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 static struct kmem_cache *bio_slab __read_mostly;
34 static mempool_t *bio_split_pool __read_mostly;
37 * if you change this list, also change bvec_alloc or things will
38 * break badly! cannot be bigger than what you can fit into an
42 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
43 static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
44 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
49 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
50 * IO code that does not need private memory pools.
52 struct bio_set *fs_bio_set;
54 unsigned int bvec_nr_vecs(unsigned short idx)
56 return bvec_slabs[idx].nr_vecs;
59 struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct bio_set *bs)
64 * If 'bs' is given, lookup the pool and do the mempool alloc.
65 * If not, this is a bio_kmalloc() allocation and just do a
66 * kzalloc() for the exact number of vecs right away.
70 * see comment near bvec_array define!
88 case 129 ... BIO_MAX_PAGES:
96 * idx now points to the pool we want to allocate from
98 bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
101 bvec_nr_vecs(*idx) * sizeof(struct bio_vec));
103 bvl = kzalloc(nr * sizeof(struct bio_vec), gfp_mask);
108 void bio_free(struct bio *bio, struct bio_set *bio_set)
110 if (bio->bi_io_vec) {
111 const int pool_idx = BIO_POOL_IDX(bio);
113 BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
115 mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
118 if (bio_integrity(bio))
119 bio_integrity_free(bio, bio_set);
121 mempool_free(bio, bio_set->bio_pool);
125 * default destructor for a bio allocated with bio_alloc_bioset()
127 static void bio_fs_destructor(struct bio *bio)
129 bio_free(bio, fs_bio_set);
132 static void bio_kmalloc_destructor(struct bio *bio)
134 kfree(bio->bi_io_vec);
138 void bio_init(struct bio *bio)
140 memset(bio, 0, sizeof(*bio));
141 bio->bi_flags = 1 << BIO_UPTODATE;
142 bio->bi_comp_cpu = -1;
143 atomic_set(&bio->bi_cnt, 1);
147 * bio_alloc_bioset - allocate a bio for I/O
148 * @gfp_mask: the GFP_ mask given to the slab allocator
149 * @nr_iovecs: number of iovecs to pre-allocate
150 * @bs: the bio_set to allocate from. If %NULL, just use kmalloc
153 * bio_alloc_bioset will first try its own mempool to satisfy the allocation.
154 * If %__GFP_WAIT is set then we will block on the internal pool waiting
155 * for a &struct bio to become free. If a %NULL @bs is passed in, we will
156 * fall back to just using @kmalloc to allocate the required memory.
158 * allocate bio and iovecs from the memory pools specified by the
159 * bio_set structure, or @kmalloc if none given.
161 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
166 bio = mempool_alloc(bs->bio_pool, gfp_mask);
168 bio = kmalloc(sizeof(*bio), gfp_mask);
171 struct bio_vec *bvl = NULL;
174 if (likely(nr_iovecs)) {
175 unsigned long uninitialized_var(idx);
177 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
178 if (unlikely(!bvl)) {
180 mempool_free(bio, bs->bio_pool);
186 bio->bi_flags |= idx << BIO_POOL_OFFSET;
187 bio->bi_max_vecs = bvec_nr_vecs(idx);
189 bio->bi_io_vec = bvl;
195 struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
197 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
200 bio->bi_destructor = bio_fs_destructor;
206 * Like bio_alloc(), but doesn't use a mempool backing. This means that
207 * it CAN fail, but while bio_alloc() can only be used for allocations
208 * that have a short (finite) life span, bio_kmalloc() should be used
209 * for more permanent bio allocations (like allocating some bio's for
210 * initalization or setup purposes).
212 struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
214 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
217 bio->bi_destructor = bio_kmalloc_destructor;
222 void zero_fill_bio(struct bio *bio)
228 bio_for_each_segment(bv, bio, i) {
229 char *data = bvec_kmap_irq(bv, &flags);
230 memset(data, 0, bv->bv_len);
231 flush_dcache_page(bv->bv_page);
232 bvec_kunmap_irq(data, &flags);
235 EXPORT_SYMBOL(zero_fill_bio);
238 * bio_put - release a reference to a bio
239 * @bio: bio to release reference to
242 * Put a reference to a &struct bio, either one you have gotten with
243 * bio_alloc or bio_get. The last put of a bio will free it.
245 void bio_put(struct bio *bio)
247 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
252 if (atomic_dec_and_test(&bio->bi_cnt)) {
254 bio->bi_destructor(bio);
258 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
260 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
261 blk_recount_segments(q, bio);
263 return bio->bi_phys_segments;
267 * __bio_clone - clone a bio
268 * @bio: destination bio
269 * @bio_src: bio to clone
271 * Clone a &bio. Caller will own the returned bio, but not
272 * the actual data it points to. Reference count of returned
275 void __bio_clone(struct bio *bio, struct bio *bio_src)
277 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
278 bio_src->bi_max_vecs * sizeof(struct bio_vec));
281 * most users will be overriding ->bi_bdev with a new target,
282 * so we don't set nor calculate new physical/hw segment counts here
284 bio->bi_sector = bio_src->bi_sector;
285 bio->bi_bdev = bio_src->bi_bdev;
286 bio->bi_flags |= 1 << BIO_CLONED;
287 bio->bi_rw = bio_src->bi_rw;
288 bio->bi_vcnt = bio_src->bi_vcnt;
289 bio->bi_size = bio_src->bi_size;
290 bio->bi_idx = bio_src->bi_idx;
294 * bio_clone - clone a bio
296 * @gfp_mask: allocation priority
298 * Like __bio_clone, only also allocates the returned bio
300 struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
302 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
307 b->bi_destructor = bio_fs_destructor;
310 if (bio_integrity(bio)) {
313 ret = bio_integrity_clone(b, bio, fs_bio_set);
323 * bio_get_nr_vecs - return approx number of vecs
326 * Return the approximate number of pages we can send to this target.
327 * There's no guarantee that you will be able to fit this number of pages
328 * into a bio, it does not account for dynamic restrictions that vary
331 int bio_get_nr_vecs(struct block_device *bdev)
333 struct request_queue *q = bdev_get_queue(bdev);
336 nr_pages = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
337 if (nr_pages > q->max_phys_segments)
338 nr_pages = q->max_phys_segments;
339 if (nr_pages > q->max_hw_segments)
340 nr_pages = q->max_hw_segments;
345 static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
346 *page, unsigned int len, unsigned int offset,
347 unsigned short max_sectors)
349 int retried_segments = 0;
350 struct bio_vec *bvec;
353 * cloned bio must not modify vec list
355 if (unlikely(bio_flagged(bio, BIO_CLONED)))
358 if (((bio->bi_size + len) >> 9) > max_sectors)
362 * For filesystems with a blocksize smaller than the pagesize
363 * we will often be called with the same page as last time and
364 * a consecutive offset. Optimize this special case.
366 if (bio->bi_vcnt > 0) {
367 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
369 if (page == prev->bv_page &&
370 offset == prev->bv_offset + prev->bv_len) {
373 if (q->merge_bvec_fn) {
374 struct bvec_merge_data bvm = {
375 .bi_bdev = bio->bi_bdev,
376 .bi_sector = bio->bi_sector,
377 .bi_size = bio->bi_size,
381 if (q->merge_bvec_fn(q, &bvm, prev) < len) {
391 if (bio->bi_vcnt >= bio->bi_max_vecs)
395 * we might lose a segment or two here, but rather that than
396 * make this too complex.
399 while (bio->bi_phys_segments >= q->max_phys_segments
400 || bio->bi_phys_segments >= q->max_hw_segments) {
402 if (retried_segments)
405 retried_segments = 1;
406 blk_recount_segments(q, bio);
410 * setup the new entry, we might clear it again later if we
411 * cannot add the page
413 bvec = &bio->bi_io_vec[bio->bi_vcnt];
414 bvec->bv_page = page;
416 bvec->bv_offset = offset;
419 * if queue has other restrictions (eg varying max sector size
420 * depending on offset), it can specify a merge_bvec_fn in the
421 * queue to get further control
423 if (q->merge_bvec_fn) {
424 struct bvec_merge_data bvm = {
425 .bi_bdev = bio->bi_bdev,
426 .bi_sector = bio->bi_sector,
427 .bi_size = bio->bi_size,
432 * merge_bvec_fn() returns number of bytes it can accept
435 if (q->merge_bvec_fn(q, &bvm, bvec) < len) {
436 bvec->bv_page = NULL;
443 /* If we may be able to merge these biovecs, force a recount */
444 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
445 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
448 bio->bi_phys_segments++;
455 * bio_add_pc_page - attempt to add page to bio
456 * @q: the target queue
457 * @bio: destination bio
459 * @len: vec entry length
460 * @offset: vec entry offset
462 * Attempt to add a page to the bio_vec maplist. This can fail for a
463 * number of reasons, such as the bio being full or target block
464 * device limitations. The target block device must allow bio's
465 * smaller than PAGE_SIZE, so it is always possible to add a single
466 * page to an empty bio. This should only be used by REQ_PC bios.
468 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
469 unsigned int len, unsigned int offset)
471 return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
475 * bio_add_page - attempt to add page to bio
476 * @bio: destination bio
478 * @len: vec entry length
479 * @offset: vec entry offset
481 * Attempt to add a page to the bio_vec maplist. This can fail for a
482 * number of reasons, such as the bio being full or target block
483 * device limitations. The target block device must allow bio's
484 * smaller than PAGE_SIZE, so it is always possible to add a single
485 * page to an empty bio.
487 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
490 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
491 return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
494 struct bio_map_data {
495 struct bio_vec *iovecs;
496 struct sg_iovec *sgvecs;
501 static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
502 struct sg_iovec *iov, int iov_count,
505 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
506 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
507 bmd->nr_sgvecs = iov_count;
508 bmd->is_our_pages = is_our_pages;
509 bio->bi_private = bmd;
512 static void bio_free_map_data(struct bio_map_data *bmd)
519 static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count,
522 struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
527 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
533 bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
542 static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
543 struct sg_iovec *iov, int iov_count, int uncopy,
547 struct bio_vec *bvec;
549 unsigned int iov_off = 0;
550 int read = bio_data_dir(bio) == READ;
552 __bio_for_each_segment(bvec, bio, i, 0) {
553 char *bv_addr = page_address(bvec->bv_page);
554 unsigned int bv_len = iovecs[i].bv_len;
556 while (bv_len && iov_idx < iov_count) {
560 bytes = min_t(unsigned int,
561 iov[iov_idx].iov_len - iov_off, bv_len);
562 iov_addr = iov[iov_idx].iov_base + iov_off;
565 if (!read && !uncopy)
566 ret = copy_from_user(bv_addr, iov_addr,
569 ret = copy_to_user(iov_addr, bv_addr,
581 if (iov[iov_idx].iov_len == iov_off) {
588 __free_page(bvec->bv_page);
595 * bio_uncopy_user - finish previously mapped bio
596 * @bio: bio being terminated
598 * Free pages allocated from bio_copy_user() and write back data
599 * to user space in case of a read.
601 int bio_uncopy_user(struct bio *bio)
603 struct bio_map_data *bmd = bio->bi_private;
606 if (!bio_flagged(bio, BIO_NULL_MAPPED))
607 ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
608 bmd->nr_sgvecs, 1, bmd->is_our_pages);
609 bio_free_map_data(bmd);
615 * bio_copy_user_iov - copy user data to bio
616 * @q: destination block queue
617 * @map_data: pointer to the rq_map_data holding pages (if necessary)
619 * @iov_count: number of elements in the iovec
620 * @write_to_vm: bool indicating writing to pages or not
621 * @gfp_mask: memory allocation flags
623 * Prepares and returns a bio for indirect user io, bouncing data
624 * to/from kernel pages as necessary. Must be paired with
625 * call bio_uncopy_user() on io completion.
627 struct bio *bio_copy_user_iov(struct request_queue *q,
628 struct rq_map_data *map_data,
629 struct sg_iovec *iov, int iov_count,
630 int write_to_vm, gfp_t gfp_mask)
632 struct bio_map_data *bmd;
633 struct bio_vec *bvec;
638 unsigned int len = 0;
640 for (i = 0; i < iov_count; i++) {
645 uaddr = (unsigned long)iov[i].iov_base;
646 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
647 start = uaddr >> PAGE_SHIFT;
649 nr_pages += end - start;
650 len += iov[i].iov_len;
653 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
655 return ERR_PTR(-ENOMEM);
658 bio = bio_alloc(gfp_mask, nr_pages);
662 bio->bi_rw |= (!write_to_vm << BIO_RW);
670 bytes = 1U << (PAGE_SHIFT + map_data->page_order);
678 if (i == map_data->nr_entries) {
682 page = map_data->pages[i++];
684 page = alloc_page(q->bounce_gfp | gfp_mask);
690 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
703 ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 0);
708 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
712 bio_for_each_segment(bvec, bio, i)
713 __free_page(bvec->bv_page);
717 bio_free_map_data(bmd);
722 * bio_copy_user - copy user data to bio
723 * @q: destination block queue
724 * @map_data: pointer to the rq_map_data holding pages (if necessary)
725 * @uaddr: start of user address
726 * @len: length in bytes
727 * @write_to_vm: bool indicating writing to pages or not
728 * @gfp_mask: memory allocation flags
730 * Prepares and returns a bio for indirect user io, bouncing data
731 * to/from kernel pages as necessary. Must be paired with
732 * call bio_uncopy_user() on io completion.
734 struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
735 unsigned long uaddr, unsigned int len,
736 int write_to_vm, gfp_t gfp_mask)
740 iov.iov_base = (void __user *)uaddr;
743 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
746 static struct bio *__bio_map_user_iov(struct request_queue *q,
747 struct block_device *bdev,
748 struct sg_iovec *iov, int iov_count,
749 int write_to_vm, gfp_t gfp_mask)
758 for (i = 0; i < iov_count; i++) {
759 unsigned long uaddr = (unsigned long)iov[i].iov_base;
760 unsigned long len = iov[i].iov_len;
761 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
762 unsigned long start = uaddr >> PAGE_SHIFT;
764 nr_pages += end - start;
766 * buffer must be aligned to at least hardsector size for now
768 if (uaddr & queue_dma_alignment(q))
769 return ERR_PTR(-EINVAL);
773 return ERR_PTR(-EINVAL);
775 bio = bio_alloc(gfp_mask, nr_pages);
777 return ERR_PTR(-ENOMEM);
780 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
784 for (i = 0; i < iov_count; i++) {
785 unsigned long uaddr = (unsigned long)iov[i].iov_base;
786 unsigned long len = iov[i].iov_len;
787 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
788 unsigned long start = uaddr >> PAGE_SHIFT;
789 const int local_nr_pages = end - start;
790 const int page_limit = cur_page + local_nr_pages;
792 ret = get_user_pages_fast(uaddr, local_nr_pages,
793 write_to_vm, &pages[cur_page]);
794 if (ret < local_nr_pages) {
799 offset = uaddr & ~PAGE_MASK;
800 for (j = cur_page; j < page_limit; j++) {
801 unsigned int bytes = PAGE_SIZE - offset;
812 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
822 * release the pages we didn't map into the bio, if any
824 while (j < page_limit)
825 page_cache_release(pages[j++]);
831 * set data direction, and check if mapped pages need bouncing
834 bio->bi_rw |= (1 << BIO_RW);
837 bio->bi_flags |= (1 << BIO_USER_MAPPED);
841 for (i = 0; i < nr_pages; i++) {
844 page_cache_release(pages[i]);
853 * bio_map_user - map user address into bio
854 * @q: the struct request_queue for the bio
855 * @bdev: destination block device
856 * @uaddr: start of user address
857 * @len: length in bytes
858 * @write_to_vm: bool indicating writing to pages or not
859 * @gfp_mask: memory allocation flags
861 * Map the user space address into a bio suitable for io to a block
862 * device. Returns an error pointer in case of error.
864 struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
865 unsigned long uaddr, unsigned int len, int write_to_vm,
870 iov.iov_base = (void __user *)uaddr;
873 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
877 * bio_map_user_iov - map user sg_iovec table into bio
878 * @q: the struct request_queue for the bio
879 * @bdev: destination block device
881 * @iov_count: number of elements in the iovec
882 * @write_to_vm: bool indicating writing to pages or not
883 * @gfp_mask: memory allocation flags
885 * Map the user space address into a bio suitable for io to a block
886 * device. Returns an error pointer in case of error.
888 struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
889 struct sg_iovec *iov, int iov_count,
890 int write_to_vm, gfp_t gfp_mask)
894 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
900 * subtle -- if __bio_map_user() ended up bouncing a bio,
901 * it would normally disappear when its bi_end_io is run.
902 * however, we need it for the unmap, so grab an extra
910 static void __bio_unmap_user(struct bio *bio)
912 struct bio_vec *bvec;
916 * make sure we dirty pages we wrote to
918 __bio_for_each_segment(bvec, bio, i, 0) {
919 if (bio_data_dir(bio) == READ)
920 set_page_dirty_lock(bvec->bv_page);
922 page_cache_release(bvec->bv_page);
929 * bio_unmap_user - unmap a bio
930 * @bio: the bio being unmapped
932 * Unmap a bio previously mapped by bio_map_user(). Must be called with
935 * bio_unmap_user() may sleep.
937 void bio_unmap_user(struct bio *bio)
939 __bio_unmap_user(bio);
943 static void bio_map_kern_endio(struct bio *bio, int err)
949 static struct bio *__bio_map_kern(struct request_queue *q, void *data,
950 unsigned int len, gfp_t gfp_mask)
952 unsigned long kaddr = (unsigned long)data;
953 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
954 unsigned long start = kaddr >> PAGE_SHIFT;
955 const int nr_pages = end - start;
959 bio = bio_alloc(gfp_mask, nr_pages);
961 return ERR_PTR(-ENOMEM);
963 offset = offset_in_page(kaddr);
964 for (i = 0; i < nr_pages; i++) {
965 unsigned int bytes = PAGE_SIZE - offset;
973 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
982 bio->bi_end_io = bio_map_kern_endio;
987 * bio_map_kern - map kernel address into bio
988 * @q: the struct request_queue for the bio
989 * @data: pointer to buffer to map
990 * @len: length in bytes
991 * @gfp_mask: allocation flags for bio allocation
993 * Map the kernel address into a bio suitable for io to a block
994 * device. Returns an error pointer in case of error.
996 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1001 bio = __bio_map_kern(q, data, len, gfp_mask);
1005 if (bio->bi_size == len)
1009 * Don't support partial mappings.
1012 return ERR_PTR(-EINVAL);
1015 static void bio_copy_kern_endio(struct bio *bio, int err)
1017 struct bio_vec *bvec;
1018 const int read = bio_data_dir(bio) == READ;
1019 struct bio_map_data *bmd = bio->bi_private;
1021 char *p = bmd->sgvecs[0].iov_base;
1023 __bio_for_each_segment(bvec, bio, i, 0) {
1024 char *addr = page_address(bvec->bv_page);
1025 int len = bmd->iovecs[i].bv_len;
1028 memcpy(p, addr, len);
1030 __free_page(bvec->bv_page);
1034 bio_free_map_data(bmd);
1039 * bio_copy_kern - copy kernel address into bio
1040 * @q: the struct request_queue for the bio
1041 * @data: pointer to buffer to copy
1042 * @len: length in bytes
1043 * @gfp_mask: allocation flags for bio and page allocation
1044 * @reading: data direction is READ
1046 * copy the kernel address into a bio suitable for io to a block
1047 * device. Returns an error pointer in case of error.
1049 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1050 gfp_t gfp_mask, int reading)
1053 struct bio_vec *bvec;
1056 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
1063 bio_for_each_segment(bvec, bio, i) {
1064 char *addr = page_address(bvec->bv_page);
1066 memcpy(addr, p, bvec->bv_len);
1071 bio->bi_end_io = bio_copy_kern_endio;
1077 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1078 * for performing direct-IO in BIOs.
1080 * The problem is that we cannot run set_page_dirty() from interrupt context
1081 * because the required locks are not interrupt-safe. So what we can do is to
1082 * mark the pages dirty _before_ performing IO. And in interrupt context,
1083 * check that the pages are still dirty. If so, fine. If not, redirty them
1084 * in process context.
1086 * We special-case compound pages here: normally this means reads into hugetlb
1087 * pages. The logic in here doesn't really work right for compound pages
1088 * because the VM does not uniformly chase down the head page in all cases.
1089 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1090 * handle them at all. So we skip compound pages here at an early stage.
1092 * Note that this code is very hard to test under normal circumstances because
1093 * direct-io pins the pages with get_user_pages(). This makes
1094 * is_page_cache_freeable return false, and the VM will not clean the pages.
1095 * But other code (eg, pdflush) could clean the pages if they are mapped
1098 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1099 * deferred bio dirtying paths.
1103 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1105 void bio_set_pages_dirty(struct bio *bio)
1107 struct bio_vec *bvec = bio->bi_io_vec;
1110 for (i = 0; i < bio->bi_vcnt; i++) {
1111 struct page *page = bvec[i].bv_page;
1113 if (page && !PageCompound(page))
1114 set_page_dirty_lock(page);
1118 static void bio_release_pages(struct bio *bio)
1120 struct bio_vec *bvec = bio->bi_io_vec;
1123 for (i = 0; i < bio->bi_vcnt; i++) {
1124 struct page *page = bvec[i].bv_page;
1132 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1133 * If they are, then fine. If, however, some pages are clean then they must
1134 * have been written out during the direct-IO read. So we take another ref on
1135 * the BIO and the offending pages and re-dirty the pages in process context.
1137 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1138 * here on. It will run one page_cache_release() against each page and will
1139 * run one bio_put() against the BIO.
1142 static void bio_dirty_fn(struct work_struct *work);
1144 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1145 static DEFINE_SPINLOCK(bio_dirty_lock);
1146 static struct bio *bio_dirty_list;
1149 * This runs in process context
1151 static void bio_dirty_fn(struct work_struct *work)
1153 unsigned long flags;
1156 spin_lock_irqsave(&bio_dirty_lock, flags);
1157 bio = bio_dirty_list;
1158 bio_dirty_list = NULL;
1159 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1162 struct bio *next = bio->bi_private;
1164 bio_set_pages_dirty(bio);
1165 bio_release_pages(bio);
1171 void bio_check_pages_dirty(struct bio *bio)
1173 struct bio_vec *bvec = bio->bi_io_vec;
1174 int nr_clean_pages = 0;
1177 for (i = 0; i < bio->bi_vcnt; i++) {
1178 struct page *page = bvec[i].bv_page;
1180 if (PageDirty(page) || PageCompound(page)) {
1181 page_cache_release(page);
1182 bvec[i].bv_page = NULL;
1188 if (nr_clean_pages) {
1189 unsigned long flags;
1191 spin_lock_irqsave(&bio_dirty_lock, flags);
1192 bio->bi_private = bio_dirty_list;
1193 bio_dirty_list = bio;
1194 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1195 schedule_work(&bio_dirty_work);
1202 * bio_endio - end I/O on a bio
1204 * @error: error, if any
1207 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1208 * preferred way to end I/O on a bio, it takes care of clearing
1209 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1210 * established -Exxxx (-EIO, for instance) error values in case
1211 * something went wrong. Noone should call bi_end_io() directly on a
1212 * bio unless they own it and thus know that it has an end_io
1215 void bio_endio(struct bio *bio, int error)
1218 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1219 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1223 bio->bi_end_io(bio, error);
1226 void bio_pair_release(struct bio_pair *bp)
1228 if (atomic_dec_and_test(&bp->cnt)) {
1229 struct bio *master = bp->bio1.bi_private;
1231 bio_endio(master, bp->error);
1232 mempool_free(bp, bp->bio2.bi_private);
1236 static void bio_pair_end_1(struct bio *bi, int err)
1238 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1243 bio_pair_release(bp);
1246 static void bio_pair_end_2(struct bio *bi, int err)
1248 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1253 bio_pair_release(bp);
1257 * split a bio - only worry about a bio with a single page
1260 struct bio_pair *bio_split(struct bio *bi, int first_sectors)
1262 struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
1267 trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1268 bi->bi_sector + first_sectors);
1270 BUG_ON(bi->bi_vcnt != 1);
1271 BUG_ON(bi->bi_idx != 0);
1272 atomic_set(&bp->cnt, 3);
1276 bp->bio2.bi_sector += first_sectors;
1277 bp->bio2.bi_size -= first_sectors << 9;
1278 bp->bio1.bi_size = first_sectors << 9;
1280 bp->bv1 = bi->bi_io_vec[0];
1281 bp->bv2 = bi->bi_io_vec[0];
1282 bp->bv2.bv_offset += first_sectors << 9;
1283 bp->bv2.bv_len -= first_sectors << 9;
1284 bp->bv1.bv_len = first_sectors << 9;
1286 bp->bio1.bi_io_vec = &bp->bv1;
1287 bp->bio2.bi_io_vec = &bp->bv2;
1289 bp->bio1.bi_max_vecs = 1;
1290 bp->bio2.bi_max_vecs = 1;
1292 bp->bio1.bi_end_io = bio_pair_end_1;
1293 bp->bio2.bi_end_io = bio_pair_end_2;
1295 bp->bio1.bi_private = bi;
1296 bp->bio2.bi_private = bio_split_pool;
1298 if (bio_integrity(bi))
1299 bio_integrity_split(bi, bp, first_sectors);
1305 * bio_sector_offset - Find hardware sector offset in bio
1306 * @bio: bio to inspect
1307 * @index: bio_vec index
1308 * @offset: offset in bv_page
1310 * Return the number of hardware sectors between beginning of bio
1311 * and an end point indicated by a bio_vec index and an offset
1312 * within that vector's page.
1314 sector_t bio_sector_offset(struct bio *bio, unsigned short index,
1315 unsigned int offset)
1317 unsigned int sector_sz = queue_hardsect_size(bio->bi_bdev->bd_disk->queue);
1324 if (index >= bio->bi_idx)
1325 index = bio->bi_vcnt - 1;
1327 __bio_for_each_segment(bv, bio, i, 0) {
1329 if (offset > bv->bv_offset)
1330 sectors += (offset - bv->bv_offset) / sector_sz;
1334 sectors += bv->bv_len / sector_sz;
1339 EXPORT_SYMBOL(bio_sector_offset);
1342 * create memory pools for biovec's in a bio_set.
1343 * use the global biovec slabs created for general use.
1345 static int biovec_create_pools(struct bio_set *bs, int pool_entries)
1349 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1350 struct biovec_slab *bp = bvec_slabs + i;
1351 mempool_t **bvp = bs->bvec_pools + i;
1353 *bvp = mempool_create_slab_pool(pool_entries, bp->slab);
1360 static void biovec_free_pools(struct bio_set *bs)
1364 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1365 mempool_t *bvp = bs->bvec_pools[i];
1368 mempool_destroy(bvp);
1373 void bioset_free(struct bio_set *bs)
1376 mempool_destroy(bs->bio_pool);
1378 bioset_integrity_free(bs);
1379 biovec_free_pools(bs);
1384 struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size)
1386 struct bio_set *bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1391 bs->bio_pool = mempool_create_slab_pool(bio_pool_size, bio_slab);
1395 if (bioset_integrity_create(bs, bio_pool_size))
1398 if (!biovec_create_pools(bs, bvec_pool_size))
1406 static void __init biovec_init_slabs(void)
1410 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1412 struct biovec_slab *bvs = bvec_slabs + i;
1414 size = bvs->nr_vecs * sizeof(struct bio_vec);
1415 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1416 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1420 static int __init init_bio(void)
1422 bio_slab = KMEM_CACHE(bio, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
1424 bio_integrity_init_slab();
1425 biovec_init_slabs();
1427 fs_bio_set = bioset_create(BIO_POOL_SIZE, 2);
1429 panic("bio: can't allocate bios\n");
1431 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
1432 sizeof(struct bio_pair));
1433 if (!bio_split_pool)
1434 panic("bio: can't create split pool\n");
1439 subsys_initcall(init_bio);
1441 EXPORT_SYMBOL(bio_alloc);
1442 EXPORT_SYMBOL(bio_kmalloc);
1443 EXPORT_SYMBOL(bio_put);
1444 EXPORT_SYMBOL(bio_free);
1445 EXPORT_SYMBOL(bio_endio);
1446 EXPORT_SYMBOL(bio_init);
1447 EXPORT_SYMBOL(__bio_clone);
1448 EXPORT_SYMBOL(bio_clone);
1449 EXPORT_SYMBOL(bio_phys_segments);
1450 EXPORT_SYMBOL(bio_add_page);
1451 EXPORT_SYMBOL(bio_add_pc_page);
1452 EXPORT_SYMBOL(bio_get_nr_vecs);
1453 EXPORT_SYMBOL(bio_map_user);
1454 EXPORT_SYMBOL(bio_unmap_user);
1455 EXPORT_SYMBOL(bio_map_kern);
1456 EXPORT_SYMBOL(bio_copy_kern);
1457 EXPORT_SYMBOL(bio_pair_release);
1458 EXPORT_SYMBOL(bio_split);
1459 EXPORT_SYMBOL(bio_copy_user);
1460 EXPORT_SYMBOL(bio_uncopy_user);
1461 EXPORT_SYMBOL(bioset_create);
1462 EXPORT_SYMBOL(bioset_free);
1463 EXPORT_SYMBOL(bio_alloc_bioset);