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 memset(bvl
, 0, bvec_nr_vecs(*idx
) * sizeof(struct bio_vec
));
86 void bio_free(struct bio
*bio
, struct bio_set
*bio_set
)
89 const int pool_idx
= BIO_POOL_IDX(bio
);
91 BIO_BUG_ON(pool_idx
>= BIOVEC_NR_POOLS
);
93 mempool_free(bio
->bi_io_vec
, bio_set
->bvec_pools
[pool_idx
]);
96 if (bio_integrity(bio
))
97 bio_integrity_free(bio
, bio_set
);
99 mempool_free(bio
, bio_set
->bio_pool
);
103 * default destructor for a bio allocated with bio_alloc_bioset()
105 static void bio_fs_destructor(struct bio
*bio
)
107 bio_free(bio
, fs_bio_set
);
110 void bio_init(struct bio
*bio
)
112 memset(bio
, 0, sizeof(*bio
));
113 bio
->bi_flags
= 1 << BIO_UPTODATE
;
114 bio
->bi_comp_cpu
= -1;
115 atomic_set(&bio
->bi_cnt
, 1);
119 * bio_alloc_bioset - allocate a bio for I/O
120 * @gfp_mask: the GFP_ mask given to the slab allocator
121 * @nr_iovecs: number of iovecs to pre-allocate
122 * @bs: the bio_set to allocate from
125 * bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
126 * If %__GFP_WAIT is set then we will block on the internal pool waiting
127 * for a &struct bio to become free.
129 * allocate bio and iovecs from the memory pools specified by the
132 struct bio
*bio_alloc_bioset(gfp_t gfp_mask
, int nr_iovecs
, struct bio_set
*bs
)
134 struct bio
*bio
= mempool_alloc(bs
->bio_pool
, gfp_mask
);
137 struct bio_vec
*bvl
= NULL
;
140 if (likely(nr_iovecs
)) {
141 unsigned long uninitialized_var(idx
);
143 bvl
= bvec_alloc_bs(gfp_mask
, nr_iovecs
, &idx
, bs
);
144 if (unlikely(!bvl
)) {
145 mempool_free(bio
, bs
->bio_pool
);
149 bio
->bi_flags
|= idx
<< BIO_POOL_OFFSET
;
150 bio
->bi_max_vecs
= bvec_nr_vecs(idx
);
152 bio
->bi_io_vec
= bvl
;
158 struct bio
*bio_alloc(gfp_t gfp_mask
, int nr_iovecs
)
160 struct bio
*bio
= bio_alloc_bioset(gfp_mask
, nr_iovecs
, fs_bio_set
);
163 bio
->bi_destructor
= bio_fs_destructor
;
168 void zero_fill_bio(struct bio
*bio
)
174 bio_for_each_segment(bv
, bio
, i
) {
175 char *data
= bvec_kmap_irq(bv
, &flags
);
176 memset(data
, 0, bv
->bv_len
);
177 flush_dcache_page(bv
->bv_page
);
178 bvec_kunmap_irq(data
, &flags
);
181 EXPORT_SYMBOL(zero_fill_bio
);
184 * bio_put - release a reference to a bio
185 * @bio: bio to release reference to
188 * Put a reference to a &struct bio, either one you have gotten with
189 * bio_alloc or bio_get. The last put of a bio will free it.
191 void bio_put(struct bio
*bio
)
193 BIO_BUG_ON(!atomic_read(&bio
->bi_cnt
));
198 if (atomic_dec_and_test(&bio
->bi_cnt
)) {
200 bio
->bi_destructor(bio
);
204 inline int bio_phys_segments(struct request_queue
*q
, struct bio
*bio
)
206 if (unlikely(!bio_flagged(bio
, BIO_SEG_VALID
)))
207 blk_recount_segments(q
, bio
);
209 return bio
->bi_phys_segments
;
213 * __bio_clone - clone a bio
214 * @bio: destination bio
215 * @bio_src: bio to clone
217 * Clone a &bio. Caller will own the returned bio, but not
218 * the actual data it points to. Reference count of returned
221 void __bio_clone(struct bio
*bio
, struct bio
*bio_src
)
223 memcpy(bio
->bi_io_vec
, bio_src
->bi_io_vec
,
224 bio_src
->bi_max_vecs
* sizeof(struct bio_vec
));
227 * most users will be overriding ->bi_bdev with a new target,
228 * so we don't set nor calculate new physical/hw segment counts here
230 bio
->bi_sector
= bio_src
->bi_sector
;
231 bio
->bi_bdev
= bio_src
->bi_bdev
;
232 bio
->bi_flags
|= 1 << BIO_CLONED
;
233 bio
->bi_rw
= bio_src
->bi_rw
;
234 bio
->bi_vcnt
= bio_src
->bi_vcnt
;
235 bio
->bi_size
= bio_src
->bi_size
;
236 bio
->bi_idx
= bio_src
->bi_idx
;
240 * bio_clone - clone a bio
242 * @gfp_mask: allocation priority
244 * Like __bio_clone, only also allocates the returned bio
246 struct bio
*bio_clone(struct bio
*bio
, gfp_t gfp_mask
)
248 struct bio
*b
= bio_alloc_bioset(gfp_mask
, bio
->bi_max_vecs
, fs_bio_set
);
253 b
->bi_destructor
= bio_fs_destructor
;
256 if (bio_integrity(bio
)) {
259 ret
= bio_integrity_clone(b
, bio
, fs_bio_set
);
269 * bio_get_nr_vecs - return approx number of vecs
272 * Return the approximate number of pages we can send to this target.
273 * There's no guarantee that you will be able to fit this number of pages
274 * into a bio, it does not account for dynamic restrictions that vary
277 int bio_get_nr_vecs(struct block_device
*bdev
)
279 struct request_queue
*q
= bdev_get_queue(bdev
);
282 nr_pages
= ((q
->max_sectors
<< 9) + PAGE_SIZE
- 1) >> PAGE_SHIFT
;
283 if (nr_pages
> q
->max_phys_segments
)
284 nr_pages
= q
->max_phys_segments
;
285 if (nr_pages
> q
->max_hw_segments
)
286 nr_pages
= q
->max_hw_segments
;
291 static int __bio_add_page(struct request_queue
*q
, struct bio
*bio
, struct page
292 *page
, unsigned int len
, unsigned int offset
,
293 unsigned short max_sectors
)
295 int retried_segments
= 0;
296 struct bio_vec
*bvec
;
299 * cloned bio must not modify vec list
301 if (unlikely(bio_flagged(bio
, BIO_CLONED
)))
304 if (((bio
->bi_size
+ len
) >> 9) > max_sectors
)
308 * For filesystems with a blocksize smaller than the pagesize
309 * we will often be called with the same page as last time and
310 * a consecutive offset. Optimize this special case.
312 if (bio
->bi_vcnt
> 0) {
313 struct bio_vec
*prev
= &bio
->bi_io_vec
[bio
->bi_vcnt
- 1];
315 if (page
== prev
->bv_page
&&
316 offset
== prev
->bv_offset
+ prev
->bv_len
) {
319 if (q
->merge_bvec_fn
) {
320 struct bvec_merge_data bvm
= {
321 .bi_bdev
= bio
->bi_bdev
,
322 .bi_sector
= bio
->bi_sector
,
323 .bi_size
= bio
->bi_size
,
327 if (q
->merge_bvec_fn(q
, &bvm
, prev
) < len
) {
337 if (bio
->bi_vcnt
>= bio
->bi_max_vecs
)
341 * we might lose a segment or two here, but rather that than
342 * make this too complex.
345 while (bio
->bi_phys_segments
>= q
->max_phys_segments
346 || bio
->bi_phys_segments
>= q
->max_hw_segments
) {
348 if (retried_segments
)
351 retried_segments
= 1;
352 blk_recount_segments(q
, bio
);
356 * setup the new entry, we might clear it again later if we
357 * cannot add the page
359 bvec
= &bio
->bi_io_vec
[bio
->bi_vcnt
];
360 bvec
->bv_page
= page
;
362 bvec
->bv_offset
= offset
;
365 * if queue has other restrictions (eg varying max sector size
366 * depending on offset), it can specify a merge_bvec_fn in the
367 * queue to get further control
369 if (q
->merge_bvec_fn
) {
370 struct bvec_merge_data bvm
= {
371 .bi_bdev
= bio
->bi_bdev
,
372 .bi_sector
= bio
->bi_sector
,
373 .bi_size
= bio
->bi_size
,
378 * merge_bvec_fn() returns number of bytes it can accept
381 if (q
->merge_bvec_fn(q
, &bvm
, bvec
) < len
) {
382 bvec
->bv_page
= NULL
;
389 /* If we may be able to merge these biovecs, force a recount */
390 if (bio
->bi_vcnt
&& (BIOVEC_PHYS_MERGEABLE(bvec
-1, bvec
)))
391 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
394 bio
->bi_phys_segments
++;
401 * bio_add_pc_page - attempt to add page to bio
402 * @q: the target queue
403 * @bio: destination bio
405 * @len: vec entry length
406 * @offset: vec entry offset
408 * Attempt to add a page to the bio_vec maplist. This can fail for a
409 * number of reasons, such as the bio being full or target block
410 * device limitations. The target block device must allow bio's
411 * smaller than PAGE_SIZE, so it is always possible to add a single
412 * page to an empty bio. This should only be used by REQ_PC bios.
414 int bio_add_pc_page(struct request_queue
*q
, struct bio
*bio
, struct page
*page
,
415 unsigned int len
, unsigned int offset
)
417 return __bio_add_page(q
, bio
, page
, len
, offset
, q
->max_hw_sectors
);
421 * bio_add_page - attempt to add page to bio
422 * @bio: destination bio
424 * @len: vec entry length
425 * @offset: vec entry offset
427 * Attempt to add a page to the bio_vec maplist. This can fail for a
428 * number of reasons, such as the bio being full or target block
429 * device limitations. The target block device must allow bio's
430 * smaller than PAGE_SIZE, so it is always possible to add a single
431 * page to an empty bio.
433 int bio_add_page(struct bio
*bio
, struct page
*page
, unsigned int len
,
436 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
437 return __bio_add_page(q
, bio
, page
, len
, offset
, q
->max_sectors
);
440 struct bio_map_data
{
441 struct bio_vec
*iovecs
;
443 struct sg_iovec
*sgvecs
;
446 static void bio_set_map_data(struct bio_map_data
*bmd
, struct bio
*bio
,
447 struct sg_iovec
*iov
, int iov_count
)
449 memcpy(bmd
->iovecs
, bio
->bi_io_vec
, sizeof(struct bio_vec
) * bio
->bi_vcnt
);
450 memcpy(bmd
->sgvecs
, iov
, sizeof(struct sg_iovec
) * iov_count
);
451 bmd
->nr_sgvecs
= iov_count
;
452 bio
->bi_private
= bmd
;
455 static void bio_free_map_data(struct bio_map_data
*bmd
)
462 static struct bio_map_data
*bio_alloc_map_data(int nr_segs
, int iov_count
,
465 struct bio_map_data
*bmd
= kmalloc(sizeof(*bmd
), gfp_mask
);
470 bmd
->iovecs
= kmalloc(sizeof(struct bio_vec
) * nr_segs
, gfp_mask
);
476 bmd
->sgvecs
= kmalloc(sizeof(struct sg_iovec
) * iov_count
, gfp_mask
);
485 static int __bio_copy_iov(struct bio
*bio
, struct bio_vec
*iovecs
,
486 struct sg_iovec
*iov
, int iov_count
, int uncopy
)
489 struct bio_vec
*bvec
;
491 unsigned int iov_off
= 0;
492 int read
= bio_data_dir(bio
) == READ
;
494 __bio_for_each_segment(bvec
, bio
, i
, 0) {
495 char *bv_addr
= page_address(bvec
->bv_page
);
496 unsigned int bv_len
= iovecs
[i
].bv_len
;
498 while (bv_len
&& iov_idx
< iov_count
) {
502 bytes
= min_t(unsigned int,
503 iov
[iov_idx
].iov_len
- iov_off
, bv_len
);
504 iov_addr
= iov
[iov_idx
].iov_base
+ iov_off
;
507 if (!read
&& !uncopy
)
508 ret
= copy_from_user(bv_addr
, iov_addr
,
511 ret
= copy_to_user(iov_addr
, bv_addr
,
523 if (iov
[iov_idx
].iov_len
== iov_off
) {
530 __free_page(bvec
->bv_page
);
537 * bio_uncopy_user - finish previously mapped bio
538 * @bio: bio being terminated
540 * Free pages allocated from bio_copy_user() and write back data
541 * to user space in case of a read.
543 int bio_uncopy_user(struct bio
*bio
)
545 struct bio_map_data
*bmd
= bio
->bi_private
;
548 ret
= __bio_copy_iov(bio
, bmd
->iovecs
, bmd
->sgvecs
, bmd
->nr_sgvecs
, 1);
550 bio_free_map_data(bmd
);
556 * bio_copy_user_iov - copy user data to bio
557 * @q: destination block queue
559 * @iov_count: number of elements in the iovec
560 * @write_to_vm: bool indicating writing to pages or not
562 * Prepares and returns a bio for indirect user io, bouncing data
563 * to/from kernel pages as necessary. Must be paired with
564 * call bio_uncopy_user() on io completion.
566 struct bio
*bio_copy_user_iov(struct request_queue
*q
, struct sg_iovec
*iov
,
567 int iov_count
, int write_to_vm
)
569 struct bio_map_data
*bmd
;
570 struct bio_vec
*bvec
;
575 unsigned int len
= 0;
577 for (i
= 0; i
< iov_count
; i
++) {
582 uaddr
= (unsigned long)iov
[i
].iov_base
;
583 end
= (uaddr
+ iov
[i
].iov_len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
584 start
= uaddr
>> PAGE_SHIFT
;
586 nr_pages
+= end
- start
;
587 len
+= iov
[i
].iov_len
;
590 bmd
= bio_alloc_map_data(nr_pages
, iov_count
, GFP_KERNEL
);
592 return ERR_PTR(-ENOMEM
);
595 bio
= bio_alloc(GFP_KERNEL
, nr_pages
);
599 bio
->bi_rw
|= (!write_to_vm
<< BIO_RW
);
603 unsigned int bytes
= PAGE_SIZE
;
608 page
= alloc_page(q
->bounce_gfp
| GFP_KERNEL
);
614 if (bio_add_pc_page(q
, bio
, page
, bytes
, 0) < bytes
)
627 ret
= __bio_copy_iov(bio
, bio
->bi_io_vec
, iov
, iov_count
, 0);
632 bio_set_map_data(bmd
, bio
, iov
, iov_count
);
635 bio_for_each_segment(bvec
, bio
, i
)
636 __free_page(bvec
->bv_page
);
640 bio_free_map_data(bmd
);
645 * bio_copy_user - copy user data to bio
646 * @q: destination block queue
647 * @uaddr: start of user address
648 * @len: length in bytes
649 * @write_to_vm: bool indicating writing to pages or not
651 * Prepares and returns a bio for indirect user io, bouncing data
652 * to/from kernel pages as necessary. Must be paired with
653 * call bio_uncopy_user() on io completion.
655 struct bio
*bio_copy_user(struct request_queue
*q
, unsigned long uaddr
,
656 unsigned int len
, int write_to_vm
)
660 iov
.iov_base
= (void __user
*)uaddr
;
663 return bio_copy_user_iov(q
, &iov
, 1, write_to_vm
);
666 static struct bio
*__bio_map_user_iov(struct request_queue
*q
,
667 struct block_device
*bdev
,
668 struct sg_iovec
*iov
, int iov_count
,
678 for (i
= 0; i
< iov_count
; i
++) {
679 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
680 unsigned long len
= iov
[i
].iov_len
;
681 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
682 unsigned long start
= uaddr
>> PAGE_SHIFT
;
684 nr_pages
+= end
- start
;
686 * buffer must be aligned to at least hardsector size for now
688 if (uaddr
& queue_dma_alignment(q
))
689 return ERR_PTR(-EINVAL
);
693 return ERR_PTR(-EINVAL
);
695 bio
= bio_alloc(GFP_KERNEL
, nr_pages
);
697 return ERR_PTR(-ENOMEM
);
700 pages
= kcalloc(nr_pages
, sizeof(struct page
*), GFP_KERNEL
);
704 for (i
= 0; i
< iov_count
; i
++) {
705 unsigned long uaddr
= (unsigned long)iov
[i
].iov_base
;
706 unsigned long len
= iov
[i
].iov_len
;
707 unsigned long end
= (uaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
708 unsigned long start
= uaddr
>> PAGE_SHIFT
;
709 const int local_nr_pages
= end
- start
;
710 const int page_limit
= cur_page
+ local_nr_pages
;
712 ret
= get_user_pages_fast(uaddr
, local_nr_pages
,
713 write_to_vm
, &pages
[cur_page
]);
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 struct bio_map_data
*bmd
= bio
->bi_private
;
938 char *p
= bmd
->sgvecs
[0].iov_base
;
940 __bio_for_each_segment(bvec
, bio
, i
, 0) {
941 char *addr
= page_address(bvec
->bv_page
);
942 int len
= bmd
->iovecs
[i
].bv_len
;
945 memcpy(p
, addr
, len
);
947 __free_page(bvec
->bv_page
);
951 bio_free_map_data(bmd
);
956 * bio_copy_kern - copy kernel address into bio
957 * @q: the struct request_queue for the bio
958 * @data: pointer to buffer to copy
959 * @len: length in bytes
960 * @gfp_mask: allocation flags for bio and page allocation
961 * @reading: data direction is READ
963 * copy the kernel address into a bio suitable for io to a block
964 * device. Returns an error pointer in case of error.
966 struct bio
*bio_copy_kern(struct request_queue
*q
, void *data
, unsigned int len
,
967 gfp_t gfp_mask
, int reading
)
969 unsigned long kaddr
= (unsigned long)data
;
970 unsigned long end
= (kaddr
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
971 unsigned long start
= kaddr
>> PAGE_SHIFT
;
972 const int nr_pages
= end
- start
;
974 struct bio_vec
*bvec
;
975 struct bio_map_data
*bmd
;
982 bmd
= bio_alloc_map_data(nr_pages
, 1, gfp_mask
);
984 return ERR_PTR(-ENOMEM
);
987 bio
= bio_alloc(gfp_mask
, nr_pages
);
993 unsigned int bytes
= PAGE_SIZE
;
998 page
= alloc_page(q
->bounce_gfp
| gfp_mask
);
1004 if (bio_add_pc_page(q
, bio
, page
, bytes
, 0) < bytes
) {
1015 bio_for_each_segment(bvec
, bio
, i
) {
1016 char *addr
= page_address(bvec
->bv_page
);
1018 memcpy(addr
, p
, bvec
->bv_len
);
1023 bio
->bi_private
= bmd
;
1024 bio
->bi_end_io
= bio_copy_kern_endio
;
1026 bio_set_map_data(bmd
, bio
, &iov
, 1);
1029 bio_for_each_segment(bvec
, bio
, i
)
1030 __free_page(bvec
->bv_page
);
1034 bio_free_map_data(bmd
);
1036 return ERR_PTR(ret
);
1040 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1041 * for performing direct-IO in BIOs.
1043 * The problem is that we cannot run set_page_dirty() from interrupt context
1044 * because the required locks are not interrupt-safe. So what we can do is to
1045 * mark the pages dirty _before_ performing IO. And in interrupt context,
1046 * check that the pages are still dirty. If so, fine. If not, redirty them
1047 * in process context.
1049 * We special-case compound pages here: normally this means reads into hugetlb
1050 * pages. The logic in here doesn't really work right for compound pages
1051 * because the VM does not uniformly chase down the head page in all cases.
1052 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1053 * handle them at all. So we skip compound pages here at an early stage.
1055 * Note that this code is very hard to test under normal circumstances because
1056 * direct-io pins the pages with get_user_pages(). This makes
1057 * is_page_cache_freeable return false, and the VM will not clean the pages.
1058 * But other code (eg, pdflush) could clean the pages if they are mapped
1061 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1062 * deferred bio dirtying paths.
1066 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1068 void bio_set_pages_dirty(struct bio
*bio
)
1070 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1073 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1074 struct page
*page
= bvec
[i
].bv_page
;
1076 if (page
&& !PageCompound(page
))
1077 set_page_dirty_lock(page
);
1081 static void bio_release_pages(struct bio
*bio
)
1083 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1086 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1087 struct page
*page
= bvec
[i
].bv_page
;
1095 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1096 * If they are, then fine. If, however, some pages are clean then they must
1097 * have been written out during the direct-IO read. So we take another ref on
1098 * the BIO and the offending pages and re-dirty the pages in process context.
1100 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1101 * here on. It will run one page_cache_release() against each page and will
1102 * run one bio_put() against the BIO.
1105 static void bio_dirty_fn(struct work_struct
*work
);
1107 static DECLARE_WORK(bio_dirty_work
, bio_dirty_fn
);
1108 static DEFINE_SPINLOCK(bio_dirty_lock
);
1109 static struct bio
*bio_dirty_list
;
1112 * This runs in process context
1114 static void bio_dirty_fn(struct work_struct
*work
)
1116 unsigned long flags
;
1119 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1120 bio
= bio_dirty_list
;
1121 bio_dirty_list
= NULL
;
1122 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1125 struct bio
*next
= bio
->bi_private
;
1127 bio_set_pages_dirty(bio
);
1128 bio_release_pages(bio
);
1134 void bio_check_pages_dirty(struct bio
*bio
)
1136 struct bio_vec
*bvec
= bio
->bi_io_vec
;
1137 int nr_clean_pages
= 0;
1140 for (i
= 0; i
< bio
->bi_vcnt
; i
++) {
1141 struct page
*page
= bvec
[i
].bv_page
;
1143 if (PageDirty(page
) || PageCompound(page
)) {
1144 page_cache_release(page
);
1145 bvec
[i
].bv_page
= NULL
;
1151 if (nr_clean_pages
) {
1152 unsigned long flags
;
1154 spin_lock_irqsave(&bio_dirty_lock
, flags
);
1155 bio
->bi_private
= bio_dirty_list
;
1156 bio_dirty_list
= bio
;
1157 spin_unlock_irqrestore(&bio_dirty_lock
, flags
);
1158 schedule_work(&bio_dirty_work
);
1165 * bio_endio - end I/O on a bio
1167 * @error: error, if any
1170 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1171 * preferred way to end I/O on a bio, it takes care of clearing
1172 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1173 * established -Exxxx (-EIO, for instance) error values in case
1174 * something went wrong. Noone should call bi_end_io() directly on a
1175 * bio unless they own it and thus know that it has an end_io
1178 void bio_endio(struct bio
*bio
, int error
)
1181 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
1182 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
1186 bio
->bi_end_io(bio
, error
);
1189 void bio_pair_release(struct bio_pair
*bp
)
1191 if (atomic_dec_and_test(&bp
->cnt
)) {
1192 struct bio
*master
= bp
->bio1
.bi_private
;
1194 bio_endio(master
, bp
->error
);
1195 mempool_free(bp
, bp
->bio2
.bi_private
);
1199 static void bio_pair_end_1(struct bio
*bi
, int err
)
1201 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio1
);
1206 bio_pair_release(bp
);
1209 static void bio_pair_end_2(struct bio
*bi
, int err
)
1211 struct bio_pair
*bp
= container_of(bi
, struct bio_pair
, bio2
);
1216 bio_pair_release(bp
);
1220 * split a bio - only worry about a bio with a single page
1223 struct bio_pair
*bio_split(struct bio
*bi
, mempool_t
*pool
, int first_sectors
)
1225 struct bio_pair
*bp
= mempool_alloc(pool
, GFP_NOIO
);
1230 blk_add_trace_pdu_int(bdev_get_queue(bi
->bi_bdev
), BLK_TA_SPLIT
, bi
,
1231 bi
->bi_sector
+ first_sectors
);
1233 BUG_ON(bi
->bi_vcnt
!= 1);
1234 BUG_ON(bi
->bi_idx
!= 0);
1235 atomic_set(&bp
->cnt
, 3);
1239 bp
->bio2
.bi_sector
+= first_sectors
;
1240 bp
->bio2
.bi_size
-= first_sectors
<< 9;
1241 bp
->bio1
.bi_size
= first_sectors
<< 9;
1243 bp
->bv1
= bi
->bi_io_vec
[0];
1244 bp
->bv2
= bi
->bi_io_vec
[0];
1245 bp
->bv2
.bv_offset
+= first_sectors
<< 9;
1246 bp
->bv2
.bv_len
-= first_sectors
<< 9;
1247 bp
->bv1
.bv_len
= first_sectors
<< 9;
1249 bp
->bio1
.bi_io_vec
= &bp
->bv1
;
1250 bp
->bio2
.bi_io_vec
= &bp
->bv2
;
1252 bp
->bio1
.bi_max_vecs
= 1;
1253 bp
->bio2
.bi_max_vecs
= 1;
1255 bp
->bio1
.bi_end_io
= bio_pair_end_1
;
1256 bp
->bio2
.bi_end_io
= bio_pair_end_2
;
1258 bp
->bio1
.bi_private
= bi
;
1259 bp
->bio2
.bi_private
= pool
;
1261 if (bio_integrity(bi
))
1262 bio_integrity_split(bi
, bp
, first_sectors
);
1269 * create memory pools for biovec's in a bio_set.
1270 * use the global biovec slabs created for general use.
1272 static int biovec_create_pools(struct bio_set
*bs
, int pool_entries
)
1276 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1277 struct biovec_slab
*bp
= bvec_slabs
+ i
;
1278 mempool_t
**bvp
= bs
->bvec_pools
+ i
;
1280 *bvp
= mempool_create_slab_pool(pool_entries
, bp
->slab
);
1287 static void biovec_free_pools(struct bio_set
*bs
)
1291 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1292 mempool_t
*bvp
= bs
->bvec_pools
[i
];
1295 mempool_destroy(bvp
);
1300 void bioset_free(struct bio_set
*bs
)
1303 mempool_destroy(bs
->bio_pool
);
1305 bioset_integrity_free(bs
);
1306 biovec_free_pools(bs
);
1311 struct bio_set
*bioset_create(int bio_pool_size
, int bvec_pool_size
)
1313 struct bio_set
*bs
= kzalloc(sizeof(*bs
), GFP_KERNEL
);
1318 bs
->bio_pool
= mempool_create_slab_pool(bio_pool_size
, bio_slab
);
1322 if (bioset_integrity_create(bs
, bio_pool_size
))
1325 if (!biovec_create_pools(bs
, bvec_pool_size
))
1333 static void __init
biovec_init_slabs(void)
1337 for (i
= 0; i
< BIOVEC_NR_POOLS
; i
++) {
1339 struct biovec_slab
*bvs
= bvec_slabs
+ i
;
1341 size
= bvs
->nr_vecs
* sizeof(struct bio_vec
);
1342 bvs
->slab
= kmem_cache_create(bvs
->name
, size
, 0,
1343 SLAB_HWCACHE_ALIGN
|SLAB_PANIC
, NULL
);
1347 static int __init
init_bio(void)
1349 bio_slab
= KMEM_CACHE(bio
, SLAB_HWCACHE_ALIGN
|SLAB_PANIC
);
1351 bio_integrity_init_slab();
1352 biovec_init_slabs();
1354 fs_bio_set
= bioset_create(BIO_POOL_SIZE
, 2);
1356 panic("bio: can't allocate bios\n");
1358 bio_split_pool
= mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES
,
1359 sizeof(struct bio_pair
));
1360 if (!bio_split_pool
)
1361 panic("bio: can't create split pool\n");
1366 subsys_initcall(init_bio
);
1368 EXPORT_SYMBOL(bio_alloc
);
1369 EXPORT_SYMBOL(bio_put
);
1370 EXPORT_SYMBOL(bio_free
);
1371 EXPORT_SYMBOL(bio_endio
);
1372 EXPORT_SYMBOL(bio_init
);
1373 EXPORT_SYMBOL(__bio_clone
);
1374 EXPORT_SYMBOL(bio_clone
);
1375 EXPORT_SYMBOL(bio_phys_segments
);
1376 EXPORT_SYMBOL(bio_add_page
);
1377 EXPORT_SYMBOL(bio_add_pc_page
);
1378 EXPORT_SYMBOL(bio_get_nr_vecs
);
1379 EXPORT_SYMBOL(bio_map_user
);
1380 EXPORT_SYMBOL(bio_unmap_user
);
1381 EXPORT_SYMBOL(bio_map_kern
);
1382 EXPORT_SYMBOL(bio_copy_kern
);
1383 EXPORT_SYMBOL(bio_pair_release
);
1384 EXPORT_SYMBOL(bio_split
);
1385 EXPORT_SYMBOL(bio_split_pool
);
1386 EXPORT_SYMBOL(bio_copy_user
);
1387 EXPORT_SYMBOL(bio_uncopy_user
);
1388 EXPORT_SYMBOL(bioset_create
);
1389 EXPORT_SYMBOL(bioset_free
);
1390 EXPORT_SYMBOL(bio_alloc_bioset
);