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_copy_data - copy contents of data buffers from one chain of bios to
835 * @src: source bio list
836 * @dst: destination bio list
838 * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
839 * @src and @dst as linked lists of bios.
841 * Stops when it reaches the end of either @src or @dst - that is, copies
842 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
844 void bio_copy_data(struct bio
*dst
, struct bio
*src
)
846 struct bio_vec
*src_bv
, *dst_bv
;
847 unsigned src_offset
, dst_offset
, bytes
;
850 src_bv
= bio_iovec(src
);
851 dst_bv
= bio_iovec(dst
);
853 src_offset
= src_bv
->bv_offset
;
854 dst_offset
= dst_bv
->bv_offset
;
857 if (src_offset
== src_bv
->bv_offset
+ src_bv
->bv_len
) {
859 if (src_bv
== bio_iovec_idx(src
, src
->bi_vcnt
)) {
864 src_bv
= bio_iovec(src
);
867 src_offset
= src_bv
->bv_offset
;
870 if (dst_offset
== dst_bv
->bv_offset
+ dst_bv
->bv_len
) {
872 if (dst_bv
== bio_iovec_idx(dst
, dst
->bi_vcnt
)) {
877 dst_bv
= bio_iovec(dst
);
880 dst_offset
= dst_bv
->bv_offset
;
883 bytes
= min(dst_bv
->bv_offset
+ dst_bv
->bv_len
- dst_offset
,
884 src_bv
->bv_offset
+ src_bv
->bv_len
- src_offset
);
886 src_p
= kmap_atomic(src_bv
->bv_page
);
887 dst_p
= kmap_atomic(dst_bv
->bv_page
);
889 memcpy(dst_p
+ dst_bv
->bv_offset
,
890 src_p
+ src_bv
->bv_offset
,
893 kunmap_atomic(dst_p
);
894 kunmap_atomic(src_p
);
900 EXPORT_SYMBOL(bio_copy_data
);
902 struct bio_map_data
{
903 struct bio_vec
*iovecs
;
904 struct sg_iovec
*sgvecs
;
909 static void bio_set_map_data(struct bio_map_data
*bmd
, struct bio
*bio
,
910 struct sg_iovec
*iov
, int iov_count
,
913 memcpy(bmd
->iovecs
, bio
->bi_io_vec
, sizeof(struct bio_vec
) * bio
->bi_vcnt
);
914 memcpy(bmd
->sgvecs
, iov
, sizeof(struct sg_iovec
) * iov_count
);
915 bmd
->nr_sgvecs
= iov_count
;
916 bmd
->is_our_pages
= is_our_pages
;
917 bio
->bi_private
= bmd
;
920 static void bio_free_map_data(struct bio_map_data
*bmd
)
927 static struct bio_map_data
*bio_alloc_map_data(int nr_segs
,
928 unsigned int iov_count
,
931 struct bio_map_data
*bmd
;
933 if (iov_count
> UIO_MAXIOV
)
936 bmd
= kmalloc(sizeof(*bmd
), gfp_mask
);
940 bmd
->iovecs
= kmalloc(sizeof(struct bio_vec
) * nr_segs
, gfp_mask
);
946 bmd
->sgvecs
= kmalloc(sizeof(struct sg_iovec
) * iov_count
, gfp_mask
);
955 static int __bio_copy_iov(struct bio
*bio
, struct bio_vec
*iovecs
,
956 struct sg_iovec
*iov
, int iov_count
,
957 int to_user
, int from_user
, int do_free_page
)
960 struct bio_vec
*bvec
;
962 unsigned int iov_off
= 0;
964 bio_for_each_segment_all(bvec
, bio
, i
) {
965 char *bv_addr
= page_address(bvec
->bv_page
);
966 unsigned int bv_len
= iovecs
[i
].bv_len
;
968 while (bv_len
&& iov_idx
< iov_count
) {
970 char __user
*iov_addr
;
972 bytes
= min_t(unsigned int,
973 iov
[iov_idx
].iov_len
- iov_off
, bv_len
);
974 iov_addr
= iov
[iov_idx
].iov_base
+ iov_off
;
978 ret
= copy_to_user(iov_addr
, bv_addr
,
982 ret
= copy_from_user(bv_addr
, iov_addr
,
994 if (iov
[iov_idx
].iov_len
== iov_off
) {
1001 __free_page(bvec
->bv_page
);
1008 * bio_uncopy_user - finish previously mapped bio
1009 * @bio: bio being terminated
1011 * Free pages allocated from bio_copy_user() and write back data
1012 * to user space in case of a read.
1014 int bio_uncopy_user(struct bio
*bio
)
1016 struct bio_map_data
*bmd
= bio
->bi_private
;
1019 if (!bio_flagged(bio
, BIO_NULL_MAPPED
))
1020 ret
= __bio_copy_iov(bio
, bmd
->iovecs
, bmd
->sgvecs
,
1021 bmd
->nr_sgvecs
, bio_data_dir(bio
) == READ
,
1022 0, bmd
->is_our_pages
);
1023 bio_free_map_data(bmd
);
1027 EXPORT_SYMBOL(bio_uncopy_user
);
1030 * bio_copy_user_iov - copy user data to bio
1031 * @q: destination block queue
1032 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1034 * @iov_count: number of elements in the iovec
1035 * @write_to_vm: bool indicating writing to pages or not
1036 * @gfp_mask: memory allocation flags
1038 * Prepares and returns a bio for indirect user io, bouncing data
1039 * to/from kernel pages as necessary. Must be paired with
1040 * call bio_uncopy_user() on io completion.
1042 struct bio
*bio_copy_user_iov(struct request_queue
*q
,
1043 struct rq_map_data
*map_data
,
1044 struct sg_iovec
*iov
, int iov_count
,
1045 int write_to_vm
, gfp_t gfp_mask
)
1047 struct bio_map_data
*bmd
;
1048 struct bio_vec
*bvec
;
1053 unsigned int len
= 0;
1054 unsigned int offset
= map_data
? map_data
->offset
& ~PAGE_MASK
: 0;
1056 for (i
= 0; i
< iov_count
; i
++) {
1057 unsigned long uaddr
;
1059 unsigned long start
;
1061 uaddr
= (unsigned long)iov
[i
].iov_base
;
1062 end
= (uaddr
+ iov
[i
].iov_len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1063 start
= uaddr
>> PAGE_SHIFT
;
1069 return ERR_PTR(-EINVAL
);
1071 nr_pages
+= end
- start
;
1072 len
+= iov
[i
].iov_len
;
1078 bmd
= bio_alloc_map_data(nr_pages
, iov_count
, gfp_mask
);
1080 return ERR_PTR(-ENOMEM
);
1083 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1088 bio
->bi_rw
|= REQ_WRITE
;
1093 nr_pages
= 1 << map_data
->page_order
;
1094 i
= map_data
->offset
/ PAGE_SIZE
;
1097 unsigned int bytes
= PAGE_SIZE
;
1105 if (i
== map_data
->nr_entries
* nr_pages
) {
1110 page
= map_data
->pages
[i
/ nr_pages
];
1111 page
+= (i
% nr_pages
);
1115 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
1122 if (bio_add_pc_page(q
, bio
, page
, bytes
, offset
) < bytes
)
1135 if ((!write_to_vm
&& (!map_data
|| !map_data
->null_mapped
)) ||
1136 (map_data
&& map_data
->from_user
)) {
1137 ret
= __bio_copy_iov(bio
, bio
->bi_io_vec
, iov
, iov_count
, 0, 1, 0);
1142 bio_set_map_data(bmd
, bio
, iov
, iov_count
, map_data
? 0 : 1);
1146 bio_for_each_segment_all(bvec
, bio
, i
)
1147 __free_page(bvec
->bv_page
);
1151 bio_free_map_data(bmd
);
1152 return ERR_PTR(ret
);
1156 * bio_copy_user - copy user data to bio
1157 * @q: destination block queue
1158 * @map_data: pointer to the rq_map_data holding pages (if necessary)
1159 * @uaddr: start of user address
1160 * @len: length in bytes
1161 * @write_to_vm: bool indicating writing to pages or not
1162 * @gfp_mask: memory allocation flags
1164 * Prepares and returns a bio for indirect user io, bouncing data
1165 * to/from kernel pages as necessary. Must be paired with
1166 * call bio_uncopy_user() on io completion.
1168 struct bio
*bio_copy_user(struct request_queue
*q
, struct rq_map_data
*map_data
,
1169 unsigned long uaddr
, unsigned int len
,
1170 int write_to_vm
, gfp_t gfp_mask
)
1172 struct sg_iovec iov
;
1174 iov
.iov_base
= (void __user
*)uaddr
;
1177 return bio_copy_user_iov(q
, map_data
, &iov
, 1, write_to_vm
, gfp_mask
);
1179 EXPORT_SYMBOL(bio_copy_user
);
1181 static struct bio
*__bio_map_user_iov(struct request_queue
*q
,
1182 struct block_device
*bdev
,
1183 struct sg_iovec
*iov
, int iov_count
,
1184 int write_to_vm
, gfp_t gfp_mask
)
1188 struct page
**pages
;
1193 for (i
= 0; i
< iov_count
; i
++) {
1194 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
1195 unsigned long len
= iov
[i
].iov_len
;
1196 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1197 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1203 return ERR_PTR(-EINVAL
);
1205 nr_pages
+= end
- start
;
1207 * buffer must be aligned to at least hardsector size for now
1209 if (uaddr
& queue_dma_alignment(q
))
1210 return ERR_PTR(-EINVAL
);
1214 return ERR_PTR(-EINVAL
);
1216 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1218 return ERR_PTR(-ENOMEM
);
1221 pages
= kcalloc(nr_pages
, sizeof(struct page
*), gfp_mask
);
1225 for (i
= 0; i
< iov_count
; i
++) {
1226 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
1227 unsigned long len
= iov
[i
].iov_len
;
1228 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1229 unsigned long start
= uaddr
>> PAGE_SHIFT
;
1230 const int local_nr_pages
= end
- start
;
1231 const int page_limit
= cur_page
+ local_nr_pages
;
1233 ret
= get_user_pages_fast(uaddr
, local_nr_pages
,
1234 write_to_vm
, &pages
[cur_page
]);
1235 if (ret
< local_nr_pages
) {
1240 offset
= uaddr
& ~PAGE_MASK
;
1241 for (j
= cur_page
; j
< page_limit
; j
++) {
1242 unsigned int bytes
= PAGE_SIZE
- offset
;
1253 if (bio_add_pc_page(q
, bio
, pages
[j
], bytes
, offset
) <
1263 * release the pages we didn't map into the bio, if any
1265 while (j
< page_limit
)
1266 page_cache_release(pages
[j
++]);
1272 * set data direction, and check if mapped pages need bouncing
1275 bio
->bi_rw
|= REQ_WRITE
;
1277 bio
->bi_bdev
= bdev
;
1278 bio
->bi_flags
|= (1 << BIO_USER_MAPPED
);
1282 for (i
= 0; i
< nr_pages
; i
++) {
1285 page_cache_release(pages
[i
]);
1290 return ERR_PTR(ret
);
1294 * bio_map_user - map user address into bio
1295 * @q: the struct request_queue for the bio
1296 * @bdev: destination block device
1297 * @uaddr: start of user address
1298 * @len: length in bytes
1299 * @write_to_vm: bool indicating writing to pages or not
1300 * @gfp_mask: memory allocation flags
1302 * Map the user space address into a bio suitable for io to a block
1303 * device. Returns an error pointer in case of error.
1305 struct bio
*bio_map_user(struct request_queue
*q
, struct block_device
*bdev
,
1306 unsigned long uaddr
, unsigned int len
, int write_to_vm
,
1309 struct sg_iovec iov
;
1311 iov
.iov_base
= (void __user
*)uaddr
;
1314 return bio_map_user_iov(q
, bdev
, &iov
, 1, write_to_vm
, gfp_mask
);
1316 EXPORT_SYMBOL(bio_map_user
);
1319 * bio_map_user_iov - map user sg_iovec table into bio
1320 * @q: the struct request_queue for the bio
1321 * @bdev: destination block device
1323 * @iov_count: number of elements in the iovec
1324 * @write_to_vm: bool indicating writing to pages or not
1325 * @gfp_mask: memory allocation flags
1327 * Map the user space address into a bio suitable for io to a block
1328 * device. Returns an error pointer in case of error.
1330 struct bio
*bio_map_user_iov(struct request_queue
*q
, struct block_device
*bdev
,
1331 struct sg_iovec
*iov
, int iov_count
,
1332 int write_to_vm
, gfp_t gfp_mask
)
1336 bio
= __bio_map_user_iov(q
, bdev
, iov
, iov_count
, write_to_vm
,
1342 * subtle -- if __bio_map_user() ended up bouncing a bio,
1343 * it would normally disappear when its bi_end_io is run.
1344 * however, we need it for the unmap, so grab an extra
1352 static void __bio_unmap_user(struct bio
*bio
)
1354 struct bio_vec
*bvec
;
1358 * make sure we dirty pages we wrote to
1360 bio_for_each_segment_all(bvec
, bio
, i
) {
1361 if (bio_data_dir(bio
) == READ
)
1362 set_page_dirty_lock(bvec
->bv_page
);
1364 page_cache_release(bvec
->bv_page
);
1371 * bio_unmap_user - unmap a bio
1372 * @bio: the bio being unmapped
1374 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1375 * a process context.
1377 * bio_unmap_user() may sleep.
1379 void bio_unmap_user(struct bio
*bio
)
1381 __bio_unmap_user(bio
);
1384 EXPORT_SYMBOL(bio_unmap_user
);
1386 static void bio_map_kern_endio(struct bio
*bio
, int err
)
1391 static struct bio
*__bio_map_kern(struct request_queue
*q
, void *data
,
1392 unsigned int len
, gfp_t gfp_mask
)
1394 unsigned long kaddr
= (unsigned long)data
;
1395 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1396 unsigned long start
= kaddr
>> PAGE_SHIFT
;
1397 const int nr_pages
= end
- start
;
1401 bio
= bio_kmalloc(gfp_mask
, nr_pages
);
1403 return ERR_PTR(-ENOMEM
);
1405 offset
= offset_in_page(kaddr
);
1406 for (i
= 0; i
< nr_pages
; i
++) {
1407 unsigned int bytes
= PAGE_SIZE
- offset
;
1415 if (bio_add_pc_page(q
, bio
, virt_to_page(data
), bytes
,
1424 bio
->bi_end_io
= bio_map_kern_endio
;
1429 * bio_map_kern - map kernel address into bio
1430 * @q: the struct request_queue for the bio
1431 * @data: pointer to buffer to map
1432 * @len: length in bytes
1433 * @gfp_mask: allocation flags for bio allocation
1435 * Map the kernel address into a bio suitable for io to a block
1436 * device. Returns an error pointer in case of error.
1438 struct bio
*bio_map_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1443 bio
= __bio_map_kern(q
, data
, len
, gfp_mask
);
1447 if (bio
->bi_size
== len
)
1451 * Don't support partial mappings.
1454 return ERR_PTR(-EINVAL
);
1456 EXPORT_SYMBOL(bio_map_kern
);
1458 static void bio_copy_kern_endio(struct bio
*bio
, int err
)
1460 struct bio_vec
*bvec
;
1461 const int read
= bio_data_dir(bio
) == READ
;
1462 struct bio_map_data
*bmd
= bio
->bi_private
;
1464 char *p
= bmd
->sgvecs
[0].iov_base
;
1466 bio_for_each_segment_all(bvec
, bio
, i
) {
1467 char *addr
= page_address(bvec
->bv_page
);
1468 int len
= bmd
->iovecs
[i
].bv_len
;
1471 memcpy(p
, addr
, len
);
1473 __free_page(bvec
->bv_page
);
1477 bio_free_map_data(bmd
);
1482 * bio_copy_kern - copy kernel address into bio
1483 * @q: the struct request_queue for the bio
1484 * @data: pointer to buffer to copy
1485 * @len: length in bytes
1486 * @gfp_mask: allocation flags for bio and page allocation
1487 * @reading: data direction is READ
1489 * copy the kernel address into a bio suitable for io to a block
1490 * device. Returns an error pointer in case of error.
1492 struct bio
*bio_copy_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1493 gfp_t gfp_mask
, int reading
)
1496 struct bio_vec
*bvec
;
1499 bio
= bio_copy_user(q
, NULL
, (unsigned long)data
, len
, 1, gfp_mask
);
1506 bio_for_each_segment_all(bvec
, bio
, i
) {
1507 char *addr
= page_address(bvec
->bv_page
);
1509 memcpy(addr
, p
, bvec
->bv_len
);
1514 bio
->bi_end_io
= bio_copy_kern_endio
;
1518 EXPORT_SYMBOL(bio_copy_kern
);
1521 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1522 * for performing direct-IO in BIOs.
1524 * The problem is that we cannot run set_page_dirty() from interrupt context
1525 * because the required locks are not interrupt-safe. So what we can do is to
1526 * mark the pages dirty _before_ performing IO. And in interrupt context,
1527 * check that the pages are still dirty. If so, fine. If not, redirty them
1528 * in process context.
1530 * We special-case compound pages here: normally this means reads into hugetlb
1531 * pages. The logic in here doesn't really work right for compound pages
1532 * because the VM does not uniformly chase down the head page in all cases.
1533 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1534 * handle them at all. So we skip compound pages here at an early stage.
1536 * Note that this code is very hard to test under normal circumstances because
1537 * direct-io pins the pages with get_user_pages(). This makes
1538 * is_page_cache_freeable return false, and the VM will not clean the pages.
1539 * But other code (eg, flusher threads) could clean the pages if they are mapped
1542 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1543 * deferred bio dirtying paths.
1547 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1549 void bio_set_pages_dirty(struct bio
*bio
)
1551 struct bio_vec
*bvec
;
1554 bio_for_each_segment_all(bvec
, bio
, i
) {
1555 struct page
*page
= bvec
->bv_page
;
1557 if (page
&& !PageCompound(page
))
1558 set_page_dirty_lock(page
);
1562 static void bio_release_pages(struct bio
*bio
)
1564 struct bio_vec
*bvec
;
1567 bio_for_each_segment_all(bvec
, bio
, i
) {
1568 struct page
*page
= bvec
->bv_page
;
1576 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1577 * If they are, then fine. If, however, some pages are clean then they must
1578 * have been written out during the direct-IO read. So we take another ref on
1579 * the BIO and the offending pages and re-dirty the pages in process context.
1581 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1582 * here on. It will run one page_cache_release() against each page and will
1583 * run one bio_put() against the BIO.
1586 static void bio_dirty_fn(struct work_struct
*work
);
1588 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1589 static DEFINE_SPINLOCK(bio_dirty_lock
);
1590 static struct bio
*bio_dirty_list
;
1593 * This runs in process context
1595 static void bio_dirty_fn(struct work_struct
*work
)
1597 unsigned long flags
;
1600 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1601 bio
= bio_dirty_list
;
1602 bio_dirty_list
= NULL
;
1603 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1606 struct bio
*next
= bio
->bi_private
;
1608 bio_set_pages_dirty(bio
);
1609 bio_release_pages(bio
);
1615 void bio_check_pages_dirty(struct bio
*bio
)
1617 struct bio_vec
*bvec
;
1618 int nr_clean_pages
= 0;
1621 bio_for_each_segment_all(bvec
, bio
, i
) {
1622 struct page
*page
= bvec
->bv_page
;
1624 if (PageDirty(page
) || PageCompound(page
)) {
1625 page_cache_release(page
);
1626 bvec
->bv_page
= NULL
;
1632 if (nr_clean_pages
) {
1633 unsigned long flags
;
1635 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1636 bio
->bi_private
= bio_dirty_list
;
1637 bio_dirty_list
= bio
;
1638 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1639 schedule_work(&bio_dirty_work
);
1645 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1646 void bio_flush_dcache_pages(struct bio
*bi
)
1649 struct bio_vec
*bvec
;
1651 bio_for_each_segment(bvec
, bi
, i
)
1652 flush_dcache_page(bvec
->bv_page
);
1654 EXPORT_SYMBOL(bio_flush_dcache_pages
);
1658 * bio_endio - end I/O on a bio
1660 * @error: error, if any
1663 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1664 * preferred way to end I/O on a bio, it takes care of clearing
1665 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1666 * established -Exxxx (-EIO, for instance) error values in case
1667 * something went wrong. No one should call bi_end_io() directly on a
1668 * bio unless they own it and thus know that it has an end_io
1671 void bio_endio(struct bio
*bio
, int error
)
1674 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1675 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
1678 trace_block_bio_complete(bio
, error
);
1681 bio
->bi_end_io(bio
, error
);
1683 EXPORT_SYMBOL(bio_endio
);
1685 void bio_pair_release(struct bio_pair
*bp
)
1687 if (atomic_dec_and_test(&bp
->cnt
)) {
1688 struct bio
*master
= bp
->bio1
.bi_private
;
1690 bio_endio(master
, bp
->error
);
1691 mempool_free(bp
, bp
->bio2
.bi_private
);
1694 EXPORT_SYMBOL(bio_pair_release
);
1696 static void bio_pair_end_1(struct bio
*bi
, int err
)
1698 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio1
);
1703 bio_pair_release(bp
);
1706 static void bio_pair_end_2(struct bio
*bi
, int err
)
1708 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio2
);
1713 bio_pair_release(bp
);
1717 * split a bio - only worry about a bio with a single page in its iovec
1719 struct bio_pair
*bio_split(struct bio
*bi
, int first_sectors
)
1721 struct bio_pair
*bp
= mempool_alloc(bio_split_pool
, GFP_NOIO
);
1726 trace_block_split(bdev_get_queue(bi
->bi_bdev
), bi
,
1727 bi
->bi_sector
+ first_sectors
);
1729 BUG_ON(bio_segments(bi
) > 1);
1730 atomic_set(&bp
->cnt
, 3);
1734 bp
->bio2
.bi_sector
+= first_sectors
;
1735 bp
->bio2
.bi_size
-= first_sectors
<< 9;
1736 bp
->bio1
.bi_size
= first_sectors
<< 9;
1738 if (bi
->bi_vcnt
!= 0) {
1739 bp
->bv1
= *bio_iovec(bi
);
1740 bp
->bv2
= *bio_iovec(bi
);
1742 if (bio_is_rw(bi
)) {
1743 bp
->bv2
.bv_offset
+= first_sectors
<< 9;
1744 bp
->bv2
.bv_len
-= first_sectors
<< 9;
1745 bp
->bv1
.bv_len
= first_sectors
<< 9;
1748 bp
->bio1
.bi_io_vec
= &bp
->bv1
;
1749 bp
->bio2
.bi_io_vec
= &bp
->bv2
;
1751 bp
->bio1
.bi_max_vecs
= 1;
1752 bp
->bio2
.bi_max_vecs
= 1;
1755 bp
->bio1
.bi_end_io
= bio_pair_end_1
;
1756 bp
->bio2
.bi_end_io
= bio_pair_end_2
;
1758 bp
->bio1
.bi_private
= bi
;
1759 bp
->bio2
.bi_private
= bio_split_pool
;
1761 if (bio_integrity(bi
))
1762 bio_integrity_split(bi
, bp
, first_sectors
);
1766 EXPORT_SYMBOL(bio_split
);
1769 * bio_sector_offset - Find hardware sector offset in bio
1770 * @bio: bio to inspect
1771 * @index: bio_vec index
1772 * @offset: offset in bv_page
1774 * Return the number of hardware sectors between beginning of bio
1775 * and an end point indicated by a bio_vec index and an offset
1776 * within that vector's page.
1778 sector_t
bio_sector_offset(struct bio
*bio
, unsigned short index
,
1779 unsigned int offset
)
1781 unsigned int sector_sz
;
1786 sector_sz
= queue_logical_block_size(bio
->bi_bdev
->bd_disk
->queue
);
1789 if (index
>= bio
->bi_idx
)
1790 index
= bio
->bi_vcnt
- 1;
1792 bio_for_each_segment_all(bv
, bio
, i
) {
1794 if (offset
> bv
->bv_offset
)
1795 sectors
+= (offset
- bv
->bv_offset
) / sector_sz
;
1799 sectors
+= bv
->bv_len
/ sector_sz
;
1804 EXPORT_SYMBOL(bio_sector_offset
);
1807 * create memory pools for biovec's in a bio_set.
1808 * use the global biovec slabs created for general use.
1810 mempool_t
*biovec_create_pool(struct bio_set
*bs
, int pool_entries
)
1812 struct biovec_slab
*bp
= bvec_slabs
+ BIOVEC_MAX_IDX
;
1814 return mempool_create_slab_pool(pool_entries
, bp
->slab
);
1817 void bioset_free(struct bio_set
*bs
)
1819 if (bs
->rescue_workqueue
)
1820 destroy_workqueue(bs
->rescue_workqueue
);
1823 mempool_destroy(bs
->bio_pool
);
1826 mempool_destroy(bs
->bvec_pool
);
1828 bioset_integrity_free(bs
);
1833 EXPORT_SYMBOL(bioset_free
);
1836 * bioset_create - Create a bio_set
1837 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1838 * @front_pad: Number of bytes to allocate in front of the returned bio
1841 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1842 * to ask for a number of bytes to be allocated in front of the bio.
1843 * Front pad allocation is useful for embedding the bio inside
1844 * another structure, to avoid allocating extra data to go with the bio.
1845 * Note that the bio must be embedded at the END of that structure always,
1846 * or things will break badly.
1848 struct bio_set
*bioset_create(unsigned int pool_size
, unsigned int front_pad
)
1850 unsigned int back_pad
= BIO_INLINE_VECS
* sizeof(struct bio_vec
);
1853 bs
= kzalloc(sizeof(*bs
), GFP_KERNEL
);
1857 bs
->front_pad
= front_pad
;
1859 spin_lock_init(&bs
->rescue_lock
);
1860 bio_list_init(&bs
->rescue_list
);
1861 INIT_WORK(&bs
->rescue_work
, bio_alloc_rescue
);
1863 bs
->bio_slab
= bio_find_or_create_slab(front_pad
+ back_pad
);
1864 if (!bs
->bio_slab
) {
1869 bs
->bio_pool
= mempool_create_slab_pool(pool_size
, bs
->bio_slab
);
1873 bs
->bvec_pool
= biovec_create_pool(bs
, pool_size
);
1877 bs
->rescue_workqueue
= alloc_workqueue("bioset", WQ_MEM_RECLAIM
, 0);
1878 if (!bs
->rescue_workqueue
)
1886 EXPORT_SYMBOL(bioset_create
);
1888 #ifdef CONFIG_BLK_CGROUP
1890 * bio_associate_current - associate a bio with %current
1893 * Associate @bio with %current if it hasn't been associated yet. Block
1894 * layer will treat @bio as if it were issued by %current no matter which
1895 * task actually issues it.
1897 * This function takes an extra reference of @task's io_context and blkcg
1898 * which will be put when @bio is released. The caller must own @bio,
1899 * ensure %current->io_context exists, and is responsible for synchronizing
1900 * calls to this function.
1902 int bio_associate_current(struct bio
*bio
)
1904 struct io_context
*ioc
;
1905 struct cgroup_subsys_state
*css
;
1910 ioc
= current
->io_context
;
1914 /* acquire active ref on @ioc and associate */
1915 get_io_context_active(ioc
);
1918 /* associate blkcg if exists */
1920 css
= task_subsys_state(current
, blkio_subsys_id
);
1921 if (css
&& css_tryget(css
))
1929 * bio_disassociate_task - undo bio_associate_current()
1932 void bio_disassociate_task(struct bio
*bio
)
1935 put_io_context(bio
->bi_ioc
);
1939 css_put(bio
->bi_css
);
1944 #endif /* CONFIG_BLK_CGROUP */
1946 static void __init
biovec_init_slabs(void)
1950 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1952 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
1954 if (bvs
->nr_vecs
<= BIO_INLINE_VECS
) {
1959 size
= bvs
->nr_vecs
* sizeof(struct bio_vec
);
1960 bvs
->slab
= kmem_cache_create(bvs
->name
, size
, 0,
1961 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1965 static int __init
init_bio(void)
1969 bio_slabs
= kzalloc(bio_slab_max
* sizeof(struct bio_slab
), GFP_KERNEL
);
1971 panic("bio: can't allocate bios\n");
1973 bio_integrity_init();
1974 biovec_init_slabs();
1976 fs_bio_set
= bioset_create(BIO_POOL_SIZE
, 0);
1978 panic("bio: can't allocate bios\n");
1980 if (bioset_integrity_create(fs_bio_set
, BIO_POOL_SIZE
))
1981 panic("bio: can't create integrity pool\n");
1983 bio_split_pool
= mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES
,
1984 sizeof(struct bio_pair
));
1985 if (!bio_split_pool
)
1986 panic("bio: can't create split pool\n");
1990 subsys_initcall(init_bio
);