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 <scsi/sg.h> /* for struct sg_iovec */
31 static struct kmem_cache
*bio_slab __read_mostly
;
33 mempool_t
*bio_split_pool __read_mostly
;
36 * if you change this list, also change bvec_alloc or things will
37 * break badly! cannot be bigger than what you can fit into an
41 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
42 static struct biovec_slab bvec_slabs
[BIOVEC_NR_POOLS
] __read_mostly
= {
43 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES
),
48 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
49 * IO code that does not need private memory pools.
51 struct bio_set
*fs_bio_set
;
53 unsigned int bvec_nr_vecs(unsigned short idx
)
55 return bvec_slabs
[idx
].nr_vecs
;
58 struct bio_vec
*bvec_alloc_bs(gfp_t gfp_mask
, int nr
, unsigned long *idx
, struct bio_set
*bs
)
63 * see comment near bvec_array define!
66 case 1 : *idx
= 0; break;
67 case 2 ... 4: *idx
= 1; break;
68 case 5 ... 16: *idx
= 2; break;
69 case 17 ... 64: *idx
= 3; break;
70 case 65 ... 128: *idx
= 4; break;
71 case 129 ... BIO_MAX_PAGES
: *idx
= 5; break;
76 * idx now points to the pool we want to allocate from
79 bvl
= mempool_alloc(bs
->bvec_pools
[*idx
], gfp_mask
);
81 struct biovec_slab
*bp
= bvec_slabs
+ *idx
;
83 memset(bvl
, 0, bp
->nr_vecs
* sizeof(struct bio_vec
));
89 void bio_free(struct bio
*bio
, struct bio_set
*bio_set
)
92 const int pool_idx
= BIO_POOL_IDX(bio
);
94 BIO_BUG_ON(pool_idx
>= BIOVEC_NR_POOLS
);
96 mempool_free(bio
->bi_io_vec
, bio_set
->bvec_pools
[pool_idx
]);
99 if (bio_integrity(bio
))
100 bio_integrity_free(bio
, bio_set
);
102 mempool_free(bio
, bio_set
->bio_pool
);
106 * default destructor for a bio allocated with bio_alloc_bioset()
108 static void bio_fs_destructor(struct bio
*bio
)
110 bio_free(bio
, fs_bio_set
);
113 void bio_init(struct bio
*bio
)
115 memset(bio
, 0, sizeof(*bio
));
116 bio
->bi_flags
= 1 << BIO_UPTODATE
;
117 atomic_set(&bio
->bi_cnt
, 1);
121 * bio_alloc_bioset - allocate a bio for I/O
122 * @gfp_mask: the GFP_ mask given to the slab allocator
123 * @nr_iovecs: number of iovecs to pre-allocate
124 * @bs: the bio_set to allocate from
127 * bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
128 * If %__GFP_WAIT is set then we will block on the internal pool waiting
129 * for a &struct bio to become free.
131 * allocate bio and iovecs from the memory pools specified by the
134 struct bio
*bio_alloc_bioset(gfp_t gfp_mask
, int nr_iovecs
, struct bio_set
*bs
)
136 struct bio
*bio
= mempool_alloc(bs
->bio_pool
, gfp_mask
);
139 struct bio_vec
*bvl
= NULL
;
142 if (likely(nr_iovecs
)) {
143 unsigned long uninitialized_var(idx
);
145 bvl
= bvec_alloc_bs(gfp_mask
, nr_iovecs
, &idx
, bs
);
146 if (unlikely(!bvl
)) {
147 mempool_free(bio
, bs
->bio_pool
);
151 bio
->bi_flags
|= idx
<< BIO_POOL_OFFSET
;
152 bio
->bi_max_vecs
= bvec_slabs
[idx
].nr_vecs
;
154 bio
->bi_io_vec
= bvl
;
160 struct bio
*bio_alloc(gfp_t gfp_mask
, int nr_iovecs
)
162 struct bio
*bio
= bio_alloc_bioset(gfp_mask
, nr_iovecs
, fs_bio_set
);
165 bio
->bi_destructor
= bio_fs_destructor
;
170 void zero_fill_bio(struct bio
*bio
)
176 bio_for_each_segment(bv
, bio
, i
) {
177 char *data
= bvec_kmap_irq(bv
, &flags
);
178 memset(data
, 0, bv
->bv_len
);
179 flush_dcache_page(bv
->bv_page
);
180 bvec_kunmap_irq(data
, &flags
);
183 EXPORT_SYMBOL(zero_fill_bio
);
186 * bio_put - release a reference to a bio
187 * @bio: bio to release reference to
190 * Put a reference to a &struct bio, either one you have gotten with
191 * bio_alloc or bio_get. The last put of a bio will free it.
193 void bio_put(struct bio
*bio
)
195 BIO_BUG_ON(!atomic_read(&bio
->bi_cnt
));
200 if (atomic_dec_and_test(&bio
->bi_cnt
)) {
202 bio
->bi_destructor(bio
);
206 inline int bio_phys_segments(struct request_queue
*q
, struct bio
*bio
)
208 if (unlikely(!bio_flagged(bio
, BIO_SEG_VALID
)))
209 blk_recount_segments(q
, bio
);
211 return bio
->bi_phys_segments
;
214 inline int bio_hw_segments(struct request_queue
*q
, struct bio
*bio
)
216 if (unlikely(!bio_flagged(bio
, BIO_SEG_VALID
)))
217 blk_recount_segments(q
, bio
);
219 return bio
->bi_hw_segments
;
223 * __bio_clone - clone a bio
224 * @bio: destination bio
225 * @bio_src: bio to clone
227 * Clone a &bio. Caller will own the returned bio, but not
228 * the actual data it points to. Reference count of returned
231 void __bio_clone(struct bio
*bio
, struct bio
*bio_src
)
233 memcpy(bio
->bi_io_vec
, bio_src
->bi_io_vec
,
234 bio_src
->bi_max_vecs
* sizeof(struct bio_vec
));
237 * most users will be overriding ->bi_bdev with a new target,
238 * so we don't set nor calculate new physical/hw segment counts here
240 bio
->bi_sector
= bio_src
->bi_sector
;
241 bio
->bi_bdev
= bio_src
->bi_bdev
;
242 bio
->bi_flags
|= 1 << BIO_CLONED
;
243 bio
->bi_rw
= bio_src
->bi_rw
;
244 bio
->bi_vcnt
= bio_src
->bi_vcnt
;
245 bio
->bi_size
= bio_src
->bi_size
;
246 bio
->bi_idx
= bio_src
->bi_idx
;
250 * bio_clone - clone a bio
252 * @gfp_mask: allocation priority
254 * Like __bio_clone, only also allocates the returned bio
256 struct bio
*bio_clone(struct bio
*bio
, gfp_t gfp_mask
)
258 struct bio
*b
= bio_alloc_bioset(gfp_mask
, bio
->bi_max_vecs
, fs_bio_set
);
263 b
->bi_destructor
= bio_fs_destructor
;
266 if (bio_integrity(bio
)) {
269 ret
= bio_integrity_clone(b
, bio
, fs_bio_set
);
279 * bio_get_nr_vecs - return approx number of vecs
282 * Return the approximate number of pages we can send to this target.
283 * There's no guarantee that you will be able to fit this number of pages
284 * into a bio, it does not account for dynamic restrictions that vary
287 int bio_get_nr_vecs(struct block_device
*bdev
)
289 struct request_queue
*q
= bdev_get_queue(bdev
);
292 nr_pages
= ((q
->max_sectors
<< 9) + PAGE_SIZE
- 1) >> PAGE_SHIFT
;
293 if (nr_pages
> q
->max_phys_segments
)
294 nr_pages
= q
->max_phys_segments
;
295 if (nr_pages
> q
->max_hw_segments
)
296 nr_pages
= q
->max_hw_segments
;
301 static int __bio_add_page(struct request_queue
*q
, struct bio
*bio
, struct page
302 *page
, unsigned int len
, unsigned int offset
,
303 unsigned short max_sectors
)
305 int retried_segments
= 0;
306 struct bio_vec
*bvec
;
309 * cloned bio must not modify vec list
311 if (unlikely(bio_flagged(bio
, BIO_CLONED
)))
314 if (((bio
->bi_size
+ len
) >> 9) > max_sectors
)
318 * For filesystems with a blocksize smaller than the pagesize
319 * we will often be called with the same page as last time and
320 * a consecutive offset. Optimize this special case.
322 if (bio
->bi_vcnt
> 0) {
323 struct bio_vec
*prev
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
325 if (page
== prev
->bv_page
&&
326 offset
== prev
->bv_offset
+ prev
->bv_len
) {
328 if (q
->merge_bvec_fn
&&
329 q
->merge_bvec_fn(q
, bio
, prev
) < len
) {
338 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
342 * we might lose a segment or two here, but rather that than
343 * make this too complex.
346 while (bio
->bi_phys_segments
>= q
->max_phys_segments
347 || bio
->bi_hw_segments
>= q
->max_hw_segments
348 || BIOVEC_VIRT_OVERSIZE(bio
->bi_size
)) {
350 if (retried_segments
)
353 retried_segments
= 1;
354 blk_recount_segments(q
, bio
);
358 * setup the new entry, we might clear it again later if we
359 * cannot add the page
361 bvec
= &bio
->bi_io_vec
[bio
->bi_vcnt
];
362 bvec
->bv_page
= page
;
364 bvec
->bv_offset
= offset
;
367 * if queue has other restrictions (eg varying max sector size
368 * depending on offset), it can specify a merge_bvec_fn in the
369 * queue to get further control
371 if (q
->merge_bvec_fn
) {
373 * merge_bvec_fn() returns number of bytes it can accept
376 if (q
->merge_bvec_fn(q
, bio
, bvec
) < len
) {
377 bvec
->bv_page
= NULL
;
384 /* If we may be able to merge these biovecs, force a recount */
385 if (bio
->bi_vcnt
&& (BIOVEC_PHYS_MERGEABLE(bvec
-1, bvec
) ||
386 BIOVEC_VIRT_MERGEABLE(bvec
-1, bvec
)))
387 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
390 bio
->bi_phys_segments
++;
391 bio
->bi_hw_segments
++;
398 * bio_add_pc_page - attempt to add page to bio
399 * @q: the target queue
400 * @bio: destination bio
402 * @len: vec entry length
403 * @offset: vec entry offset
405 * Attempt to add a page to the bio_vec maplist. This can fail for a
406 * number of reasons, such as the bio being full or target block
407 * device limitations. The target block device must allow bio's
408 * smaller than PAGE_SIZE, so it is always possible to add a single
409 * page to an empty bio. This should only be used by REQ_PC bios.
411 int bio_add_pc_page(struct request_queue
*q
, struct bio
*bio
, struct page
*page
,
412 unsigned int len
, unsigned int offset
)
414 return __bio_add_page(q
, bio
, page
, len
, offset
, q
->max_hw_sectors
);
418 * bio_add_page - attempt to add page to bio
419 * @bio: destination bio
421 * @len: vec entry length
422 * @offset: vec entry offset
424 * Attempt to add a page to the bio_vec maplist. This can fail for a
425 * number of reasons, such as the bio being full or target block
426 * device limitations. The target block device must allow bio's
427 * smaller than PAGE_SIZE, so it is always possible to add a single
428 * page to an empty bio.
430 int bio_add_page(struct bio
*bio
, struct page
*page
, unsigned int len
,
433 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
434 return __bio_add_page(q
, bio
, page
, len
, offset
, q
->max_sectors
);
437 struct bio_map_data
{
438 struct bio_vec
*iovecs
;
440 struct sg_iovec
*sgvecs
;
443 static void bio_set_map_data(struct bio_map_data
*bmd
, struct bio
*bio
,
444 struct sg_iovec
*iov
, int iov_count
)
446 memcpy(bmd
->iovecs
, bio
->bi_io_vec
, sizeof(struct bio_vec
) * bio
->bi_vcnt
);
447 memcpy(bmd
->sgvecs
, iov
, sizeof(struct sg_iovec
) * iov_count
);
448 bmd
->nr_sgvecs
= iov_count
;
449 bio
->bi_private
= bmd
;
452 static void bio_free_map_data(struct bio_map_data
*bmd
)
459 static struct bio_map_data
*bio_alloc_map_data(int nr_segs
, int iov_count
)
461 struct bio_map_data
*bmd
= kmalloc(sizeof(*bmd
), GFP_KERNEL
);
466 bmd
->iovecs
= kmalloc(sizeof(struct bio_vec
) * nr_segs
, GFP_KERNEL
);
472 bmd
->sgvecs
= kmalloc(sizeof(struct sg_iovec
) * iov_count
, GFP_KERNEL
);
481 static int __bio_copy_iov(struct bio
*bio
, struct sg_iovec
*iov
, int iov_count
,
485 struct bio_vec
*bvec
;
487 unsigned int iov_off
= 0;
488 int read
= bio_data_dir(bio
) == READ
;
490 __bio_for_each_segment(bvec
, bio
, i
, 0) {
491 char *bv_addr
= page_address(bvec
->bv_page
);
492 unsigned int bv_len
= bvec
->bv_len
;
494 while (bv_len
&& iov_idx
< iov_count
) {
498 bytes
= min_t(unsigned int,
499 iov
[iov_idx
].iov_len
- iov_off
, bv_len
);
500 iov_addr
= iov
[iov_idx
].iov_base
+ iov_off
;
503 if (!read
&& !uncopy
)
504 ret
= copy_from_user(bv_addr
, iov_addr
,
507 ret
= copy_to_user(iov_addr
, bv_addr
,
519 if (iov
[iov_idx
].iov_len
== iov_off
) {
526 __free_page(bvec
->bv_page
);
533 * bio_uncopy_user - finish previously mapped bio
534 * @bio: bio being terminated
536 * Free pages allocated from bio_copy_user() and write back data
537 * to user space in case of a read.
539 int bio_uncopy_user(struct bio
*bio
)
541 struct bio_map_data
*bmd
= bio
->bi_private
;
544 ret
= __bio_copy_iov(bio
, bmd
->sgvecs
, bmd
->nr_sgvecs
, 1);
546 bio_free_map_data(bmd
);
552 * bio_copy_user_iov - copy user data to bio
553 * @q: destination block queue
555 * @iov_count: number of elements in the iovec
556 * @write_to_vm: bool indicating writing to pages or not
558 * Prepares and returns a bio for indirect user io, bouncing data
559 * to/from kernel pages as necessary. Must be paired with
560 * call bio_uncopy_user() on io completion.
562 struct bio
*bio_copy_user_iov(struct request_queue
*q
, struct sg_iovec
*iov
,
563 int iov_count
, int write_to_vm
)
565 struct bio_map_data
*bmd
;
566 struct bio_vec
*bvec
;
571 unsigned int len
= 0;
573 for (i
= 0; i
< iov_count
; i
++) {
578 uaddr
= (unsigned long)iov
[i
].iov_base
;
579 end
= (uaddr
+ iov
[i
].iov_len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
580 start
= uaddr
>> PAGE_SHIFT
;
582 nr_pages
+= end
- start
;
583 len
+= iov
[i
].iov_len
;
586 bmd
= bio_alloc_map_data(nr_pages
, iov_count
);
588 return ERR_PTR(-ENOMEM
);
591 bio
= bio_alloc(GFP_KERNEL
, nr_pages
);
595 bio
->bi_rw
|= (!write_to_vm
<< BIO_RW
);
599 unsigned int bytes
= PAGE_SIZE
;
604 page
= alloc_page(q
->bounce_gfp
| GFP_KERNEL
);
610 if (bio_add_pc_page(q
, bio
, page
, bytes
, 0) < bytes
)
623 ret
= __bio_copy_iov(bio
, iov
, iov_count
, 0);
628 bio_set_map_data(bmd
, bio
, iov
, iov_count
);
631 bio_for_each_segment(bvec
, bio
, i
)
632 __free_page(bvec
->bv_page
);
636 bio_free_map_data(bmd
);
641 * bio_copy_user - copy user data to bio
642 * @q: destination block queue
643 * @uaddr: start of user address
644 * @len: length in bytes
645 * @write_to_vm: bool indicating writing to pages or not
647 * Prepares and returns a bio for indirect user io, bouncing data
648 * to/from kernel pages as necessary. Must be paired with
649 * call bio_uncopy_user() on io completion.
651 struct bio
*bio_copy_user(struct request_queue
*q
, unsigned long uaddr
,
652 unsigned int len
, int write_to_vm
)
656 iov
.iov_base
= (void __user
*)uaddr
;
659 return bio_copy_user_iov(q
, &iov
, 1, write_to_vm
);
662 static struct bio
*__bio_map_user_iov(struct request_queue
*q
,
663 struct block_device
*bdev
,
664 struct sg_iovec
*iov
, int iov_count
,
674 for (i
= 0; i
< iov_count
; i
++) {
675 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
676 unsigned long len
= iov
[i
].iov_len
;
677 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
678 unsigned long start
= uaddr
>> PAGE_SHIFT
;
680 nr_pages
+= end
- start
;
682 * buffer must be aligned to at least hardsector size for now
684 if (uaddr
& queue_dma_alignment(q
))
685 return ERR_PTR(-EINVAL
);
689 return ERR_PTR(-EINVAL
);
691 bio
= bio_alloc(GFP_KERNEL
, nr_pages
);
693 return ERR_PTR(-ENOMEM
);
696 pages
= kcalloc(nr_pages
, sizeof(struct page
*), GFP_KERNEL
);
700 for (i
= 0; i
< iov_count
; i
++) {
701 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
702 unsigned long len
= iov
[i
].iov_len
;
703 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
704 unsigned long start
= uaddr
>> PAGE_SHIFT
;
705 const int local_nr_pages
= end
- start
;
706 const int page_limit
= cur_page
+ local_nr_pages
;
708 down_read(¤t
->mm
->mmap_sem
);
709 ret
= get_user_pages(current
, current
->mm
, uaddr
,
711 write_to_vm
, 0, &pages
[cur_page
], NULL
);
712 up_read(¤t
->mm
->mmap_sem
);
714 if (ret
< local_nr_pages
) {
719 offset
= uaddr
& ~PAGE_MASK
;
720 for (j
= cur_page
; j
< page_limit
; j
++) {
721 unsigned int bytes
= PAGE_SIZE
- offset
;
732 if (bio_add_pc_page(q
, bio
, pages
[j
], bytes
, offset
) <
742 * release the pages we didn't map into the bio, if any
744 while (j
< page_limit
)
745 page_cache_release(pages
[j
++]);
751 * set data direction, and check if mapped pages need bouncing
754 bio
->bi_rw
|= (1 << BIO_RW
);
757 bio
->bi_flags
|= (1 << BIO_USER_MAPPED
);
761 for (i
= 0; i
< nr_pages
; i
++) {
764 page_cache_release(pages
[i
]);
773 * bio_map_user - map user address into bio
774 * @q: the struct request_queue for the bio
775 * @bdev: destination block device
776 * @uaddr: start of user address
777 * @len: length in bytes
778 * @write_to_vm: bool indicating writing to pages or not
780 * Map the user space address into a bio suitable for io to a block
781 * device. Returns an error pointer in case of error.
783 struct bio
*bio_map_user(struct request_queue
*q
, struct block_device
*bdev
,
784 unsigned long uaddr
, unsigned int len
, int write_to_vm
)
788 iov
.iov_base
= (void __user
*)uaddr
;
791 return bio_map_user_iov(q
, bdev
, &iov
, 1, write_to_vm
);
795 * bio_map_user_iov - map user sg_iovec table into bio
796 * @q: the struct request_queue for the bio
797 * @bdev: destination block device
799 * @iov_count: number of elements in the iovec
800 * @write_to_vm: bool indicating writing to pages or not
802 * Map the user space address into a bio suitable for io to a block
803 * device. Returns an error pointer in case of error.
805 struct bio
*bio_map_user_iov(struct request_queue
*q
, struct block_device
*bdev
,
806 struct sg_iovec
*iov
, int iov_count
,
811 bio
= __bio_map_user_iov(q
, bdev
, iov
, iov_count
, write_to_vm
);
817 * subtle -- if __bio_map_user() ended up bouncing a bio,
818 * it would normally disappear when its bi_end_io is run.
819 * however, we need it for the unmap, so grab an extra
827 static void __bio_unmap_user(struct bio
*bio
)
829 struct bio_vec
*bvec
;
833 * make sure we dirty pages we wrote to
835 __bio_for_each_segment(bvec
, bio
, i
, 0) {
836 if (bio_data_dir(bio
) == READ
)
837 set_page_dirty_lock(bvec
->bv_page
);
839 page_cache_release(bvec
->bv_page
);
846 * bio_unmap_user - unmap a bio
847 * @bio: the bio being unmapped
849 * Unmap a bio previously mapped by bio_map_user(). Must be called with
852 * bio_unmap_user() may sleep.
854 void bio_unmap_user(struct bio
*bio
)
856 __bio_unmap_user(bio
);
860 static void bio_map_kern_endio(struct bio
*bio
, int err
)
866 static struct bio
*__bio_map_kern(struct request_queue
*q
, void *data
,
867 unsigned int len
, gfp_t gfp_mask
)
869 unsigned long kaddr
= (unsigned long)data
;
870 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
871 unsigned long start
= kaddr
>> PAGE_SHIFT
;
872 const int nr_pages
= end
- start
;
876 bio
= bio_alloc(gfp_mask
, nr_pages
);
878 return ERR_PTR(-ENOMEM
);
880 offset
= offset_in_page(kaddr
);
881 for (i
= 0; i
< nr_pages
; i
++) {
882 unsigned int bytes
= PAGE_SIZE
- offset
;
890 if (bio_add_pc_page(q
, bio
, virt_to_page(data
), bytes
,
899 bio
->bi_end_io
= bio_map_kern_endio
;
904 * bio_map_kern - map kernel address into bio
905 * @q: the struct request_queue for the bio
906 * @data: pointer to buffer to map
907 * @len: length in bytes
908 * @gfp_mask: allocation flags for bio allocation
910 * Map the kernel address into a bio suitable for io to a block
911 * device. Returns an error pointer in case of error.
913 struct bio
*bio_map_kern(struct request_queue
*q
, void *data
, unsigned int len
,
918 bio
= __bio_map_kern(q
, data
, len
, gfp_mask
);
922 if (bio
->bi_size
== len
)
926 * Don't support partial mappings.
929 return ERR_PTR(-EINVAL
);
932 static void bio_copy_kern_endio(struct bio
*bio
, int err
)
934 struct bio_vec
*bvec
;
935 const int read
= bio_data_dir(bio
) == READ
;
936 char *p
= bio
->bi_private
;
939 __bio_for_each_segment(bvec
, bio
, i
, 0) {
940 char *addr
= page_address(bvec
->bv_page
);
943 memcpy(p
, addr
, bvec
->bv_len
);
945 __free_page(bvec
->bv_page
);
953 * bio_copy_kern - copy kernel address into bio
954 * @q: the struct request_queue for the bio
955 * @data: pointer to buffer to copy
956 * @len: length in bytes
957 * @gfp_mask: allocation flags for bio and page allocation
958 * @reading: data direction is READ
960 * copy the kernel address into a bio suitable for io to a block
961 * device. Returns an error pointer in case of error.
963 struct bio
*bio_copy_kern(struct request_queue
*q
, void *data
, unsigned int len
,
964 gfp_t gfp_mask
, int reading
)
966 unsigned long kaddr
= (unsigned long)data
;
967 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
968 unsigned long start
= kaddr
>> PAGE_SHIFT
;
969 const int nr_pages
= end
- start
;
971 struct bio_vec
*bvec
;
974 bio
= bio_alloc(gfp_mask
, nr_pages
);
976 return ERR_PTR(-ENOMEM
);
980 unsigned int bytes
= PAGE_SIZE
;
985 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
991 if (bio_add_pc_page(q
, bio
, page
, bytes
, 0) < bytes
) {
1002 bio_for_each_segment(bvec
, bio
, i
) {
1003 char *addr
= page_address(bvec
->bv_page
);
1005 memcpy(addr
, p
, bvec
->bv_len
);
1010 bio
->bi_private
= data
;
1011 bio
->bi_end_io
= bio_copy_kern_endio
;
1014 bio_for_each_segment(bvec
, bio
, i
)
1015 __free_page(bvec
->bv_page
);
1019 return ERR_PTR(ret
);
1023 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1024 * for performing direct-IO in BIOs.
1026 * The problem is that we cannot run set_page_dirty() from interrupt context
1027 * because the required locks are not interrupt-safe. So what we can do is to
1028 * mark the pages dirty _before_ performing IO. And in interrupt context,
1029 * check that the pages are still dirty. If so, fine. If not, redirty them
1030 * in process context.
1032 * We special-case compound pages here: normally this means reads into hugetlb
1033 * pages. The logic in here doesn't really work right for compound pages
1034 * because the VM does not uniformly chase down the head page in all cases.
1035 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1036 * handle them at all. So we skip compound pages here at an early stage.
1038 * Note that this code is very hard to test under normal circumstances because
1039 * direct-io pins the pages with get_user_pages(). This makes
1040 * is_page_cache_freeable return false, and the VM will not clean the pages.
1041 * But other code (eg, pdflush) could clean the pages if they are mapped
1044 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1045 * deferred bio dirtying paths.
1049 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1051 void bio_set_pages_dirty(struct bio
*bio
)
1053 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1056 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1057 struct page
*page
= bvec
[i
].bv_page
;
1059 if (page
&& !PageCompound(page
))
1060 set_page_dirty_lock(page
);
1064 static void bio_release_pages(struct bio
*bio
)
1066 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1069 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1070 struct page
*page
= bvec
[i
].bv_page
;
1078 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1079 * If they are, then fine. If, however, some pages are clean then they must
1080 * have been written out during the direct-IO read. So we take another ref on
1081 * the BIO and the offending pages and re-dirty the pages in process context.
1083 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1084 * here on. It will run one page_cache_release() against each page and will
1085 * run one bio_put() against the BIO.
1088 static void bio_dirty_fn(struct work_struct
*work
);
1090 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1091 static DEFINE_SPINLOCK(bio_dirty_lock
);
1092 static struct bio
*bio_dirty_list
;
1095 * This runs in process context
1097 static void bio_dirty_fn(struct work_struct
*work
)
1099 unsigned long flags
;
1102 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1103 bio
= bio_dirty_list
;
1104 bio_dirty_list
= NULL
;
1105 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1108 struct bio
*next
= bio
->bi_private
;
1110 bio_set_pages_dirty(bio
);
1111 bio_release_pages(bio
);
1117 void bio_check_pages_dirty(struct bio
*bio
)
1119 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1120 int nr_clean_pages
= 0;
1123 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1124 struct page
*page
= bvec
[i
].bv_page
;
1126 if (PageDirty(page
) || PageCompound(page
)) {
1127 page_cache_release(page
);
1128 bvec
[i
].bv_page
= NULL
;
1134 if (nr_clean_pages
) {
1135 unsigned long flags
;
1137 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1138 bio
->bi_private
= bio_dirty_list
;
1139 bio_dirty_list
= bio
;
1140 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1141 schedule_work(&bio_dirty_work
);
1148 * bio_endio - end I/O on a bio
1150 * @error: error, if any
1153 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1154 * preferred way to end I/O on a bio, it takes care of clearing
1155 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1156 * established -Exxxx (-EIO, for instance) error values in case
1157 * something went wrong. Noone should call bi_end_io() directly on a
1158 * bio unless they own it and thus know that it has an end_io
1161 void bio_endio(struct bio
*bio
, int error
)
1164 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1165 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
1169 bio
->bi_end_io(bio
, error
);
1172 void bio_pair_release(struct bio_pair
*bp
)
1174 if (atomic_dec_and_test(&bp
->cnt
)) {
1175 struct bio
*master
= bp
->bio1
.bi_private
;
1177 bio_endio(master
, bp
->error
);
1178 mempool_free(bp
, bp
->bio2
.bi_private
);
1182 static void bio_pair_end_1(struct bio
*bi
, int err
)
1184 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio1
);
1189 bio_pair_release(bp
);
1192 static void bio_pair_end_2(struct bio
*bi
, int err
)
1194 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio2
);
1199 bio_pair_release(bp
);
1203 * split a bio - only worry about a bio with a single page
1206 struct bio_pair
*bio_split(struct bio
*bi
, mempool_t
*pool
, int first_sectors
)
1208 struct bio_pair
*bp
= mempool_alloc(pool
, GFP_NOIO
);
1213 blk_add_trace_pdu_int(bdev_get_queue(bi
->bi_bdev
), BLK_TA_SPLIT
, bi
,
1214 bi
->bi_sector
+ first_sectors
);
1216 BUG_ON(bi
->bi_vcnt
!= 1);
1217 BUG_ON(bi
->bi_idx
!= 0);
1218 atomic_set(&bp
->cnt
, 3);
1222 bp
->bio2
.bi_sector
+= first_sectors
;
1223 bp
->bio2
.bi_size
-= first_sectors
<< 9;
1224 bp
->bio1
.bi_size
= first_sectors
<< 9;
1226 bp
->bv1
= bi
->bi_io_vec
[0];
1227 bp
->bv2
= bi
->bi_io_vec
[0];
1228 bp
->bv2
.bv_offset
+= first_sectors
<< 9;
1229 bp
->bv2
.bv_len
-= first_sectors
<< 9;
1230 bp
->bv1
.bv_len
= first_sectors
<< 9;
1232 bp
->bio1
.bi_io_vec
= &bp
->bv1
;
1233 bp
->bio2
.bi_io_vec
= &bp
->bv2
;
1235 bp
->bio1
.bi_max_vecs
= 1;
1236 bp
->bio2
.bi_max_vecs
= 1;
1238 bp
->bio1
.bi_end_io
= bio_pair_end_1
;
1239 bp
->bio2
.bi_end_io
= bio_pair_end_2
;
1241 bp
->bio1
.bi_private
= bi
;
1242 bp
->bio2
.bi_private
= pool
;
1244 if (bio_integrity(bi
))
1245 bio_integrity_split(bi
, bp
, first_sectors
);
1252 * create memory pools for biovec's in a bio_set.
1253 * use the global biovec slabs created for general use.
1255 static int biovec_create_pools(struct bio_set
*bs
, int pool_entries
)
1259 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1260 struct biovec_slab
*bp
= bvec_slabs
+ i
;
1261 mempool_t
**bvp
= bs
->bvec_pools
+ i
;
1263 *bvp
= mempool_create_slab_pool(pool_entries
, bp
->slab
);
1270 static void biovec_free_pools(struct bio_set
*bs
)
1274 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1275 mempool_t
*bvp
= bs
->bvec_pools
[i
];
1278 mempool_destroy(bvp
);
1283 void bioset_free(struct bio_set
*bs
)
1286 mempool_destroy(bs
->bio_pool
);
1288 bioset_integrity_free(bs
);
1289 biovec_free_pools(bs
);
1294 struct bio_set
*bioset_create(int bio_pool_size
, int bvec_pool_size
)
1296 struct bio_set
*bs
= kzalloc(sizeof(*bs
), GFP_KERNEL
);
1301 bs
->bio_pool
= mempool_create_slab_pool(bio_pool_size
, bio_slab
);
1305 if (bioset_integrity_create(bs
, bio_pool_size
))
1308 if (!biovec_create_pools(bs
, bvec_pool_size
))
1316 static void __init
biovec_init_slabs(void)
1320 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1322 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
1324 size
= bvs
->nr_vecs
* sizeof(struct bio_vec
);
1325 bvs
->slab
= kmem_cache_create(bvs
->name
, size
, 0,
1326 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1330 static int __init
init_bio(void)
1332 bio_slab
= KMEM_CACHE(bio
, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
);
1334 bio_integrity_init_slab();
1335 biovec_init_slabs();
1337 fs_bio_set
= bioset_create(BIO_POOL_SIZE
, 2);
1339 panic("bio: can't allocate bios\n");
1341 bio_split_pool
= mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES
,
1342 sizeof(struct bio_pair
));
1343 if (!bio_split_pool
)
1344 panic("bio: can't create split pool\n");
1349 subsys_initcall(init_bio
);
1351 EXPORT_SYMBOL(bio_alloc
);
1352 EXPORT_SYMBOL(bio_put
);
1353 EXPORT_SYMBOL(bio_free
);
1354 EXPORT_SYMBOL(bio_endio
);
1355 EXPORT_SYMBOL(bio_init
);
1356 EXPORT_SYMBOL(__bio_clone
);
1357 EXPORT_SYMBOL(bio_clone
);
1358 EXPORT_SYMBOL(bio_phys_segments
);
1359 EXPORT_SYMBOL(bio_hw_segments
);
1360 EXPORT_SYMBOL(bio_add_page
);
1361 EXPORT_SYMBOL(bio_add_pc_page
);
1362 EXPORT_SYMBOL(bio_get_nr_vecs
);
1363 EXPORT_SYMBOL(bio_map_user
);
1364 EXPORT_SYMBOL(bio_unmap_user
);
1365 EXPORT_SYMBOL(bio_map_kern
);
1366 EXPORT_SYMBOL(bio_copy_kern
);
1367 EXPORT_SYMBOL(bio_pair_release
);
1368 EXPORT_SYMBOL(bio_split
);
1369 EXPORT_SYMBOL(bio_split_pool
);
1370 EXPORT_SYMBOL(bio_copy_user
);
1371 EXPORT_SYMBOL(bio_uncopy_user
);
1372 EXPORT_SYMBOL(bioset_create
);
1373 EXPORT_SYMBOL(bioset_free
);
1374 EXPORT_SYMBOL(bio_alloc_bioset
);