 unsigned int bytes
= PAGE_SIZE
- offset
;
1325 if (bio_add_pc_page(q
, bio
, pages
[j
], bytes
, offset
) <
1335 * release the pages we didn't map into the bio, if any
1337 while (j
< page_limit
)
1338 put_page(pages
[j
++]);
1344 * set data direction, and check if mapped pages need bouncing
1346 if (iter
->type
& WRITE
)
1347 bio_set_op_attrs(bio
, REQ_OP_WRITE
, 0);
1349 bio_set_flag(bio
, BIO_USER_MAPPED
);
1352 * subtle -- if __bio_map_user() ended up bouncing a bio,
1353 * it would normally disappear when its bi_end_io is run.
1354 * however, we need it for the unmap, so grab an extra
1361 for (j
= 0; j
< nr_pages
; j
++) {
1369 return ERR_PTR(ret
);
1372 static void __bio_unmap_user(struct bio
*bio
)
1374 struct bio_vec
*bvec
;
1378 * make sure we dirty pages we wrote to
1380 bio_for_each_segment_all(bvec
, bio
, i
) {
1381 if (bio_data_dir(bio
) == READ
)
1382 set_page_dirty_lock(bvec
->bv_page
);
1384 put_page(bvec
->bv_page
);
1391 * bio_unmap_user - unmap a bio
1392 * @bio: the bio being unmapped
1394 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1395 * a process context.
1397 * bio_unmap_user() may sleep.
1399 void bio_unmap_user(struct bio
*bio
)
1401 __bio_unmap_user(bio
);
1405 static void bio_map_kern_endio(struct bio
*bio
)
1411 * bio_map_kern - map kernel address into bio
1412 * @q: the struct request_queue for the bio
1413 * @data: pointer to buffer to map
1414 * @len: length in bytes
1415 * @gfp_mask: allocation flags for bio allocation
1417 * Map the kernel address into a bio suitable for io to a block
1418 * device. Returns an error pointer in case of error.
1420 struct bio
*bio_map_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1423 unsigned long kaddr
= (unsigned long)data
;
1424 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1425 unsigned long start
= kaddr
>> PAGE_SHIFT
;
1426 const int nr_pages
= end
- start
;
1430 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1432 return ERR_PTR(-ENOMEM
);
1434 offset
= offset_in_page(kaddr
);
1435 for (i
= 0; i
< nr_pages
; i
++) {
1436 unsigned int bytes
= PAGE_SIZE
- offset
;
1444 if (bio_add_pc_page(q
, bio
, virt_to_page(data
), bytes
,
1446 /* we don't support partial mappings */
1448 return ERR_PTR(-EINVAL
);
1456 bio
->bi_end_io
= bio_map_kern_endio
;
1459 EXPORT_SYMBOL(bio_map_kern
);
1461 static void bio_copy_kern_endio(struct bio
*bio
)
1463 bio_free_pages(bio
);
1467 static void bio_copy_kern_endio_read(struct bio
*bio
)
1469 char *p
= bio
->bi_private
;
1470 struct bio_vec
*bvec
;
1473 bio_for_each_segment_all(bvec
, bio
, i
) {
1474 memcpy(p
, page_address(bvec
->bv_page
), bvec
->bv_len
);
1478 bio_copy_kern_endio(bio
);
1482 * bio_copy_kern - copy kernel address into bio
1483 * @q: the struct request_queue for the bio
1484 * @data: pointer to buffer to copy
1485 * @len: length in bytes
1486 * @gfp_mask: allocation flags for bio and page allocation
1487 * @reading: data direction is READ
1489 * copy the kernel address into a bio suitable for io to a block
1490 * device. Returns an error pointer in case of error.
1492 struct bio
*bio_copy_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1493 gfp_t gfp_mask
, int reading
)
1495 unsigned long kaddr
= (unsigned long)data
;
1496 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1497 unsigned long start
= kaddr
>> PAGE_SHIFT
;
1506 return ERR_PTR(-EINVAL
);
1508 nr_pages
= end
- start
;
1509 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1511 return ERR_PTR(-ENOMEM
);
1515 unsigned int bytes
= PAGE_SIZE
;
1520 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
1525 memcpy(page_address(page
), p
, bytes
);
1527 if (bio_add_pc_page(q
, bio
, page
, bytes
, 0) < bytes
)
1535 bio
->bi_end_io
= bio_copy_kern_endio_read
;
1536 bio
->bi_private
= data
;
1538 bio
->bi_end_io
= bio_copy_kern_endio
;
1539 bio_set_op_attrs(bio
, REQ_OP_WRITE
, 0);
1545 bio_free_pages(bio
);
1547 return ERR_PTR(-ENOMEM
);
1551 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1552 * for performing direct-IO in BIOs.
1554 * The problem is that we cannot run set_page_dirty() from interrupt context
1555 * because the required locks are not interrupt-safe. So what we can do is to
1556 * mark the pages dirty _before_ performing IO. And in interrupt context,
1557 * check that the pages are still dirty. If so, fine. If not, redirty them
1558 * in process context.
1560 * We special-case compound pages here: normally this means reads into hugetlb
1561 * pages. The logic in here doesn't really work right for compound pages
1562 * because the VM does not uniformly chase down the head page in all cases.
1563 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1564 * handle them at all. So we skip compound pages here at an early stage.
1566 * Note that this code is very hard to test under normal circumstances because
1567 * direct-io pins the pages with get_user_pages(). This makes
1568 * is_page_cache_freeable return false, and the VM will not clean the pages.
1569 * But other code (eg, flusher threads) could clean the pages if they are mapped
1572 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1573 * deferred bio dirtying paths.
1577 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1579 void bio_set_pages_dirty(struct bio
*bio
)
1581 struct bio_vec
*bvec
;
1584 bio_for_each_segment_all(bvec
, bio
, i
) {
1585 struct page
*page
= bvec
->bv_page
;
1587 if (page
&& !PageCompound(page
))
1588 set_page_dirty_lock(page
);
1592 static void bio_release_pages(struct bio
*bio
)
1594 struct bio_vec
*bvec
;
1597 bio_for_each_segment_all(bvec
, bio
, i
) {
1598 struct page
*page
= bvec
->bv_page
;
1606 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1607 * If they are, then fine. If, however, some pages are clean then they must
1608 * have been written out during the direct-IO read. So we take another ref on
1609 * the BIO and the offending pages and re-dirty the pages in process context.
1611 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1612 * here on. It will run one put_page() against each page and will run one
1613 * bio_put() against the BIO.
1616 static void bio_dirty_fn(struct work_struct
*work
);
1618 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1619 static DEFINE_SPINLOCK(bio_dirty_lock
);
1620 static struct bio
*bio_dirty_list
;
1623 * This runs in process context
1625 static void bio_dirty_fn(struct work_struct
*work
)
1627 unsigned long flags
;
1630 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1631 bio
= bio_dirty_list
;
1632 bio_dirty_list
= NULL
;
1633 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1636 struct bio
*next
= bio
->bi_private
;
1638 bio_set_pages_dirty(bio
);
1639 bio_release_pages(bio
);
1645 void bio_check_pages_dirty(struct bio
*bio
)
1647 struct bio_vec
*bvec
;
1648 int nr_clean_pages
= 0;
1651 bio_for_each_segment_all(bvec
, bio
, i
) {
1652 struct page
*page
= bvec
->bv_page
;
1654 if (PageDirty(page
) || PageCompound(page
)) {
1656 bvec
->bv_page
= NULL
;
1662 if (nr_clean_pages
) {
1663 unsigned long flags
;
1665 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1666 bio
->bi_private
= bio_dirty_list
;
1667 bio_dirty_list
= bio
;
1668 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1669 schedule_work(&bio_dirty_work
);
1675 void generic_start_io_acct(int rw
, unsigned long sectors
,
1676 struct hd_struct
*part
)
1678 int cpu
= part_stat_lock();
1680 part_round_stats(cpu
, part
);
1681 part_stat_inc(cpu
, part
, ios
[rw
]);
1682 part_stat_add(cpu
, part
, sectors
[rw
], sectors
);
1683 part_inc_in_flight(part
, rw
);
1687 EXPORT_SYMBOL(generic_start_io_acct
);
1689 void generic_end_io_acct(int rw
, struct hd_struct
*part
,
1690 unsigned long start_time
)
1692 unsigned long duration
= jiffies
- start_time
;
1693 int cpu
= part_stat_lock();
1695 part_stat_add(cpu
, part
, ticks
[rw
], duration
);
1696 part_round_stats(cpu
, part
);
1697 part_dec_in_flight(part
, rw
);
1701 EXPORT_SYMBOL(generic_end_io_acct
);
1703 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1704 void bio_flush_dcache_pages(struct bio
*bi
)
1706 struct bio_vec bvec
;
1707 struct bvec_iter iter
;
1709 bio_for_each_segment(bvec
, bi
, iter
)
1710 flush_dcache_page(bvec
.bv_page
);
1712 EXPORT_SYMBOL(bio_flush_dcache_pages
);
1715 static inline bool bio_remaining_done(struct bio
*bio
)
1718 * If we're not chaining, then ->__bi_remaining is always 1 and
1719 * we always end io on the first invocation.
1721 if (!bio_flagged(bio
, BIO_CHAIN
))
1724 BUG_ON(atomic_read(&bio
->__bi_remaining
) <= 0);
1726 if (atomic_dec_and_test(&bio
->__bi_remaining
)) {
1727 bio_clear_flag(bio
, BIO_CHAIN
);
1735 * bio_endio - end I/O on a bio
1739 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
1740 * way to end I/O on a bio. No one should call bi_end_io() directly on a
1741 * bio unless they own it and thus know that it has an end_io function.
1743 void bio_endio(struct bio
*bio
)
1746 if (!bio_remaining_done(bio
))
1750 * Need to have a real endio function for chained bios, otherwise
1751 * various corner cases will break (like stacking block devices that
1752 * save/restore bi_end_io) - however, we want to avoid unbounded
1753 * recursion and blowing the stack. Tail call optimization would
1754 * handle this, but compiling with frame pointers also disables
1755 * gcc's sibling call optimization.
1757 if (bio
->bi_end_io
== bio_chain_endio
) {
1758 bio
= __bio_chain_endio(bio
);
1763 bio
->bi_end_io(bio
);
1765 EXPORT_SYMBOL(bio_endio
);
1768 * bio_split - split a bio
1769 * @bio: bio to split
1770 * @sectors: number of sectors to split from the front of @bio
1772 * @bs: bio set to allocate from
1774 * Allocates and returns a new bio which represents @sectors from the start of
1775 * @bio, and updates @bio to represent the remaining sectors.
1777 * Unless this is a discard request the newly allocated bio will point
1778 * to @bio's bi_io_vec; it is the caller's responsibility to ensure that
1779 * @bio is not freed before the split.
1781 struct bio
*bio_split(struct bio
*bio
, int sectors
,
1782 gfp_t gfp
, struct bio_set
*bs
)
1784 struct bio
*split
= NULL
;
1786 BUG_ON(sectors
<= 0);
1787 BUG_ON(sectors
>= bio_sectors(bio
));
1790 * Discards need a mutable bio_vec to accommodate the payload
1791 * required by the DSM TRIM and UNMAP commands.
1793 if (bio_op(bio
) == REQ_OP_DISCARD
|| bio_op(bio
) == REQ_OP_SECURE_ERASE
)
1794 split
= bio_clone_bioset(bio
, gfp
, bs
);
1796 split
= bio_clone_fast(bio
, gfp
, bs
);
1801 split
->bi_iter
.bi_size
= sectors
<< 9;
1803 if (bio_integrity(split
))
1804 bio_integrity_trim(split
, 0, sectors
);
1806 bio_advance(bio
, split
->bi_iter
.bi_size
);
1810 EXPORT_SYMBOL(bio_split
);
1813 * bio_trim - trim a bio
1815 * @offset: number of sectors to trim from the front of @bio
1816 * @size: size we want to trim @bio to, in sectors
1818 void bio_trim(struct bio
*bio
, int offset
, int size
)
1820 /* 'bio' is a cloned bio which we need to trim to match
1821 * the given offset and size.
1825 if (offset
== 0 && size
== bio
->bi_iter
.bi_size
)
1828 bio_clear_flag(bio
, BIO_SEG_VALID
);
1830 bio_advance(bio
, offset
<< 9);
1832 bio
->bi_iter
.bi_size
= size
;
1834 EXPORT_SYMBOL_GPL(bio_trim
);
1837 * create memory pools for biovec's in a bio_set.
1838 * use the global biovec slabs created for general use.
1840 mempool_t
*biovec_create_pool(int pool_entries
)
1842 struct biovec_slab
*bp
= bvec_slabs
+ BVEC_POOL_MAX
;
1844 return mempool_create_slab_pool(pool_entries
, bp
->slab
);
1847 void bioset_free(struct bio_set
*bs
)
1849 if (bs
->rescue_workqueue
)
1850 destroy_workqueue(bs
->rescue_workqueue
);
1853 mempool_destroy(bs
->bio_pool
);
1856 mempool_destroy(bs
->bvec_pool
);
1858 bioset_integrity_free(bs
);
1863 EXPORT_SYMBOL(bioset_free
);
1865 static struct bio_set
*__bioset_create(unsigned int pool_size
,
1866 unsigned int front_pad
,
1867 bool create_bvec_pool
)
1869 unsigned int back_pad
= BIO_INLINE_VECS
* sizeof(struct bio_vec
);
1872 bs
= kzalloc(sizeof(*bs
), GFP_KERNEL
);
1876 bs
->front_pad
= front_pad
;
1878 spin_lock_init(&bs
->rescue_lock
);
1879 bio_list_init(&bs
->rescue_list
);
1880 INIT_WORK(&bs
->rescue_work
, bio_alloc_rescue
);
1882 bs
->bio_slab
= bio_find_or_create_slab(front_pad
+ back_pad
);
1883 if (!bs
->bio_slab
) {
1888 bs
->bio_pool
= mempool_create_slab_pool(pool_size
, bs
->bio_slab
);
1892 if (create_bvec_pool
) {
1893 bs
->bvec_pool
= biovec_create_pool(pool_size
);
1898 bs
->rescue_workqueue
= alloc_workqueue("bioset", WQ_MEM_RECLAIM
, 0);
1899 if (!bs
->rescue_workqueue
)
1909 * bioset_create - Create a bio_set
1910 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1911 * @front_pad: Number of bytes to allocate in front of the returned bio
1914 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1915 * to ask for a number of bytes to be allocated in front of the bio.
1916 * Front pad allocation is useful for embedding the bio inside
1917 * another structure, to avoid allocating extra data to go with the bio.
1918 * Note that the bio must be embedded at the END of that structure always,
1919 * or things will break badly.
1921 struct bio_set
*bioset_create(unsigned int pool_size
, unsigned int front_pad
)
1923 return __bioset_create(pool_size
, front_pad
, true);
1925 EXPORT_SYMBOL(bioset_create
);
1928 * bioset_create_nobvec - Create a bio_set without bio_vec mempool
1929 * @pool_size: Number of bio to cache in the mempool
1930 * @front_pad: Number of bytes to allocate in front of the returned bio
1933 * Same functionality as bioset_create() except that mempool is not
1934 * created for bio_vecs. Saving some memory for bio_clone_fast() users.
1936 struct bio_set
*bioset_create_nobvec(unsigned int pool_size
, unsigned int front_pad
)
1938 return __bioset_create(pool_size
, front_pad
, false);
1940 EXPORT_SYMBOL(bioset_create_nobvec
);
1942 #ifdef CONFIG_BLK_CGROUP
1945 * bio_associate_blkcg - associate a bio with the specified blkcg
1947 * @blkcg_css: css of the blkcg to associate
1949 * Associate @bio with the blkcg specified by @blkcg_css. Block layer will
1950 * treat @bio as if it were issued by a task which belongs to the blkcg.
1952 * This function takes an extra reference of @blkcg_css which will be put
1953 * when @bio is released. The caller must own @bio and is responsible for
1954 * synchronizing calls to this function.
1956 int bio_associate_blkcg(struct bio
*bio
, struct cgroup_subsys_state
*blkcg_css
)
1958 if (unlikely(bio
->bi_css
))
1961 bio
->bi_css
= blkcg_css
;
1964 EXPORT_SYMBOL_GPL(bio_associate_blkcg
);
1967 * bio_associate_current - associate a bio with %current
1970 * Associate @bio with %current if it hasn't been associated yet. Block
1971 * layer will treat @bio as if it were issued by %current no matter which
1972 * task actually issues it.
1974 * This function takes an extra reference of @task's io_context and blkcg
1975 * which will be put when @bio is released. The caller must own @bio,
1976 * ensure %current->io_context exists, and is responsible for synchronizing
1977 * calls to this function.
1979 int bio_associate_current(struct bio
*bio
)
1981 struct io_context
*ioc
;
1986 ioc
= current
->io_context
;
1990 get_io_context_active(ioc
);
1992 bio
->bi_css
= task_get_css(current
, io_cgrp_id
);
1995 EXPORT_SYMBOL_GPL(bio_associate_current
);
1998 * bio_disassociate_task - undo bio_associate_current()
2001 void bio_disassociate_task(struct bio
*bio
)
2004 put_io_context(bio
->bi_ioc
);
2008 css_put(bio
->bi_css
);
2014 * bio_clone_blkcg_association - clone blkcg association from src to dst bio
2015 * @dst: destination bio
2018 void bio_clone_blkcg_association(struct bio
*dst
, struct bio
*src
)
2021 WARN_ON(bio_associate_blkcg(dst
, src
->bi_css
));
2024 #endif /* CONFIG_BLK_CGROUP */
2026 static void __init
biovec_init_slabs(void)
2030 for (i
= 0; i
< BVEC_POOL_NR
; i
++) {
2032 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
2034 if (bvs
->nr_vecs
<= BIO_INLINE_VECS
) {
2039 size
= bvs
->nr_vecs
* sizeof(struct bio_vec
);
2040 bvs
->slab
= kmem_cache_create(bvs
->name
, size
, 0,
2041 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
2045 static int __init
init_bio(void)
2049 bio_slabs
= kzalloc(bio_slab_max
* sizeof(struct bio_slab
), GFP_KERNEL
);
2051 panic("bio: can't allocate bios\n");
2053 bio_integrity_init();
2054 biovec_init_slabs();
2056 fs_bio_set
= bioset_create(BIO_POOL_SIZE
, 0);
2058 panic("bio: can't allocate bios\n");
2060 if (bioset_integrity_create(fs_bio_set
, BIO_POOL_SIZE
))
2061 panic("bio: can't create integrity pool\n");
2065 subsys_initcall(init_bio
);