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/iocontext.h>
23 #include <linux/slab.h>
24 #include <linux/init.h>
25 #include <linux/kernel.h>
26 #include <linux/export.h>
27 #include <linux/mempool.h>
28 #include <linux/workqueue.h>
29 #include <linux/cgroup.h>
30 #include <scsi/sg.h> /* for struct sg_iovec */
32 #include <trace/events/block.h>
35 * Test patch to inline a certain number of bi_io_vec's inside the bio
36 * itself, to shrink a bio data allocation from two mempool calls to one
38 #define BIO_INLINE_VECS 4
40 static mempool_t *bio_split_pool __read_mostly;
43 * if you change this list, also change bvec_alloc or things will
44 * break badly! cannot be bigger than what you can fit into an
47 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
48 static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
49 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
54 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
55 * IO code that does not need private memory pools.
57 struct bio_set *fs_bio_set;
60 * Our slab pool management
63 struct kmem_cache *slab;
64 unsigned int slab_ref;
65 unsigned int slab_size;
68 static DEFINE_MUTEX(bio_slab_lock);
69 static struct bio_slab *bio_slabs;
70 static unsigned int bio_slab_nr, bio_slab_max;
72 static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
74 unsigned int sz = sizeof(struct bio) + extra_size;
75 struct kmem_cache *slab = NULL;
76 struct bio_slab *bslab, *new_bio_slabs;
77 unsigned int i, entry = -1;
79 mutex_lock(&bio_slab_lock);
82 while (i < bio_slab_nr) {
83 bslab = &bio_slabs[i];
85 if (!bslab->slab && entry == -1)
87 else if (bslab->slab_size == sz) {
98 if (bio_slab_nr == bio_slab_max && entry == -1) {
100 new_bio_slabs = krealloc(bio_slabs,
101 bio_slab_max * sizeof(struct bio_slab),
105 bio_slabs = new_bio_slabs;
108 entry = bio_slab_nr++;
110 bslab = &bio_slabs[entry];
112 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
113 slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
117 printk(KERN_INFO "bio: create slab <%s> at %d\n", bslab->name, entry);
120 bslab->slab_size = sz;
122 mutex_unlock(&bio_slab_lock);
126 static void bio_put_slab(struct bio_set *bs)
128 struct bio_slab *bslab = NULL;
131 mutex_lock(&bio_slab_lock);
133 for (i = 0; i < bio_slab_nr; i++) {
134 if (bs->bio_slab == bio_slabs[i].slab) {
135 bslab = &bio_slabs[i];
140 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
143 WARN_ON(!bslab->slab_ref);
145 if (--bslab->slab_ref)
148 kmem_cache_destroy(bslab->slab);
152 mutex_unlock(&bio_slab_lock);
155 unsigned int bvec_nr_vecs(unsigned short idx)
157 return bvec_slabs[idx].nr_vecs;
160 void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
162 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
164 if (idx == BIOVEC_MAX_IDX)
165 mempool_free(bv, bs->bvec_pool);
167 struct biovec_slab *bvs = bvec_slabs + idx;
169 kmem_cache_free(bvs->slab, bv);
173 struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
179 * see comment near bvec_array define!
197 case 129 ... BIO_MAX_PAGES:
205 * idx now points to the pool we want to allocate from. only the
206 * 1-vec entry pool is mempool backed.
208 if (*idx == BIOVEC_MAX_IDX) {
210 bvl = mempool_alloc(bs->bvec_pool, gfp_mask);
212 struct biovec_slab *bvs = bvec_slabs + *idx;
213 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
216 * Make this allocation restricted and don't dump info on
217 * allocation failures, since we'll fallback to the mempool
218 * in case of failure.
220 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
223 * Try a slab allocation. If this fails and __GFP_WAIT
224 * is set, retry with the 1-entry mempool
226 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
227 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
228 *idx = BIOVEC_MAX_IDX;
236 void bio_free(struct bio *bio, struct bio_set *bs)
240 if (bio_has_allocated_vec(bio))
241 bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
243 if (bio_integrity(bio))
244 bio_integrity_free(bio);
247 * If we have front padding, adjust the bio pointer before freeing
253 mempool_free(p, bs->bio_pool);
255 EXPORT_SYMBOL(bio_free);
257 void bio_init(struct bio *bio)
259 memset(bio, 0, sizeof(*bio));
260 bio->bi_flags = 1 << BIO_UPTODATE;
261 atomic_set(&bio->bi_cnt, 1);
263 EXPORT_SYMBOL(bio_init);
266 * bio_reset - reinitialize a bio
270 * After calling bio_reset(), @bio will be in the same state as a freshly
271 * allocated bio returned bio bio_alloc_bioset() - the only fields that are
272 * preserved are the ones that are initialized by bio_alloc_bioset(). See
273 * comment in struct bio.
275 void bio_reset(struct bio *bio)
277 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
279 if (bio_integrity(bio))
280 bio_integrity_free(bio);
282 bio_disassociate_task(bio);
284 memset(bio, 0, BIO_RESET_BYTES);
285 bio->bi_flags = flags|(1 << BIO_UPTODATE);
287 EXPORT_SYMBOL(bio_reset);
290 * bio_alloc_bioset - allocate a bio for I/O
291 * @gfp_mask: the GFP_ mask given to the slab allocator
292 * @nr_iovecs: number of iovecs to pre-allocate
293 * @bs: the bio_set to allocate from.
296 * bio_alloc_bioset will try its own mempool to satisfy the allocation.
297 * If %__GFP_WAIT is set then we will block on the internal pool waiting
298 * for a &struct bio to become free.
300 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
302 unsigned long idx = BIO_POOL_NONE;
303 struct bio_vec *bvl = NULL;
307 p = mempool_alloc(bs->bio_pool, gfp_mask);
310 bio = p + bs->front_pad;
315 if (unlikely(!nr_iovecs))
318 if (nr_iovecs <= BIO_INLINE_VECS) {
319 bvl = bio->bi_inline_vecs;
320 nr_iovecs = BIO_INLINE_VECS;
322 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
326 nr_iovecs = bvec_nr_vecs(idx);
329 bio->bi_flags |= idx << BIO_POOL_OFFSET;
330 bio->bi_max_vecs = nr_iovecs;
331 bio->bi_io_vec = bvl;
335 mempool_free(p, bs->bio_pool);
338 EXPORT_SYMBOL(bio_alloc_bioset);
341 * bio_alloc - allocate a new bio, memory pool backed
342 * @gfp_mask: allocation mask to use
343 * @nr_iovecs: number of iovecs
345 * bio_alloc will allocate a bio and associated bio_vec array that can hold
346 * at least @nr_iovecs entries. Allocations will be done from the
347 * fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc.
349 * If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
350 * a bio. This is due to the mempool guarantees. To make this work, callers
351 * must never allocate more than 1 bio at a time from this pool. Callers
352 * that need to allocate more than 1 bio must always submit the previously
353 * allocated bio for IO before attempting to allocate a new one. Failure to
354 * do so can cause livelocks under memory pressure.
357 * Pointer to new bio on success, NULL on failure.
359 struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
361 return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
363 EXPORT_SYMBOL(bio_alloc);
365 static void bio_kmalloc_destructor(struct bio *bio)
367 if (bio_integrity(bio))
368 bio_integrity_free(bio);
373 * bio_kmalloc - allocate a bio for I/O using kmalloc()
374 * @gfp_mask: the GFP_ mask given to the slab allocator
375 * @nr_iovecs: number of iovecs to pre-allocate
378 * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask contains
379 * %__GFP_WAIT, the allocation is guaranteed to succeed.
382 struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
386 if (nr_iovecs > UIO_MAXIOV)
389 bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec),
395 bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
396 bio->bi_max_vecs = nr_iovecs;
397 bio->bi_io_vec = bio->bi_inline_vecs;
398 bio->bi_destructor = bio_kmalloc_destructor;
402 EXPORT_SYMBOL(bio_kmalloc);
404 void zero_fill_bio(struct bio *bio)
410 bio_for_each_segment(bv, bio, i) {
411 char *data = bvec_kmap_irq(bv, &flags);
412 memset(data, 0, bv->bv_len);
413 flush_dcache_page(bv->bv_page);
414 bvec_kunmap_irq(data, &flags);
417 EXPORT_SYMBOL(zero_fill_bio);
420 * bio_put - release a reference to a bio
421 * @bio: bio to release reference to
424 * Put a reference to a &struct bio, either one you have gotten with
425 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
427 void bio_put(struct bio *bio)
429 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
434 if (atomic_dec_and_test(&bio->bi_cnt)) {
435 bio_disassociate_task(bio);
439 * This if statement is temporary - bi_pool is replacing
440 * bi_destructor, but bi_destructor will be taken out in another
444 bio_free(bio, bio->bi_pool);
446 bio->bi_destructor(bio);
449 EXPORT_SYMBOL(bio_put);
451 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
453 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
454 blk_recount_segments(q, bio);
456 return bio->bi_phys_segments;
458 EXPORT_SYMBOL(bio_phys_segments);
461 * __bio_clone - clone a bio
462 * @bio: destination bio
463 * @bio_src: bio to clone
465 * Clone a &bio. Caller will own the returned bio, but not
466 * the actual data it points to. Reference count of returned
469 void __bio_clone(struct bio *bio, struct bio *bio_src)
471 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
472 bio_src->bi_max_vecs * sizeof(struct bio_vec));
475 * most users will be overriding ->bi_bdev with a new target,
476 * so we don't set nor calculate new physical/hw segment counts here
478 bio->bi_sector = bio_src->bi_sector;
479 bio->bi_bdev = bio_src->bi_bdev;
480 bio->bi_flags |= 1 << BIO_CLONED;
481 bio->bi_rw = bio_src->bi_rw;
482 bio->bi_vcnt = bio_src->bi_vcnt;
483 bio->bi_size = bio_src->bi_size;
484 bio->bi_idx = bio_src->bi_idx;
486 EXPORT_SYMBOL(__bio_clone);
489 * bio_clone - clone a bio
491 * @gfp_mask: allocation priority
493 * Like __bio_clone, only also allocates the returned bio
495 struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
497 struct bio *b = bio_alloc(gfp_mask, bio->bi_max_vecs);
504 if (bio_integrity(bio)) {
507 ret = bio_integrity_clone(b, bio, gfp_mask);
517 EXPORT_SYMBOL(bio_clone);
520 * bio_get_nr_vecs - return approx number of vecs
523 * Return the approximate number of pages we can send to this target.
524 * There's no guarantee that you will be able to fit this number of pages
525 * into a bio, it does not account for dynamic restrictions that vary
528 int bio_get_nr_vecs(struct block_device *bdev)
530 struct request_queue *q = bdev_get_queue(bdev);
533 nr_pages = min_t(unsigned,
534 queue_max_segments(q),
535 queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1);
537 return min_t(unsigned, nr_pages, BIO_MAX_PAGES);
540 EXPORT_SYMBOL(bio_get_nr_vecs);
542 static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
543 *page, unsigned int len, unsigned int offset,
544 unsigned short max_sectors)
546 int retried_segments = 0;
547 struct bio_vec *bvec;
550 * cloned bio must not modify vec list
552 if (unlikely(bio_flagged(bio, BIO_CLONED)))
555 if (((bio->bi_size + len) >> 9) > max_sectors)
559 * For filesystems with a blocksize smaller than the pagesize
560 * we will often be called with the same page as last time and
561 * a consecutive offset. Optimize this special case.
563 if (bio->bi_vcnt > 0) {
564 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
566 if (page == prev->bv_page &&
567 offset == prev->bv_offset + prev->bv_len) {
568 unsigned int prev_bv_len = prev->bv_len;
571 if (q->merge_bvec_fn) {
572 struct bvec_merge_data bvm = {
573 /* prev_bvec is already charged in
574 bi_size, discharge it in order to
575 simulate merging updated prev_bvec
577 .bi_bdev = bio->bi_bdev,
578 .bi_sector = bio->bi_sector,
579 .bi_size = bio->bi_size - prev_bv_len,
583 if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
593 if (bio->bi_vcnt >= bio->bi_max_vecs)
597 * we might lose a segment or two here, but rather that than
598 * make this too complex.
601 while (bio->bi_phys_segments >= queue_max_segments(q)) {
603 if (retried_segments)
606 retried_segments = 1;
607 blk_recount_segments(q, bio);
611 * setup the new entry, we might clear it again later if we
612 * cannot add the page
614 bvec = &bio->bi_io_vec[bio->bi_vcnt];
615 bvec->bv_page = page;
617 bvec->bv_offset = offset;
620 * if queue has other restrictions (eg varying max sector size
621 * depending on offset), it can specify a merge_bvec_fn in the
622 * queue to get further control
624 if (q->merge_bvec_fn) {
625 struct bvec_merge_data bvm = {
626 .bi_bdev = bio->bi_bdev,
627 .bi_sector = bio->bi_sector,
628 .bi_size = bio->bi_size,
633 * merge_bvec_fn() returns number of bytes it can accept
636 if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
637 bvec->bv_page = NULL;
644 /* If we may be able to merge these biovecs, force a recount */
645 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
646 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
649 bio->bi_phys_segments++;
656 * bio_add_pc_page - attempt to add page to bio
657 * @q: the target queue
658 * @bio: destination bio
660 * @len: vec entry length
661 * @offset: vec entry offset
663 * Attempt to add a page to the bio_vec maplist. This can fail for a
664 * number of reasons, such as the bio being full or target block device
665 * limitations. The target block device must allow bio's up to PAGE_SIZE,
666 * so it is always possible to add a single page to an empty bio.
668 * This should only be used by REQ_PC bios.
670 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
671 unsigned int len, unsigned int offset)
673 return __bio_add_page(q, bio, page, len, offset,
674 queue_max_hw_sectors(q));
676 EXPORT_SYMBOL(bio_add_pc_page);
679 * bio_add_page - attempt to add page to bio
680 * @bio: destination bio
682 * @len: vec entry length
683 * @offset: vec entry offset
685 * Attempt to add a page to the bio_vec maplist. This can fail for a
686 * number of reasons, such as the bio being full or target block device
687 * limitations. The target block device must allow bio's up to PAGE_SIZE,
688 * so it is always possible to add a single page to an empty bio.
690 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
693 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
694 return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
696 EXPORT_SYMBOL(bio_add_page);
698 struct bio_map_data {
699 struct bio_vec *iovecs;
700 struct sg_iovec *sgvecs;
705 static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
706 struct sg_iovec *iov, int iov_count,
709 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
710 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
711 bmd->nr_sgvecs = iov_count;
712 bmd->is_our_pages = is_our_pages;
713 bio->bi_private = bmd;
716 static void bio_free_map_data(struct bio_map_data *bmd)
723 static struct bio_map_data *bio_alloc_map_data(int nr_segs,
724 unsigned int iov_count,
727 struct bio_map_data *bmd;
729 if (iov_count > UIO_MAXIOV)
732 bmd = kmalloc(sizeof(*bmd), gfp_mask);
736 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
742 bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
751 static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
752 struct sg_iovec *iov, int iov_count,
753 int to_user, int from_user, int do_free_page)
756 struct bio_vec *bvec;
758 unsigned int iov_off = 0;
760 __bio_for_each_segment(bvec, bio, i, 0) {
761 char *bv_addr = page_address(bvec->bv_page);
762 unsigned int bv_len = iovecs[i].bv_len;
764 while (bv_len && iov_idx < iov_count) {
766 char __user *iov_addr;
768 bytes = min_t(unsigned int,
769 iov[iov_idx].iov_len - iov_off, bv_len);
770 iov_addr = iov[iov_idx].iov_base + iov_off;
774 ret = copy_to_user(iov_addr, bv_addr,
778 ret = copy_from_user(bv_addr, iov_addr,
790 if (iov[iov_idx].iov_len == iov_off) {
797 __free_page(bvec->bv_page);
804 * bio_uncopy_user - finish previously mapped bio
805 * @bio: bio being terminated
807 * Free pages allocated from bio_copy_user() and write back data
808 * to user space in case of a read.
810 int bio_uncopy_user(struct bio *bio)
812 struct bio_map_data *bmd = bio->bi_private;
815 if (!bio_flagged(bio, BIO_NULL_MAPPED))
816 ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
817 bmd->nr_sgvecs, bio_data_dir(bio) == READ,
818 0, bmd->is_our_pages);
819 bio_free_map_data(bmd);
823 EXPORT_SYMBOL(bio_uncopy_user);
826 * bio_copy_user_iov - copy user data to bio
827 * @q: destination block queue
828 * @map_data: pointer to the rq_map_data holding pages (if necessary)
830 * @iov_count: number of elements in the iovec
831 * @write_to_vm: bool indicating writing to pages or not
832 * @gfp_mask: memory allocation flags
834 * Prepares and returns a bio for indirect user io, bouncing data
835 * to/from kernel pages as necessary. Must be paired with
836 * call bio_uncopy_user() on io completion.
838 struct bio *bio_copy_user_iov(struct request_queue *q,
839 struct rq_map_data *map_data,
840 struct sg_iovec *iov, int iov_count,
841 int write_to_vm, gfp_t gfp_mask)
843 struct bio_map_data *bmd;
844 struct bio_vec *bvec;
849 unsigned int len = 0;
850 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
852 for (i = 0; i < iov_count; i++) {
857 uaddr = (unsigned long)iov[i].iov_base;
858 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
859 start = uaddr >> PAGE_SHIFT;
865 return ERR_PTR(-EINVAL);
867 nr_pages += end - start;
868 len += iov[i].iov_len;
874 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
876 return ERR_PTR(-ENOMEM);
879 bio = bio_kmalloc(gfp_mask, nr_pages);
884 bio->bi_rw |= REQ_WRITE;
889 nr_pages = 1 << map_data->page_order;
890 i = map_data->offset / PAGE_SIZE;
893 unsigned int bytes = PAGE_SIZE;
901 if (i == map_data->nr_entries * nr_pages) {
906 page = map_data->pages[i / nr_pages];
907 page += (i % nr_pages);
911 page = alloc_page(q->bounce_gfp | gfp_mask);
918 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
931 if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
932 (map_data && map_data->from_user)) {
933 ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
938 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
942 bio_for_each_segment(bvec, bio, i)
943 __free_page(bvec->bv_page);
947 bio_free_map_data(bmd);
952 * bio_copy_user - copy user data to bio
953 * @q: destination block queue
954 * @map_data: pointer to the rq_map_data holding pages (if necessary)
955 * @uaddr: start of user address
956 * @len: length in bytes
957 * @write_to_vm: bool indicating writing to pages or not
958 * @gfp_mask: memory allocation flags
960 * Prepares and returns a bio for indirect user io, bouncing data
961 * to/from kernel pages as necessary. Must be paired with
962 * call bio_uncopy_user() on io completion.
964 struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
965 unsigned long uaddr, unsigned int len,
966 int write_to_vm, gfp_t gfp_mask)
970 iov.iov_base = (void __user *)uaddr;
973 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
975 EXPORT_SYMBOL(bio_copy_user);
977 static struct bio *__bio_map_user_iov(struct request_queue *q,
978 struct block_device *bdev,
979 struct sg_iovec *iov, int iov_count,
980 int write_to_vm, gfp_t gfp_mask)
989 for (i = 0; i < iov_count; i++) {
990 unsigned long uaddr = (unsigned long)iov[i].iov_base;
991 unsigned long len = iov[i].iov_len;
992 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
993 unsigned long start = uaddr >> PAGE_SHIFT;
999 return ERR_PTR(-EINVAL);
1001 nr_pages += end - start;
1003 * buffer must be aligned to at least hardsector size for now
1005 if (uaddr & queue_dma_alignment(q))
1006 return ERR_PTR(-EINVAL);
1010 return ERR_PTR(-EINVAL);
1012 bio = bio_kmalloc(gfp_mask, nr_pages);
1014 return ERR_PTR(-ENOMEM);
1017 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
1021 for (i = 0; i < iov_count; i++) {
1022 unsigned long uaddr = (unsigned long)iov[i].iov_base;
1023 unsigned long len = iov[i].iov_len;
1024 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1025 unsigned long start = uaddr >> PAGE_SHIFT;
1026 const int local_nr_pages = end - start;
1027 const int page_limit = cur_page + local_nr_pages;
1029 ret = get_user_pages_fast(uaddr, local_nr_pages,
1030 write_to_vm, &pages[cur_page]);
1031 if (ret < local_nr_pages) {
1036 offset = uaddr & ~PAGE_MASK;
1037 for (j = cur_page; j < page_limit; j++) {
1038 unsigned int bytes = PAGE_SIZE - offset;
1049 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1059 * release the pages we didn't map into the bio, if any
1061 while (j < page_limit)
1062 page_cache_release(pages[j++]);
1068 * set data direction, and check if mapped pages need bouncing
1071 bio->bi_rw |= REQ_WRITE;
1073 bio->bi_bdev = bdev;
1074 bio->bi_flags |= (1 << BIO_USER_MAPPED);
1078 for (i = 0; i < nr_pages; i++) {
1081 page_cache_release(pages[i]);
1086 return ERR_PTR(ret);
1090 * bio_map_user - map user address into bio
1091 * @q: the struct request_queue for the bio
1092 * @bdev: destination block device
1093 * @uaddr: start of user address
1094 * @len: length in bytes
1095 * @write_to_vm: bool indicating writing to pages or not
1096 * @gfp_mask: memory allocation flags
1098 * Map the user space address into a bio suitable for io to a block
1099 * device. Returns an error pointer in case of error.
1101 struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1102 unsigned long uaddr, unsigned int len, int write_to_vm,
1105 struct sg_iovec iov;
1107 iov.iov_base = (void __user *)uaddr;
1110 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1112 EXPORT_SYMBOL(bio_map_user);
1115 * bio_map_user_iov - map user sg_iovec table into bio
1116 * @q: the struct request_queue for the bio
1117 * @bdev: destination block device
1119 * @iov_count: number of elements in the iovec
1120 * @write_to_vm: bool indicating writing to pages or not
1121 * @gfp_mask: memory allocation flags
1123 * Map the user space address into a bio suitable for io to a block
1124 * device. Returns an error pointer in case of error.
1126 struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1127 struct sg_iovec *iov, int iov_count,
1128 int write_to_vm, gfp_t gfp_mask)
1132 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
1138 * subtle -- if __bio_map_user() ended up bouncing a bio,
1139 * it would normally disappear when its bi_end_io is run.
1140 * however, we need it for the unmap, so grab an extra
1148 static void __bio_unmap_user(struct bio *bio)
1150 struct bio_vec *bvec;
1154 * make sure we dirty pages we wrote to
1156 __bio_for_each_segment(bvec, bio, i, 0) {
1157 if (bio_data_dir(bio) == READ)
1158 set_page_dirty_lock(bvec->bv_page);
1160 page_cache_release(bvec->bv_page);
1167 * bio_unmap_user - unmap a bio
1168 * @bio: the bio being unmapped
1170 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1171 * a process context.
1173 * bio_unmap_user() may sleep.
1175 void bio_unmap_user(struct bio *bio)
1177 __bio_unmap_user(bio);
1180 EXPORT_SYMBOL(bio_unmap_user);
1182 static void bio_map_kern_endio(struct bio *bio, int err)
1187 static struct bio *__bio_map_kern(struct request_queue *q, void *data,
1188 unsigned int len, gfp_t gfp_mask)
1190 unsigned long kaddr = (unsigned long)data;
1191 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1192 unsigned long start = kaddr >> PAGE_SHIFT;
1193 const int nr_pages = end - start;
1197 bio = bio_kmalloc(gfp_mask, nr_pages);
1199 return ERR_PTR(-ENOMEM);
1201 offset = offset_in_page(kaddr);
1202 for (i = 0; i < nr_pages; i++) {
1203 unsigned int bytes = PAGE_SIZE - offset;
1211 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1220 bio->bi_end_io = bio_map_kern_endio;
1225 * bio_map_kern - map kernel address into bio
1226 * @q: the struct request_queue for the bio
1227 * @data: pointer to buffer to map
1228 * @len: length in bytes
1229 * @gfp_mask: allocation flags for bio allocation
1231 * Map the kernel address into a bio suitable for io to a block
1232 * device. Returns an error pointer in case of error.
1234 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1239 bio = __bio_map_kern(q, data, len, gfp_mask);
1243 if (bio->bi_size == len)
1247 * Don't support partial mappings.
1250 return ERR_PTR(-EINVAL);
1252 EXPORT_SYMBOL(bio_map_kern);
1254 static void bio_copy_kern_endio(struct bio *bio, int err)
1256 struct bio_vec *bvec;
1257 const int read = bio_data_dir(bio) == READ;
1258 struct bio_map_data *bmd = bio->bi_private;
1260 char *p = bmd->sgvecs[0].iov_base;
1262 __bio_for_each_segment(bvec, bio, i, 0) {
1263 char *addr = page_address(bvec->bv_page);
1264 int len = bmd->iovecs[i].bv_len;
1267 memcpy(p, addr, len);
1269 __free_page(bvec->bv_page);
1273 bio_free_map_data(bmd);
1278 * bio_copy_kern - copy kernel address into bio
1279 * @q: the struct request_queue for the bio
1280 * @data: pointer to buffer to copy
1281 * @len: length in bytes
1282 * @gfp_mask: allocation flags for bio and page allocation
1283 * @reading: data direction is READ
1285 * copy the kernel address into a bio suitable for io to a block
1286 * device. Returns an error pointer in case of error.
1288 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1289 gfp_t gfp_mask, int reading)
1292 struct bio_vec *bvec;
1295 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
1302 bio_for_each_segment(bvec, bio, i) {
1303 char *addr = page_address(bvec->bv_page);
1305 memcpy(addr, p, bvec->bv_len);
1310 bio->bi_end_io = bio_copy_kern_endio;
1314 EXPORT_SYMBOL(bio_copy_kern);
1317 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1318 * for performing direct-IO in BIOs.
1320 * The problem is that we cannot run set_page_dirty() from interrupt context
1321 * because the required locks are not interrupt-safe. So what we can do is to
1322 * mark the pages dirty _before_ performing IO. And in interrupt context,
1323 * check that the pages are still dirty. If so, fine. If not, redirty them
1324 * in process context.
1326 * We special-case compound pages here: normally this means reads into hugetlb
1327 * pages. The logic in here doesn't really work right for compound pages
1328 * because the VM does not uniformly chase down the head page in all cases.
1329 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1330 * handle them at all. So we skip compound pages here at an early stage.
1332 * Note that this code is very hard to test under normal circumstances because
1333 * direct-io pins the pages with get_user_pages(). This makes
1334 * is_page_cache_freeable return false, and the VM will not clean the pages.
1335 * But other code (eg, flusher threads) could clean the pages if they are mapped
1338 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1339 * deferred bio dirtying paths.
1343 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1345 void bio_set_pages_dirty(struct bio *bio)
1347 struct bio_vec *bvec = bio->bi_io_vec;
1350 for (i = 0; i < bio->bi_vcnt; i++) {
1351 struct page *page = bvec[i].bv_page;
1353 if (page && !PageCompound(page))
1354 set_page_dirty_lock(page);
1358 static void bio_release_pages(struct bio *bio)
1360 struct bio_vec *bvec = bio->bi_io_vec;
1363 for (i = 0; i < bio->bi_vcnt; i++) {
1364 struct page *page = bvec[i].bv_page;
1372 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1373 * If they are, then fine. If, however, some pages are clean then they must
1374 * have been written out during the direct-IO read. So we take another ref on
1375 * the BIO and the offending pages and re-dirty the pages in process context.
1377 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1378 * here on. It will run one page_cache_release() against each page and will
1379 * run one bio_put() against the BIO.
1382 static void bio_dirty_fn(struct work_struct *work);
1384 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1385 static DEFINE_SPINLOCK(bio_dirty_lock);
1386 static struct bio *bio_dirty_list;
1389 * This runs in process context
1391 static void bio_dirty_fn(struct work_struct *work)
1393 unsigned long flags;
1396 spin_lock_irqsave(&bio_dirty_lock, flags);
1397 bio = bio_dirty_list;
1398 bio_dirty_list = NULL;
1399 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1402 struct bio *next = bio->bi_private;
1404 bio_set_pages_dirty(bio);
1405 bio_release_pages(bio);
1411 void bio_check_pages_dirty(struct bio *bio)
1413 struct bio_vec *bvec = bio->bi_io_vec;
1414 int nr_clean_pages = 0;
1417 for (i = 0; i < bio->bi_vcnt; i++) {
1418 struct page *page = bvec[i].bv_page;
1420 if (PageDirty(page) || PageCompound(page)) {
1421 page_cache_release(page);
1422 bvec[i].bv_page = NULL;
1428 if (nr_clean_pages) {
1429 unsigned long flags;
1431 spin_lock_irqsave(&bio_dirty_lock, flags);
1432 bio->bi_private = bio_dirty_list;
1433 bio_dirty_list = bio;
1434 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1435 schedule_work(&bio_dirty_work);
1441 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1442 void bio_flush_dcache_pages(struct bio *bi)
1445 struct bio_vec *bvec;
1447 bio_for_each_segment(bvec, bi, i)
1448 flush_dcache_page(bvec->bv_page);
1450 EXPORT_SYMBOL(bio_flush_dcache_pages);
1454 * bio_endio - end I/O on a bio
1456 * @error: error, if any
1459 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1460 * preferred way to end I/O on a bio, it takes care of clearing
1461 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1462 * established -Exxxx (-EIO, for instance) error values in case
1463 * something went wrong. No one should call bi_end_io() directly on a
1464 * bio unless they own it and thus know that it has an end_io
1467 void bio_endio(struct bio *bio, int error)
1470 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1471 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1475 bio->bi_end_io(bio, error);
1477 EXPORT_SYMBOL(bio_endio);
1479 void bio_pair_release(struct bio_pair *bp)
1481 if (atomic_dec_and_test(&bp->cnt)) {
1482 struct bio *master = bp->bio1.bi_private;
1484 bio_endio(master, bp->error);
1485 mempool_free(bp, bp->bio2.bi_private);
1488 EXPORT_SYMBOL(bio_pair_release);
1490 static void bio_pair_end_1(struct bio *bi, int err)
1492 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1497 bio_pair_release(bp);
1500 static void bio_pair_end_2(struct bio *bi, int err)
1502 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1507 bio_pair_release(bp);
1511 * split a bio - only worry about a bio with a single page in its iovec
1513 struct bio_pair *bio_split(struct bio *bi, int first_sectors)
1515 struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
1520 trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1521 bi->bi_sector + first_sectors);
1523 BUG_ON(bi->bi_vcnt != 1);
1524 BUG_ON(bi->bi_idx != 0);
1525 atomic_set(&bp->cnt, 3);
1529 bp->bio2.bi_sector += first_sectors;
1530 bp->bio2.bi_size -= first_sectors << 9;
1531 bp->bio1.bi_size = first_sectors << 9;
1533 bp->bv1 = bi->bi_io_vec[0];
1534 bp->bv2 = bi->bi_io_vec[0];
1535 bp->bv2.bv_offset += first_sectors << 9;
1536 bp->bv2.bv_len -= first_sectors << 9;
1537 bp->bv1.bv_len = first_sectors << 9;
1539 bp->bio1.bi_io_vec = &bp->bv1;
1540 bp->bio2.bi_io_vec = &bp->bv2;
1542 bp->bio1.bi_max_vecs = 1;
1543 bp->bio2.bi_max_vecs = 1;
1545 bp->bio1.bi_end_io = bio_pair_end_1;
1546 bp->bio2.bi_end_io = bio_pair_end_2;
1548 bp->bio1.bi_private = bi;
1549 bp->bio2.bi_private = bio_split_pool;
1551 if (bio_integrity(bi))
1552 bio_integrity_split(bi, bp, first_sectors);
1556 EXPORT_SYMBOL(bio_split);
1559 * bio_sector_offset - Find hardware sector offset in bio
1560 * @bio: bio to inspect
1561 * @index: bio_vec index
1562 * @offset: offset in bv_page
1564 * Return the number of hardware sectors between beginning of bio
1565 * and an end point indicated by a bio_vec index and an offset
1566 * within that vector's page.
1568 sector_t bio_sector_offset(struct bio *bio, unsigned short index,
1569 unsigned int offset)
1571 unsigned int sector_sz;
1576 sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1579 if (index >= bio->bi_idx)
1580 index = bio->bi_vcnt - 1;
1582 __bio_for_each_segment(bv, bio, i, 0) {
1584 if (offset > bv->bv_offset)
1585 sectors += (offset - bv->bv_offset) / sector_sz;
1589 sectors += bv->bv_len / sector_sz;
1594 EXPORT_SYMBOL(bio_sector_offset);
1597 * create memory pools for biovec's in a bio_set.
1598 * use the global biovec slabs created for general use.
1600 static int biovec_create_pools(struct bio_set *bs, int pool_entries)
1602 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
1604 bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
1611 static void biovec_free_pools(struct bio_set *bs)
1613 mempool_destroy(bs->bvec_pool);
1616 void bioset_free(struct bio_set *bs)
1619 mempool_destroy(bs->bio_pool);
1621 bioset_integrity_free(bs);
1622 biovec_free_pools(bs);
1627 EXPORT_SYMBOL(bioset_free);
1630 * bioset_create - Create a bio_set
1631 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1632 * @front_pad: Number of bytes to allocate in front of the returned bio
1635 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1636 * to ask for a number of bytes to be allocated in front of the bio.
1637 * Front pad allocation is useful for embedding the bio inside
1638 * another structure, to avoid allocating extra data to go with the bio.
1639 * Note that the bio must be embedded at the END of that structure always,
1640 * or things will break badly.
1642 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1644 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1647 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1651 bs->front_pad = front_pad;
1653 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1654 if (!bs->bio_slab) {
1659 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1663 if (!biovec_create_pools(bs, pool_size))
1670 EXPORT_SYMBOL(bioset_create);
1672 #ifdef CONFIG_BLK_CGROUP
1674 * bio_associate_current - associate a bio with %current
1677 * Associate @bio with %current if it hasn't been associated yet. Block
1678 * layer will treat @bio as if it were issued by %current no matter which
1679 * task actually issues it.
1681 * This function takes an extra reference of @task's io_context and blkcg
1682 * which will be put when @bio is released. The caller must own @bio,
1683 * ensure %current->io_context exists, and is responsible for synchronizing
1684 * calls to this function.
1686 int bio_associate_current(struct bio *bio)
1688 struct io_context *ioc;
1689 struct cgroup_subsys_state *css;
1694 ioc = current->io_context;
1698 /* acquire active ref on @ioc and associate */
1699 get_io_context_active(ioc);
1702 /* associate blkcg if exists */
1704 css = task_subsys_state(current, blkio_subsys_id);
1705 if (css && css_tryget(css))
1713 * bio_disassociate_task - undo bio_associate_current()
1716 void bio_disassociate_task(struct bio *bio)
1719 put_io_context(bio->bi_ioc);
1723 css_put(bio->bi_css);
1728 #endif /* CONFIG_BLK_CGROUP */
1730 static void __init biovec_init_slabs(void)
1734 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1736 struct biovec_slab *bvs = bvec_slabs + i;
1738 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
1743 size = bvs->nr_vecs * sizeof(struct bio_vec);
1744 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1745 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1749 static int __init init_bio(void)
1753 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
1755 panic("bio: can't allocate bios\n");
1757 bio_integrity_init();
1758 biovec_init_slabs();
1760 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
1762 panic("bio: can't allocate bios\n");
1764 if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
1765 panic("bio: can't create integrity pool\n");
1767 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
1768 sizeof(struct bio_pair));
1769 if (!bio_split_pool)
1770 panic("bio: can't create split pool\n");
1774 subsys_initcall(init_bio);