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>
31 #include <scsi/sg.h> /* for struct sg_iovec */
33 #include <trace/events/block.h>
36 * Test patch to inline a certain number of bi_io_vec's inside the bio
37 * itself, to shrink a bio data allocation from two mempool calls to one
39 #define BIO_INLINE_VECS 4
42 * if you change this list, also change bvec_alloc or things will
43 * break badly! cannot be bigger than what you can fit into an
46 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
47 static struct biovec_slab bvec_slabs
[BIOVEC_NR_POOLS
] __read_mostly
= {
48 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES
),
53 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
54 * IO code that does not need private memory pools.
56 struct bio_set
*fs_bio_set
;
57 EXPORT_SYMBOL(fs_bio_set
);
60 * Our slab pool management
63 struct kmem_cache
*slab
;
64 unsigned int slab_ref
;
65 unsigned int slab_size
;
68 static DEFINE_MUTEX(bio_slab_lock
);
69 static struct bio_slab
*bio_slabs
;
70 static unsigned int bio_slab_nr
, bio_slab_max
;
72 static struct kmem_cache
*bio_find_or_create_slab(unsigned int extra_size
)
74 unsigned int sz
= sizeof(struct bio
) + extra_size
;
75 struct kmem_cache
*slab
= NULL
;
76 struct bio_slab
*bslab
, *new_bio_slabs
;
77 unsigned int new_bio_slab_max
;
78 unsigned int i
, entry
= -1;
80 mutex_lock(&bio_slab_lock
);
83 while (i
< bio_slab_nr
) {
84 bslab
= &bio_slabs
[i
];
86 if (!bslab
->slab
&& entry
== -1)
88 else if (bslab
->slab_size
== sz
) {
99 if (bio_slab_nr
== bio_slab_max
&& entry
== -1) {
100 new_bio_slab_max
= bio_slab_max
<< 1;
101 new_bio_slabs
= krealloc(bio_slabs
,
102 new_bio_slab_max
* sizeof(struct bio_slab
),
106 bio_slab_max
= new_bio_slab_max
;
107 bio_slabs
= new_bio_slabs
;
110 entry
= bio_slab_nr
++;
112 bslab
= &bio_slabs
[entry
];
114 snprintf(bslab
->name
, sizeof(bslab
->name
), "bio-%d", entry
);
115 slab
= kmem_cache_create(bslab
->name
, sz
, ARCH_KMALLOC_MINALIGN
,
116 SLAB_HWCACHE_ALIGN
, NULL
);
122 bslab
->slab_size
= sz
;
124 mutex_unlock(&bio_slab_lock
);
128 static void bio_put_slab(struct bio_set
*bs
)
130 struct bio_slab
*bslab
= NULL
;
133 mutex_lock(&bio_slab_lock
);
135 for (i
= 0; i
< bio_slab_nr
; i
++) {
136 if (bs
->bio_slab
== bio_slabs
[i
].slab
) {
137 bslab
= &bio_slabs
[i
];
142 if (WARN(!bslab
, KERN_ERR
"bio: unable to find slab!\n"))
145 WARN_ON(!bslab
->slab_ref
);
147 if (--bslab
->slab_ref
)
150 kmem_cache_destroy(bslab
->slab
);
154 mutex_unlock(&bio_slab_lock
);
157 unsigned int bvec_nr_vecs(unsigned short idx
)
159 return bvec_slabs
[idx
].nr_vecs
;
162 void bvec_free(mempool_t
*pool
, struct bio_vec
*bv
, unsigned int idx
)
164 BIO_BUG_ON(idx
>= BIOVEC_NR_POOLS
);
166 if (idx
== BIOVEC_MAX_IDX
)
167 mempool_free(bv
, pool
);
169 struct biovec_slab
*bvs
= bvec_slabs
+ idx
;
171 kmem_cache_free(bvs
->slab
, bv
);
175 struct bio_vec
*bvec_alloc(gfp_t gfp_mask
, int nr
, unsigned long *idx
,
181 * see comment near bvec_array define!
199 case 129 ... BIO_MAX_PAGES
:
207 * idx now points to the pool we want to allocate from. only the
208 * 1-vec entry pool is mempool backed.
210 if (*idx
== BIOVEC_MAX_IDX
) {
212 bvl
= mempool_alloc(pool
, gfp_mask
);
214 struct biovec_slab
*bvs
= bvec_slabs
+ *idx
;
215 gfp_t __gfp_mask
= gfp_mask
& ~(__GFP_WAIT
| __GFP_IO
);
218 * Make this allocation restricted and don't dump info on
219 * allocation failures, since we'll fallback to the mempool
220 * in case of failure.
222 __gfp_mask
|= __GFP_NOMEMALLOC
| __GFP_NORETRY
| __GFP_NOWARN
;
225 * Try a slab allocation. If this fails and __GFP_WAIT
226 * is set, retry with the 1-entry mempool
228 bvl
= kmem_cache_alloc(bvs
->slab
, __gfp_mask
);
229 if (unlikely(!bvl
&& (gfp_mask
& __GFP_WAIT
))) {
230 *idx
= BIOVEC_MAX_IDX
;
238 static void __bio_free(struct bio
*bio
)
240 bio_disassociate_task(bio
);
242 if (bio_integrity(bio
))
243 bio_integrity_free(bio
);
246 static void bio_free(struct bio
*bio
)
248 struct bio_set
*bs
= bio
->bi_pool
;
254 if (bio_flagged(bio
, BIO_OWNS_VEC
))
255 bvec_free(bs
->bvec_pool
, bio
->bi_io_vec
, BIO_POOL_IDX(bio
));
258 * If we have front padding, adjust the bio pointer before freeing
263 mempool_free(p
, bs
->bio_pool
);
265 /* Bio was allocated by bio_kmalloc() */
270 void bio_init(struct bio
*bio
)
272 memset(bio
, 0, sizeof(*bio
));
273 bio
->bi_flags
= 1 << BIO_UPTODATE
;
274 atomic_set(&bio
->bi_remaining
, 1);
275 atomic_set(&bio
->bi_cnt
, 1);
277 EXPORT_SYMBOL(bio_init
);
280 * bio_reset - reinitialize a bio
284 * After calling bio_reset(), @bio will be in the same state as a freshly
285 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
286 * preserved are the ones that are initialized by bio_alloc_bioset(). See
287 * comment in struct bio.
289 void bio_reset(struct bio
*bio
)
291 unsigned long flags
= bio
->bi_flags
& (~0UL << BIO_RESET_BITS
);
295 memset(bio
, 0, BIO_RESET_BYTES
);
296 bio
->bi_flags
= flags
|(1 << BIO_UPTODATE
);
297 atomic_set(&bio
->bi_remaining
, 1);
299 EXPORT_SYMBOL(bio_reset
);
301 static void bio_chain_endio(struct bio
*bio
, int error
)
303 bio_endio(bio
->bi_private
, error
);
308 * bio_chain - chain bio completions
309 * @bio: the target bio
310 * @parent: the @bio's parent bio
312 * The caller won't have a bi_end_io called when @bio completes - instead,
313 * @parent's bi_end_io won't be called until both @parent and @bio have
314 * completed; the chained bio will also be freed when it completes.
316 * The caller must not set bi_private or bi_end_io in @bio.
318 void bio_chain(struct bio
*bio
, struct bio
*parent
)
320 BUG_ON(bio
->bi_private
|| bio
->bi_end_io
);
322 bio
->bi_private
= parent
;
323 bio
->bi_end_io
= bio_chain_endio
;
324 atomic_inc(&parent
->bi_remaining
);
326 EXPORT_SYMBOL(bio_chain
);
328 static void bio_alloc_rescue(struct work_struct
*work
)
330 struct bio_set
*bs
= container_of(work
, struct bio_set
, rescue_work
);
334 spin_lock(&bs
->rescue_lock
);
335 bio
= bio_list_pop(&bs
->rescue_list
);
336 spin_unlock(&bs
->rescue_lock
);
341 generic_make_request(bio
);
345 static void punt_bios_to_rescuer(struct bio_set
*bs
)
347 struct bio_list punt
, nopunt
;
351 * In order to guarantee forward progress we must punt only bios that
352 * were allocated from this bio_set; otherwise, if there was a bio on
353 * there for a stacking driver higher up in the stack, processing it
354 * could require allocating bios from this bio_set, and doing that from
355 * our own rescuer would be bad.
357 * Since bio lists are singly linked, pop them all instead of trying to
358 * remove from the middle of the list:
361 bio_list_init(&punt
);
362 bio_list_init(&nopunt
);
364 while ((bio
= bio_list_pop(current
->bio_list
)))
365 bio_list_add(bio
->bi_pool
== bs
? &punt
: &nopunt
, bio
);
367 *current
->bio_list
= nopunt
;
369 spin_lock(&bs
->rescue_lock
);
370 bio_list_merge(&bs
->rescue_list
, &punt
);
371 spin_unlock(&bs
->rescue_lock
);
373 queue_work(bs
->rescue_workqueue
, &bs
->rescue_work
);
377 * bio_alloc_bioset - allocate a bio for I/O
378 * @gfp_mask: the GFP_ mask given to the slab allocator
379 * @nr_iovecs: number of iovecs to pre-allocate
380 * @bs: the bio_set to allocate from.
383 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
384 * backed by the @bs's mempool.
386 * When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
387 * able to allocate a bio. This is due to the mempool guarantees. To make this
388 * work, callers must never allocate more than 1 bio at a time from this pool.
389 * Callers that need to allocate more than 1 bio must always submit the
390 * previously allocated bio for IO before attempting to allocate a new one.
391 * Failure to do so can cause deadlocks under memory pressure.
393 * Note that when running under generic_make_request() (i.e. any block
394 * driver), bios are not submitted until after you return - see the code in
395 * generic_make_request() that converts recursion into iteration, to prevent
398 * This would normally mean allocating multiple bios under
399 * generic_make_request() would be susceptible to deadlocks, but we have
400 * deadlock avoidance code that resubmits any blocked bios from a rescuer
403 * However, we do not guarantee forward progress for allocations from other
404 * mempools. Doing multiple allocations from the same mempool under
405 * generic_make_request() should be avoided - instead, use bio_set's front_pad
406 * for per bio allocations.
409 * Pointer to new bio on success, NULL on failure.
411 struct bio
*bio_alloc_bioset(gfp_t gfp_mask
, int nr_iovecs
, struct bio_set
*bs
)
413 gfp_t saved_gfp
= gfp_mask
;
415 unsigned inline_vecs
;
416 unsigned long idx
= BIO_POOL_NONE
;
417 struct bio_vec
*bvl
= NULL
;
422 if (nr_iovecs
> UIO_MAXIOV
)
425 p
= kmalloc(sizeof(struct bio
) +
426 nr_iovecs
* sizeof(struct bio_vec
),
429 inline_vecs
= nr_iovecs
;
431 /* should not use nobvec bioset for nr_iovecs > 0 */
432 if (WARN_ON_ONCE(!bs
->bvec_pool
&& nr_iovecs
> 0))
435 * generic_make_request() converts recursion to iteration; this
436 * means if we're running beneath it, any bios we allocate and
437 * submit will not be submitted (and thus freed) until after we
440 * This exposes us to a potential deadlock if we allocate
441 * multiple bios from the same bio_set() while running
442 * underneath generic_make_request(). If we were to allocate
443 * multiple bios (say a stacking block driver that was splitting
444 * bios), we would deadlock if we exhausted the mempool's
447 * We solve this, and guarantee forward progress, with a rescuer
448 * workqueue per bio_set. If we go to allocate and there are
449 * bios on current->bio_list, we first try the allocation
450 * without __GFP_WAIT; if that fails, we punt those bios we
451 * would be blocking to the rescuer workqueue before we retry
452 * with the original gfp_flags.
455 if (current
->bio_list
&& !bio_list_empty(current
->bio_list
))
456 gfp_mask
&= ~__GFP_WAIT
;
458 p
= mempool_alloc(bs
->bio_pool
, gfp_mask
);
459 if (!p
&& gfp_mask
!= saved_gfp
) {
460 punt_bios_to_rescuer(bs
);
461 gfp_mask
= saved_gfp
;
462 p
= mempool_alloc(bs
->bio_pool
, gfp_mask
);
465 front_pad
= bs
->front_pad
;
466 inline_vecs
= BIO_INLINE_VECS
;
475 if (nr_iovecs
> inline_vecs
) {
476 bvl
= bvec_alloc(gfp_mask
, nr_iovecs
, &idx
, bs
->bvec_pool
);
477 if (!bvl
&& gfp_mask
!= saved_gfp
) {
478 punt_bios_to_rescuer(bs
);
479 gfp_mask
= saved_gfp
;
480 bvl
= bvec_alloc(gfp_mask
, nr_iovecs
, &idx
, bs
->bvec_pool
);
486 bio
->bi_flags
|= 1 << BIO_OWNS_VEC
;
487 } else if (nr_iovecs
) {
488 bvl
= bio
->bi_inline_vecs
;
492 bio
->bi_flags
|= idx
<< BIO_POOL_OFFSET
;
493 bio
->bi_max_vecs
= nr_iovecs
;
494 bio
->bi_io_vec
= bvl
;
498 mempool_free(p
, bs
->bio_pool
);
501 EXPORT_SYMBOL(bio_alloc_bioset
);
503 void zero_fill_bio(struct bio
*bio
)
507 struct bvec_iter iter
;
509 bio_for_each_segment(bv
, bio
, iter
) {
510 char *data
= bvec_kmap_irq(&bv
, &flags
);
511 memset(data
, 0, bv
.bv_len
);
512 flush_dcache_page(bv
.bv_page
);
513 bvec_kunmap_irq(data
, &flags
);
516 EXPORT_SYMBOL(zero_fill_bio
);
519 * bio_put - release a reference to a bio
520 * @bio: bio to release reference to
523 * Put a reference to a &struct bio, either one you have gotten with
524 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
526 void bio_put(struct bio
*bio
)
528 BIO_BUG_ON(!atomic_read(&bio
->bi_cnt
));
533 if (atomic_dec_and_test(&bio
->bi_cnt
))
536 EXPORT_SYMBOL(bio_put
);
538 inline int bio_phys_segments(struct request_queue
*q
, struct bio
*bio
)
540 if (unlikely(!bio_flagged(bio
, BIO_SEG_VALID
)))
541 blk_recount_segments(q
, bio
);
543 return bio
->bi_phys_segments
;
545 EXPORT_SYMBOL(bio_phys_segments
);
548 * __bio_clone_fast - clone a bio that shares the original bio's biovec
549 * @bio: destination bio
550 * @bio_src: bio to clone
552 * Clone a &bio. Caller will own the returned bio, but not
553 * the actual data it points to. Reference count of returned
556 * Caller must ensure that @bio_src is not freed before @bio.
558 void __bio_clone_fast(struct bio
*bio
, struct bio
*bio_src
)
560 BUG_ON(bio
->bi_pool
&& BIO_POOL_IDX(bio
) != BIO_POOL_NONE
);
563 * most users will be overriding ->bi_bdev with a new target,
564 * so we don't set nor calculate new physical/hw segment counts here
566 bio
->bi_bdev
= bio_src
->bi_bdev
;
567 bio
->bi_flags
|= 1 << BIO_CLONED
;
568 bio
->bi_rw
= bio_src
->bi_rw
;
569 bio
->bi_iter
= bio_src
->bi_iter
;
570 bio
->bi_io_vec
= bio_src
->bi_io_vec
;
572 EXPORT_SYMBOL(__bio_clone_fast
);
575 * bio_clone_fast - clone a bio that shares the original bio's biovec
577 * @gfp_mask: allocation priority
578 * @bs: bio_set to allocate from
580 * Like __bio_clone_fast, only also allocates the returned bio
582 struct bio
*bio_clone_fast(struct bio
*bio
, gfp_t gfp_mask
, struct bio_set
*bs
)
586 b
= bio_alloc_bioset(gfp_mask
, 0, bs
);
590 __bio_clone_fast(b
, bio
);
592 if (bio_integrity(bio
)) {
595 ret
= bio_integrity_clone(b
, bio
, gfp_mask
);
605 EXPORT_SYMBOL(bio_clone_fast
);
608 * bio_clone_bioset - clone a bio
609 * @bio_src: bio to clone
610 * @gfp_mask: allocation priority
611 * @bs: bio_set to allocate from
613 * Clone bio. Caller will own the returned bio, but not the actual data it
614 * points to. Reference count of returned bio will be one.
616 struct bio
*bio_clone_bioset(struct bio
*bio_src
, gfp_t gfp_mask
,
619 struct bvec_iter iter
;
624 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
625 * bio_src->bi_io_vec to bio->bi_io_vec.
627 * We can't do that anymore, because:
629 * - The point of cloning the biovec is to produce a bio with a biovec
630 * the caller can modify: bi_idx and bi_bvec_done should be 0.
632 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if
633 * we tried to clone the whole thing bio_alloc_bioset() would fail.
634 * But the clone should succeed as long as the number of biovecs we
635 * actually need to allocate is fewer than BIO_MAX_PAGES.
637 * - Lastly, bi_vcnt should not be looked at or relied upon by code
638 * that does not own the bio - reason being drivers don't use it for
639 * iterating over the biovec anymore, so expecting it to be kept up
640 * to date (i.e. for clones that share the parent biovec) is just
641 * asking for trouble and would force extra work on
642 * __bio_clone_fast() anyways.
645 bio
= bio_alloc_bioset(gfp_mask
, bio_segments(bio_src
), bs
);
649 bio
->bi_bdev
= bio_src
->bi_bdev
;
650 bio
->bi_rw
= bio_src
->bi_rw
;
651 bio
->bi_iter
.bi_sector
= bio_src
->bi_iter
.bi_sector
;
652 bio
->bi_iter
.bi_size
= bio_src
->bi_iter
.bi_size
;
654 if (bio
->bi_rw
& REQ_DISCARD
)
655 goto integrity_clone
;
657 if (bio
->bi_rw
& REQ_WRITE_SAME
) {
658 bio
->bi_io_vec
[bio
->bi_vcnt
++] = bio_src
->bi_io_vec
[0];
659 goto integrity_clone
;
662 bio_for_each_segment(bv
, bio_src
, iter
)
663 bio
->bi_io_vec
[bio
->bi_vcnt
++] = bv
;
666 if (bio_integrity(bio_src
)) {
669 ret
= bio_integrity_clone(bio
, bio_src
, gfp_mask
);
678 EXPORT_SYMBOL(bio_clone_bioset
);
681 * bio_get_nr_vecs - return approx number of vecs
684 * Return the approximate number of pages we can send to this target.
685 * There's no guarantee that you will be able to fit this number of pages
686 * into a bio, it does not account for dynamic restrictions that vary
689 int bio_get_nr_vecs(struct block_device
*bdev
)
691 struct request_queue
*q
= bdev_get_queue(bdev
);
694 nr_pages
= min_t(unsigned,
695 queue_max_segments(q
),
696 queue_max_sectors(q
) / (PAGE_SIZE
>> 9) + 1);
698 return min_t(unsigned, nr_pages
, BIO_MAX_PAGES
);
701 EXPORT_SYMBOL(bio_get_nr_vecs
);
703 static int __bio_add_page(struct request_queue
*q
, struct bio
*bio
, struct page
704 *page
, unsigned int len
, unsigned int offset
,
705 unsigned int max_sectors
)
707 int retried_segments
= 0;
708 struct bio_vec
*bvec
;
711 * cloned bio must not modify vec list
713 if (unlikely(bio_flagged(bio
, BIO_CLONED
)))
716 if (((bio
->bi_iter
.bi_size
+ len
) >> 9) > max_sectors
)
720 * For filesystems with a blocksize smaller than the pagesize
721 * we will often be called with the same page as last time and
722 * a consecutive offset. Optimize this special case.
724 if (bio
->bi_vcnt
> 0) {
725 struct bio_vec
*prev
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
727 if (page
== prev
->bv_page
&&
728 offset
== prev
->bv_offset
+ prev
->bv_len
) {
729 unsigned int prev_bv_len
= prev
->bv_len
;
732 if (q
->merge_bvec_fn
) {
733 struct bvec_merge_data bvm
= {
734 /* prev_bvec is already charged in
735 bi_size, discharge it in order to
736 simulate merging updated prev_bvec
738 .bi_bdev
= bio
->bi_bdev
,
739 .bi_sector
= bio
->bi_iter
.bi_sector
,
740 .bi_size
= bio
->bi_iter
.bi_size
-
745 if (q
->merge_bvec_fn(q
, &bvm
, prev
) < prev
->bv_len
) {
751 bio
->bi_iter
.bi_size
+= len
;
756 * If the queue doesn't support SG gaps and adding this
757 * offset would create a gap, disallow it.
759 if (q
->queue_flags
& (1 << QUEUE_FLAG_SG_GAPS
) &&
760 bvec_gap_to_prev(prev
, offset
))
764 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
768 * setup the new entry, we might clear it again later if we
769 * cannot add the page
771 bvec
= &bio
->bi_io_vec
[bio
->bi_vcnt
];
772 bvec
->bv_page
= page
;
774 bvec
->bv_offset
= offset
;
776 bio
->bi_phys_segments
++;
777 bio
->bi_iter
.bi_size
+= len
;
780 * Perform a recount if the number of segments is greater
781 * than queue_max_segments(q).
784 while (bio
->bi_phys_segments
> queue_max_segments(q
)) {
786 if (retried_segments
)
789 retried_segments
= 1;
790 blk_recount_segments(q
, bio
);
794 * if queue has other restrictions (eg varying max sector size
795 * depending on offset), it can specify a merge_bvec_fn in the
796 * queue to get further control
798 if (q
->merge_bvec_fn
) {
799 struct bvec_merge_data bvm
= {
800 .bi_bdev
= bio
->bi_bdev
,
801 .bi_sector
= bio
->bi_iter
.bi_sector
,
802 .bi_size
= bio
->bi_iter
.bi_size
- len
,
807 * merge_bvec_fn() returns number of bytes it can accept
810 if (q
->merge_bvec_fn(q
, &bvm
, bvec
) < bvec
->bv_len
)
814 /* If we may be able to merge these biovecs, force a recount */
815 if (bio
->bi_vcnt
> 1 && (BIOVEC_PHYS_MERGEABLE(bvec
-1, bvec
)))
816 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
822 bvec
->bv_page
= NULL
;
826 bio
->bi_iter
.bi_size
-= len
;
827 blk_recount_segments(q
, bio
);
832 * bio_add_pc_page - attempt to add page to bio
833 * @q: the target queue
834 * @bio: destination bio
836 * @len: vec entry length
837 * @offset: vec entry offset
839 * Attempt to add a page to the bio_vec maplist. This can fail for a
840 * number of reasons, such as the bio being full or target block device
841 * limitations. The target block device must allow bio's up to PAGE_SIZE,
842 * so it is always possible to add a single page to an empty bio.
844 * This should only be used by REQ_PC bios.
846 int bio_add_pc_page(struct request_queue
*q
, struct bio
*bio
, struct page
*page
,
847 unsigned int len
, unsigned int offset
)
849 return __bio_add_page(q
, bio
, page
, len
, offset
,
850 queue_max_hw_sectors(q
));
852 EXPORT_SYMBOL(bio_add_pc_page
);
855 * bio_add_page - attempt to add page to bio
856 * @bio: destination bio
858 * @len: vec entry length
859 * @offset: vec entry offset
861 * Attempt to add a page to the bio_vec maplist. This can fail for a
862 * number of reasons, such as the bio being full or target block device
863 * limitations. The target block device must allow bio's up to PAGE_SIZE,
864 * so it is always possible to add a single page to an empty bio.
866 int bio_add_page(struct bio
*bio
, struct page
*page
, unsigned int len
,
869 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
870 unsigned int max_sectors
;
872 max_sectors
= blk_max_size_offset(q
, bio
->bi_iter
.bi_sector
);
873 if ((max_sectors
< (len
>> 9)) && !bio
->bi_iter
.bi_size
)
874 max_sectors
= len
>> 9;
876 return __bio_add_page(q
, bio
, page
, len
, offset
, max_sectors
);
878 EXPORT_SYMBOL(bio_add_page
);
880 struct submit_bio_ret
{
881 struct completion event
;
885 static void submit_bio_wait_endio(struct bio
*bio
, int error
)
887 struct submit_bio_ret
*ret
= bio
->bi_private
;
890 complete(&ret
->event
);
894 * submit_bio_wait - submit a bio, and wait until it completes
895 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
896 * @bio: The &struct bio which describes the I/O
898 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
899 * bio_endio() on failure.
901 int submit_bio_wait(int rw
, struct bio
*bio
)
903 struct submit_bio_ret ret
;
906 init_completion(&ret
.event
);
907 bio
->bi_private
= &ret
;
908 bio
->bi_end_io
= submit_bio_wait_endio
;
910 wait_for_completion(&ret
.event
);
914 EXPORT_SYMBOL(submit_bio_wait
);
917 * bio_advance - increment/complete a bio by some number of bytes
918 * @bio: bio to advance
919 * @bytes: number of bytes to complete
921 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
922 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
923 * be updated on the last bvec as well.
925 * @bio will then represent the remaining, uncompleted portion of the io.
927 void bio_advance(struct bio
*bio
, unsigned bytes
)
929 if (bio_integrity(bio
))
930 bio_integrity_advance(bio
, bytes
);
932 bio_advance_iter(bio
, &bio
->bi_iter
, bytes
);
934 EXPORT_SYMBOL(bio_advance
);
937 * bio_alloc_pages - allocates a single page for each bvec in a bio
938 * @bio: bio to allocate pages for
939 * @gfp_mask: flags for allocation
941 * Allocates pages up to @bio->bi_vcnt.
943 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
946 int bio_alloc_pages(struct bio
*bio
, gfp_t gfp_mask
)
951 bio_for_each_segment_all(bv
, bio
, i
) {
952 bv
->bv_page
= alloc_page(gfp_mask
);
954 while (--bv
>= bio
->bi_io_vec
)
955 __free_page(bv
->bv_page
);
962 EXPORT_SYMBOL(bio_alloc_pages
);
965 * bio_copy_data - copy contents of data buffers from one chain of bios to
967 * @src: source bio list
968 * @dst: destination bio list
970 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
971 * @src and @dst as linked lists of bios.
973 * Stops when it reaches the end of either @src or @dst - that is, copies
974 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
976 void bio_copy_data(struct bio
*dst
, struct bio
*src
)
978 struct bvec_iter src_iter
, dst_iter
;
979 struct bio_vec src_bv
, dst_bv
;
983 src_iter
= src
->bi_iter
;
984 dst_iter
= dst
->bi_iter
;
987 if (!src_iter
.bi_size
) {
992 src_iter
= src
->bi_iter
;
995 if (!dst_iter
.bi_size
) {
1000 dst_iter
= dst
->bi_iter
;
1003 src_bv
= bio_iter_iovec(src
, src_iter
);
1004 dst_bv
= bio_iter_iovec(dst
, dst_iter
);
1006 bytes
= min(src_bv
.bv_len
, dst_bv
.bv_len
);
1008 src_p
= kmap_atomic(src_bv
.bv_page
);
1009 dst_p
= kmap_atomic(dst_bv
.bv_page
);
1011 memcpy(dst_p
+ dst_bv
.bv_offset
,
1012 src_p
+ src_bv
.bv_offset
,
1015 kunmap_atomic(dst_p
);
1016 kunmap_atomic(src_p
);
1018 bio_advance_iter(src
, &src_iter
, bytes
);
1019 bio_advance_iter(dst
, &dst_iter
, bytes
);
1022 EXPORT_SYMBOL(bio_copy_data
);
1024 struct bio_map_data
{
1027 struct sg_iovec sgvecs
[];
1030 static void bio_set_map_data(struct bio_map_data
*bmd
, struct bio
*bio
,
1031 const struct sg_iovec
*iov
, int iov_count
,
1034 memcpy(bmd
->sgvecs
, iov
, sizeof(struct sg_iovec
) * iov_count
);
1035 bmd
->nr_sgvecs
= iov_count
;
1036 bmd
->is_our_pages
= is_our_pages
;
1037 bio
->bi_private
= bmd
;
1040 static struct bio_map_data
*bio_alloc_map_data(unsigned int iov_count
,
1043 if (iov_count
> UIO_MAXIOV
)
1046 return kmalloc(sizeof(struct bio_map_data
) +
1047 sizeof(struct sg_iovec
) * iov_count
, gfp_mask
);
1050 static int __bio_copy_iov(struct bio
*bio
, const struct sg_iovec
*iov
, int iov_count
,
1051 int to_user
, int from_user
, int do_free_page
)
1054 struct bio_vec
*bvec
;
1056 unsigned int iov_off
= 0;
1058 bio_for_each_segment_all(bvec
, bio
, i
) {
1059 char *bv_addr
= page_address(bvec
->bv_page
);
1060 unsigned int bv_len
= bvec
->bv_len
;
1062 while (bv_len
&& iov_idx
< iov_count
) {
1064 char __user
*iov_addr
;
1066 bytes
= min_t(unsigned int,
1067 iov
[iov_idx
].iov_len
- iov_off
, bv_len
);
1068 iov_addr
= iov
[iov_idx
].iov_base
+ iov_off
;
1072 ret
= copy_to_user(iov_addr
, bv_addr
,
1076 ret
= copy_from_user(bv_addr
, iov_addr
,
1088 if (iov
[iov_idx
].iov_len
== iov_off
) {
1095 __free_page(bvec
->bv_page
);
1102 * bio_uncopy_user - finish previously mapped bio
1103 * @bio: bio being terminated
1105 * Free pages allocated from bio_copy_user() and write back data
1106 * to user space in case of a read.
1108 int bio_uncopy_user(struct bio
*bio
)
1110 struct bio_map_data
*bmd
= bio
->bi_private
;
1111 struct bio_vec
*bvec
;
1114 if (!bio_flagged(bio
, BIO_NULL_MAPPED
)) {
1116 * if we're in a workqueue, the request is orphaned, so
1117 * don't copy into a random user address space, just free.
1120 ret
= __bio_copy_iov(bio
, bmd
->sgvecs
, bmd
->nr_sgvecs
,
1121 bio_data_dir(bio
) == READ
,
1122 0, bmd
->is_our_pages
);
1123 else if (bmd
->is_our_pages
)
1124 bio_for_each_segment_all(bvec
, bio
, i
)
1125 __free_page(bvec
->bv_page
);
1131 EXPORT_SYMBOL(bio_uncopy_user
);
1134 * bio_copy_user_iov - copy user data to bio
1135 * @q: destination block queue
1136 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1138 * @iov_count: number of elements in the iovec
1139 * @write_to_vm: bool indicating writing to pages or not
1140 * @gfp_mask: memory allocation flags
1142 * Prepares and returns a bio for indirect user io, bouncing data
1143 * to/from kernel pages as necessary. Must be paired with
1144 * call bio_uncopy_user() on io completion.
1146 struct bio
*bio_copy_user_iov(struct request_queue
*q
,
1147 struct rq_map_data
*map_data
,
1148 const struct sg_iovec
*iov
, int iov_count
,
1149 int write_to_vm
, gfp_t gfp_mask
)
1151 struct bio_map_data
*bmd
;
1152 struct bio_vec
*bvec
;
1157 unsigned int len
= 0;
1158 unsigned int offset
= map_data
? map_data
->offset
& ~PAGE_MASK
: 0;
1160 for (i
= 0; i
< iov_count
; i
++) {
1161 unsigned long uaddr
;
1163 unsigned long start
;
1165 uaddr
= (unsigned long)iov
[i
].iov_base
;
1166 end
= (uaddr
+ iov
[i
].iov_len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1167 start
= uaddr
>> PAGE_SHIFT
;
1173 return ERR_PTR(-EINVAL
);
1175 nr_pages
+= end
- start
;
1176 len
+= iov
[i
].iov_len
;
1182 bmd
= bio_alloc_map_data(iov_count
, gfp_mask
);
1184 return ERR_PTR(-ENOMEM
);
1187 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1192 bio
->bi_rw
|= REQ_WRITE
;
1197 nr_pages
= 1 << map_data
->page_order
;
1198 i
= map_data
->offset
/ PAGE_SIZE
;
1201 unsigned int bytes
= PAGE_SIZE
;
1209 if (i
== map_data
->nr_entries
* nr_pages
) {
1214 page
= map_data
->pages
[i
/ nr_pages
];
1215 page
+= (i
% nr_pages
);
1219 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
1226 if (bio_add_pc_page(q
, bio
, page
, bytes
, offset
) < bytes
)
1239 if ((!write_to_vm
&& (!map_data
|| !map_data
->null_mapped
)) ||
1240 (map_data
&& map_data
->from_user
)) {
1241 ret
= __bio_copy_iov(bio
, iov
, iov_count
, 0, 1, 0);
1246 bio_set_map_data(bmd
, bio
, iov
, iov_count
, map_data
? 0 : 1);
1250 bio_for_each_segment_all(bvec
, bio
, i
)
1251 __free_page(bvec
->bv_page
);
1256 return ERR_PTR(ret
);
1260 * bio_copy_user - copy user data to bio
1261 * @q: destination block queue
1262 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1263 * @uaddr: start of user address
1264 * @len: length in bytes
1265 * @write_to_vm: bool indicating writing to pages or not
1266 * @gfp_mask: memory allocation flags
1268 * Prepares and returns a bio for indirect user io, bouncing data
1269 * to/from kernel pages as necessary. Must be paired with
1270 * call bio_uncopy_user() on io completion.
1272 struct bio
*bio_copy_user(struct request_queue
*q
, struct rq_map_data
*map_data
,
1273 unsigned long uaddr
, unsigned int len
,
1274 int write_to_vm
, gfp_t gfp_mask
)
1276 struct sg_iovec iov
;
1278 iov
.iov_base
= (void __user
*)uaddr
;
1281 return bio_copy_user_iov(q
, map_data
, &iov
, 1, write_to_vm
, gfp_mask
);
1283 EXPORT_SYMBOL(bio_copy_user
);
1285 static struct bio
*__bio_map_user_iov(struct request_queue
*q
,
1286 struct block_device
*bdev
,
1287 const struct sg_iovec
*iov
, int iov_count
,
1288 int write_to_vm
, gfp_t gfp_mask
)
1292 struct page
**pages
;
1297 for (i
= 0; i
< iov_count
; i
++) {
1298 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
1299 unsigned long len
= iov
[i
].iov_len
;
1300 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1301 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1307 return ERR_PTR(-EINVAL
);
1309 nr_pages
+= end
- start
;
1311 * buffer must be aligned to at least hardsector size for now
1313 if (uaddr
& queue_dma_alignment(q
))
1314 return ERR_PTR(-EINVAL
);
1318 return ERR_PTR(-EINVAL
);
1320 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1322 return ERR_PTR(-ENOMEM
);
1325 pages
= kcalloc(nr_pages
, sizeof(struct page
*), gfp_mask
);
1329 for (i
= 0; i
< iov_count
; i
++) {
1330 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
1331 unsigned long len
= iov
[i
].iov_len
;
1332 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1333 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1334 const int local_nr_pages
= end
- start
;
1335 const int page_limit
= cur_page
+ local_nr_pages
;
1337 ret
= get_user_pages_fast(uaddr
, local_nr_pages
,
1338 write_to_vm
, &pages
[cur_page
]);
1339 if (ret
< local_nr_pages
) {
1344 offset
= uaddr
& ~PAGE_MASK
;
1345 for (j
= cur_page
; j
< page_limit
; j
++) {
1346 unsigned int bytes
= PAGE_SIZE
- offset
;
1357 if (bio_add_pc_page(q
, bio
, pages
[j
], bytes
, offset
) <
1367 * release the pages we didn't map into the bio, if any
1369 while (j
< page_limit
)
1370 page_cache_release(pages
[j
++]);
1376 * set data direction, and check if mapped pages need bouncing
1379 bio
->bi_rw
|= REQ_WRITE
;
1381 bio
->bi_bdev
= bdev
;
1382 bio
->bi_flags
|= (1 << BIO_USER_MAPPED
);
1386 for (i
= 0; i
< nr_pages
; i
++) {
1389 page_cache_release(pages
[i
]);
1394 return ERR_PTR(ret
);
1398 * bio_map_user - map user address into bio
1399 * @q: the struct request_queue for the bio
1400 * @bdev: destination block device
1401 * @uaddr: start of user address
1402 * @len: length in bytes
1403 * @write_to_vm: bool indicating writing to pages or not
1404 * @gfp_mask: memory allocation flags
1406 * Map the user space address into a bio suitable for io to a block
1407 * device. Returns an error pointer in case of error.
1409 struct bio
*bio_map_user(struct request_queue
*q
, struct block_device
*bdev
,
1410 unsigned long uaddr
, unsigned int len
, int write_to_vm
,
1413 struct sg_iovec iov
;
1415 iov
.iov_base
= (void __user
*)uaddr
;
1418 return bio_map_user_iov(q
, bdev
, &iov
, 1, write_to_vm
, gfp_mask
);
1420 EXPORT_SYMBOL(bio_map_user
);
1423 * bio_map_user_iov - map user sg_iovec table into bio
1424 * @q: the struct request_queue for the bio
1425 * @bdev: destination block device
1427 * @iov_count: number of elements in the iovec
1428 * @write_to_vm: bool indicating writing to pages or not
1429 * @gfp_mask: memory allocation flags
1431 * Map the user space address into a bio suitable for io to a block
1432 * device. Returns an error pointer in case of error.
1434 struct bio
*bio_map_user_iov(struct request_queue
*q
, struct block_device
*bdev
,
1435 const struct sg_iovec
*iov
, int iov_count
,
1436 int write_to_vm
, gfp_t gfp_mask
)
1440 bio
= __bio_map_user_iov(q
, bdev
, iov
, iov_count
, write_to_vm
,
1446 * subtle -- if __bio_map_user() ended up bouncing a bio,
1447 * it would normally disappear when its bi_end_io is run.
1448 * however, we need it for the unmap, so grab an extra
1456 static void __bio_unmap_user(struct bio
*bio
)
1458 struct bio_vec
*bvec
;
1462 * make sure we dirty pages we wrote to
1464 bio_for_each_segment_all(bvec
, bio
, i
) {
1465 if (bio_data_dir(bio
) == READ
)
1466 set_page_dirty_lock(bvec
->bv_page
);
1468 page_cache_release(bvec
->bv_page
);
1475 * bio_unmap_user - unmap a bio
1476 * @bio: the bio being unmapped
1478 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1479 * a process context.
1481 * bio_unmap_user() may sleep.
1483 void bio_unmap_user(struct bio
*bio
)
1485 __bio_unmap_user(bio
);
1488 EXPORT_SYMBOL(bio_unmap_user
);
1490 static void bio_map_kern_endio(struct bio
*bio
, int err
)
1495 static struct bio
*__bio_map_kern(struct request_queue
*q
, void *data
,
1496 unsigned int len
, gfp_t gfp_mask
)
1498 unsigned long kaddr
= (unsigned long)data
;
1499 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1500 unsigned long start
= kaddr
>> PAGE_SHIFT
;
1501 const int nr_pages
= end
- start
;
1505 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1507 return ERR_PTR(-ENOMEM
);
1509 offset
= offset_in_page(kaddr
);
1510 for (i
= 0; i
< nr_pages
; i
++) {
1511 unsigned int bytes
= PAGE_SIZE
- offset
;
1519 if (bio_add_pc_page(q
, bio
, virt_to_page(data
), bytes
,
1528 bio
->bi_end_io
= bio_map_kern_endio
;
1533 * bio_map_kern - map kernel address into bio
1534 * @q: the struct request_queue for the bio
1535 * @data: pointer to buffer to map
1536 * @len: length in bytes
1537 * @gfp_mask: allocation flags for bio allocation
1539 * Map the kernel address into a bio suitable for io to a block
1540 * device. Returns an error pointer in case of error.
1542 struct bio
*bio_map_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1547 bio
= __bio_map_kern(q
, data
, len
, gfp_mask
);
1551 if (bio
->bi_iter
.bi_size
== len
)
1555 * Don't support partial mappings.
1558 return ERR_PTR(-EINVAL
);
1560 EXPORT_SYMBOL(bio_map_kern
);
1562 static void bio_copy_kern_endio(struct bio
*bio
, int err
)
1564 struct bio_vec
*bvec
;
1565 const int read
= bio_data_dir(bio
) == READ
;
1566 struct bio_map_data
*bmd
= bio
->bi_private
;
1568 char *p
= bmd
->sgvecs
[0].iov_base
;
1570 bio_for_each_segment_all(bvec
, bio
, i
) {
1571 char *addr
= page_address(bvec
->bv_page
);
1574 memcpy(p
, addr
, bvec
->bv_len
);
1576 __free_page(bvec
->bv_page
);
1585 * bio_copy_kern - copy kernel address into bio
1586 * @q: the struct request_queue for the bio
1587 * @data: pointer to buffer to copy
1588 * @len: length in bytes
1589 * @gfp_mask: allocation flags for bio and page allocation
1590 * @reading: data direction is READ
1592 * copy the kernel address into a bio suitable for io to a block
1593 * device. Returns an error pointer in case of error.
1595 struct bio
*bio_copy_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1596 gfp_t gfp_mask
, int reading
)
1599 struct bio_vec
*bvec
;
1602 bio
= bio_copy_user(q
, NULL
, (unsigned long)data
, len
, 1, gfp_mask
);
1609 bio_for_each_segment_all(bvec
, bio
, i
) {
1610 char *addr
= page_address(bvec
->bv_page
);
1612 memcpy(addr
, p
, bvec
->bv_len
);
1617 bio
->bi_end_io
= bio_copy_kern_endio
;
1621 EXPORT_SYMBOL(bio_copy_kern
);
1624 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1625 * for performing direct-IO in BIOs.
1627 * The problem is that we cannot run set_page_dirty() from interrupt context
1628 * because the required locks are not interrupt-safe. So what we can do is to
1629 * mark the pages dirty _before_ performing IO. And in interrupt context,
1630 * check that the pages are still dirty. If so, fine. If not, redirty them
1631 * in process context.
1633 * We special-case compound pages here: normally this means reads into hugetlb
1634 * pages. The logic in here doesn't really work right for compound pages
1635 * because the VM does not uniformly chase down the head page in all cases.
1636 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1637 * handle them at all. So we skip compound pages here at an early stage.
1639 * Note that this code is very hard to test under normal circumstances because
1640 * direct-io pins the pages with get_user_pages(). This makes
1641 * is_page_cache_freeable return false, and the VM will not clean the pages.
1642 * But other code (eg, flusher threads) could clean the pages if they are mapped
1645 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1646 * deferred bio dirtying paths.
1650 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1652 void bio_set_pages_dirty(struct bio
*bio
)
1654 struct bio_vec
*bvec
;
1657 bio_for_each_segment_all(bvec
, bio
, i
) {
1658 struct page
*page
= bvec
->bv_page
;
1660 if (page
&& !PageCompound(page
))
1661 set_page_dirty_lock(page
);
1665 static void bio_release_pages(struct bio
*bio
)
1667 struct bio_vec
*bvec
;
1670 bio_for_each_segment_all(bvec
, bio
, i
) {
1671 struct page
*page
= bvec
->bv_page
;
1679 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1680 * If they are, then fine. If, however, some pages are clean then they must
1681 * have been written out during the direct-IO read. So we take another ref on
1682 * the BIO and the offending pages and re-dirty the pages in process context.
1684 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1685 * here on. It will run one page_cache_release() against each page and will
1686 * run one bio_put() against the BIO.
1689 static void bio_dirty_fn(struct work_struct
*work
);
1691 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1692 static DEFINE_SPINLOCK(bio_dirty_lock
);
1693 static struct bio
*bio_dirty_list
;
1696 * This runs in process context
1698 static void bio_dirty_fn(struct work_struct
*work
)
1700 unsigned long flags
;
1703 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1704 bio
= bio_dirty_list
;
1705 bio_dirty_list
= NULL
;
1706 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1709 struct bio
*next
= bio
->bi_private
;
1711 bio_set_pages_dirty(bio
);
1712 bio_release_pages(bio
);
1718 void bio_check_pages_dirty(struct bio
*bio
)
1720 struct bio_vec
*bvec
;
1721 int nr_clean_pages
= 0;
1724 bio_for_each_segment_all(bvec
, bio
, i
) {
1725 struct page
*page
= bvec
->bv_page
;
1727 if (PageDirty(page
) || PageCompound(page
)) {
1728 page_cache_release(page
);
1729 bvec
->bv_page
= NULL
;
1735 if (nr_clean_pages
) {
1736 unsigned long flags
;
1738 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1739 bio
->bi_private
= bio_dirty_list
;
1740 bio_dirty_list
= bio
;
1741 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1742 schedule_work(&bio_dirty_work
);
1748 void generic_start_io_acct(int rw
, unsigned long sectors
,
1749 struct hd_struct
*part
)
1751 int cpu
= part_stat_lock();
1753 part_round_stats(cpu
, part
);
1754 part_stat_inc(cpu
, part
, ios
[rw
]);
1755 part_stat_add(cpu
, part
, sectors
[rw
], sectors
);
1756 part_inc_in_flight(part
, rw
);
1760 EXPORT_SYMBOL(generic_start_io_acct
);
1762 void generic_end_io_acct(int rw
, struct hd_struct
*part
,
1763 unsigned long start_time
)
1765 unsigned long duration
= jiffies
- start_time
;
1766 int cpu
= part_stat_lock();
1768 part_stat_add(cpu
, part
, ticks
[rw
], duration
);
1769 part_round_stats(cpu
, part
);
1770 part_dec_in_flight(part
, rw
);
1774 EXPORT_SYMBOL(generic_end_io_acct
);
1776 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1777 void bio_flush_dcache_pages(struct bio
*bi
)
1779 struct bio_vec bvec
;
1780 struct bvec_iter iter
;
1782 bio_for_each_segment(bvec
, bi
, iter
)
1783 flush_dcache_page(bvec
.bv_page
);
1785 EXPORT_SYMBOL(bio_flush_dcache_pages
);
1789 * bio_endio - end I/O on a bio
1791 * @error: error, if any
1794 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1795 * preferred way to end I/O on a bio, it takes care of clearing
1796 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1797 * established -Exxxx (-EIO, for instance) error values in case
1798 * something went wrong. No one should call bi_end_io() directly on a
1799 * bio unless they own it and thus know that it has an end_io
1802 void bio_endio(struct bio
*bio
, int error
)
1805 BUG_ON(atomic_read(&bio
->bi_remaining
) <= 0);
1808 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1809 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
1812 if (!atomic_dec_and_test(&bio
->bi_remaining
))
1816 * Need to have a real endio function for chained bios,
1817 * otherwise various corner cases will break (like stacking
1818 * block devices that save/restore bi_end_io) - however, we want
1819 * to avoid unbounded recursion and blowing the stack. Tail call
1820 * optimization would handle this, but compiling with frame
1821 * pointers also disables gcc's sibling call optimization.
1823 if (bio
->bi_end_io
== bio_chain_endio
) {
1824 struct bio
*parent
= bio
->bi_private
;
1829 bio
->bi_end_io(bio
, error
);
1834 EXPORT_SYMBOL(bio_endio
);
1837 * bio_endio_nodec - end I/O on a bio, without decrementing bi_remaining
1839 * @error: error, if any
1841 * For code that has saved and restored bi_end_io; thing hard before using this
1842 * function, probably you should've cloned the entire bio.
1844 void bio_endio_nodec(struct bio
*bio
, int error
)
1846 atomic_inc(&bio
->bi_remaining
);
1847 bio_endio(bio
, error
);
1849 EXPORT_SYMBOL(bio_endio_nodec
);
1852 * bio_split - split a bio
1853 * @bio: bio to split
1854 * @sectors: number of sectors to split from the front of @bio
1856 * @bs: bio set to allocate from
1858 * Allocates and returns a new bio which represents @sectors from the start of
1859 * @bio, and updates @bio to represent the remaining sectors.
1861 * The newly allocated bio will point to @bio's bi_io_vec; it is the caller's
1862 * responsibility to ensure that @bio is not freed before the split.
1864 struct bio
*bio_split(struct bio
*bio
, int sectors
,
1865 gfp_t gfp
, struct bio_set
*bs
)
1867 struct bio
*split
= NULL
;
1869 BUG_ON(sectors
<= 0);
1870 BUG_ON(sectors
>= bio_sectors(bio
));
1872 split
= bio_clone_fast(bio
, gfp
, bs
);
1876 split
->bi_iter
.bi_size
= sectors
<< 9;
1878 if (bio_integrity(split
))
1879 bio_integrity_trim(split
, 0, sectors
);
1881 bio_advance(bio
, split
->bi_iter
.bi_size
);
1885 EXPORT_SYMBOL(bio_split
);
1888 * bio_trim - trim a bio
1890 * @offset: number of sectors to trim from the front of @bio
1891 * @size: size we want to trim @bio to, in sectors
1893 void bio_trim(struct bio
*bio
, int offset
, int size
)
1895 /* 'bio' is a cloned bio which we need to trim to match
1896 * the given offset and size.
1900 if (offset
== 0 && size
== bio
->bi_iter
.bi_size
)
1903 clear_bit(BIO_SEG_VALID
, &bio
->bi_flags
);
1905 bio_advance(bio
, offset
<< 9);
1907 bio
->bi_iter
.bi_size
= size
;
1909 EXPORT_SYMBOL_GPL(bio_trim
);
1912 * create memory pools for biovec's in a bio_set.
1913 * use the global biovec slabs created for general use.
1915 mempool_t
*biovec_create_pool(int pool_entries
)
1917 struct biovec_slab
*bp
= bvec_slabs
+ BIOVEC_MAX_IDX
;
1919 return mempool_create_slab_pool(pool_entries
, bp
->slab
);
1922 void bioset_free(struct bio_set
*bs
)
1924 if (bs
->rescue_workqueue
)
1925 destroy_workqueue(bs
->rescue_workqueue
);
1928 mempool_destroy(bs
->bio_pool
);
1931 mempool_destroy(bs
->bvec_pool
);
1933 bioset_integrity_free(bs
);
1938 EXPORT_SYMBOL(bioset_free
);
1940 static struct bio_set
*__bioset_create(unsigned int pool_size
,
1941 unsigned int front_pad
,
1942 bool create_bvec_pool
)
1944 unsigned int back_pad
= BIO_INLINE_VECS
* sizeof(struct bio_vec
);
1947 bs
= kzalloc(sizeof(*bs
), GFP_KERNEL
);
1951 bs
->front_pad
= front_pad
;
1953 spin_lock_init(&bs
->rescue_lock
);
1954 bio_list_init(&bs
->rescue_list
);
1955 INIT_WORK(&bs
->rescue_work
, bio_alloc_rescue
);
1957 bs
->bio_slab
= bio_find_or_create_slab(front_pad
+ back_pad
);
1958 if (!bs
->bio_slab
) {
1963 bs
->bio_pool
= mempool_create_slab_pool(pool_size
, bs
->bio_slab
);
1967 if (create_bvec_pool
) {
1968 bs
->bvec_pool
= biovec_create_pool(pool_size
);
1973 bs
->rescue_workqueue
= alloc_workqueue("bioset", WQ_MEM_RECLAIM
, 0);
1974 if (!bs
->rescue_workqueue
)
1984 * bioset_create - Create a bio_set
1985 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1986 * @front_pad: Number of bytes to allocate in front of the returned bio
1989 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1990 * to ask for a number of bytes to be allocated in front of the bio.
1991 * Front pad allocation is useful for embedding the bio inside
1992 * another structure, to avoid allocating extra data to go with the bio.
1993 * Note that the bio must be embedded at the END of that structure always,
1994 * or things will break badly.
1996 struct bio_set
*bioset_create(unsigned int pool_size
, unsigned int front_pad
)
1998 return __bioset_create(pool_size
, front_pad
, true);
2000 EXPORT_SYMBOL(bioset_create
);
2003 * bioset_create_nobvec - Create a bio_set without bio_vec mempool
2004 * @pool_size: Number of bio to cache in the mempool
2005 * @front_pad: Number of bytes to allocate in front of the returned bio
2008 * Same functionality as bioset_create() except that mempool is not
2009 * created for bio_vecs. Saving some memory for bio_clone_fast() users.
2011 struct bio_set
*bioset_create_nobvec(unsigned int pool_size
, unsigned int front_pad
)
2013 return __bioset_create(pool_size
, front_pad
, false);
2015 EXPORT_SYMBOL(bioset_create_nobvec
);
2017 #ifdef CONFIG_BLK_CGROUP
2019 * bio_associate_current - associate a bio with %current
2022 * Associate @bio with %current if it hasn't been associated yet. Block
2023 * layer will treat @bio as if it were issued by %current no matter which
2024 * task actually issues it.
2026 * This function takes an extra reference of @task's io_context and blkcg
2027 * which will be put when @bio is released. The caller must own @bio,
2028 * ensure %current->io_context exists, and is responsible for synchronizing
2029 * calls to this function.
2031 int bio_associate_current(struct bio
*bio
)
2033 struct io_context
*ioc
;
2034 struct cgroup_subsys_state
*css
;
2039 ioc
= current
->io_context
;
2043 /* acquire active ref on @ioc and associate */
2044 get_io_context_active(ioc
);
2047 /* associate blkcg if exists */
2049 css
= task_css(current
, blkio_cgrp_id
);
2050 if (css
&& css_tryget_online(css
))
2058 * bio_disassociate_task - undo bio_associate_current()
2061 void bio_disassociate_task(struct bio
*bio
)
2064 put_io_context(bio
->bi_ioc
);
2068 css_put(bio
->bi_css
);
2073 #endif /* CONFIG_BLK_CGROUP */
2075 static void __init
biovec_init_slabs(void)
2079 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
2081 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
2083 if (bvs
->nr_vecs
<= BIO_INLINE_VECS
) {
2088 size
= bvs
->nr_vecs
* sizeof(struct bio_vec
);
2089 bvs
->slab
= kmem_cache_create(bvs
->name
, size
, 0,
2090 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
2094 static int __init
init_bio(void)
2098 bio_slabs
= kzalloc(bio_slab_max
* sizeof(struct bio_slab
), GFP_KERNEL
);
2100 panic("bio: can't allocate bios\n");
2102 bio_integrity_init();
2103 biovec_init_slabs();
2105 fs_bio_set
= bioset_create(BIO_POOL_SIZE
, 0);
2107 panic("bio: can't allocate bios\n");
2109 if (bioset_integrity_create(fs_bio_set
, BIO_POOL_SIZE
))
2110 panic("bio: can't create integrity pool\n");
2114 subsys_initcall(init_bio
);
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