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
561 * @gfp_mask: memory allocation flags
563 * Prepares and returns a bio for indirect user io, bouncing data
564 * to/from kernel pages as necessary. Must be paired with
565 * call bio_uncopy_user() on io completion.
567 struct bio *bio_copy_user_iov(struct request_queue *q, struct sg_iovec *iov,
568 int iov_count, int write_to_vm, gfp_t gfp_mask)
570 struct bio_map_data *bmd;
571 struct bio_vec *bvec;
576 unsigned int len = 0;
578 for (i = 0; i < iov_count; i++) {
583 uaddr = (unsigned long)iov[i].iov_base;
584 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
585 start = uaddr >> PAGE_SHIFT;
587 nr_pages += end - start;
588 len += iov[i].iov_len;
591 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
593 return ERR_PTR(-ENOMEM);
596 bio = bio_alloc(gfp_mask, nr_pages);
600 bio->bi_rw |= (!write_to_vm << BIO_RW);
604 unsigned int bytes = PAGE_SIZE;
609 page = alloc_page(q->bounce_gfp | gfp_mask);
615 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
628 ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0);
633 bio_set_map_data(bmd, bio, iov, iov_count);
636 bio_for_each_segment(bvec, bio, i)
637 __free_page(bvec->bv_page);
641 bio_free_map_data(bmd);
646 * bio_copy_user - copy user data to bio
647 * @q: destination block queue
648 * @uaddr: start of user address
649 * @len: length in bytes
650 * @write_to_vm: bool indicating writing to pages or not
651 * @gfp_mask: memory allocation flags
653 * Prepares and returns a bio for indirect user io, bouncing data
654 * to/from kernel pages as necessary. Must be paired with
655 * call bio_uncopy_user() on io completion.
657 struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
658 unsigned int len, int write_to_vm, gfp_t gfp_mask)
662 iov.iov_base = (void __user *)uaddr;
665 return bio_copy_user_iov(q, &iov, 1, write_to_vm, gfp_mask);
668 static struct bio *__bio_map_user_iov(struct request_queue *q,
669 struct block_device *bdev,
670 struct sg_iovec *iov, int iov_count,
671 int write_to_vm, gfp_t gfp_mask)
680 for (i = 0; i < iov_count; i++) {
681 unsigned long uaddr = (unsigned long)iov[i].iov_base;
682 unsigned long len = iov[i].iov_len;
683 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
684 unsigned long start = uaddr >> PAGE_SHIFT;
686 nr_pages += end - start;
688 * buffer must be aligned to at least hardsector size for now
690 if (uaddr & queue_dma_alignment(q))
691 return ERR_PTR(-EINVAL);
695 return ERR_PTR(-EINVAL);
697 bio = bio_alloc(gfp_mask, nr_pages);
699 return ERR_PTR(-ENOMEM);
702 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
706 for (i = 0; i < iov_count; i++) {
707 unsigned long uaddr = (unsigned long)iov[i].iov_base;
708 unsigned long len = iov[i].iov_len;
709 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
710 unsigned long start = uaddr >> PAGE_SHIFT;
711 const int local_nr_pages = end - start;
712 const int page_limit = cur_page + local_nr_pages;
714 ret = get_user_pages_fast(uaddr, local_nr_pages,
715 write_to_vm, &pages[cur_page]);
716 if (ret < local_nr_pages) {
721 offset = uaddr & ~PAGE_MASK;
722 for (j = cur_page; j < page_limit; j++) {
723 unsigned int bytes = PAGE_SIZE - offset;
734 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
744 * release the pages we didn't map into the bio, if any
746 while (j < page_limit)
747 page_cache_release(pages[j++]);
753 * set data direction, and check if mapped pages need bouncing
756 bio->bi_rw |= (1 << BIO_RW);
759 bio->bi_flags |= (1 << BIO_USER_MAPPED);
763 for (i = 0; i < nr_pages; i++) {
766 page_cache_release(pages[i]);
775 * bio_map_user - map user address into bio
776 * @q: the struct request_queue for the bio
777 * @bdev: destination block device
778 * @uaddr: start of user address
779 * @len: length in bytes
780 * @write_to_vm: bool indicating writing to pages or not
781 * @gfp_mask: memory allocation flags
783 * Map the user space address into a bio suitable for io to a block
784 * device. Returns an error pointer in case of error.
786 struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
787 unsigned long uaddr, unsigned int len, int write_to_vm,
792 iov.iov_base = (void __user *)uaddr;
795 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
799 * bio_map_user_iov - map user sg_iovec table into bio
800 * @q: the struct request_queue for the bio
801 * @bdev: destination block device
803 * @iov_count: number of elements in the iovec
804 * @write_to_vm: bool indicating writing to pages or not
805 * @gfp_mask: memory allocation flags
807 * Map the user space address into a bio suitable for io to a block
808 * device. Returns an error pointer in case of error.
810 struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
811 struct sg_iovec *iov, int iov_count,
812 int write_to_vm, gfp_t gfp_mask)
816 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
822 * subtle -- if __bio_map_user() ended up bouncing a bio,
823 * it would normally disappear when its bi_end_io is run.
824 * however, we need it for the unmap, so grab an extra
832 static void __bio_unmap_user(struct bio *bio)
834 struct bio_vec *bvec;
838 * make sure we dirty pages we wrote to
840 __bio_for_each_segment(bvec, bio, i, 0) {
841 if (bio_data_dir(bio) == READ)
842 set_page_dirty_lock(bvec->bv_page);
844 page_cache_release(bvec->bv_page);
851 * bio_unmap_user - unmap a bio
852 * @bio: the bio being unmapped
854 * Unmap a bio previously mapped by bio_map_user(). Must be called with
857 * bio_unmap_user() may sleep.
859 void bio_unmap_user(struct bio *bio)
861 __bio_unmap_user(bio);
865 static void bio_map_kern_endio(struct bio *bio, int err)
871 static struct bio *__bio_map_kern(struct request_queue *q, void *data,
872 unsigned int len, gfp_t gfp_mask)
874 unsigned long kaddr = (unsigned long)data;
875 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
876 unsigned long start = kaddr >> PAGE_SHIFT;
877 const int nr_pages = end - start;
881 bio = bio_alloc(gfp_mask, nr_pages);
883 return ERR_PTR(-ENOMEM);
885 offset = offset_in_page(kaddr);
886 for (i = 0; i < nr_pages; i++) {
887 unsigned int bytes = PAGE_SIZE - offset;
895 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
904 bio->bi_end_io = bio_map_kern_endio;
909 * bio_map_kern - map kernel address into bio
910 * @q: the struct request_queue for the bio
911 * @data: pointer to buffer to map
912 * @len: length in bytes
913 * @gfp_mask: allocation flags for bio allocation
915 * Map the kernel address into a bio suitable for io to a block
916 * device. Returns an error pointer in case of error.
918 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
923 bio = __bio_map_kern(q, data, len, gfp_mask);
927 if (bio->bi_size == len)
931 * Don't support partial mappings.
934 return ERR_PTR(-EINVAL);
937 static void bio_copy_kern_endio(struct bio *bio, int err)
939 struct bio_vec *bvec;
940 const int read = bio_data_dir(bio) == READ;
941 struct bio_map_data *bmd = bio->bi_private;
943 char *p = bmd->sgvecs[0].iov_base;
945 __bio_for_each_segment(bvec, bio, i, 0) {
946 char *addr = page_address(bvec->bv_page);
947 int len = bmd->iovecs[i].bv_len;
950 memcpy(p, addr, len);
952 __free_page(bvec->bv_page);
956 bio_free_map_data(bmd);
961 * bio_copy_kern - copy kernel address into bio
962 * @q: the struct request_queue for the bio
963 * @data: pointer to buffer to copy
964 * @len: length in bytes
965 * @gfp_mask: allocation flags for bio and page allocation
966 * @reading: data direction is READ
968 * copy the kernel address into a bio suitable for io to a block
969 * device. Returns an error pointer in case of error.
971 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
972 gfp_t gfp_mask, int reading)
974 unsigned long kaddr = (unsigned long)data;
975 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
976 unsigned long start = kaddr >> PAGE_SHIFT;
977 const int nr_pages = end - start;
979 struct bio_vec *bvec;
980 struct bio_map_data *bmd;
987 bmd = bio_alloc_map_data(nr_pages, 1, gfp_mask);
989 return ERR_PTR(-ENOMEM);
992 bio = bio_alloc(gfp_mask, nr_pages);
998 unsigned int bytes = PAGE_SIZE;
1003 page = alloc_page(q->bounce_gfp | gfp_mask);
1009 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) {
1020 bio_for_each_segment(bvec, bio, i) {
1021 char *addr = page_address(bvec->bv_page);
1023 memcpy(addr, p, bvec->bv_len);
1028 bio->bi_private = bmd;
1029 bio->bi_end_io = bio_copy_kern_endio;
1031 bio_set_map_data(bmd, bio, &iov, 1);
1034 bio_for_each_segment(bvec, bio, i)
1035 __free_page(bvec->bv_page);
1039 bio_free_map_data(bmd);
1041 return ERR_PTR(ret);
1045 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1046 * for performing direct-IO in BIOs.
1048 * The problem is that we cannot run set_page_dirty() from interrupt context
1049 * because the required locks are not interrupt-safe. So what we can do is to
1050 * mark the pages dirty _before_ performing IO. And in interrupt context,
1051 * check that the pages are still dirty. If so, fine. If not, redirty them
1052 * in process context.
1054 * We special-case compound pages here: normally this means reads into hugetlb
1055 * pages. The logic in here doesn't really work right for compound pages
1056 * because the VM does not uniformly chase down the head page in all cases.
1057 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1058 * handle them at all. So we skip compound pages here at an early stage.
1060 * Note that this code is very hard to test under normal circumstances because
1061 * direct-io pins the pages with get_user_pages(). This makes
1062 * is_page_cache_freeable return false, and the VM will not clean the pages.
1063 * But other code (eg, pdflush) could clean the pages if they are mapped
1066 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1067 * deferred bio dirtying paths.
1071 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1073 void bio_set_pages_dirty(struct bio *bio)
1075 struct bio_vec *bvec = bio->bi_io_vec;
1078 for (i = 0; i < bio->bi_vcnt; i++) {
1079 struct page *page = bvec[i].bv_page;
1081 if (page && !PageCompound(page))
1082 set_page_dirty_lock(page);
1086 static void bio_release_pages(struct bio *bio)
1088 struct bio_vec *bvec = bio->bi_io_vec;
1091 for (i = 0; i < bio->bi_vcnt; i++) {
1092 struct page *page = bvec[i].bv_page;
1100 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1101 * If they are, then fine. If, however, some pages are clean then they must
1102 * have been written out during the direct-IO read. So we take another ref on
1103 * the BIO and the offending pages and re-dirty the pages in process context.
1105 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1106 * here on. It will run one page_cache_release() against each page and will
1107 * run one bio_put() against the BIO.
1110 static void bio_dirty_fn(struct work_struct *work);
1112 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1113 static DEFINE_SPINLOCK(bio_dirty_lock);
1114 static struct bio *bio_dirty_list;
1117 * This runs in process context
1119 static void bio_dirty_fn(struct work_struct *work)
1121 unsigned long flags;
1124 spin_lock_irqsave(&bio_dirty_lock, flags);
1125 bio = bio_dirty_list;
1126 bio_dirty_list = NULL;
1127 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1130 struct bio *next = bio->bi_private;
1132 bio_set_pages_dirty(bio);
1133 bio_release_pages(bio);
1139 void bio_check_pages_dirty(struct bio *bio)
1141 struct bio_vec *bvec = bio->bi_io_vec;
1142 int nr_clean_pages = 0;
1145 for (i = 0; i < bio->bi_vcnt; i++) {
1146 struct page *page = bvec[i].bv_page;
1148 if (PageDirty(page) || PageCompound(page)) {
1149 page_cache_release(page);
1150 bvec[i].bv_page = NULL;
1156 if (nr_clean_pages) {
1157 unsigned long flags;
1159 spin_lock_irqsave(&bio_dirty_lock, flags);
1160 bio->bi_private = bio_dirty_list;
1161 bio_dirty_list = bio;
1162 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1163 schedule_work(&bio_dirty_work);
1170 * bio_endio - end I/O on a bio
1172 * @error: error, if any
1175 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1176 * preferred way to end I/O on a bio, it takes care of clearing
1177 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1178 * established -Exxxx (-EIO, for instance) error values in case
1179 * something went wrong. Noone should call bi_end_io() directly on a
1180 * bio unless they own it and thus know that it has an end_io
1183 void bio_endio(struct bio *bio, int error)
1186 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1187 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1191 bio->bi_end_io(bio, error);
1194 void bio_pair_release(struct bio_pair *bp)
1196 if (atomic_dec_and_test(&bp->cnt)) {
1197 struct bio *master = bp->bio1.bi_private;
1199 bio_endio(master, bp->error);
1200 mempool_free(bp, bp->bio2.bi_private);
1204 static void bio_pair_end_1(struct bio *bi, int err)
1206 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1211 bio_pair_release(bp);
1214 static void bio_pair_end_2(struct bio *bi, int err)
1216 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1221 bio_pair_release(bp);
1225 * split a bio - only worry about a bio with a single page
1228 struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
1230 struct bio_pair *bp = mempool_alloc(pool, GFP_NOIO);
1235 blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
1236 bi->bi_sector + first_sectors);
1238 BUG_ON(bi->bi_vcnt != 1);
1239 BUG_ON(bi->bi_idx != 0);
1240 atomic_set(&bp->cnt, 3);
1244 bp->bio2.bi_sector += first_sectors;
1245 bp->bio2.bi_size -= first_sectors << 9;
1246 bp->bio1.bi_size = first_sectors << 9;
1248 bp->bv1 = bi->bi_io_vec[0];
1249 bp->bv2 = bi->bi_io_vec[0];
1250 bp->bv2.bv_offset += first_sectors << 9;
1251 bp->bv2.bv_len -= first_sectors << 9;
1252 bp->bv1.bv_len = first_sectors << 9;
1254 bp->bio1.bi_io_vec = &bp->bv1;
1255 bp->bio2.bi_io_vec = &bp->bv2;
1257 bp->bio1.bi_max_vecs = 1;
1258 bp->bio2.bi_max_vecs = 1;
1260 bp->bio1.bi_end_io = bio_pair_end_1;
1261 bp->bio2.bi_end_io = bio_pair_end_2;
1263 bp->bio1.bi_private = bi;
1264 bp->bio2.bi_private = pool;
1266 if (bio_integrity(bi))
1267 bio_integrity_split(bi, bp, first_sectors);
1274 * create memory pools for biovec's in a bio_set.
1275 * use the global biovec slabs created for general use.
1277 static int biovec_create_pools(struct bio_set *bs, int pool_entries)
1281 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1282 struct biovec_slab *bp = bvec_slabs + i;
1283 mempool_t **bvp = bs->bvec_pools + i;
1285 *bvp = mempool_create_slab_pool(pool_entries, bp->slab);
1292 static void biovec_free_pools(struct bio_set *bs)
1296 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1297 mempool_t *bvp = bs->bvec_pools[i];
1300 mempool_destroy(bvp);
1305 void bioset_free(struct bio_set *bs)
1308 mempool_destroy(bs->bio_pool);
1310 bioset_integrity_free(bs);
1311 biovec_free_pools(bs);
1316 struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size)
1318 struct bio_set *bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1323 bs->bio_pool = mempool_create_slab_pool(bio_pool_size, bio_slab);
1327 if (bioset_integrity_create(bs, bio_pool_size))
1330 if (!biovec_create_pools(bs, bvec_pool_size))
1338 static void __init biovec_init_slabs(void)
1342 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1344 struct biovec_slab *bvs = bvec_slabs + i;
1346 size = bvs->nr_vecs * sizeof(struct bio_vec);
1347 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1348 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1352 static int __init init_bio(void)
1354 bio_slab = KMEM_CACHE(bio, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
1356 bio_integrity_init_slab();
1357 biovec_init_slabs();
1359 fs_bio_set = bioset_create(BIO_POOL_SIZE, 2);
1361 panic("bio: can't allocate bios\n");
1363 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
1364 sizeof(struct bio_pair));
1365 if (!bio_split_pool)
1366 panic("bio: can't create split pool\n");
1371 subsys_initcall(init_bio);
1373 EXPORT_SYMBOL(bio_alloc);
1374 EXPORT_SYMBOL(bio_put);
1375 EXPORT_SYMBOL(bio_free);
1376 EXPORT_SYMBOL(bio_endio);
1377 EXPORT_SYMBOL(bio_init);
1378 EXPORT_SYMBOL(__bio_clone);
1379 EXPORT_SYMBOL(bio_clone);
1380 EXPORT_SYMBOL(bio_phys_segments);
1381 EXPORT_SYMBOL(bio_add_page);
1382 EXPORT_SYMBOL(bio_add_pc_page);
1383 EXPORT_SYMBOL(bio_get_nr_vecs);
1384 EXPORT_SYMBOL(bio_map_user);
1385 EXPORT_SYMBOL(bio_unmap_user);
1386 EXPORT_SYMBOL(bio_map_kern);
1387 EXPORT_SYMBOL(bio_copy_kern);
1388 EXPORT_SYMBOL(bio_pair_release);
1389 EXPORT_SYMBOL(bio_split);
1390 EXPORT_SYMBOL(bio_split_pool);
1391 EXPORT_SYMBOL(bio_copy_user);
1392 EXPORT_SYMBOL(bio_uncopy_user);
1393 EXPORT_SYMBOL(bioset_create);
1394 EXPORT_SYMBOL(bioset_free);
1395 EXPORT_SYMBOL(bio_alloc_bioset);