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/iocontext.h>
23 #include <linux/slab.h>
24 #include <linux/init.h>
25 #include <linux/kernel.h>
26 #include <linux/export.h>
27 #include <linux/mempool.h>
28 #include <linux/workqueue.h>
29 #include <linux/cgroup.h>
30 #include <scsi/sg.h> /* for struct sg_iovec */
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
40 static mempool_t
*bio_split_pool __read_mostly
;
43 * if you change this list, also change bvec_alloc or things will
44 * break badly! cannot be bigger than what you can fit into an
47 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
48 static struct biovec_slab bvec_slabs
[BIOVEC_NR_POOLS
] __read_mostly
= {
49 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES
),
54 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
55 * IO code that does not need private memory pools.
57 struct bio_set
*fs_bio_set
;
58 EXPORT_SYMBOL(fs_bio_set
);
61 * Our slab pool management
64 struct kmem_cache
*slab
;
65 unsigned int slab_ref
;
66 unsigned int slab_size
;
69 static DEFINE_MUTEX(bio_slab_lock
);
70 static struct bio_slab
*bio_slabs
;
71 static unsigned int bio_slab_nr
, bio_slab_max
;
73 static struct kmem_cache
*bio_find_or_create_slab(unsigned int extra_size
)
75 unsigned int sz
= sizeof(struct bio
) + extra_size
;
76 struct kmem_cache
*slab
= NULL
;
77 struct bio_slab
*bslab
, *new_bio_slabs
;
78 unsigned int new_bio_slab_max
;
79 unsigned int i
, entry
= -1;
81 mutex_lock(&bio_slab_lock
);
84 while (i
< bio_slab_nr
) {
85 bslab
= &bio_slabs
[i
];
87 if (!bslab
->slab
&& entry
== -1)
89 else if (bslab
->slab_size
== sz
) {
100 if (bio_slab_nr
== bio_slab_max
&& entry
== -1) {
101 new_bio_slab_max
= bio_slab_max
<< 1;
102 new_bio_slabs
= krealloc(bio_slabs
,
103 new_bio_slab_max
* sizeof(struct bio_slab
),
107 bio_slab_max
= new_bio_slab_max
;
108 bio_slabs
= new_bio_slabs
;
111 entry
= bio_slab_nr
++;
113 bslab
= &bio_slabs
[entry
];
115 snprintf(bslab
->name
, sizeof(bslab
->name
), "bio-%d", entry
);
116 slab
= kmem_cache_create(bslab
->name
, sz
, 0, SLAB_HWCACHE_ALIGN
, NULL
);
120 printk(KERN_INFO
"bio: create slab <%s> at %d\n", bslab
->name
, entry
);
123 bslab
->slab_size
= sz
;
125 mutex_unlock(&bio_slab_lock
);
129 static void bio_put_slab(struct bio_set
*bs
)
131 struct bio_slab
*bslab
= NULL
;
134 mutex_lock(&bio_slab_lock
);
136 for (i
= 0; i
< bio_slab_nr
; i
++) {
137 if (bs
->bio_slab
== bio_slabs
[i
].slab
) {
138 bslab
= &bio_slabs
[i
];
143 if (WARN(!bslab
, KERN_ERR
"bio: unable to find slab!\n"))
146 WARN_ON(!bslab
->slab_ref
);
148 if (--bslab
->slab_ref
)
151 kmem_cache_destroy(bslab
->slab
);
155 mutex_unlock(&bio_slab_lock
);
158 unsigned int bvec_nr_vecs(unsigned short idx
)
160 return bvec_slabs
[idx
].nr_vecs
;
163 void bvec_free(mempool_t
*pool
, struct bio_vec
*bv
, unsigned int idx
)
165 BIO_BUG_ON(idx
>= BIOVEC_NR_POOLS
);
167 if (idx
== BIOVEC_MAX_IDX
)
168 mempool_free(bv
, pool
);
170 struct biovec_slab
*bvs
= bvec_slabs
+ idx
;
172 kmem_cache_free(bvs
->slab
, bv
);
176 struct bio_vec
*bvec_alloc(gfp_t gfp_mask
, int nr
, unsigned long *idx
,
182 * see comment near bvec_array define!
200 case 129 ... BIO_MAX_PAGES
:
208 * idx now points to the pool we want to allocate from. only the
209 * 1-vec entry pool is mempool backed.
211 if (*idx
== BIOVEC_MAX_IDX
) {
213 bvl
= mempool_alloc(pool
, gfp_mask
);
215 struct biovec_slab
*bvs
= bvec_slabs
+ *idx
;
216 gfp_t __gfp_mask
= gfp_mask
& ~(__GFP_WAIT
| __GFP_IO
);
219 * Make this allocation restricted and don't dump info on
220 * allocation failures, since we'll fallback to the mempool
221 * in case of failure.
223 __gfp_mask
|= __GFP_NOMEMALLOC
| __GFP_NORETRY
| __GFP_NOWARN
;
226 * Try a slab allocation. If this fails and __GFP_WAIT
227 * is set, retry with the 1-entry mempool
229 bvl
= kmem_cache_alloc(bvs
->slab
, __gfp_mask
);
230 if (unlikely(!bvl
&& (gfp_mask
& __GFP_WAIT
))) {
231 *idx
= BIOVEC_MAX_IDX
;
239 static void __bio_free(struct bio
*bio
)
241 bio_disassociate_task(bio
);
243 if (bio_integrity(bio
))
244 bio_integrity_free(bio
);
247 static void bio_free(struct bio
*bio
)
249 struct bio_set
*bs
= bio
->bi_pool
;
255 if (bio_has_allocated_vec(bio
))
256 bvec_free(bs
->bvec_pool
, bio
->bi_io_vec
, BIO_POOL_IDX(bio
));
259 * If we have front padding, adjust the bio pointer before freeing
264 mempool_free(p
, bs
->bio_pool
);
266 /* Bio was allocated by bio_kmalloc() */
271 void bio_init(struct bio
*bio
)
273 memset(bio
, 0, sizeof(*bio
));
274 bio
->bi_flags
= 1 << BIO_UPTODATE
;
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
);
298 EXPORT_SYMBOL(bio_reset
);
300 static void bio_alloc_rescue(struct work_struct
*work
)
302 struct bio_set
*bs
= container_of(work
, struct bio_set
, rescue_work
);
306 spin_lock(&bs
->rescue_lock
);
307 bio
= bio_list_pop(&bs
->rescue_list
);
308 spin_unlock(&bs
->rescue_lock
);
313 generic_make_request(bio
);
317 static void punt_bios_to_rescuer(struct bio_set
*bs
)
319 struct bio_list punt
, nopunt
;
323 * In order to guarantee forward progress we must punt only bios that
324 * were allocated from this bio_set; otherwise, if there was a bio on
325 * there for a stacking driver higher up in the stack, processing it
326 * could require allocating bios from this bio_set, and doing that from
327 * our own rescuer would be bad.
329 * Since bio lists are singly linked, pop them all instead of trying to
330 * remove from the middle of the list:
333 bio_list_init(&punt
);
334 bio_list_init(&nopunt
);
336 while ((bio
= bio_list_pop(current
->bio_list
)))
337 bio_list_add(bio
->bi_pool
== bs
? &punt
: &nopunt
, bio
);
339 *current
->bio_list
= nopunt
;
341 spin_lock(&bs
->rescue_lock
);
342 bio_list_merge(&bs
->rescue_list
, &punt
);
343 spin_unlock(&bs
->rescue_lock
);
345 queue_work(bs
->rescue_workqueue
, &bs
->rescue_work
);
349 * bio_alloc_bioset - allocate a bio for I/O
350 * @gfp_mask: the GFP_ mask given to the slab allocator
351 * @nr_iovecs: number of iovecs to pre-allocate
352 * @bs: the bio_set to allocate from.
355 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is
356 * backed by the @bs's mempool.
358 * When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
359 * able to allocate a bio. This is due to the mempool guarantees. To make this
360 * work, callers must never allocate more than 1 bio at a time from this pool.
361 * Callers that need to allocate more than 1 bio must always submit the
362 * previously allocated bio for IO before attempting to allocate a new one.
363 * Failure to do so can cause deadlocks under memory pressure.
365 * Note that when running under generic_make_request() (i.e. any block
366 * driver), bios are not submitted until after you return - see the code in
367 * generic_make_request() that converts recursion into iteration, to prevent
370 * This would normally mean allocating multiple bios under
371 * generic_make_request() would be susceptible to deadlocks, but we have
372 * deadlock avoidance code that resubmits any blocked bios from a rescuer
375 * However, we do not guarantee forward progress for allocations from other
376 * mempools. Doing multiple allocations from the same mempool under
377 * generic_make_request() should be avoided - instead, use bio_set's front_pad
378 * for per bio allocations.
381 * Pointer to new bio on success, NULL on failure.
383 struct bio
*bio_alloc_bioset(gfp_t gfp_mask
, int nr_iovecs
, struct bio_set
*bs
)
385 gfp_t saved_gfp
= gfp_mask
;
387 unsigned inline_vecs
;
388 unsigned long idx
= BIO_POOL_NONE
;
389 struct bio_vec
*bvl
= NULL
;
394 if (nr_iovecs
> UIO_MAXIOV
)
397 p
= kmalloc(sizeof(struct bio
) +
398 nr_iovecs
* sizeof(struct bio_vec
),
401 inline_vecs
= nr_iovecs
;
404 * generic_make_request() converts recursion to iteration; this
405 * means if we're running beneath it, any bios we allocate and
406 * submit will not be submitted (and thus freed) until after we
409 * This exposes us to a potential deadlock if we allocate
410 * multiple bios from the same bio_set() while running
411 * underneath generic_make_request(). If we were to allocate
412 * multiple bios (say a stacking block driver that was splitting
413 * bios), we would deadlock if we exhausted the mempool's
416 * We solve this, and guarantee forward progress, with a rescuer
417 * workqueue per bio_set. If we go to allocate and there are
418 * bios on current->bio_list, we first try the allocation
419 * without __GFP_WAIT; if that fails, we punt those bios we
420 * would be blocking to the rescuer workqueue before we retry
421 * with the original gfp_flags.
424 if (current
->bio_list
&& !bio_list_empty(current
->bio_list
))
425 gfp_mask
&= ~__GFP_WAIT
;
427 p
= mempool_alloc(bs
->bio_pool
, gfp_mask
);
428 if (!p
&& gfp_mask
!= saved_gfp
) {
429 punt_bios_to_rescuer(bs
);
430 gfp_mask
= saved_gfp
;
431 p
= mempool_alloc(bs
->bio_pool
, gfp_mask
);
434 front_pad
= bs
->front_pad
;
435 inline_vecs
= BIO_INLINE_VECS
;
444 if (nr_iovecs
> inline_vecs
) {
445 bvl
= bvec_alloc(gfp_mask
, nr_iovecs
, &idx
, bs
->bvec_pool
);
446 if (!bvl
&& gfp_mask
!= saved_gfp
) {
447 punt_bios_to_rescuer(bs
);
448 gfp_mask
= saved_gfp
;
449 bvl
= bvec_alloc(gfp_mask
, nr_iovecs
, &idx
, bs
->bvec_pool
);
454 } else if (nr_iovecs
) {
455 bvl
= bio
->bi_inline_vecs
;
459 bio
->bi_flags
|= idx
<< BIO_POOL_OFFSET
;
460 bio
->bi_max_vecs
= nr_iovecs
;
461 bio
->bi_io_vec
= bvl
;
465 mempool_free(p
, bs
->bio_pool
);
468 EXPORT_SYMBOL(bio_alloc_bioset
);
470 void zero_fill_bio(struct bio
*bio
)
476 bio_for_each_segment(bv
, bio
, i
) {
477 char *data
= bvec_kmap_irq(bv
, &flags
);
478 memset(data
, 0, bv
->bv_len
);
479 flush_dcache_page(bv
->bv_page
);
480 bvec_kunmap_irq(data
, &flags
);
483 EXPORT_SYMBOL(zero_fill_bio
);
486 * bio_put - release a reference to a bio
487 * @bio: bio to release reference to
490 * Put a reference to a &struct bio, either one you have gotten with
491 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
493 void bio_put(struct bio
*bio
)
495 BIO_BUG_ON(!atomic_read(&bio
->bi_cnt
));
500 if (atomic_dec_and_test(&bio
->bi_cnt
))
503 EXPORT_SYMBOL(bio_put
);
505 inline int bio_phys_segments(struct request_queue
*q
, struct bio
*bio
)
507 if (unlikely(!bio_flagged(bio
, BIO_SEG_VALID
)))
508 blk_recount_segments(q
, bio
);
510 return bio
->bi_phys_segments
;
512 EXPORT_SYMBOL(bio_phys_segments
);
515 * __bio_clone - clone a bio
516 * @bio: destination bio
517 * @bio_src: bio to clone
519 * Clone a &bio. Caller will own the returned bio, but not
520 * the actual data it points to. Reference count of returned
523 void __bio_clone(struct bio
*bio
, struct bio
*bio_src
)
525 memcpy(bio
->bi_io_vec
, bio_src
->bi_io_vec
,
526 bio_src
->bi_max_vecs
* sizeof(struct bio_vec
));
529 * most users will be overriding ->bi_bdev with a new target,
530 * so we don't set nor calculate new physical/hw segment counts here
532 bio
->bi_sector
= bio_src
->bi_sector
;
533 bio
->bi_bdev
= bio_src
->bi_bdev
;
534 bio
->bi_flags
|= 1 << BIO_CLONED
;
535 bio
->bi_rw
= bio_src
->bi_rw
;
536 bio
->bi_vcnt
= bio_src
->bi_vcnt
;
537 bio
->bi_size
= bio_src
->bi_size
;
538 bio
->bi_idx
= bio_src
->bi_idx
;
540 EXPORT_SYMBOL(__bio_clone
);
543 * bio_clone_bioset - clone a bio
545 * @gfp_mask: allocation priority
546 * @bs: bio_set to allocate from
548 * Like __bio_clone, only also allocates the returned bio
550 struct bio
*bio_clone_bioset(struct bio
*bio
, gfp_t gfp_mask
,
555 b
= bio_alloc_bioset(gfp_mask
, bio
->bi_max_vecs
, bs
);
561 if (bio_integrity(bio
)) {
564 ret
= bio_integrity_clone(b
, bio
, gfp_mask
);
574 EXPORT_SYMBOL(bio_clone_bioset
);
577 * bio_get_nr_vecs - return approx number of vecs
580 * Return the approximate number of pages we can send to this target.
581 * There's no guarantee that you will be able to fit this number of pages
582 * into a bio, it does not account for dynamic restrictions that vary
585 int bio_get_nr_vecs(struct block_device
*bdev
)
587 struct request_queue
*q
= bdev_get_queue(bdev
);
590 nr_pages
= min_t(unsigned,
591 queue_max_segments(q
),
592 queue_max_sectors(q
) / (PAGE_SIZE
>> 9) + 1);
594 return min_t(unsigned, nr_pages
, BIO_MAX_PAGES
);
597 EXPORT_SYMBOL(bio_get_nr_vecs
);
599 static int __bio_add_page(struct request_queue
*q
, struct bio
*bio
, struct page
600 *page
, unsigned int len
, unsigned int offset
,
601 unsigned short max_sectors
)
603 int retried_segments
= 0;
604 struct bio_vec
*bvec
;
607 * cloned bio must not modify vec list
609 if (unlikely(bio_flagged(bio
, BIO_CLONED
)))
612 if (((bio
->bi_size
+ len
) >> 9) > max_sectors
)
616 * For filesystems with a blocksize smaller than the pagesize
617 * we will often be called with the same page as last time and
618 * a consecutive offset. Optimize this special case.
620 if (bio
->bi_vcnt
> 0) {
621 struct bio_vec
*prev
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
623 if (page
== prev
->bv_page
&&
624 offset
== prev
->bv_offset
+ prev
->bv_len
) {
625 unsigned int prev_bv_len
= prev
->bv_len
;
628 if (q
->merge_bvec_fn
) {
629 struct bvec_merge_data bvm
= {
630 /* prev_bvec is already charged in
631 bi_size, discharge it in order to
632 simulate merging updated prev_bvec
634 .bi_bdev
= bio
->bi_bdev
,
635 .bi_sector
= bio
->bi_sector
,
636 .bi_size
= bio
->bi_size
- prev_bv_len
,
640 if (q
->merge_bvec_fn(q
, &bvm
, prev
) < prev
->bv_len
) {
650 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
654 * we might lose a segment or two here, but rather that than
655 * make this too complex.
658 while (bio
->bi_phys_segments
>= queue_max_segments(q
)) {
660 if (retried_segments
)
663 retried_segments
= 1;
664 blk_recount_segments(q
, bio
);
668 * setup the new entry, we might clear it again later if we
669 * cannot add the page
671 bvec
= &bio
->bi_io_vec
[bio
->bi_vcnt
];
672 bvec
->bv_page
= page
;
674 bvec
->bv_offset
= offset
;
677 * if queue has other restrictions (eg varying max sector size
678 * depending on offset), it can specify a merge_bvec_fn in the
679 * queue to get further control
681 if (q
->merge_bvec_fn
) {
682 struct bvec_merge_data bvm
= {
683 .bi_bdev
= bio
->bi_bdev
,
684 .bi_sector
= bio
->bi_sector
,
685 .bi_size
= bio
->bi_size
,
690 * merge_bvec_fn() returns number of bytes it can accept
693 if (q
->merge_bvec_fn(q
, &bvm
, bvec
) < bvec
->bv_len
) {
694 bvec
->bv_page
= NULL
;
701 /* If we may be able to merge these biovecs, force a recount */
702 if (bio
->bi_vcnt
&& (BIOVEC_PHYS_MERGEABLE(bvec
-1, bvec
)))
703 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
706 bio
->bi_phys_segments
++;
713 * bio_add_pc_page - attempt to add page to bio
714 * @q: the target queue
715 * @bio: destination bio
717 * @len: vec entry length
718 * @offset: vec entry offset
720 * Attempt to add a page to the bio_vec maplist. This can fail for a
721 * number of reasons, such as the bio being full or target block device
722 * limitations. The target block device must allow bio's up to PAGE_SIZE,
723 * so it is always possible to add a single page to an empty bio.
725 * This should only be used by REQ_PC bios.
727 int bio_add_pc_page(struct request_queue
*q
, struct bio
*bio
, struct page
*page
,
728 unsigned int len
, unsigned int offset
)
730 return __bio_add_page(q
, bio
, page
, len
, offset
,
731 queue_max_hw_sectors(q
));
733 EXPORT_SYMBOL(bio_add_pc_page
);
736 * bio_add_page - attempt to add page to bio
737 * @bio: destination bio
739 * @len: vec entry length
740 * @offset: vec entry offset
742 * Attempt to add a page to the bio_vec maplist. This can fail for a
743 * number of reasons, such as the bio being full or target block device
744 * limitations. The target block device must allow bio's up to PAGE_SIZE,
745 * so it is always possible to add a single page to an empty bio.
747 int bio_add_page(struct bio
*bio
, struct page
*page
, unsigned int len
,
750 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
751 return __bio_add_page(q
, bio
, page
, len
, offset
, queue_max_sectors(q
));
753 EXPORT_SYMBOL(bio_add_page
);
755 struct submit_bio_ret
{
756 struct completion event
;
760 static void submit_bio_wait_endio(struct bio
*bio
, int error
)
762 struct submit_bio_ret
*ret
= bio
->bi_private
;
765 complete(&ret
->event
);
769 * submit_bio_wait - submit a bio, and wait until it completes
770 * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
771 * @bio: The &struct bio which describes the I/O
773 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from
774 * bio_endio() on failure.
776 int submit_bio_wait(int rw
, struct bio
*bio
)
778 struct submit_bio_ret ret
;
781 init_completion(&ret
.event
);
782 bio
->bi_private
= &ret
;
783 bio
->bi_end_io
= submit_bio_wait_endio
;
785 wait_for_completion(&ret
.event
);
789 EXPORT_SYMBOL(submit_bio_wait
);
792 * bio_advance - increment/complete a bio by some number of bytes
793 * @bio: bio to advance
794 * @bytes: number of bytes to complete
796 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to
797 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will
798 * be updated on the last bvec as well.
800 * @bio will then represent the remaining, uncompleted portion of the io.
802 void bio_advance(struct bio
*bio
, unsigned bytes
)
804 if (bio_integrity(bio
))
805 bio_integrity_advance(bio
, bytes
);
807 bio
->bi_sector
+= bytes
>> 9;
808 bio
->bi_size
-= bytes
;
810 if (bio
->bi_rw
& BIO_NO_ADVANCE_ITER_MASK
)
814 if (unlikely(bio
->bi_idx
>= bio
->bi_vcnt
)) {
815 WARN_ONCE(1, "bio idx %d >= vcnt %d\n",
816 bio
->bi_idx
, bio
->bi_vcnt
);
820 if (bytes
>= bio_iovec(bio
)->bv_len
) {
821 bytes
-= bio_iovec(bio
)->bv_len
;
824 bio_iovec(bio
)->bv_len
-= bytes
;
825 bio_iovec(bio
)->bv_offset
+= bytes
;
830 EXPORT_SYMBOL(bio_advance
);
833 * bio_alloc_pages - allocates a single page for each bvec in a bio
834 * @bio: bio to allocate pages for
835 * @gfp_mask: flags for allocation
837 * Allocates pages up to @bio->bi_vcnt.
839 * Returns 0 on success, -ENOMEM on failure. On failure, any allocated pages are
842 int bio_alloc_pages(struct bio
*bio
, gfp_t gfp_mask
)
847 bio_for_each_segment_all(bv
, bio
, i
) {
848 bv
->bv_page
= alloc_page(gfp_mask
);
850 while (--bv
>= bio
->bi_io_vec
)
851 __free_page(bv
->bv_page
);
858 EXPORT_SYMBOL(bio_alloc_pages
);
861 * bio_copy_data - copy contents of data buffers from one chain of bios to
863 * @src: source bio list
864 * @dst: destination bio list
866 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
867 * @src and @dst as linked lists of bios.
869 * Stops when it reaches the end of either @src or @dst - that is, copies
870 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
872 void bio_copy_data(struct bio
*dst
, struct bio
*src
)
874 struct bio_vec
*src_bv
, *dst_bv
;
875 unsigned src_offset
, dst_offset
, bytes
;
878 src_bv
= bio_iovec(src
);
879 dst_bv
= bio_iovec(dst
);
881 src_offset
= src_bv
->bv_offset
;
882 dst_offset
= dst_bv
->bv_offset
;
885 if (src_offset
== src_bv
->bv_offset
+ src_bv
->bv_len
) {
887 if (src_bv
== bio_iovec_idx(src
, src
->bi_vcnt
)) {
892 src_bv
= bio_iovec(src
);
895 src_offset
= src_bv
->bv_offset
;
898 if (dst_offset
== dst_bv
->bv_offset
+ dst_bv
->bv_len
) {
900 if (dst_bv
== bio_iovec_idx(dst
, dst
->bi_vcnt
)) {
905 dst_bv
= bio_iovec(dst
);
908 dst_offset
= dst_bv
->bv_offset
;
911 bytes
= min(dst_bv
->bv_offset
+ dst_bv
->bv_len
- dst_offset
,
912 src_bv
->bv_offset
+ src_bv
->bv_len
- src_offset
);
914 src_p
= kmap_atomic(src_bv
->bv_page
);
915 dst_p
= kmap_atomic(dst_bv
->bv_page
);
917 memcpy(dst_p
+ dst_bv
->bv_offset
,
918 src_p
+ src_bv
->bv_offset
,
921 kunmap_atomic(dst_p
);
922 kunmap_atomic(src_p
);
928 EXPORT_SYMBOL(bio_copy_data
);
930 struct bio_map_data
{
931 struct bio_vec
*iovecs
;
932 struct sg_iovec
*sgvecs
;
937 static void bio_set_map_data(struct bio_map_data
*bmd
, struct bio
*bio
,
938 struct sg_iovec
*iov
, int iov_count
,
941 memcpy(bmd
->iovecs
, bio
->bi_io_vec
, sizeof(struct bio_vec
) * bio
->bi_vcnt
);
942 memcpy(bmd
->sgvecs
, iov
, sizeof(struct sg_iovec
) * iov_count
);
943 bmd
->nr_sgvecs
= iov_count
;
944 bmd
->is_our_pages
= is_our_pages
;
945 bio
->bi_private
= bmd
;
948 static void bio_free_map_data(struct bio_map_data
*bmd
)
955 static struct bio_map_data
*bio_alloc_map_data(int nr_segs
,
956 unsigned int iov_count
,
959 struct bio_map_data
*bmd
;
961 if (iov_count
> UIO_MAXIOV
)
964 bmd
= kmalloc(sizeof(*bmd
), gfp_mask
);
968 bmd
->iovecs
= kmalloc(sizeof(struct bio_vec
) * nr_segs
, gfp_mask
);
974 bmd
->sgvecs
= kmalloc(sizeof(struct sg_iovec
) * iov_count
, gfp_mask
);
983 static int __bio_copy_iov(struct bio
*bio
, struct bio_vec
*iovecs
,
984 struct sg_iovec
*iov
, int iov_count
,
985 int to_user
, int from_user
, int do_free_page
)
988 struct bio_vec
*bvec
;
990 unsigned int iov_off
= 0;
992 bio_for_each_segment_all(bvec
, bio
, i
) {
993 char *bv_addr
= page_address(bvec
->bv_page
);
994 unsigned int bv_len
= iovecs
[i
].bv_len
;
996 while (bv_len
&& iov_idx
< iov_count
) {
998 char __user
*iov_addr
;
1000 bytes
= min_t(unsigned int,
1001 iov
[iov_idx
].iov_len
- iov_off
, bv_len
);
1002 iov_addr
= iov
[iov_idx
].iov_base
+ iov_off
;
1006 ret
= copy_to_user(iov_addr
, bv_addr
,
1010 ret
= copy_from_user(bv_addr
, iov_addr
,
1022 if (iov
[iov_idx
].iov_len
== iov_off
) {
1029 __free_page(bvec
->bv_page
);
1036 * bio_uncopy_user - finish previously mapped bio
1037 * @bio: bio being terminated
1039 * Free pages allocated from bio_copy_user() and write back data
1040 * to user space in case of a read.
1042 int bio_uncopy_user(struct bio
*bio
)
1044 struct bio_map_data
*bmd
= bio
->bi_private
;
1047 if (!bio_flagged(bio
, BIO_NULL_MAPPED
))
1048 ret
= __bio_copy_iov(bio
, bmd
->iovecs
, bmd
->sgvecs
,
1049 bmd
->nr_sgvecs
, bio_data_dir(bio
) == READ
,
1050 0, bmd
->is_our_pages
);
1051 bio_free_map_data(bmd
);
1055 EXPORT_SYMBOL(bio_uncopy_user
);
1058 * bio_copy_user_iov - copy user data to bio
1059 * @q: destination block queue
1060 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1062 * @iov_count: number of elements in the iovec
1063 * @write_to_vm: bool indicating writing to pages or not
1064 * @gfp_mask: memory allocation flags
1066 * Prepares and returns a bio for indirect user io, bouncing data
1067 * to/from kernel pages as necessary. Must be paired with
1068 * call bio_uncopy_user() on io completion.
1070 struct bio
*bio_copy_user_iov(struct request_queue
*q
,
1071 struct rq_map_data
*map_data
,
1072 struct sg_iovec
*iov
, int iov_count
,
1073 int write_to_vm
, gfp_t gfp_mask
)
1075 struct bio_map_data
*bmd
;
1076 struct bio_vec
*bvec
;
1081 unsigned int len
= 0;
1082 unsigned int offset
= map_data
? map_data
->offset
& ~PAGE_MASK
: 0;
1084 for (i
= 0; i
< iov_count
; i
++) {
1085 unsigned long uaddr
;
1087 unsigned long start
;
1089 uaddr
= (unsigned long)iov
[i
].iov_base
;
1090 end
= (uaddr
+ iov
[i
].iov_len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1091 start
= uaddr
>> PAGE_SHIFT
;
1097 return ERR_PTR(-EINVAL
);
1099 nr_pages
+= end
- start
;
1100 len
+= iov
[i
].iov_len
;
1106 bmd
= bio_alloc_map_data(nr_pages
, iov_count
, gfp_mask
);
1108 return ERR_PTR(-ENOMEM
);
1111 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1116 bio
->bi_rw
|= REQ_WRITE
;
1121 nr_pages
= 1 << map_data
->page_order
;
1122 i
= map_data
->offset
/ PAGE_SIZE
;
1125 unsigned int bytes
= PAGE_SIZE
;
1133 if (i
== map_data
->nr_entries
* nr_pages
) {
1138 page
= map_data
->pages
[i
/ nr_pages
];
1139 page
+= (i
% nr_pages
);
1143 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
1150 if (bio_add_pc_page(q
, bio
, page
, bytes
, offset
) < bytes
)
1163 if ((!write_to_vm
&& (!map_data
|| !map_data
->null_mapped
)) ||
1164 (map_data
&& map_data
->from_user
)) {
1165 ret
= __bio_copy_iov(bio
, bio
->bi_io_vec
, iov
, iov_count
, 0, 1, 0);
1170 bio_set_map_data(bmd
, bio
, iov
, iov_count
, map_data
? 0 : 1);
1174 bio_for_each_segment_all(bvec
, bio
, i
)
1175 __free_page(bvec
->bv_page
);
1179 bio_free_map_data(bmd
);
1180 return ERR_PTR(ret
);
1184 * bio_copy_user - copy user data to bio
1185 * @q: destination block queue
1186 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1187 * @uaddr: start of user address
1188 * @len: length in bytes
1189 * @write_to_vm: bool indicating writing to pages or not
1190 * @gfp_mask: memory allocation flags
1192 * Prepares and returns a bio for indirect user io, bouncing data
1193 * to/from kernel pages as necessary. Must be paired with
1194 * call bio_uncopy_user() on io completion.
1196 struct bio
*bio_copy_user(struct request_queue
*q
, struct rq_map_data
*map_data
,
1197 unsigned long uaddr
, unsigned int len
,
1198 int write_to_vm
, gfp_t gfp_mask
)
1200 struct sg_iovec iov
;
1202 iov
.iov_base
= (void __user
*)uaddr
;
1205 return bio_copy_user_iov(q
, map_data
, &iov
, 1, write_to_vm
, gfp_mask
);
1207 EXPORT_SYMBOL(bio_copy_user
);
1209 static struct bio
*__bio_map_user_iov(struct request_queue
*q
,
1210 struct block_device
*bdev
,
1211 struct sg_iovec
*iov
, int iov_count
,
1212 int write_to_vm
, gfp_t gfp_mask
)
1216 struct page
**pages
;
1221 for (i
= 0; i
< iov_count
; i
++) {
1222 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
1223 unsigned long len
= iov
[i
].iov_len
;
1224 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1225 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1231 return ERR_PTR(-EINVAL
);
1233 nr_pages
+= end
- start
;
1235 * buffer must be aligned to at least hardsector size for now
1237 if (uaddr
& queue_dma_alignment(q
))
1238 return ERR_PTR(-EINVAL
);
1242 return ERR_PTR(-EINVAL
);
1244 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1246 return ERR_PTR(-ENOMEM
);
1249 pages
= kcalloc(nr_pages
, sizeof(struct page
*), gfp_mask
);
1253 for (i
= 0; i
< iov_count
; i
++) {
1254 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
1255 unsigned long len
= iov
[i
].iov_len
;
1256 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1257 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1258 const int local_nr_pages
= end
- start
;
1259 const int page_limit
= cur_page
+ local_nr_pages
;
1261 ret
= get_user_pages_fast(uaddr
, local_nr_pages
,
1262 write_to_vm
, &pages
[cur_page
]);
1263 if (ret
< local_nr_pages
) {
1268 offset
= uaddr
& ~PAGE_MASK
;
1269 for (j
= cur_page
; j
< page_limit
; j
++) {
1270 unsigned int bytes
= PAGE_SIZE
- offset
;
1281 if (bio_add_pc_page(q
, bio
, pages
[j
], bytes
, offset
) <
1291 * release the pages we didn't map into the bio, if any
1293 while (j
< page_limit
)
1294 page_cache_release(pages
[j
++]);
1300 * set data direction, and check if mapped pages need bouncing
1303 bio
->bi_rw
|= REQ_WRITE
;
1305 bio
->bi_bdev
= bdev
;
1306 bio
->bi_flags
|= (1 << BIO_USER_MAPPED
);
1310 for (i
= 0; i
< nr_pages
; i
++) {
1313 page_cache_release(pages
[i
]);
1318 return ERR_PTR(ret
);
1322 * bio_map_user - map user address into bio
1323 * @q: the struct request_queue for the bio
1324 * @bdev: destination block device
1325 * @uaddr: start of user address
1326 * @len: length in bytes
1327 * @write_to_vm: bool indicating writing to pages or not
1328 * @gfp_mask: memory allocation flags
1330 * Map the user space address into a bio suitable for io to a block
1331 * device. Returns an error pointer in case of error.
1333 struct bio
*bio_map_user(struct request_queue
*q
, struct block_device
*bdev
,
1334 unsigned long uaddr
, unsigned int len
, int write_to_vm
,
1337 struct sg_iovec iov
;
1339 iov
.iov_base
= (void __user
*)uaddr
;
1342 return bio_map_user_iov(q
, bdev
, &iov
, 1, write_to_vm
, gfp_mask
);
1344 EXPORT_SYMBOL(bio_map_user
);
1347 * bio_map_user_iov - map user sg_iovec table into bio
1348 * @q: the struct request_queue for the bio
1349 * @bdev: destination block device
1351 * @iov_count: number of elements in the iovec
1352 * @write_to_vm: bool indicating writing to pages or not
1353 * @gfp_mask: memory allocation flags
1355 * Map the user space address into a bio suitable for io to a block
1356 * device. Returns an error pointer in case of error.
1358 struct bio
*bio_map_user_iov(struct request_queue
*q
, struct block_device
*bdev
,
1359 struct sg_iovec
*iov
, int iov_count
,
1360 int write_to_vm
, gfp_t gfp_mask
)
1364 bio
= __bio_map_user_iov(q
, bdev
, iov
, iov_count
, write_to_vm
,
1370 * subtle -- if __bio_map_user() ended up bouncing a bio,
1371 * it would normally disappear when its bi_end_io is run.
1372 * however, we need it for the unmap, so grab an extra
1380 static void __bio_unmap_user(struct bio
*bio
)
1382 struct bio_vec
*bvec
;
1386 * make sure we dirty pages we wrote to
1388 bio_for_each_segment_all(bvec
, bio
, i
) {
1389 if (bio_data_dir(bio
) == READ
)
1390 set_page_dirty_lock(bvec
->bv_page
);
1392 page_cache_release(bvec
->bv_page
);
1399 * bio_unmap_user - unmap a bio
1400 * @bio: the bio being unmapped
1402 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1403 * a process context.
1405 * bio_unmap_user() may sleep.
1407 void bio_unmap_user(struct bio
*bio
)
1409 __bio_unmap_user(bio
);
1412 EXPORT_SYMBOL(bio_unmap_user
);
1414 static void bio_map_kern_endio(struct bio
*bio
, int err
)
1419 static struct bio
*__bio_map_kern(struct request_queue
*q
, void *data
,
1420 unsigned int len
, gfp_t gfp_mask
)
1422 unsigned long kaddr
= (unsigned long)data
;
1423 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1424 unsigned long start
= kaddr
>> PAGE_SHIFT
;
1425 const int nr_pages
= end
- start
;
1429 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1431 return ERR_PTR(-ENOMEM
);
1433 offset
= offset_in_page(kaddr
);
1434 for (i
= 0; i
< nr_pages
; i
++) {
1435 unsigned int bytes
= PAGE_SIZE
- offset
;
1443 if (bio_add_pc_page(q
, bio
, virt_to_page(data
), bytes
,
1452 bio
->bi_end_io
= bio_map_kern_endio
;
1457 * bio_map_kern - map kernel address into bio
1458 * @q: the struct request_queue for the bio
1459 * @data: pointer to buffer to map
1460 * @len: length in bytes
1461 * @gfp_mask: allocation flags for bio allocation
1463 * Map the kernel address into a bio suitable for io to a block
1464 * device. Returns an error pointer in case of error.
1466 struct bio
*bio_map_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1471 bio
= __bio_map_kern(q
, data
, len
, gfp_mask
);
1475 if (bio
->bi_size
== len
)
1479 * Don't support partial mappings.
1482 return ERR_PTR(-EINVAL
);
1484 EXPORT_SYMBOL(bio_map_kern
);
1486 static void bio_copy_kern_endio(struct bio
*bio
, int err
)
1488 struct bio_vec
*bvec
;
1489 const int read
= bio_data_dir(bio
) == READ
;
1490 struct bio_map_data
*bmd
= bio
->bi_private
;
1492 char *p
= bmd
->sgvecs
[0].iov_base
;
1494 bio_for_each_segment_all(bvec
, bio
, i
) {
1495 char *addr
= page_address(bvec
->bv_page
);
1496 int len
= bmd
->iovecs
[i
].bv_len
;
1499 memcpy(p
, addr
, len
);
1501 __free_page(bvec
->bv_page
);
1505 bio_free_map_data(bmd
);
1510 * bio_copy_kern - copy kernel address into bio
1511 * @q: the struct request_queue for the bio
1512 * @data: pointer to buffer to copy
1513 * @len: length in bytes
1514 * @gfp_mask: allocation flags for bio and page allocation
1515 * @reading: data direction is READ
1517 * copy the kernel address into a bio suitable for io to a block
1518 * device. Returns an error pointer in case of error.
1520 struct bio
*bio_copy_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1521 gfp_t gfp_mask
, int reading
)
1524 struct bio_vec
*bvec
;
1527 bio
= bio_copy_user(q
, NULL
, (unsigned long)data
, len
, 1, gfp_mask
);
1534 bio_for_each_segment_all(bvec
, bio
, i
) {
1535 char *addr
= page_address(bvec
->bv_page
);
1537 memcpy(addr
, p
, bvec
->bv_len
);
1542 bio
->bi_end_io
= bio_copy_kern_endio
;
1546 EXPORT_SYMBOL(bio_copy_kern
);
1549 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1550 * for performing direct-IO in BIOs.
1552 * The problem is that we cannot run set_page_dirty() from interrupt context
1553 * because the required locks are not interrupt-safe. So what we can do is to
1554 * mark the pages dirty _before_ performing IO. And in interrupt context,
1555 * check that the pages are still dirty. If so, fine. If not, redirty them
1556 * in process context.
1558 * We special-case compound pages here: normally this means reads into hugetlb
1559 * pages. The logic in here doesn't really work right for compound pages
1560 * because the VM does not uniformly chase down the head page in all cases.
1561 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1562 * handle them at all. So we skip compound pages here at an early stage.
1564 * Note that this code is very hard to test under normal circumstances because
1565 * direct-io pins the pages with get_user_pages(). This makes
1566 * is_page_cache_freeable return false, and the VM will not clean the pages.
1567 * But other code (eg, flusher threads) could clean the pages if they are mapped
1570 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1571 * deferred bio dirtying paths.
1575 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1577 void bio_set_pages_dirty(struct bio
*bio
)
1579 struct bio_vec
*bvec
;
1582 bio_for_each_segment_all(bvec
, bio
, i
) {
1583 struct page
*page
= bvec
->bv_page
;
1585 if (page
&& !PageCompound(page
))
1586 set_page_dirty_lock(page
);
1590 static void bio_release_pages(struct bio
*bio
)
1592 struct bio_vec
*bvec
;
1595 bio_for_each_segment_all(bvec
, bio
, i
) {
1596 struct page
*page
= bvec
->bv_page
;
1604 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1605 * If they are, then fine. If, however, some pages are clean then they must
1606 * have been written out during the direct-IO read. So we take another ref on
1607 * the BIO and the offending pages and re-dirty the pages in process context.
1609 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1610 * here on. It will run one page_cache_release() against each page and will
1611 * run one bio_put() against the BIO.
1614 static void bio_dirty_fn(struct work_struct
*work
);
1616 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1617 static DEFINE_SPINLOCK(bio_dirty_lock
);
1618 static struct bio
*bio_dirty_list
;
1621 * This runs in process context
1623 static void bio_dirty_fn(struct work_struct
*work
)
1625 unsigned long flags
;
1628 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1629 bio
= bio_dirty_list
;
1630 bio_dirty_list
= NULL
;
1631 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1634 struct bio
*next
= bio
->bi_private
;
1636 bio_set_pages_dirty(bio
);
1637 bio_release_pages(bio
);
1643 void bio_check_pages_dirty(struct bio
*bio
)
1645 struct bio_vec
*bvec
;
1646 int nr_clean_pages
= 0;
1649 bio_for_each_segment_all(bvec
, bio
, i
) {
1650 struct page
*page
= bvec
->bv_page
;
1652 if (PageDirty(page
) || PageCompound(page
)) {
1653 page_cache_release(page
);
1654 bvec
->bv_page
= NULL
;
1660 if (nr_clean_pages
) {
1661 unsigned long flags
;
1663 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1664 bio
->bi_private
= bio_dirty_list
;
1665 bio_dirty_list
= bio
;
1666 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1667 schedule_work(&bio_dirty_work
);
1673 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1674 void bio_flush_dcache_pages(struct bio
*bi
)
1677 struct bio_vec
*bvec
;
1679 bio_for_each_segment(bvec
, bi
, i
)
1680 flush_dcache_page(bvec
->bv_page
);
1682 EXPORT_SYMBOL(bio_flush_dcache_pages
);
1686 * bio_endio - end I/O on a bio
1688 * @error: error, if any
1691 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1692 * preferred way to end I/O on a bio, it takes care of clearing
1693 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1694 * established -Exxxx (-EIO, for instance) error values in case
1695 * something went wrong. No one should call bi_end_io() directly on a
1696 * bio unless they own it and thus know that it has an end_io
1699 void bio_endio(struct bio
*bio
, int error
)
1702 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1703 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
1706 trace_block_bio_complete(bio
, error
);
1709 bio
->bi_end_io(bio
, error
);
1711 EXPORT_SYMBOL(bio_endio
);
1713 void bio_pair_release(struct bio_pair
*bp
)
1715 if (atomic_dec_and_test(&bp
->cnt
)) {
1716 struct bio
*master
= bp
->bio1
.bi_private
;
1718 bio_endio(master
, bp
->error
);
1719 mempool_free(bp
, bp
->bio2
.bi_private
);
1722 EXPORT_SYMBOL(bio_pair_release
);
1724 static void bio_pair_end_1(struct bio
*bi
, int err
)
1726 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio1
);
1731 bio_pair_release(bp
);
1734 static void bio_pair_end_2(struct bio
*bi
, int err
)
1736 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio2
);
1741 bio_pair_release(bp
);
1745 * split a bio - only worry about a bio with a single page in its iovec
1747 struct bio_pair
*bio_split(struct bio
*bi
, int first_sectors
)
1749 struct bio_pair
*bp
= mempool_alloc(bio_split_pool
, GFP_NOIO
);
1754 trace_block_split(bdev_get_queue(bi
->bi_bdev
), bi
,
1755 bi
->bi_sector
+ first_sectors
);
1757 BUG_ON(bio_segments(bi
) > 1);
1758 atomic_set(&bp
->cnt
, 3);
1762 bp
->bio2
.bi_sector
+= first_sectors
;
1763 bp
->bio2
.bi_size
-= first_sectors
<< 9;
1764 bp
->bio1
.bi_size
= first_sectors
<< 9;
1766 if (bi
->bi_vcnt
!= 0) {
1767 bp
->bv1
= *bio_iovec(bi
);
1768 bp
->bv2
= *bio_iovec(bi
);
1770 if (bio_is_rw(bi
)) {
1771 bp
->bv2
.bv_offset
+= first_sectors
<< 9;
1772 bp
->bv2
.bv_len
-= first_sectors
<< 9;
1773 bp
->bv1
.bv_len
= first_sectors
<< 9;
1776 bp
->bio1
.bi_io_vec
= &bp
->bv1
;
1777 bp
->bio2
.bi_io_vec
= &bp
->bv2
;
1779 bp
->bio1
.bi_max_vecs
= 1;
1780 bp
->bio2
.bi_max_vecs
= 1;
1783 bp
->bio1
.bi_end_io
= bio_pair_end_1
;
1784 bp
->bio2
.bi_end_io
= bio_pair_end_2
;
1786 bp
->bio1
.bi_private
= bi
;
1787 bp
->bio2
.bi_private
= bio_split_pool
;
1789 if (bio_integrity(bi
))
1790 bio_integrity_split(bi
, bp
, first_sectors
);
1794 EXPORT_SYMBOL(bio_split
);
1797 * bio_sector_offset - Find hardware sector offset in bio
1798 * @bio: bio to inspect
1799 * @index: bio_vec index
1800 * @offset: offset in bv_page
1802 * Return the number of hardware sectors between beginning of bio
1803 * and an end point indicated by a bio_vec index and an offset
1804 * within that vector's page.
1806 sector_t
bio_sector_offset(struct bio
*bio
, unsigned short index
,
1807 unsigned int offset
)
1809 unsigned int sector_sz
;
1814 sector_sz
= queue_logical_block_size(bio
->bi_bdev
->bd_disk
->queue
);
1817 if (index
>= bio
->bi_idx
)
1818 index
= bio
->bi_vcnt
- 1;
1820 bio_for_each_segment_all(bv
, bio
, i
) {
1822 if (offset
> bv
->bv_offset
)
1823 sectors
+= (offset
- bv
->bv_offset
) / sector_sz
;
1827 sectors
+= bv
->bv_len
/ sector_sz
;
1832 EXPORT_SYMBOL(bio_sector_offset
);
1835 * create memory pools for biovec's in a bio_set.
1836 * use the global biovec slabs created for general use.
1838 mempool_t
*biovec_create_pool(struct bio_set
*bs
, int pool_entries
)
1840 struct biovec_slab
*bp
= bvec_slabs
+ BIOVEC_MAX_IDX
;
1842 return mempool_create_slab_pool(pool_entries
, bp
->slab
);
1845 void bioset_free(struct bio_set
*bs
)
1847 if (bs
->rescue_workqueue
)
1848 destroy_workqueue(bs
->rescue_workqueue
);
1851 mempool_destroy(bs
->bio_pool
);
1854 mempool_destroy(bs
->bvec_pool
);
1856 bioset_integrity_free(bs
);
1861 EXPORT_SYMBOL(bioset_free
);
1864 * bioset_create - Create a bio_set
1865 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1866 * @front_pad: Number of bytes to allocate in front of the returned bio
1869 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1870 * to ask for a number of bytes to be allocated in front of the bio.
1871 * Front pad allocation is useful for embedding the bio inside
1872 * another structure, to avoid allocating extra data to go with the bio.
1873 * Note that the bio must be embedded at the END of that structure always,
1874 * or things will break badly.
1876 struct bio_set
*bioset_create(unsigned int pool_size
, unsigned int front_pad
)
1878 unsigned int back_pad
= BIO_INLINE_VECS
* sizeof(struct bio_vec
);
1881 bs
= kzalloc(sizeof(*bs
), GFP_KERNEL
);
1885 bs
->front_pad
= front_pad
;
1887 spin_lock_init(&bs
->rescue_lock
);
1888 bio_list_init(&bs
->rescue_list
);
1889 INIT_WORK(&bs
->rescue_work
, bio_alloc_rescue
);
1891 bs
->bio_slab
= bio_find_or_create_slab(front_pad
+ back_pad
);
1892 if (!bs
->bio_slab
) {
1897 bs
->bio_pool
= mempool_create_slab_pool(pool_size
, bs
->bio_slab
);
1901 bs
->bvec_pool
= biovec_create_pool(bs
, pool_size
);
1905 bs
->rescue_workqueue
= alloc_workqueue("bioset", WQ_MEM_RECLAIM
, 0);
1906 if (!bs
->rescue_workqueue
)
1914 EXPORT_SYMBOL(bioset_create
);
1916 #ifdef CONFIG_BLK_CGROUP
1918 * bio_associate_current - associate a bio with %current
1921 * Associate @bio with %current if it hasn't been associated yet. Block
1922 * layer will treat @bio as if it were issued by %current no matter which
1923 * task actually issues it.
1925 * This function takes an extra reference of @task's io_context and blkcg
1926 * which will be put when @bio is released. The caller must own @bio,
1927 * ensure %current->io_context exists, and is responsible for synchronizing
1928 * calls to this function.
1930 int bio_associate_current(struct bio
*bio
)
1932 struct io_context
*ioc
;
1933 struct cgroup_subsys_state
*css
;
1938 ioc
= current
->io_context
;
1942 /* acquire active ref on @ioc and associate */
1943 get_io_context_active(ioc
);
1946 /* associate blkcg if exists */
1948 css
= task_subsys_state(current
, blkio_subsys_id
);
1949 if (css
&& css_tryget(css
))
1957 * bio_disassociate_task - undo bio_associate_current()
1960 void bio_disassociate_task(struct bio
*bio
)
1963 put_io_context(bio
->bi_ioc
);
1967 css_put(bio
->bi_css
);
1972 #endif /* CONFIG_BLK_CGROUP */
1974 static void __init
biovec_init_slabs(void)
1978 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1980 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
1982 if (bvs
->nr_vecs
<= BIO_INLINE_VECS
) {
1987 size
= bvs
->nr_vecs
* sizeof(struct bio_vec
);
1988 bvs
->slab
= kmem_cache_create(bvs
->name
, size
, 0,
1989 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1993 static int __init
init_bio(void)
1997 bio_slabs
= kzalloc(bio_slab_max
* sizeof(struct bio_slab
), GFP_KERNEL
);
1999 panic("bio: can't allocate bios\n");
2001 bio_integrity_init();
2002 biovec_init_slabs();
2004 fs_bio_set
= bioset_create(BIO_POOL_SIZE
, 0);
2006 panic("bio: can't allocate bios\n");
2008 if (bioset_integrity_create(fs_bio_set
, BIO_POOL_SIZE
))
2009 panic("bio: can't create integrity pool\n");
2011 bio_split_pool
= mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES
,
2012 sizeof(struct bio_pair
));
2013 if (!bio_split_pool
)
2014 panic("bio: can't create split pool\n");
2018 subsys_initcall(init_bio
);