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/slab.h>
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/mempool.h>
27 #include <linux/workqueue.h>
28 #include <linux/blktrace_api.h>
29 #include <trace/block.h>
30 #include <scsi/sg.h> /* for struct sg_iovec */
32 DEFINE_TRACE(block_split
);
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 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
;
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
;
77 unsigned int i
, entry
= -1;
79 mutex_lock(&bio_slab_lock
);
82 while (i
< bio_slab_nr
) {
83 struct bio_slab
*bslab
= &bio_slabs
[i
];
85 if (!bslab
->slab
&& entry
== -1)
87 else if (bslab
->slab_size
== sz
) {
98 if (bio_slab_nr
== bio_slab_max
&& entry
== -1) {
100 bio_slabs
= krealloc(bio_slabs
,
101 bio_slab_max
* sizeof(struct bio_slab
),
107 entry
= bio_slab_nr
++;
109 bslab
= &bio_slabs
[entry
];
111 snprintf(bslab
->name
, sizeof(bslab
->name
), "bio-%d", entry
);
112 slab
= kmem_cache_create(bslab
->name
, sz
, 0, SLAB_HWCACHE_ALIGN
, NULL
);
116 printk("bio: create slab <%s> at %d\n", bslab
->name
, entry
);
119 bslab
->slab_size
= sz
;
121 mutex_unlock(&bio_slab_lock
);
125 static void bio_put_slab(struct bio_set
*bs
)
127 struct bio_slab
*bslab
= NULL
;
130 mutex_lock(&bio_slab_lock
);
132 for (i
= 0; i
< bio_slab_nr
; i
++) {
133 if (bs
->bio_slab
== bio_slabs
[i
].slab
) {
134 bslab
= &bio_slabs
[i
];
139 if (WARN(!bslab
, KERN_ERR
"bio: unable to find slab!\n"))
142 WARN_ON(!bslab
->slab_ref
);
144 if (--bslab
->slab_ref
)
147 kmem_cache_destroy(bslab
->slab
);
151 mutex_unlock(&bio_slab_lock
);
154 unsigned int bvec_nr_vecs(unsigned short idx
)
156 return bvec_slabs
[idx
].nr_vecs
;
159 void bvec_free_bs(struct bio_set
*bs
, struct bio_vec
*bv
, unsigned int idx
)
161 BIO_BUG_ON(idx
>= BIOVEC_NR_POOLS
);
163 if (idx
== BIOVEC_MAX_IDX
)
164 mempool_free(bv
, bs
->bvec_pool
);
166 struct biovec_slab
*bvs
= bvec_slabs
+ idx
;
168 kmem_cache_free(bvs
->slab
, bv
);
172 struct bio_vec
*bvec_alloc_bs(gfp_t gfp_mask
, int nr
, unsigned long *idx
,
178 * If 'bs' is given, lookup the pool and do the mempool alloc.
179 * If not, this is a bio_kmalloc() allocation and just do a
180 * kzalloc() for the exact number of vecs right away.
183 bvl
= kmalloc(nr
* sizeof(struct bio_vec
), gfp_mask
);
186 * see comment near bvec_array define!
204 case 129 ... BIO_MAX_PAGES
:
212 * idx now points to the pool we want to allocate from. only the
213 * 1-vec entry pool is mempool backed.
215 if (*idx
== BIOVEC_MAX_IDX
) {
217 bvl
= mempool_alloc(bs
->bvec_pool
, gfp_mask
);
219 struct biovec_slab
*bvs
= bvec_slabs
+ *idx
;
220 gfp_t __gfp_mask
= gfp_mask
& ~(__GFP_WAIT
| __GFP_IO
);
223 * Make this allocation restricted and don't dump info on
224 * allocation failures, since we'll fallback to the mempool
225 * in case of failure.
227 __gfp_mask
|= __GFP_NOMEMALLOC
| __GFP_NORETRY
| __GFP_NOWARN
;
230 * Try a slab allocation. If this fails and __GFP_WAIT
231 * is set, retry with the 1-entry mempool
233 bvl
= kmem_cache_alloc(bvs
->slab
, __gfp_mask
);
234 if (unlikely(!bvl
&& (gfp_mask
& __GFP_WAIT
))) {
235 *idx
= BIOVEC_MAX_IDX
;
243 void bio_free(struct bio
*bio
, struct bio_set
*bs
)
247 if (bio_has_allocated_vec(bio
))
248 bvec_free_bs(bs
, bio
->bi_io_vec
, BIO_POOL_IDX(bio
));
250 if (bio_integrity(bio
))
251 bio_integrity_free(bio
, bs
);
254 * If we have front padding, adjust the bio pointer before freeing
260 mempool_free(p
, bs
->bio_pool
);
264 * default destructor for a bio allocated with bio_alloc_bioset()
266 static void bio_fs_destructor(struct bio
*bio
)
268 bio_free(bio
, fs_bio_set
);
271 static void bio_kmalloc_destructor(struct bio
*bio
)
273 if (bio_has_allocated_vec(bio
))
274 kfree(bio
->bi_io_vec
);
278 void bio_init(struct bio
*bio
)
280 memset(bio
, 0, sizeof(*bio
));
281 bio
->bi_flags
= 1 << BIO_UPTODATE
;
282 bio
->bi_comp_cpu
= -1;
283 atomic_set(&bio
->bi_cnt
, 1);
287 * bio_alloc_bioset - allocate a bio for I/O
288 * @gfp_mask: the GFP_ mask given to the slab allocator
289 * @nr_iovecs: number of iovecs to pre-allocate
290 * @bs: the bio_set to allocate from. If %NULL, just use kmalloc
293 * bio_alloc_bioset will first try its own mempool to satisfy the allocation.
294 * If %__GFP_WAIT is set then we will block on the internal pool waiting
295 * for a &struct bio to become free. If a %NULL @bs is passed in, we will
296 * fall back to just using @kmalloc to allocate the required memory.
298 * Note that the caller must set ->bi_destructor on succesful return
299 * of a bio, to do the appropriate freeing of the bio once the reference
300 * count drops to zero.
302 struct bio
*bio_alloc_bioset(gfp_t gfp_mask
, int nr_iovecs
, struct bio_set
*bs
)
304 struct bio
*bio
= NULL
;
307 void *p
= mempool_alloc(bs
->bio_pool
, gfp_mask
);
310 bio
= p
+ bs
->front_pad
;
312 bio
= kmalloc(sizeof(*bio
), gfp_mask
);
315 struct bio_vec
*bvl
= NULL
;
318 if (likely(nr_iovecs
)) {
319 unsigned long uninitialized_var(idx
);
321 if (nr_iovecs
<= BIO_INLINE_VECS
) {
323 bvl
= bio
->bi_inline_vecs
;
324 nr_iovecs
= BIO_INLINE_VECS
;
326 bvl
= bvec_alloc_bs(gfp_mask
, nr_iovecs
, &idx
,
328 nr_iovecs
= bvec_nr_vecs(idx
);
330 if (unlikely(!bvl
)) {
332 mempool_free(bio
, bs
->bio_pool
);
338 bio
->bi_flags
|= idx
<< BIO_POOL_OFFSET
;
339 bio
->bi_max_vecs
= nr_iovecs
;
341 bio
->bi_io_vec
= bvl
;
347 struct bio
*bio_alloc(gfp_t gfp_mask
, int nr_iovecs
)
349 struct bio
*bio
= bio_alloc_bioset(gfp_mask
, nr_iovecs
, fs_bio_set
);
352 bio
->bi_destructor
= bio_fs_destructor
;
358 * Like bio_alloc(), but doesn't use a mempool backing. This means that
359 * it CAN fail, but while bio_alloc() can only be used for allocations
360 * that have a short (finite) life span, bio_kmalloc() should be used
361 * for more permanent bio allocations (like allocating some bio's for
362 * initalization or setup purposes).
364 struct bio
*bio_kmalloc(gfp_t gfp_mask
, int nr_iovecs
)
366 struct bio
*bio
= bio_alloc_bioset(gfp_mask
, nr_iovecs
, NULL
);
369 bio
->bi_destructor
= bio_kmalloc_destructor
;
374 void zero_fill_bio(struct bio
*bio
)
380 bio_for_each_segment(bv
, bio
, i
) {
381 char *data
= bvec_kmap_irq(bv
, &flags
);
382 memset(data
, 0, bv
->bv_len
);
383 flush_dcache_page(bv
->bv_page
);
384 bvec_kunmap_irq(data
, &flags
);
387 EXPORT_SYMBOL(zero_fill_bio
);
390 * bio_put - release a reference to a bio
391 * @bio: bio to release reference to
394 * Put a reference to a &struct bio, either one you have gotten with
395 * bio_alloc or bio_get. The last put of a bio will free it.
397 void bio_put(struct bio
*bio
)
399 BIO_BUG_ON(!atomic_read(&bio
->bi_cnt
));
404 if (atomic_dec_and_test(&bio
->bi_cnt
)) {
406 bio
->bi_destructor(bio
);
410 inline int bio_phys_segments(struct request_queue
*q
, struct bio
*bio
)
412 if (unlikely(!bio_flagged(bio
, BIO_SEG_VALID
)))
413 blk_recount_segments(q
, bio
);
415 return bio
->bi_phys_segments
;
419 * __bio_clone - clone a bio
420 * @bio: destination bio
421 * @bio_src: bio to clone
423 * Clone a &bio. Caller will own the returned bio, but not
424 * the actual data it points to. Reference count of returned
427 void __bio_clone(struct bio
*bio
, struct bio
*bio_src
)
429 memcpy(bio
->bi_io_vec
, bio_src
->bi_io_vec
,
430 bio_src
->bi_max_vecs
* sizeof(struct bio_vec
));
433 * most users will be overriding ->bi_bdev with a new target,
434 * so we don't set nor calculate new physical/hw segment counts here
436 bio
->bi_sector
= bio_src
->bi_sector
;
437 bio
->bi_bdev
= bio_src
->bi_bdev
;
438 bio
->bi_flags
|= 1 << BIO_CLONED
;
439 bio
->bi_rw
= bio_src
->bi_rw
;
440 bio
->bi_vcnt
= bio_src
->bi_vcnt
;
441 bio
->bi_size
= bio_src
->bi_size
;
442 bio
->bi_idx
= bio_src
->bi_idx
;
446 * bio_clone - clone a bio
448 * @gfp_mask: allocation priority
450 * Like __bio_clone, only also allocates the returned bio
452 struct bio
*bio_clone(struct bio
*bio
, gfp_t gfp_mask
)
454 struct bio
*b
= bio_alloc_bioset(gfp_mask
, bio
->bi_max_vecs
, fs_bio_set
);
459 b
->bi_destructor
= bio_fs_destructor
;
462 if (bio_integrity(bio
)) {
465 ret
= bio_integrity_clone(b
, bio
, fs_bio_set
);
475 * bio_get_nr_vecs - return approx number of vecs
478 * Return the approximate number of pages we can send to this target.
479 * There's no guarantee that you will be able to fit this number of pages
480 * into a bio, it does not account for dynamic restrictions that vary
483 int bio_get_nr_vecs(struct block_device
*bdev
)
485 struct request_queue
*q
= bdev_get_queue(bdev
);
488 nr_pages
= ((q
->max_sectors
<< 9) + PAGE_SIZE
- 1) >> PAGE_SHIFT
;
489 if (nr_pages
> q
->max_phys_segments
)
490 nr_pages
= q
->max_phys_segments
;
491 if (nr_pages
> q
->max_hw_segments
)
492 nr_pages
= q
->max_hw_segments
;
497 static int __bio_add_page(struct request_queue
*q
, struct bio
*bio
, struct page
498 *page
, unsigned int len
, unsigned int offset
,
499 unsigned short max_sectors
)
501 int retried_segments
= 0;
502 struct bio_vec
*bvec
;
505 * cloned bio must not modify vec list
507 if (unlikely(bio_flagged(bio
, BIO_CLONED
)))
510 if (((bio
->bi_size
+ len
) >> 9) > max_sectors
)
514 * For filesystems with a blocksize smaller than the pagesize
515 * we will often be called with the same page as last time and
516 * a consecutive offset. Optimize this special case.
518 if (bio
->bi_vcnt
> 0) {
519 struct bio_vec
*prev
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
521 if (page
== prev
->bv_page
&&
522 offset
== prev
->bv_offset
+ prev
->bv_len
) {
525 if (q
->merge_bvec_fn
) {
526 struct bvec_merge_data bvm
= {
527 .bi_bdev
= bio
->bi_bdev
,
528 .bi_sector
= bio
->bi_sector
,
529 .bi_size
= bio
->bi_size
,
533 if (q
->merge_bvec_fn(q
, &bvm
, prev
) < len
) {
543 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
547 * we might lose a segment or two here, but rather that than
548 * make this too complex.
551 while (bio
->bi_phys_segments
>= q
->max_phys_segments
552 || bio
->bi_phys_segments
>= q
->max_hw_segments
) {
554 if (retried_segments
)
557 retried_segments
= 1;
558 blk_recount_segments(q
, bio
);
562 * setup the new entry, we might clear it again later if we
563 * cannot add the page
565 bvec
= &bio
->bi_io_vec
[bio
->bi_vcnt
];
566 bvec
->bv_page
= page
;
568 bvec
->bv_offset
= offset
;
571 * if queue has other restrictions (eg varying max sector size
572 * depending on offset), it can specify a merge_bvec_fn in the
573 * queue to get further control
575 if (q
->merge_bvec_fn
) {
576 struct bvec_merge_data bvm
= {
577 .bi_bdev
= bio
->bi_bdev
,
578 .bi_sector
= bio
->bi_sector
,
579 .bi_size
= bio
->bi_size
,
584 * merge_bvec_fn() returns number of bytes it can accept
587 if (q
->merge_bvec_fn(q
, &bvm
, bvec
) < len
) {
588 bvec
->bv_page
= NULL
;
595 /* If we may be able to merge these biovecs, force a recount */
596 if (bio
->bi_vcnt
&& (BIOVEC_PHYS_MERGEABLE(bvec
-1, bvec
)))
597 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
600 bio
->bi_phys_segments
++;
607 * bio_add_pc_page - attempt to add page to bio
608 * @q: the target queue
609 * @bio: destination bio
611 * @len: vec entry length
612 * @offset: vec entry offset
614 * Attempt to add a page to the bio_vec maplist. This can fail for a
615 * number of reasons, such as the bio being full or target block
616 * device limitations. The target block device must allow bio's
617 * smaller than PAGE_SIZE, so it is always possible to add a single
618 * page to an empty bio. This should only be used by REQ_PC bios.
620 int bio_add_pc_page(struct request_queue
*q
, struct bio
*bio
, struct page
*page
,
621 unsigned int len
, unsigned int offset
)
623 return __bio_add_page(q
, bio
, page
, len
, offset
, q
->max_hw_sectors
);
627 * bio_add_page - attempt to add page to bio
628 * @bio: destination bio
630 * @len: vec entry length
631 * @offset: vec entry offset
633 * Attempt to add a page to the bio_vec maplist. This can fail for a
634 * number of reasons, such as the bio being full or target block
635 * device limitations. The target block device must allow bio's
636 * smaller than PAGE_SIZE, so it is always possible to add a single
637 * page to an empty bio.
639 int bio_add_page(struct bio
*bio
, struct page
*page
, unsigned int len
,
642 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
643 return __bio_add_page(q
, bio
, page
, len
, offset
, q
->max_sectors
);
646 struct bio_map_data
{
647 struct bio_vec
*iovecs
;
648 struct sg_iovec
*sgvecs
;
653 static void bio_set_map_data(struct bio_map_data
*bmd
, struct bio
*bio
,
654 struct sg_iovec
*iov
, int iov_count
,
657 memcpy(bmd
->iovecs
, bio
->bi_io_vec
, sizeof(struct bio_vec
) * bio
->bi_vcnt
);
658 memcpy(bmd
->sgvecs
, iov
, sizeof(struct sg_iovec
) * iov_count
);
659 bmd
->nr_sgvecs
= iov_count
;
660 bmd
->is_our_pages
= is_our_pages
;
661 bio
->bi_private
= bmd
;
664 static void bio_free_map_data(struct bio_map_data
*bmd
)
671 static struct bio_map_data
*bio_alloc_map_data(int nr_segs
, int iov_count
,
674 struct bio_map_data
*bmd
= kmalloc(sizeof(*bmd
), gfp_mask
);
679 bmd
->iovecs
= kmalloc(sizeof(struct bio_vec
) * nr_segs
, gfp_mask
);
685 bmd
->sgvecs
= kmalloc(sizeof(struct sg_iovec
) * iov_count
, gfp_mask
);
694 static int __bio_copy_iov(struct bio
*bio
, struct bio_vec
*iovecs
,
695 struct sg_iovec
*iov
, int iov_count
, int uncopy
,
699 struct bio_vec
*bvec
;
701 unsigned int iov_off
= 0;
702 int read
= bio_data_dir(bio
) == READ
;
704 __bio_for_each_segment(bvec
, bio
, i
, 0) {
705 char *bv_addr
= page_address(bvec
->bv_page
);
706 unsigned int bv_len
= iovecs
[i
].bv_len
;
708 while (bv_len
&& iov_idx
< iov_count
) {
712 bytes
= min_t(unsigned int,
713 iov
[iov_idx
].iov_len
- iov_off
, bv_len
);
714 iov_addr
= iov
[iov_idx
].iov_base
+ iov_off
;
717 if (!read
&& !uncopy
)
718 ret
= copy_from_user(bv_addr
, iov_addr
,
721 ret
= copy_to_user(iov_addr
, bv_addr
,
733 if (iov
[iov_idx
].iov_len
== iov_off
) {
740 __free_page(bvec
->bv_page
);
747 * bio_uncopy_user - finish previously mapped bio
748 * @bio: bio being terminated
750 * Free pages allocated from bio_copy_user() and write back data
751 * to user space in case of a read.
753 int bio_uncopy_user(struct bio
*bio
)
755 struct bio_map_data
*bmd
= bio
->bi_private
;
758 if (!bio_flagged(bio
, BIO_NULL_MAPPED
))
759 ret
= __bio_copy_iov(bio
, bmd
->iovecs
, bmd
->sgvecs
,
760 bmd
->nr_sgvecs
, 1, bmd
->is_our_pages
);
761 bio_free_map_data(bmd
);
767 * bio_copy_user_iov - copy user data to bio
768 * @q: destination block queue
769 * @map_data: pointer to the rq_map_data holding pages (if necessary)
771 * @iov_count: number of elements in the iovec
772 * @write_to_vm: bool indicating writing to pages or not
773 * @gfp_mask: memory allocation flags
775 * Prepares and returns a bio for indirect user io, bouncing data
776 * to/from kernel pages as necessary. Must be paired with
777 * call bio_uncopy_user() on io completion.
779 struct bio
*bio_copy_user_iov(struct request_queue
*q
,
780 struct rq_map_data
*map_data
,
781 struct sg_iovec
*iov
, int iov_count
,
782 int write_to_vm
, gfp_t gfp_mask
)
784 struct bio_map_data
*bmd
;
785 struct bio_vec
*bvec
;
790 unsigned int len
= 0;
792 for (i
= 0; i
< iov_count
; i
++) {
797 uaddr
= (unsigned long)iov
[i
].iov_base
;
798 end
= (uaddr
+ iov
[i
].iov_len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
799 start
= uaddr
>> PAGE_SHIFT
;
801 nr_pages
+= end
- start
;
802 len
+= iov
[i
].iov_len
;
805 bmd
= bio_alloc_map_data(nr_pages
, iov_count
, gfp_mask
);
807 return ERR_PTR(-ENOMEM
);
810 bio
= bio_alloc(gfp_mask
, nr_pages
);
814 bio
->bi_rw
|= (!write_to_vm
<< BIO_RW
);
819 nr_pages
= 1 << map_data
->page_order
;
821 unsigned int bytes
= PAGE_SIZE
;
827 if (i
== map_data
->nr_entries
* nr_pages
) {
832 page
= map_data
->pages
[i
/ nr_pages
];
833 page
+= (i
% nr_pages
);
837 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
844 if (bio_add_pc_page(q
, bio
, page
, bytes
, 0) < bytes
)
857 ret
= __bio_copy_iov(bio
, bio
->bi_io_vec
, iov
, iov_count
, 0, 0);
862 bio_set_map_data(bmd
, bio
, iov
, iov_count
, map_data
? 0 : 1);
866 bio_for_each_segment(bvec
, bio
, i
)
867 __free_page(bvec
->bv_page
);
871 bio_free_map_data(bmd
);
876 * bio_copy_user - copy user data to bio
877 * @q: destination block queue
878 * @map_data: pointer to the rq_map_data holding pages (if necessary)
879 * @uaddr: start of user address
880 * @len: length in bytes
881 * @write_to_vm: bool indicating writing to pages or not
882 * @gfp_mask: memory allocation flags
884 * Prepares and returns a bio for indirect user io, bouncing data
885 * to/from kernel pages as necessary. Must be paired with
886 * call bio_uncopy_user() on io completion.
888 struct bio
*bio_copy_user(struct request_queue
*q
, struct rq_map_data
*map_data
,
889 unsigned long uaddr
, unsigned int len
,
890 int write_to_vm
, gfp_t gfp_mask
)
894 iov
.iov_base
= (void __user
*)uaddr
;
897 return bio_copy_user_iov(q
, map_data
, &iov
, 1, write_to_vm
, gfp_mask
);
900 static struct bio
*__bio_map_user_iov(struct request_queue
*q
,
901 struct block_device
*bdev
,
902 struct sg_iovec
*iov
, int iov_count
,
903 int write_to_vm
, gfp_t gfp_mask
)
912 for (i
= 0; i
< iov_count
; i
++) {
913 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
914 unsigned long len
= iov
[i
].iov_len
;
915 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
916 unsigned long start
= uaddr
>> PAGE_SHIFT
;
918 nr_pages
+= end
- start
;
920 * buffer must be aligned to at least hardsector size for now
922 if (uaddr
& queue_dma_alignment(q
))
923 return ERR_PTR(-EINVAL
);
927 return ERR_PTR(-EINVAL
);
929 bio
= bio_alloc(gfp_mask
, nr_pages
);
931 return ERR_PTR(-ENOMEM
);
934 pages
= kcalloc(nr_pages
, sizeof(struct page
*), gfp_mask
);
938 for (i
= 0; i
< iov_count
; i
++) {
939 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
940 unsigned long len
= iov
[i
].iov_len
;
941 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
942 unsigned long start
= uaddr
>> PAGE_SHIFT
;
943 const int local_nr_pages
= end
- start
;
944 const int page_limit
= cur_page
+ local_nr_pages
;
946 ret
= get_user_pages_fast(uaddr
, local_nr_pages
,
947 write_to_vm
, &pages
[cur_page
]);
948 if (ret
< local_nr_pages
) {
953 offset
= uaddr
& ~PAGE_MASK
;
954 for (j
= cur_page
; j
< page_limit
; j
++) {
955 unsigned int bytes
= PAGE_SIZE
- offset
;
966 if (bio_add_pc_page(q
, bio
, pages
[j
], bytes
, offset
) <
976 * release the pages we didn't map into the bio, if any
978 while (j
< page_limit
)
979 page_cache_release(pages
[j
++]);
985 * set data direction, and check if mapped pages need bouncing
988 bio
->bi_rw
|= (1 << BIO_RW
);
991 bio
->bi_flags
|= (1 << BIO_USER_MAPPED
);
995 for (i
= 0; i
< nr_pages
; i
++) {
998 page_cache_release(pages
[i
]);
1003 return ERR_PTR(ret
);
1007 * bio_map_user - map user address into bio
1008 * @q: the struct request_queue for the bio
1009 * @bdev: destination block device
1010 * @uaddr: start of user address
1011 * @len: length in bytes
1012 * @write_to_vm: bool indicating writing to pages or not
1013 * @gfp_mask: memory allocation flags
1015 * Map the user space address into a bio suitable for io to a block
1016 * device. Returns an error pointer in case of error.
1018 struct bio
*bio_map_user(struct request_queue
*q
, struct block_device
*bdev
,
1019 unsigned long uaddr
, unsigned int len
, int write_to_vm
,
1022 struct sg_iovec iov
;
1024 iov
.iov_base
= (void __user
*)uaddr
;
1027 return bio_map_user_iov(q
, bdev
, &iov
, 1, write_to_vm
, gfp_mask
);
1031 * bio_map_user_iov - map user sg_iovec table into bio
1032 * @q: the struct request_queue for the bio
1033 * @bdev: destination block device
1035 * @iov_count: number of elements in the iovec
1036 * @write_to_vm: bool indicating writing to pages or not
1037 * @gfp_mask: memory allocation flags
1039 * Map the user space address into a bio suitable for io to a block
1040 * device. Returns an error pointer in case of error.
1042 struct bio
*bio_map_user_iov(struct request_queue
*q
, struct block_device
*bdev
,
1043 struct sg_iovec
*iov
, int iov_count
,
1044 int write_to_vm
, gfp_t gfp_mask
)
1048 bio
= __bio_map_user_iov(q
, bdev
, iov
, iov_count
, write_to_vm
,
1054 * subtle -- if __bio_map_user() ended up bouncing a bio,
1055 * it would normally disappear when its bi_end_io is run.
1056 * however, we need it for the unmap, so grab an extra
1064 static void __bio_unmap_user(struct bio
*bio
)
1066 struct bio_vec
*bvec
;
1070 * make sure we dirty pages we wrote to
1072 __bio_for_each_segment(bvec
, bio
, i
, 0) {
1073 if (bio_data_dir(bio
) == READ
)
1074 set_page_dirty_lock(bvec
->bv_page
);
1076 page_cache_release(bvec
->bv_page
);
1083 * bio_unmap_user - unmap a bio
1084 * @bio: the bio being unmapped
1086 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1087 * a process context.
1089 * bio_unmap_user() may sleep.
1091 void bio_unmap_user(struct bio
*bio
)
1093 __bio_unmap_user(bio
);
1097 static void bio_map_kern_endio(struct bio
*bio
, int err
)
1103 static struct bio
*__bio_map_kern(struct request_queue
*q
, void *data
,
1104 unsigned int len
, gfp_t gfp_mask
)
1106 unsigned long kaddr
= (unsigned long)data
;
1107 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1108 unsigned long start
= kaddr
>> PAGE_SHIFT
;
1109 const int nr_pages
= end
- start
;
1113 bio
= bio_alloc(gfp_mask
, nr_pages
);
1115 return ERR_PTR(-ENOMEM
);
1117 offset
= offset_in_page(kaddr
);
1118 for (i
= 0; i
< nr_pages
; i
++) {
1119 unsigned int bytes
= PAGE_SIZE
- offset
;
1127 if (bio_add_pc_page(q
, bio
, virt_to_page(data
), bytes
,
1136 bio
->bi_end_io
= bio_map_kern_endio
;
1141 * bio_map_kern - map kernel address into bio
1142 * @q: the struct request_queue for the bio
1143 * @data: pointer to buffer to map
1144 * @len: length in bytes
1145 * @gfp_mask: allocation flags for bio allocation
1147 * Map the kernel address into a bio suitable for io to a block
1148 * device. Returns an error pointer in case of error.
1150 struct bio
*bio_map_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1155 bio
= __bio_map_kern(q
, data
, len
, gfp_mask
);
1159 if (bio
->bi_size
== len
)
1163 * Don't support partial mappings.
1166 return ERR_PTR(-EINVAL
);
1169 static void bio_copy_kern_endio(struct bio
*bio
, int err
)
1171 struct bio_vec
*bvec
;
1172 const int read
= bio_data_dir(bio
) == READ
;
1173 struct bio_map_data
*bmd
= bio
->bi_private
;
1175 char *p
= bmd
->sgvecs
[0].iov_base
;
1177 __bio_for_each_segment(bvec
, bio
, i
, 0) {
1178 char *addr
= page_address(bvec
->bv_page
);
1179 int len
= bmd
->iovecs
[i
].bv_len
;
1182 memcpy(p
, addr
, len
);
1184 __free_page(bvec
->bv_page
);
1188 bio_free_map_data(bmd
);
1193 * bio_copy_kern - copy kernel address into bio
1194 * @q: the struct request_queue for the bio
1195 * @data: pointer to buffer to copy
1196 * @len: length in bytes
1197 * @gfp_mask: allocation flags for bio and page allocation
1198 * @reading: data direction is READ
1200 * copy the kernel address into a bio suitable for io to a block
1201 * device. Returns an error pointer in case of error.
1203 struct bio
*bio_copy_kern(struct request_queue
*q
, void *data
, unsigned int len
,
1204 gfp_t gfp_mask
, int reading
)
1207 struct bio_vec
*bvec
;
1210 bio
= bio_copy_user(q
, NULL
, (unsigned long)data
, len
, 1, gfp_mask
);
1217 bio_for_each_segment(bvec
, bio
, i
) {
1218 char *addr
= page_address(bvec
->bv_page
);
1220 memcpy(addr
, p
, bvec
->bv_len
);
1225 bio
->bi_end_io
= bio_copy_kern_endio
;
1231 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1232 * for performing direct-IO in BIOs.
1234 * The problem is that we cannot run set_page_dirty() from interrupt context
1235 * because the required locks are not interrupt-safe. So what we can do is to
1236 * mark the pages dirty _before_ performing IO. And in interrupt context,
1237 * check that the pages are still dirty. If so, fine. If not, redirty them
1238 * in process context.
1240 * We special-case compound pages here: normally this means reads into hugetlb
1241 * pages. The logic in here doesn't really work right for compound pages
1242 * because the VM does not uniformly chase down the head page in all cases.
1243 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1244 * handle them at all. So we skip compound pages here at an early stage.
1246 * Note that this code is very hard to test under normal circumstances because
1247 * direct-io pins the pages with get_user_pages(). This makes
1248 * is_page_cache_freeable return false, and the VM will not clean the pages.
1249 * But other code (eg, pdflush) could clean the pages if they are mapped
1252 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1253 * deferred bio dirtying paths.
1257 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1259 void bio_set_pages_dirty(struct bio
*bio
)
1261 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1264 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1265 struct page
*page
= bvec
[i
].bv_page
;
1267 if (page
&& !PageCompound(page
))
1268 set_page_dirty_lock(page
);
1272 static void bio_release_pages(struct bio
*bio
)
1274 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1277 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1278 struct page
*page
= bvec
[i
].bv_page
;
1286 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1287 * If they are, then fine. If, however, some pages are clean then they must
1288 * have been written out during the direct-IO read. So we take another ref on
1289 * the BIO and the offending pages and re-dirty the pages in process context.
1291 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1292 * here on. It will run one page_cache_release() against each page and will
1293 * run one bio_put() against the BIO.
1296 static void bio_dirty_fn(struct work_struct
*work
);
1298 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1299 static DEFINE_SPINLOCK(bio_dirty_lock
);
1300 static struct bio
*bio_dirty_list
;
1303 * This runs in process context
1305 static void bio_dirty_fn(struct work_struct
*work
)
1307 unsigned long flags
;
1310 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1311 bio
= bio_dirty_list
;
1312 bio_dirty_list
= NULL
;
1313 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1316 struct bio
*next
= bio
->bi_private
;
1318 bio_set_pages_dirty(bio
);
1319 bio_release_pages(bio
);
1325 void bio_check_pages_dirty(struct bio
*bio
)
1327 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1328 int nr_clean_pages
= 0;
1331 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1332 struct page
*page
= bvec
[i
].bv_page
;
1334 if (PageDirty(page
) || PageCompound(page
)) {
1335 page_cache_release(page
);
1336 bvec
[i
].bv_page
= NULL
;
1342 if (nr_clean_pages
) {
1343 unsigned long flags
;
1345 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1346 bio
->bi_private
= bio_dirty_list
;
1347 bio_dirty_list
= bio
;
1348 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1349 schedule_work(&bio_dirty_work
);
1356 * bio_endio - end I/O on a bio
1358 * @error: error, if any
1361 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1362 * preferred way to end I/O on a bio, it takes care of clearing
1363 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1364 * established -Exxxx (-EIO, for instance) error values in case
1365 * something went wrong. Noone should call bi_end_io() directly on a
1366 * bio unless they own it and thus know that it has an end_io
1369 void bio_endio(struct bio
*bio
, int error
)
1372 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1373 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
1377 bio
->bi_end_io(bio
, error
);
1380 void bio_pair_release(struct bio_pair
*bp
)
1382 if (atomic_dec_and_test(&bp
->cnt
)) {
1383 struct bio
*master
= bp
->bio1
.bi_private
;
1385 bio_endio(master
, bp
->error
);
1386 mempool_free(bp
, bp
->bio2
.bi_private
);
1390 static void bio_pair_end_1(struct bio
*bi
, int err
)
1392 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio1
);
1397 bio_pair_release(bp
);
1400 static void bio_pair_end_2(struct bio
*bi
, int err
)
1402 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio2
);
1407 bio_pair_release(bp
);
1411 * split a bio - only worry about a bio with a single page
1414 struct bio_pair
*bio_split(struct bio
*bi
, int first_sectors
)
1416 struct bio_pair
*bp
= mempool_alloc(bio_split_pool
, GFP_NOIO
);
1421 trace_block_split(bdev_get_queue(bi
->bi_bdev
), bi
,
1422 bi
->bi_sector
+ first_sectors
);
1424 BUG_ON(bi
->bi_vcnt
!= 1);
1425 BUG_ON(bi
->bi_idx
!= 0);
1426 atomic_set(&bp
->cnt
, 3);
1430 bp
->bio2
.bi_sector
+= first_sectors
;
1431 bp
->bio2
.bi_size
-= first_sectors
<< 9;
1432 bp
->bio1
.bi_size
= first_sectors
<< 9;
1434 bp
->bv1
= bi
->bi_io_vec
[0];
1435 bp
->bv2
= bi
->bi_io_vec
[0];
1436 bp
->bv2
.bv_offset
+= first_sectors
<< 9;
1437 bp
->bv2
.bv_len
-= first_sectors
<< 9;
1438 bp
->bv1
.bv_len
= first_sectors
<< 9;
1440 bp
->bio1
.bi_io_vec
= &bp
->bv1
;
1441 bp
->bio2
.bi_io_vec
= &bp
->bv2
;
1443 bp
->bio1
.bi_max_vecs
= 1;
1444 bp
->bio2
.bi_max_vecs
= 1;
1446 bp
->bio1
.bi_end_io
= bio_pair_end_1
;
1447 bp
->bio2
.bi_end_io
= bio_pair_end_2
;
1449 bp
->bio1
.bi_private
= bi
;
1450 bp
->bio2
.bi_private
= bio_split_pool
;
1452 if (bio_integrity(bi
))
1453 bio_integrity_split(bi
, bp
, first_sectors
);
1459 * bio_sector_offset - Find hardware sector offset in bio
1460 * @bio: bio to inspect
1461 * @index: bio_vec index
1462 * @offset: offset in bv_page
1464 * Return the number of hardware sectors between beginning of bio
1465 * and an end point indicated by a bio_vec index and an offset
1466 * within that vector's page.
1468 sector_t
bio_sector_offset(struct bio
*bio
, unsigned short index
,
1469 unsigned int offset
)
1471 unsigned int sector_sz
= queue_hardsect_size(bio
->bi_bdev
->bd_disk
->queue
);
1478 if (index
>= bio
->bi_idx
)
1479 index
= bio
->bi_vcnt
- 1;
1481 __bio_for_each_segment(bv
, bio
, i
, 0) {
1483 if (offset
> bv
->bv_offset
)
1484 sectors
+= (offset
- bv
->bv_offset
) / sector_sz
;
1488 sectors
+= bv
->bv_len
/ sector_sz
;
1493 EXPORT_SYMBOL(bio_sector_offset
);
1496 * create memory pools for biovec's in a bio_set.
1497 * use the global biovec slabs created for general use.
1499 static int biovec_create_pools(struct bio_set
*bs
, int pool_entries
)
1501 struct biovec_slab
*bp
= bvec_slabs
+ BIOVEC_MAX_IDX
;
1503 bs
->bvec_pool
= mempool_create_slab_pool(pool_entries
, bp
->slab
);
1510 static void biovec_free_pools(struct bio_set
*bs
)
1512 mempool_destroy(bs
->bvec_pool
);
1515 void bioset_free(struct bio_set
*bs
)
1518 mempool_destroy(bs
->bio_pool
);
1520 bioset_integrity_free(bs
);
1521 biovec_free_pools(bs
);
1528 * bioset_create - Create a bio_set
1529 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1530 * @front_pad: Number of bytes to allocate in front of the returned bio
1533 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1534 * to ask for a number of bytes to be allocated in front of the bio.
1535 * Front pad allocation is useful for embedding the bio inside
1536 * another structure, to avoid allocating extra data to go with the bio.
1537 * Note that the bio must be embedded at the END of that structure always,
1538 * or things will break badly.
1540 struct bio_set
*bioset_create(unsigned int pool_size
, unsigned int front_pad
)
1542 unsigned int back_pad
= BIO_INLINE_VECS
* sizeof(struct bio_vec
);
1545 bs
= kzalloc(sizeof(*bs
), GFP_KERNEL
);
1549 bs
->front_pad
= front_pad
;
1551 bs
->bio_slab
= bio_find_or_create_slab(front_pad
+ back_pad
);
1552 if (!bs
->bio_slab
) {
1557 bs
->bio_pool
= mempool_create_slab_pool(pool_size
, bs
->bio_slab
);
1561 if (bioset_integrity_create(bs
, pool_size
))
1564 if (!biovec_create_pools(bs
, pool_size
))
1572 static void __init
biovec_init_slabs(void)
1576 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1578 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
1580 size
= bvs
->nr_vecs
* sizeof(struct bio_vec
);
1581 bvs
->slab
= kmem_cache_create(bvs
->name
, size
, 0,
1582 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1586 static int __init
init_bio(void)
1590 bio_slabs
= kzalloc(bio_slab_max
* sizeof(struct bio_slab
), GFP_KERNEL
);
1592 panic("bio: can't allocate bios\n");
1594 bio_integrity_init_slab();
1595 biovec_init_slabs();
1597 fs_bio_set
= bioset_create(BIO_POOL_SIZE
, 0);
1599 panic("bio: can't allocate bios\n");
1601 bio_split_pool
= mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES
,
1602 sizeof(struct bio_pair
));
1603 if (!bio_split_pool
)
1604 panic("bio: can't create split pool\n");
1609 subsys_initcall(init_bio
);
1611 EXPORT_SYMBOL(bio_alloc
);
1612 EXPORT_SYMBOL(bio_kmalloc
);
1613 EXPORT_SYMBOL(bio_put
);
1614 EXPORT_SYMBOL(bio_free
);
1615 EXPORT_SYMBOL(bio_endio
);
1616 EXPORT_SYMBOL(bio_init
);
1617 EXPORT_SYMBOL(__bio_clone
);
1618 EXPORT_SYMBOL(bio_clone
);
1619 EXPORT_SYMBOL(bio_phys_segments
);
1620 EXPORT_SYMBOL(bio_add_page
);
1621 EXPORT_SYMBOL(bio_add_pc_page
);
1622 EXPORT_SYMBOL(bio_get_nr_vecs
);
1623 EXPORT_SYMBOL(bio_map_user
);
1624 EXPORT_SYMBOL(bio_unmap_user
);
1625 EXPORT_SYMBOL(bio_map_kern
);
1626 EXPORT_SYMBOL(bio_copy_kern
);
1627 EXPORT_SYMBOL(bio_pair_release
);
1628 EXPORT_SYMBOL(bio_split
);
1629 EXPORT_SYMBOL(bio_copy_user
);
1630 EXPORT_SYMBOL(bio_uncopy_user
);
1631 EXPORT_SYMBOL(bioset_create
);
1632 EXPORT_SYMBOL(bioset_free
);
1633 EXPORT_SYMBOL(bio_alloc_bioset
);