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 <scsi/sg.h> /* for struct sg_iovec */
30 #include <trace/events/block.h>
33 * Test patch to inline a certain number of bi_io_vec's inside the bio
34 * itself, to shrink a bio data allocation from two mempool calls to one
36 #define BIO_INLINE_VECS 4
38 static mempool_t *bio_split_pool __read_mostly;
41 * if you change this list, also change bvec_alloc or things will
42 * break badly! cannot be bigger than what you can fit into an
45 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
46 struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
47 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
52 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
53 * IO code that does not need private memory pools.
55 struct bio_set *fs_bio_set;
58 * Our slab pool management
61 struct kmem_cache *slab;
62 unsigned int slab_ref;
63 unsigned int slab_size;
66 static DEFINE_MUTEX(bio_slab_lock);
67 static struct bio_slab *bio_slabs;
68 static unsigned int bio_slab_nr, bio_slab_max;
70 static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
72 unsigned int sz = sizeof(struct bio) + extra_size;
73 struct kmem_cache *slab = NULL;
74 struct bio_slab *bslab;
75 unsigned int i, entry = -1;
77 mutex_lock(&bio_slab_lock);
80 while (i < bio_slab_nr) {
81 bslab = &bio_slabs[i];
83 if (!bslab->slab && entry == -1)
85 else if (bslab->slab_size == sz) {
96 if (bio_slab_nr == bio_slab_max && entry == -1) {
98 bio_slabs = krealloc(bio_slabs,
99 bio_slab_max * sizeof(struct bio_slab),
105 entry = bio_slab_nr++;
107 bslab = &bio_slabs[entry];
109 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry);
110 slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL);
114 printk("bio: create slab <%s> at %d\n", bslab->name, entry);
117 bslab->slab_size = sz;
119 mutex_unlock(&bio_slab_lock);
123 static void bio_put_slab(struct bio_set *bs)
125 struct bio_slab *bslab = NULL;
128 mutex_lock(&bio_slab_lock);
130 for (i = 0; i < bio_slab_nr; i++) {
131 if (bs->bio_slab == bio_slabs[i].slab) {
132 bslab = &bio_slabs[i];
137 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))
140 WARN_ON(!bslab->slab_ref);
142 if (--bslab->slab_ref)
145 kmem_cache_destroy(bslab->slab);
149 mutex_unlock(&bio_slab_lock);
152 unsigned int bvec_nr_vecs(unsigned short idx)
154 return bvec_slabs[idx].nr_vecs;
157 void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
159 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
161 if (idx == BIOVEC_MAX_IDX)
162 mempool_free(bv, bs->bvec_pool);
164 struct biovec_slab *bvs = bvec_slabs + idx;
166 kmem_cache_free(bvs->slab, bv);
170 struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
176 * see comment near bvec_array define!
194 case 129 ... BIO_MAX_PAGES:
202 * idx now points to the pool we want to allocate from. only the
203 * 1-vec entry pool is mempool backed.
205 if (*idx == BIOVEC_MAX_IDX) {
207 bvl = mempool_alloc(bs->bvec_pool, gfp_mask);
209 struct biovec_slab *bvs = bvec_slabs + *idx;
210 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
213 * Make this allocation restricted and don't dump info on
214 * allocation failures, since we'll fallback to the mempool
215 * in case of failure.
217 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;
220 * Try a slab allocation. If this fails and __GFP_WAIT
221 * is set, retry with the 1-entry mempool
223 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask);
224 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) {
225 *idx = BIOVEC_MAX_IDX;
233 void bio_free(struct bio *bio, struct bio_set *bs)
237 if (bio_has_allocated_vec(bio))
238 bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
240 if (bio_integrity(bio))
241 bio_integrity_free(bio, bs);
244 * If we have front padding, adjust the bio pointer before freeing
250 mempool_free(p, bs->bio_pool);
252 EXPORT_SYMBOL(bio_free);
254 void bio_init(struct bio *bio)
256 memset(bio, 0, sizeof(*bio));
257 bio->bi_flags = 1 << BIO_UPTODATE;
258 bio->bi_comp_cpu = -1;
259 atomic_set(&bio->bi_cnt, 1);
261 EXPORT_SYMBOL(bio_init);
264 * bio_alloc_bioset - allocate a bio for I/O
265 * @gfp_mask: the GFP_ mask given to the slab allocator
266 * @nr_iovecs: number of iovecs to pre-allocate
267 * @bs: the bio_set to allocate from.
270 * bio_alloc_bioset will try its own mempool to satisfy the allocation.
271 * If %__GFP_WAIT is set then we will block on the internal pool waiting
272 * for a &struct bio to become free.
274 * Note that the caller must set ->bi_destructor on successful return
275 * of a bio, to do the appropriate freeing of the bio once the reference
276 * count drops to zero.
278 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
280 unsigned long idx = BIO_POOL_NONE;
281 struct bio_vec *bvl = NULL;
285 p = mempool_alloc(bs->bio_pool, gfp_mask);
288 bio = p + bs->front_pad;
292 if (unlikely(!nr_iovecs))
295 if (nr_iovecs <= BIO_INLINE_VECS) {
296 bvl = bio->bi_inline_vecs;
297 nr_iovecs = BIO_INLINE_VECS;
299 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
303 nr_iovecs = bvec_nr_vecs(idx);
306 bio->bi_flags |= idx << BIO_POOL_OFFSET;
307 bio->bi_max_vecs = nr_iovecs;
308 bio->bi_io_vec = bvl;
312 mempool_free(p, bs->bio_pool);
315 EXPORT_SYMBOL(bio_alloc_bioset);
317 static void bio_fs_destructor(struct bio *bio)
319 bio_free(bio, fs_bio_set);
323 * bio_alloc - allocate a new bio, memory pool backed
324 * @gfp_mask: allocation mask to use
325 * @nr_iovecs: number of iovecs
327 * bio_alloc will allocate a bio and associated bio_vec array that can hold
328 * at least @nr_iovecs entries. Allocations will be done from the
329 * fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc.
331 * If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
332 * a bio. This is due to the mempool guarantees. To make this work, callers
333 * must never allocate more than 1 bio at a time from this pool. Callers
334 * that need to allocate more than 1 bio must always submit the previously
335 * allocated bio for IO before attempting to allocate a new one. Failure to
336 * do so can cause livelocks under memory pressure.
339 * Pointer to new bio on success, NULL on failure.
341 struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
343 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
346 bio->bi_destructor = bio_fs_destructor;
350 EXPORT_SYMBOL(bio_alloc);
352 static void bio_kmalloc_destructor(struct bio *bio)
354 if (bio_integrity(bio))
355 bio_integrity_free(bio, fs_bio_set);
360 * bio_kmalloc - allocate a bio for I/O using kmalloc()
361 * @gfp_mask: the GFP_ mask given to the slab allocator
362 * @nr_iovecs: number of iovecs to pre-allocate
365 * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask contains
366 * %__GFP_WAIT, the allocation is guaranteed to succeed.
369 struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
373 bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec),
379 bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
380 bio->bi_max_vecs = nr_iovecs;
381 bio->bi_io_vec = bio->bi_inline_vecs;
382 bio->bi_destructor = bio_kmalloc_destructor;
386 EXPORT_SYMBOL(bio_kmalloc);
388 void zero_fill_bio(struct bio *bio)
394 bio_for_each_segment(bv, bio, i) {
395 char *data = bvec_kmap_irq(bv, &flags);
396 memset(data, 0, bv->bv_len);
397 flush_dcache_page(bv->bv_page);
398 bvec_kunmap_irq(data, &flags);
401 EXPORT_SYMBOL(zero_fill_bio);
404 * bio_put - release a reference to a bio
405 * @bio: bio to release reference to
408 * Put a reference to a &struct bio, either one you have gotten with
409 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it.
411 void bio_put(struct bio *bio)
413 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
418 if (atomic_dec_and_test(&bio->bi_cnt)) {
420 bio->bi_destructor(bio);
423 EXPORT_SYMBOL(bio_put);
425 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
427 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
428 blk_recount_segments(q, bio);
430 return bio->bi_phys_segments;
432 EXPORT_SYMBOL(bio_phys_segments);
435 * __bio_clone - clone a bio
436 * @bio: destination bio
437 * @bio_src: bio to clone
439 * Clone a &bio. Caller will own the returned bio, but not
440 * the actual data it points to. Reference count of returned
443 void __bio_clone(struct bio *bio, struct bio *bio_src)
445 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
446 bio_src->bi_max_vecs * sizeof(struct bio_vec));
449 * most users will be overriding ->bi_bdev with a new target,
450 * so we don't set nor calculate new physical/hw segment counts here
452 bio->bi_sector = bio_src->bi_sector;
453 bio->bi_bdev = bio_src->bi_bdev;
454 bio->bi_flags |= 1 << BIO_CLONED;
455 bio->bi_rw = bio_src->bi_rw;
456 bio->bi_vcnt = bio_src->bi_vcnt;
457 bio->bi_size = bio_src->bi_size;
458 bio->bi_idx = bio_src->bi_idx;
460 EXPORT_SYMBOL(__bio_clone);
463 * bio_clone - clone a bio
465 * @gfp_mask: allocation priority
467 * Like __bio_clone, only also allocates the returned bio
469 struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
471 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
476 b->bi_destructor = bio_fs_destructor;
479 if (bio_integrity(bio)) {
482 ret = bio_integrity_clone(b, bio, gfp_mask, fs_bio_set);
492 EXPORT_SYMBOL(bio_clone);
495 * bio_get_nr_vecs - return approx number of vecs
498 * Return the approximate number of pages we can send to this target.
499 * There's no guarantee that you will be able to fit this number of pages
500 * into a bio, it does not account for dynamic restrictions that vary
503 int bio_get_nr_vecs(struct block_device *bdev)
505 struct request_queue *q = bdev_get_queue(bdev);
508 nr_pages = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
509 if (nr_pages > queue_max_phys_segments(q))
510 nr_pages = queue_max_phys_segments(q);
511 if (nr_pages > queue_max_hw_segments(q))
512 nr_pages = queue_max_hw_segments(q);
516 EXPORT_SYMBOL(bio_get_nr_vecs);
518 static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
519 *page, unsigned int len, unsigned int offset,
520 unsigned short max_sectors)
522 int retried_segments = 0;
523 struct bio_vec *bvec;
526 * cloned bio must not modify vec list
528 if (unlikely(bio_flagged(bio, BIO_CLONED)))
531 if (((bio->bi_size + len) >> 9) > max_sectors)
535 * For filesystems with a blocksize smaller than the pagesize
536 * we will often be called with the same page as last time and
537 * a consecutive offset. Optimize this special case.
539 if (bio->bi_vcnt > 0) {
540 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
542 if (page == prev->bv_page &&
543 offset == prev->bv_offset + prev->bv_len) {
544 unsigned int prev_bv_len = prev->bv_len;
547 if (q->merge_bvec_fn) {
548 struct bvec_merge_data bvm = {
549 /* prev_bvec is already charged in
550 bi_size, discharge it in order to
551 simulate merging updated prev_bvec
553 .bi_bdev = bio->bi_bdev,
554 .bi_sector = bio->bi_sector,
555 .bi_size = bio->bi_size - prev_bv_len,
559 if (q->merge_bvec_fn(q, &bvm, prev) < len) {
569 if (bio->bi_vcnt >= bio->bi_max_vecs)
573 * we might lose a segment or two here, but rather that than
574 * make this too complex.
577 while (bio->bi_phys_segments >= queue_max_phys_segments(q)
578 || bio->bi_phys_segments >= queue_max_hw_segments(q)) {
580 if (retried_segments)
583 retried_segments = 1;
584 blk_recount_segments(q, bio);
588 * setup the new entry, we might clear it again later if we
589 * cannot add the page
591 bvec = &bio->bi_io_vec[bio->bi_vcnt];
592 bvec->bv_page = page;
594 bvec->bv_offset = offset;
597 * if queue has other restrictions (eg varying max sector size
598 * depending on offset), it can specify a merge_bvec_fn in the
599 * queue to get further control
601 if (q->merge_bvec_fn) {
602 struct bvec_merge_data bvm = {
603 .bi_bdev = bio->bi_bdev,
604 .bi_sector = bio->bi_sector,
605 .bi_size = bio->bi_size,
610 * merge_bvec_fn() returns number of bytes it can accept
613 if (q->merge_bvec_fn(q, &bvm, bvec) < len) {
614 bvec->bv_page = NULL;
621 /* If we may be able to merge these biovecs, force a recount */
622 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
623 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
626 bio->bi_phys_segments++;
633 * bio_add_pc_page - attempt to add page to bio
634 * @q: the target queue
635 * @bio: destination bio
637 * @len: vec entry length
638 * @offset: vec entry offset
640 * Attempt to add a page to the bio_vec maplist. This can fail for a
641 * number of reasons, such as the bio being full or target block
642 * device limitations. The target block device must allow bio's
643 * smaller than PAGE_SIZE, so it is always possible to add a single
644 * page to an empty bio. This should only be used by REQ_PC bios.
646 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
647 unsigned int len, unsigned int offset)
649 return __bio_add_page(q, bio, page, len, offset,
650 queue_max_hw_sectors(q));
652 EXPORT_SYMBOL(bio_add_pc_page);
655 * bio_add_page - attempt to add page to bio
656 * @bio: destination bio
658 * @len: vec entry length
659 * @offset: vec entry offset
661 * Attempt to add a page to the bio_vec maplist. This can fail for a
662 * number of reasons, such as the bio being full or target block
663 * device limitations. The target block device must allow bio's
664 * smaller than PAGE_SIZE, so it is always possible to add a single
665 * page to an empty bio.
667 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
670 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
671 return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q));
673 EXPORT_SYMBOL(bio_add_page);
675 struct bio_map_data {
676 struct bio_vec *iovecs;
677 struct sg_iovec *sgvecs;
682 static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
683 struct sg_iovec *iov, int iov_count,
686 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
687 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
688 bmd->nr_sgvecs = iov_count;
689 bmd->is_our_pages = is_our_pages;
690 bio->bi_private = bmd;
693 static void bio_free_map_data(struct bio_map_data *bmd)
700 static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count,
703 struct bio_map_data *bmd = kmalloc(sizeof(*bmd), gfp_mask);
708 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
714 bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
723 static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
724 struct sg_iovec *iov, int iov_count,
725 int to_user, int from_user, int do_free_page)
728 struct bio_vec *bvec;
730 unsigned int iov_off = 0;
732 __bio_for_each_segment(bvec, bio, i, 0) {
733 char *bv_addr = page_address(bvec->bv_page);
734 unsigned int bv_len = iovecs[i].bv_len;
736 while (bv_len && iov_idx < iov_count) {
738 char __user *iov_addr;
740 bytes = min_t(unsigned int,
741 iov[iov_idx].iov_len - iov_off, bv_len);
742 iov_addr = iov[iov_idx].iov_base + iov_off;
746 ret = copy_to_user(iov_addr, bv_addr,
750 ret = copy_from_user(bv_addr, iov_addr,
762 if (iov[iov_idx].iov_len == iov_off) {
769 __free_page(bvec->bv_page);
776 * bio_uncopy_user - finish previously mapped bio
777 * @bio: bio being terminated
779 * Free pages allocated from bio_copy_user() and write back data
780 * to user space in case of a read.
782 int bio_uncopy_user(struct bio *bio)
784 struct bio_map_data *bmd = bio->bi_private;
787 if (!bio_flagged(bio, BIO_NULL_MAPPED))
788 ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
789 bmd->nr_sgvecs, bio_data_dir(bio) == READ,
790 0, bmd->is_our_pages);
791 bio_free_map_data(bmd);
795 EXPORT_SYMBOL(bio_uncopy_user);
798 * bio_copy_user_iov - copy user data to bio
799 * @q: destination block queue
800 * @map_data: pointer to the rq_map_data holding pages (if necessary)
802 * @iov_count: number of elements in the iovec
803 * @write_to_vm: bool indicating writing to pages or not
804 * @gfp_mask: memory allocation flags
806 * Prepares and returns a bio for indirect user io, bouncing data
807 * to/from kernel pages as necessary. Must be paired with
808 * call bio_uncopy_user() on io completion.
810 struct bio *bio_copy_user_iov(struct request_queue *q,
811 struct rq_map_data *map_data,
812 struct sg_iovec *iov, int iov_count,
813 int write_to_vm, gfp_t gfp_mask)
815 struct bio_map_data *bmd;
816 struct bio_vec *bvec;
821 unsigned int len = 0;
822 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0;
824 for (i = 0; i < iov_count; i++) {
829 uaddr = (unsigned long)iov[i].iov_base;
830 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
831 start = uaddr >> PAGE_SHIFT;
833 nr_pages += end - start;
834 len += iov[i].iov_len;
840 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
842 return ERR_PTR(-ENOMEM);
845 bio = bio_kmalloc(gfp_mask, nr_pages);
849 bio->bi_rw |= (!write_to_vm << BIO_RW);
854 nr_pages = 1 << map_data->page_order;
855 i = map_data->offset / PAGE_SIZE;
858 unsigned int bytes = PAGE_SIZE;
866 if (i == map_data->nr_entries * nr_pages) {
871 page = map_data->pages[i / nr_pages];
872 page += (i % nr_pages);
876 page = alloc_page(q->bounce_gfp | gfp_mask);
883 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
896 if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
897 (map_data && map_data->from_user)) {
898 ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
903 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1);
907 bio_for_each_segment(bvec, bio, i)
908 __free_page(bvec->bv_page);
912 bio_free_map_data(bmd);
917 * bio_copy_user - copy user data to bio
918 * @q: destination block queue
919 * @map_data: pointer to the rq_map_data holding pages (if necessary)
920 * @uaddr: start of user address
921 * @len: length in bytes
922 * @write_to_vm: bool indicating writing to pages or not
923 * @gfp_mask: memory allocation flags
925 * Prepares and returns a bio for indirect user io, bouncing data
926 * to/from kernel pages as necessary. Must be paired with
927 * call bio_uncopy_user() on io completion.
929 struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
930 unsigned long uaddr, unsigned int len,
931 int write_to_vm, gfp_t gfp_mask)
935 iov.iov_base = (void __user *)uaddr;
938 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
940 EXPORT_SYMBOL(bio_copy_user);
942 static struct bio *__bio_map_user_iov(struct request_queue *q,
943 struct block_device *bdev,
944 struct sg_iovec *iov, int iov_count,
945 int write_to_vm, gfp_t gfp_mask)
954 for (i = 0; i < iov_count; i++) {
955 unsigned long uaddr = (unsigned long)iov[i].iov_base;
956 unsigned long len = iov[i].iov_len;
957 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
958 unsigned long start = uaddr >> PAGE_SHIFT;
960 nr_pages += end - start;
962 * buffer must be aligned to at least hardsector size for now
964 if (uaddr & queue_dma_alignment(q))
965 return ERR_PTR(-EINVAL);
969 return ERR_PTR(-EINVAL);
971 bio = bio_kmalloc(gfp_mask, nr_pages);
973 return ERR_PTR(-ENOMEM);
976 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask);
980 for (i = 0; i < iov_count; i++) {
981 unsigned long uaddr = (unsigned long)iov[i].iov_base;
982 unsigned long len = iov[i].iov_len;
983 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
984 unsigned long start = uaddr >> PAGE_SHIFT;
985 const int local_nr_pages = end - start;
986 const int page_limit = cur_page + local_nr_pages;
988 ret = get_user_pages_fast(uaddr, local_nr_pages,
989 write_to_vm, &pages[cur_page]);
990 if (ret < local_nr_pages) {
995 offset = uaddr & ~PAGE_MASK;
996 for (j = cur_page; j < page_limit; j++) {
997 unsigned int bytes = PAGE_SIZE - offset;
1008 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
1018 * release the pages we didn't map into the bio, if any
1020 while (j < page_limit)
1021 page_cache_release(pages[j++]);
1027 * set data direction, and check if mapped pages need bouncing
1030 bio->bi_rw |= (1 << BIO_RW);
1032 bio->bi_bdev = bdev;
1033 bio->bi_flags |= (1 << BIO_USER_MAPPED);
1037 for (i = 0; i < nr_pages; i++) {
1040 page_cache_release(pages[i]);
1045 return ERR_PTR(ret);
1049 * bio_map_user - map user address into bio
1050 * @q: the struct request_queue for the bio
1051 * @bdev: destination block device
1052 * @uaddr: start of user address
1053 * @len: length in bytes
1054 * @write_to_vm: bool indicating writing to pages or not
1055 * @gfp_mask: memory allocation flags
1057 * Map the user space address into a bio suitable for io to a block
1058 * device. Returns an error pointer in case of error.
1060 struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
1061 unsigned long uaddr, unsigned int len, int write_to_vm,
1064 struct sg_iovec iov;
1066 iov.iov_base = (void __user *)uaddr;
1069 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
1071 EXPORT_SYMBOL(bio_map_user);
1074 * bio_map_user_iov - map user sg_iovec table into bio
1075 * @q: the struct request_queue for the bio
1076 * @bdev: destination block device
1078 * @iov_count: number of elements in the iovec
1079 * @write_to_vm: bool indicating writing to pages or not
1080 * @gfp_mask: memory allocation flags
1082 * Map the user space address into a bio suitable for io to a block
1083 * device. Returns an error pointer in case of error.
1085 struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
1086 struct sg_iovec *iov, int iov_count,
1087 int write_to_vm, gfp_t gfp_mask)
1091 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm,
1097 * subtle -- if __bio_map_user() ended up bouncing a bio,
1098 * it would normally disappear when its bi_end_io is run.
1099 * however, we need it for the unmap, so grab an extra
1107 static void __bio_unmap_user(struct bio *bio)
1109 struct bio_vec *bvec;
1113 * make sure we dirty pages we wrote to
1115 __bio_for_each_segment(bvec, bio, i, 0) {
1116 if (bio_data_dir(bio) == READ)
1117 set_page_dirty_lock(bvec->bv_page);
1119 page_cache_release(bvec->bv_page);
1126 * bio_unmap_user - unmap a bio
1127 * @bio: the bio being unmapped
1129 * Unmap a bio previously mapped by bio_map_user(). Must be called with
1130 * a process context.
1132 * bio_unmap_user() may sleep.
1134 void bio_unmap_user(struct bio *bio)
1136 __bio_unmap_user(bio);
1139 EXPORT_SYMBOL(bio_unmap_user);
1141 static void bio_map_kern_endio(struct bio *bio, int err)
1146 static struct bio *__bio_map_kern(struct request_queue *q, void *data,
1147 unsigned int len, gfp_t gfp_mask)
1149 unsigned long kaddr = (unsigned long)data;
1150 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1151 unsigned long start = kaddr >> PAGE_SHIFT;
1152 const int nr_pages = end - start;
1156 bio = bio_kmalloc(gfp_mask, nr_pages);
1158 return ERR_PTR(-ENOMEM);
1160 offset = offset_in_page(kaddr);
1161 for (i = 0; i < nr_pages; i++) {
1162 unsigned int bytes = PAGE_SIZE - offset;
1170 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
1179 bio->bi_end_io = bio_map_kern_endio;
1184 * bio_map_kern - map kernel address into bio
1185 * @q: the struct request_queue for the bio
1186 * @data: pointer to buffer to map
1187 * @len: length in bytes
1188 * @gfp_mask: allocation flags for bio allocation
1190 * Map the kernel address into a bio suitable for io to a block
1191 * device. Returns an error pointer in case of error.
1193 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
1198 bio = __bio_map_kern(q, data, len, gfp_mask);
1202 if (bio->bi_size == len)
1206 * Don't support partial mappings.
1209 return ERR_PTR(-EINVAL);
1211 EXPORT_SYMBOL(bio_map_kern);
1213 static void bio_copy_kern_endio(struct bio *bio, int err)
1215 struct bio_vec *bvec;
1216 const int read = bio_data_dir(bio) == READ;
1217 struct bio_map_data *bmd = bio->bi_private;
1219 char *p = bmd->sgvecs[0].iov_base;
1221 __bio_for_each_segment(bvec, bio, i, 0) {
1222 char *addr = page_address(bvec->bv_page);
1223 int len = bmd->iovecs[i].bv_len;
1226 memcpy(p, addr, len);
1228 __free_page(bvec->bv_page);
1232 bio_free_map_data(bmd);
1237 * bio_copy_kern - copy kernel address into bio
1238 * @q: the struct request_queue for the bio
1239 * @data: pointer to buffer to copy
1240 * @len: length in bytes
1241 * @gfp_mask: allocation flags for bio and page allocation
1242 * @reading: data direction is READ
1244 * copy the kernel address into a bio suitable for io to a block
1245 * device. Returns an error pointer in case of error.
1247 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len,
1248 gfp_t gfp_mask, int reading)
1251 struct bio_vec *bvec;
1254 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask);
1261 bio_for_each_segment(bvec, bio, i) {
1262 char *addr = page_address(bvec->bv_page);
1264 memcpy(addr, p, bvec->bv_len);
1269 bio->bi_end_io = bio_copy_kern_endio;
1273 EXPORT_SYMBOL(bio_copy_kern);
1276 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
1277 * for performing direct-IO in BIOs.
1279 * The problem is that we cannot run set_page_dirty() from interrupt context
1280 * because the required locks are not interrupt-safe. So what we can do is to
1281 * mark the pages dirty _before_ performing IO. And in interrupt context,
1282 * check that the pages are still dirty. If so, fine. If not, redirty them
1283 * in process context.
1285 * We special-case compound pages here: normally this means reads into hugetlb
1286 * pages. The logic in here doesn't really work right for compound pages
1287 * because the VM does not uniformly chase down the head page in all cases.
1288 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
1289 * handle them at all. So we skip compound pages here at an early stage.
1291 * Note that this code is very hard to test under normal circumstances because
1292 * direct-io pins the pages with get_user_pages(). This makes
1293 * is_page_cache_freeable return false, and the VM will not clean the pages.
1294 * But other code (eg, pdflush) could clean the pages if they are mapped
1297 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
1298 * deferred bio dirtying paths.
1302 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
1304 void bio_set_pages_dirty(struct bio *bio)
1306 struct bio_vec *bvec = bio->bi_io_vec;
1309 for (i = 0; i < bio->bi_vcnt; i++) {
1310 struct page *page = bvec[i].bv_page;
1312 if (page && !PageCompound(page))
1313 set_page_dirty_lock(page);
1317 static void bio_release_pages(struct bio *bio)
1319 struct bio_vec *bvec = bio->bi_io_vec;
1322 for (i = 0; i < bio->bi_vcnt; i++) {
1323 struct page *page = bvec[i].bv_page;
1331 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
1332 * If they are, then fine. If, however, some pages are clean then they must
1333 * have been written out during the direct-IO read. So we take another ref on
1334 * the BIO and the offending pages and re-dirty the pages in process context.
1336 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
1337 * here on. It will run one page_cache_release() against each page and will
1338 * run one bio_put() against the BIO.
1341 static void bio_dirty_fn(struct work_struct *work);
1343 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
1344 static DEFINE_SPINLOCK(bio_dirty_lock);
1345 static struct bio *bio_dirty_list;
1348 * This runs in process context
1350 static void bio_dirty_fn(struct work_struct *work)
1352 unsigned long flags;
1355 spin_lock_irqsave(&bio_dirty_lock, flags);
1356 bio = bio_dirty_list;
1357 bio_dirty_list = NULL;
1358 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1361 struct bio *next = bio->bi_private;
1363 bio_set_pages_dirty(bio);
1364 bio_release_pages(bio);
1370 void bio_check_pages_dirty(struct bio *bio)
1372 struct bio_vec *bvec = bio->bi_io_vec;
1373 int nr_clean_pages = 0;
1376 for (i = 0; i < bio->bi_vcnt; i++) {
1377 struct page *page = bvec[i].bv_page;
1379 if (PageDirty(page) || PageCompound(page)) {
1380 page_cache_release(page);
1381 bvec[i].bv_page = NULL;
1387 if (nr_clean_pages) {
1388 unsigned long flags;
1390 spin_lock_irqsave(&bio_dirty_lock, flags);
1391 bio->bi_private = bio_dirty_list;
1392 bio_dirty_list = bio;
1393 spin_unlock_irqrestore(&bio_dirty_lock, flags);
1394 schedule_work(&bio_dirty_work);
1400 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
1401 void bio_flush_dcache_pages(struct bio *bi)
1404 struct bio_vec *bvec;
1406 bio_for_each_segment(bvec, bi, i)
1407 flush_dcache_page(bvec->bv_page);
1409 EXPORT_SYMBOL(bio_flush_dcache_pages);
1413 * bio_endio - end I/O on a bio
1415 * @error: error, if any
1418 * bio_endio() will end I/O on the whole bio. bio_endio() is the
1419 * preferred way to end I/O on a bio, it takes care of clearing
1420 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
1421 * established -Exxxx (-EIO, for instance) error values in case
1422 * something went wrong. Noone should call bi_end_io() directly on a
1423 * bio unless they own it and thus know that it has an end_io
1426 void bio_endio(struct bio *bio, int error)
1429 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1430 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1434 bio->bi_end_io(bio, error);
1436 EXPORT_SYMBOL(bio_endio);
1438 void bio_pair_release(struct bio_pair *bp)
1440 if (atomic_dec_and_test(&bp->cnt)) {
1441 struct bio *master = bp->bio1.bi_private;
1443 bio_endio(master, bp->error);
1444 mempool_free(bp, bp->bio2.bi_private);
1447 EXPORT_SYMBOL(bio_pair_release);
1449 static void bio_pair_end_1(struct bio *bi, int err)
1451 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1456 bio_pair_release(bp);
1459 static void bio_pair_end_2(struct bio *bi, int err)
1461 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1466 bio_pair_release(bp);
1470 * split a bio - only worry about a bio with a single page in its iovec
1472 struct bio_pair *bio_split(struct bio *bi, int first_sectors)
1474 struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO);
1479 trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
1480 bi->bi_sector + first_sectors);
1482 BUG_ON(bi->bi_vcnt != 1);
1483 BUG_ON(bi->bi_idx != 0);
1484 atomic_set(&bp->cnt, 3);
1488 bp->bio2.bi_sector += first_sectors;
1489 bp->bio2.bi_size -= first_sectors << 9;
1490 bp->bio1.bi_size = first_sectors << 9;
1492 bp->bv1 = bi->bi_io_vec[0];
1493 bp->bv2 = bi->bi_io_vec[0];
1494 bp->bv2.bv_offset += first_sectors << 9;
1495 bp->bv2.bv_len -= first_sectors << 9;
1496 bp->bv1.bv_len = first_sectors << 9;
1498 bp->bio1.bi_io_vec = &bp->bv1;
1499 bp->bio2.bi_io_vec = &bp->bv2;
1501 bp->bio1.bi_max_vecs = 1;
1502 bp->bio2.bi_max_vecs = 1;
1504 bp->bio1.bi_end_io = bio_pair_end_1;
1505 bp->bio2.bi_end_io = bio_pair_end_2;
1507 bp->bio1.bi_private = bi;
1508 bp->bio2.bi_private = bio_split_pool;
1510 if (bio_integrity(bi))
1511 bio_integrity_split(bi, bp, first_sectors);
1515 EXPORT_SYMBOL(bio_split);
1518 * bio_sector_offset - Find hardware sector offset in bio
1519 * @bio: bio to inspect
1520 * @index: bio_vec index
1521 * @offset: offset in bv_page
1523 * Return the number of hardware sectors between beginning of bio
1524 * and an end point indicated by a bio_vec index and an offset
1525 * within that vector's page.
1527 sector_t bio_sector_offset(struct bio *bio, unsigned short index,
1528 unsigned int offset)
1530 unsigned int sector_sz;
1535 sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue);
1538 if (index >= bio->bi_idx)
1539 index = bio->bi_vcnt - 1;
1541 __bio_for_each_segment(bv, bio, i, 0) {
1543 if (offset > bv->bv_offset)
1544 sectors += (offset - bv->bv_offset) / sector_sz;
1548 sectors += bv->bv_len / sector_sz;
1553 EXPORT_SYMBOL(bio_sector_offset);
1556 * create memory pools for biovec's in a bio_set.
1557 * use the global biovec slabs created for general use.
1559 static int biovec_create_pools(struct bio_set *bs, int pool_entries)
1561 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
1563 bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
1570 static void biovec_free_pools(struct bio_set *bs)
1572 mempool_destroy(bs->bvec_pool);
1575 void bioset_free(struct bio_set *bs)
1578 mempool_destroy(bs->bio_pool);
1580 bioset_integrity_free(bs);
1581 biovec_free_pools(bs);
1586 EXPORT_SYMBOL(bioset_free);
1589 * bioset_create - Create a bio_set
1590 * @pool_size: Number of bio and bio_vecs to cache in the mempool
1591 * @front_pad: Number of bytes to allocate in front of the returned bio
1594 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
1595 * to ask for a number of bytes to be allocated in front of the bio.
1596 * Front pad allocation is useful for embedding the bio inside
1597 * another structure, to avoid allocating extra data to go with the bio.
1598 * Note that the bio must be embedded at the END of that structure always,
1599 * or things will break badly.
1601 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
1603 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
1606 bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1610 bs->front_pad = front_pad;
1612 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
1613 if (!bs->bio_slab) {
1618 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab);
1622 if (bioset_integrity_create(bs, pool_size))
1625 if (!biovec_create_pools(bs, pool_size))
1632 EXPORT_SYMBOL(bioset_create);
1634 static void __init biovec_init_slabs(void)
1638 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1640 struct biovec_slab *bvs = bvec_slabs + i;
1642 #ifndef CONFIG_BLK_DEV_INTEGRITY
1643 if (bvs->nr_vecs <= BIO_INLINE_VECS) {
1649 size = bvs->nr_vecs * sizeof(struct bio_vec);
1650 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1651 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1655 static int __init init_bio(void)
1659 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL);
1661 panic("bio: can't allocate bios\n");
1663 bio_integrity_init();
1664 biovec_init_slabs();
1666 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
1668 panic("bio: can't allocate bios\n");
1670 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
1671 sizeof(struct bio_pair));
1672 if (!bio_split_pool)
1673 panic("bio: can't create split pool\n");
1677 subsys_initcall(init_bio);