2 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public Licens
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
19 #include <linux/swap.h>
20 #include <linux/bio.h>
21 #include <linux/blkdev.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/mempool.h>
27 #include <linux/workqueue.h>
28 #include <linux/blktrace_api.h>
29 #include <scsi/sg.h> /* for struct sg_iovec */
31 #define BIO_POOL_SIZE 2
33 static struct kmem_cache *bio_slab __read_mostly;
35 #define BIOVEC_NR_POOLS 6
38 * a small number of entries is fine, not going to be performance critical.
39 * basically we just need to survive
41 #define BIO_SPLIT_ENTRIES 2
42 mempool_t *bio_split_pool __read_mostly;
47 struct kmem_cache *slab;
51 * if you change this list, also change bvec_alloc or things will
52 * break badly! cannot be bigger than what you can fit into an
56 #define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
57 static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
58 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
63 * bio_set is used to allow other portions of the IO system to
64 * allocate their own private memory pools for bio and iovec structures.
65 * These memory pools in turn all allocate from the bio_slab
66 * and the bvec_slabs[].
70 mempool_t *bvec_pools[BIOVEC_NR_POOLS];
74 * fs_bio_set is the bio_set containing bio and iovec memory pools used by
75 * IO code that does not need private memory pools.
77 static struct bio_set *fs_bio_set;
79 static inline struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct bio_set *bs)
84 * see comment near bvec_array define!
87 case 1 : *idx = 0; break;
88 case 2 ... 4: *idx = 1; break;
89 case 5 ... 16: *idx = 2; break;
90 case 17 ... 64: *idx = 3; break;
91 case 65 ... 128: *idx = 4; break;
92 case 129 ... BIO_MAX_PAGES: *idx = 5; break;
97 * idx now points to the pool we want to allocate from
100 bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
102 struct biovec_slab *bp = bvec_slabs + *idx;
104 memset(bvl, 0, bp->nr_vecs * sizeof(struct bio_vec));
110 void bio_free(struct bio *bio, struct bio_set *bio_set)
112 const int pool_idx = BIO_POOL_IDX(bio);
114 BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);
116 mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
117 mempool_free(bio, bio_set->bio_pool);
121 * default destructor for a bio allocated with bio_alloc_bioset()
123 static void bio_fs_destructor(struct bio *bio)
125 bio_free(bio, fs_bio_set);
128 void bio_init(struct bio *bio)
130 memset(bio, 0, sizeof(*bio));
131 bio->bi_flags = 1 << BIO_UPTODATE;
132 atomic_set(&bio->bi_cnt, 1);
136 * bio_alloc_bioset - allocate a bio for I/O
137 * @gfp_mask: the GFP_ mask given to the slab allocator
138 * @nr_iovecs: number of iovecs to pre-allocate
139 * @bs: the bio_set to allocate from
142 * bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
143 * If %__GFP_WAIT is set then we will block on the internal pool waiting
144 * for a &struct bio to become free.
146 * allocate bio and iovecs from the memory pools specified by the
149 struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
151 struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);
154 struct bio_vec *bvl = NULL;
157 if (likely(nr_iovecs)) {
158 unsigned long idx = 0; /* shut up gcc */
160 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
161 if (unlikely(!bvl)) {
162 mempool_free(bio, bs->bio_pool);
166 bio->bi_flags |= idx << BIO_POOL_OFFSET;
167 bio->bi_max_vecs = bvec_slabs[idx].nr_vecs;
169 bio->bi_io_vec = bvl;
175 struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
177 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
180 bio->bi_destructor = bio_fs_destructor;
185 void zero_fill_bio(struct bio *bio)
191 bio_for_each_segment(bv, bio, i) {
192 char *data = bvec_kmap_irq(bv, &flags);
193 memset(data, 0, bv->bv_len);
194 flush_dcache_page(bv->bv_page);
195 bvec_kunmap_irq(data, &flags);
198 EXPORT_SYMBOL(zero_fill_bio);
201 * bio_put - release a reference to a bio
202 * @bio: bio to release reference to
205 * Put a reference to a &struct bio, either one you have gotten with
206 * bio_alloc or bio_get. The last put of a bio will free it.
208 void bio_put(struct bio *bio)
210 BIO_BUG_ON(!atomic_read(&bio->bi_cnt));
215 if (atomic_dec_and_test(&bio->bi_cnt)) {
217 bio->bi_destructor(bio);
221 inline int bio_phys_segments(struct request_queue *q, struct bio *bio)
223 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
224 blk_recount_segments(q, bio);
226 return bio->bi_phys_segments;
229 inline int bio_hw_segments(struct request_queue *q, struct bio *bio)
231 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
232 blk_recount_segments(q, bio);
234 return bio->bi_hw_segments;
238 * __bio_clone - clone a bio
239 * @bio: destination bio
240 * @bio_src: bio to clone
242 * Clone a &bio. Caller will own the returned bio, but not
243 * the actual data it points to. Reference count of returned
246 void __bio_clone(struct bio *bio, struct bio *bio_src)
248 struct request_queue *q = bdev_get_queue(bio_src->bi_bdev);
250 memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
251 bio_src->bi_max_vecs * sizeof(struct bio_vec));
253 bio->bi_sector = bio_src->bi_sector;
254 bio->bi_bdev = bio_src->bi_bdev;
255 bio->bi_flags |= 1 << BIO_CLONED;
256 bio->bi_rw = bio_src->bi_rw;
257 bio->bi_vcnt = bio_src->bi_vcnt;
258 bio->bi_size = bio_src->bi_size;
259 bio->bi_idx = bio_src->bi_idx;
260 bio_phys_segments(q, bio);
261 bio_hw_segments(q, bio);
265 * bio_clone - clone a bio
267 * @gfp_mask: allocation priority
269 * Like __bio_clone, only also allocates the returned bio
271 struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
273 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
276 b->bi_destructor = bio_fs_destructor;
284 * bio_get_nr_vecs - return approx number of vecs
287 * Return the approximate number of pages we can send to this target.
288 * There's no guarantee that you will be able to fit this number of pages
289 * into a bio, it does not account for dynamic restrictions that vary
292 int bio_get_nr_vecs(struct block_device *bdev)
294 struct request_queue *q = bdev_get_queue(bdev);
297 nr_pages = ((q->max_sectors << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
298 if (nr_pages > q->max_phys_segments)
299 nr_pages = q->max_phys_segments;
300 if (nr_pages > q->max_hw_segments)
301 nr_pages = q->max_hw_segments;
306 static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
307 *page, unsigned int len, unsigned int offset,
308 unsigned short max_sectors)
310 int retried_segments = 0;
311 struct bio_vec *bvec;
314 * cloned bio must not modify vec list
316 if (unlikely(bio_flagged(bio, BIO_CLONED)))
319 if (((bio->bi_size + len) >> 9) > max_sectors)
323 * For filesystems with a blocksize smaller than the pagesize
324 * we will often be called with the same page as last time and
325 * a consecutive offset. Optimize this special case.
327 if (bio->bi_vcnt > 0) {
328 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
330 if (page == prev->bv_page &&
331 offset == prev->bv_offset + prev->bv_len) {
333 if (q->merge_bvec_fn &&
334 q->merge_bvec_fn(q, bio, prev) < len) {
343 if (bio->bi_vcnt >= bio->bi_max_vecs)
347 * we might lose a segment or two here, but rather that than
348 * make this too complex.
351 while (bio->bi_phys_segments >= q->max_phys_segments
352 || bio->bi_hw_segments >= q->max_hw_segments
353 || BIOVEC_VIRT_OVERSIZE(bio->bi_size)) {
355 if (retried_segments)
358 retried_segments = 1;
359 blk_recount_segments(q, bio);
363 * setup the new entry, we might clear it again later if we
364 * cannot add the page
366 bvec = &bio->bi_io_vec[bio->bi_vcnt];
367 bvec->bv_page = page;
369 bvec->bv_offset = offset;
372 * if queue has other restrictions (eg varying max sector size
373 * depending on offset), it can specify a merge_bvec_fn in the
374 * queue to get further control
376 if (q->merge_bvec_fn) {
378 * merge_bvec_fn() returns number of bytes it can accept
381 if (q->merge_bvec_fn(q, bio, bvec) < len) {
382 bvec->bv_page = NULL;
389 /* If we may be able to merge these biovecs, force a recount */
390 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec) ||
391 BIOVEC_VIRT_MERGEABLE(bvec-1, bvec)))
392 bio->bi_flags &= ~(1 << BIO_SEG_VALID);
395 bio->bi_phys_segments++;
396 bio->bi_hw_segments++;
403 * bio_add_pc_page - attempt to add page to bio
404 * @q: the target queue
405 * @bio: destination bio
407 * @len: vec entry length
408 * @offset: vec entry offset
410 * Attempt to add a page to the bio_vec maplist. This can fail for a
411 * number of reasons, such as the bio being full or target block
412 * device limitations. The target block device must allow bio's
413 * smaller than PAGE_SIZE, so it is always possible to add a single
414 * page to an empty bio. This should only be used by REQ_PC bios.
416 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page,
417 unsigned int len, unsigned int offset)
419 return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
423 * bio_add_page - attempt to add page to bio
424 * @bio: destination bio
426 * @len: vec entry length
427 * @offset: vec entry offset
429 * Attempt to add a page to the bio_vec maplist. This can fail for a
430 * number of reasons, such as the bio being full or target block
431 * device limitations. The target block device must allow bio's
432 * smaller than PAGE_SIZE, so it is always possible to add a single
433 * page to an empty bio.
435 int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
438 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
439 return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
442 struct bio_map_data {
443 struct bio_vec *iovecs;
444 void __user *userptr;
447 static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio)
449 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
450 bio->bi_private = bmd;
453 static void bio_free_map_data(struct bio_map_data *bmd)
459 static struct bio_map_data *bio_alloc_map_data(int nr_segs)
461 struct bio_map_data *bmd = kmalloc(sizeof(*bmd), GFP_KERNEL);
466 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, GFP_KERNEL);
475 * bio_uncopy_user - finish previously mapped bio
476 * @bio: bio being terminated
478 * Free pages allocated from bio_copy_user() and write back data
479 * to user space in case of a read.
481 int bio_uncopy_user(struct bio *bio)
483 struct bio_map_data *bmd = bio->bi_private;
484 const int read = bio_data_dir(bio) == READ;
485 struct bio_vec *bvec;
488 __bio_for_each_segment(bvec, bio, i, 0) {
489 char *addr = page_address(bvec->bv_page);
490 unsigned int len = bmd->iovecs[i].bv_len;
492 if (read && !ret && copy_to_user(bmd->userptr, addr, len))
495 __free_page(bvec->bv_page);
498 bio_free_map_data(bmd);
504 * bio_copy_user - copy user data to bio
505 * @q: destination block queue
506 * @uaddr: start of user address
507 * @len: length in bytes
508 * @write_to_vm: bool indicating writing to pages or not
510 * Prepares and returns a bio for indirect user io, bouncing data
511 * to/from kernel pages as necessary. Must be paired with
512 * call bio_uncopy_user() on io completion.
514 struct bio *bio_copy_user(struct request_queue *q, unsigned long uaddr,
515 unsigned int len, int write_to_vm)
517 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
518 unsigned long start = uaddr >> PAGE_SHIFT;
519 struct bio_map_data *bmd;
520 struct bio_vec *bvec;
525 bmd = bio_alloc_map_data(end - start);
527 return ERR_PTR(-ENOMEM);
529 bmd->userptr = (void __user *) uaddr;
532 bio = bio_alloc(GFP_KERNEL, end - start);
536 bio->bi_rw |= (!write_to_vm << BIO_RW);
540 unsigned int bytes = PAGE_SIZE;
545 page = alloc_page(q->bounce_gfp | GFP_KERNEL);
551 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
564 char __user *p = (char __user *) uaddr;
567 * for a write, copy in data to kernel pages
570 bio_for_each_segment(bvec, bio, i) {
571 char *addr = page_address(bvec->bv_page);
573 if (copy_from_user(addr, p, bvec->bv_len))
579 bio_set_map_data(bmd, bio);
582 bio_for_each_segment(bvec, bio, i)
583 __free_page(bvec->bv_page);
587 bio_free_map_data(bmd);
591 static struct bio *__bio_map_user_iov(struct request_queue *q,
592 struct block_device *bdev,
593 struct sg_iovec *iov, int iov_count,
603 for (i = 0; i < iov_count; i++) {
604 unsigned long uaddr = (unsigned long)iov[i].iov_base;
605 unsigned long len = iov[i].iov_len;
606 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
607 unsigned long start = uaddr >> PAGE_SHIFT;
609 nr_pages += end - start;
611 * buffer must be aligned to at least hardsector size for now
613 if (uaddr & queue_dma_alignment(q))
614 return ERR_PTR(-EINVAL);
618 return ERR_PTR(-EINVAL);
620 bio = bio_alloc(GFP_KERNEL, nr_pages);
622 return ERR_PTR(-ENOMEM);
625 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
629 for (i = 0; i < iov_count; i++) {
630 unsigned long uaddr = (unsigned long)iov[i].iov_base;
631 unsigned long len = iov[i].iov_len;
632 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
633 unsigned long start = uaddr >> PAGE_SHIFT;
634 const int local_nr_pages = end - start;
635 const int page_limit = cur_page + local_nr_pages;
637 down_read(¤t->mm->mmap_sem);
638 ret = get_user_pages(current, current->mm, uaddr,
640 write_to_vm, 0, &pages[cur_page], NULL);
641 up_read(¤t->mm->mmap_sem);
643 if (ret < local_nr_pages) {
648 offset = uaddr & ~PAGE_MASK;
649 for (j = cur_page; j < page_limit; j++) {
650 unsigned int bytes = PAGE_SIZE - offset;
661 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
671 * release the pages we didn't map into the bio, if any
673 while (j < page_limit)
674 page_cache_release(pages[j++]);
680 * set data direction, and check if mapped pages need bouncing
683 bio->bi_rw |= (1 << BIO_RW);
686 bio->bi_flags |= (1 << BIO_USER_MAPPED);
690 for (i = 0; i < nr_pages; i++) {
693 page_cache_release(pages[i]);
702 * bio_map_user - map user address into bio
703 * @q: the struct request_queue for the bio
704 * @bdev: destination block device
705 * @uaddr: start of user address
706 * @len: length in bytes
707 * @write_to_vm: bool indicating writing to pages or not
709 * Map the user space address into a bio suitable for io to a block
710 * device. Returns an error pointer in case of error.
712 struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
713 unsigned long uaddr, unsigned int len, int write_to_vm)
717 iov.iov_base = (void __user *)uaddr;
720 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm);
724 * bio_map_user_iov - map user sg_iovec table into bio
725 * @q: the struct request_queue for the bio
726 * @bdev: destination block device
728 * @iov_count: number of elements in the iovec
729 * @write_to_vm: bool indicating writing to pages or not
731 * Map the user space address into a bio suitable for io to a block
732 * device. Returns an error pointer in case of error.
734 struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev,
735 struct sg_iovec *iov, int iov_count,
740 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm);
746 * subtle -- if __bio_map_user() ended up bouncing a bio,
747 * it would normally disappear when its bi_end_io is run.
748 * however, we need it for the unmap, so grab an extra
756 static void __bio_unmap_user(struct bio *bio)
758 struct bio_vec *bvec;
762 * make sure we dirty pages we wrote to
764 __bio_for_each_segment(bvec, bio, i, 0) {
765 if (bio_data_dir(bio) == READ)
766 set_page_dirty_lock(bvec->bv_page);
768 page_cache_release(bvec->bv_page);
775 * bio_unmap_user - unmap a bio
776 * @bio: the bio being unmapped
778 * Unmap a bio previously mapped by bio_map_user(). Must be called with
781 * bio_unmap_user() may sleep.
783 void bio_unmap_user(struct bio *bio)
785 __bio_unmap_user(bio);
789 static void bio_map_kern_endio(struct bio *bio, int err)
795 static struct bio *__bio_map_kern(struct request_queue *q, void *data,
796 unsigned int len, gfp_t gfp_mask)
798 unsigned long kaddr = (unsigned long)data;
799 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
800 unsigned long start = kaddr >> PAGE_SHIFT;
801 const int nr_pages = end - start;
805 bio = bio_alloc(gfp_mask, nr_pages);
807 return ERR_PTR(-ENOMEM);
809 offset = offset_in_page(kaddr);
810 for (i = 0; i < nr_pages; i++) {
811 unsigned int bytes = PAGE_SIZE - offset;
819 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
828 bio->bi_end_io = bio_map_kern_endio;
833 * bio_map_kern - map kernel address into bio
834 * @q: the struct request_queue for the bio
835 * @data: pointer to buffer to map
836 * @len: length in bytes
837 * @gfp_mask: allocation flags for bio allocation
839 * Map the kernel address into a bio suitable for io to a block
840 * device. Returns an error pointer in case of error.
842 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
847 bio = __bio_map_kern(q, data, len, gfp_mask);
851 if (bio->bi_size == len)
855 * Don't support partial mappings.
858 return ERR_PTR(-EINVAL);
862 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions
863 * for performing direct-IO in BIOs.
865 * The problem is that we cannot run set_page_dirty() from interrupt context
866 * because the required locks are not interrupt-safe. So what we can do is to
867 * mark the pages dirty _before_ performing IO. And in interrupt context,
868 * check that the pages are still dirty. If so, fine. If not, redirty them
869 * in process context.
871 * We special-case compound pages here: normally this means reads into hugetlb
872 * pages. The logic in here doesn't really work right for compound pages
873 * because the VM does not uniformly chase down the head page in all cases.
874 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't
875 * handle them at all. So we skip compound pages here at an early stage.
877 * Note that this code is very hard to test under normal circumstances because
878 * direct-io pins the pages with get_user_pages(). This makes
879 * is_page_cache_freeable return false, and the VM will not clean the pages.
880 * But other code (eg, pdflush) could clean the pages if they are mapped
883 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the
884 * deferred bio dirtying paths.
888 * bio_set_pages_dirty() will mark all the bio's pages as dirty.
890 void bio_set_pages_dirty(struct bio *bio)
892 struct bio_vec *bvec = bio->bi_io_vec;
895 for (i = 0; i < bio->bi_vcnt; i++) {
896 struct page *page = bvec[i].bv_page;
898 if (page && !PageCompound(page))
899 set_page_dirty_lock(page);
903 void bio_release_pages(struct bio *bio)
905 struct bio_vec *bvec = bio->bi_io_vec;
908 for (i = 0; i < bio->bi_vcnt; i++) {
909 struct page *page = bvec[i].bv_page;
917 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.
918 * If they are, then fine. If, however, some pages are clean then they must
919 * have been written out during the direct-IO read. So we take another ref on
920 * the BIO and the offending pages and re-dirty the pages in process context.
922 * It is expected that bio_check_pages_dirty() will wholly own the BIO from
923 * here on. It will run one page_cache_release() against each page and will
924 * run one bio_put() against the BIO.
927 static void bio_dirty_fn(struct work_struct *work);
929 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);
930 static DEFINE_SPINLOCK(bio_dirty_lock);
931 static struct bio *bio_dirty_list;
934 * This runs in process context
936 static void bio_dirty_fn(struct work_struct *work)
941 spin_lock_irqsave(&bio_dirty_lock, flags);
942 bio = bio_dirty_list;
943 bio_dirty_list = NULL;
944 spin_unlock_irqrestore(&bio_dirty_lock, flags);
947 struct bio *next = bio->bi_private;
949 bio_set_pages_dirty(bio);
950 bio_release_pages(bio);
956 void bio_check_pages_dirty(struct bio *bio)
958 struct bio_vec *bvec = bio->bi_io_vec;
959 int nr_clean_pages = 0;
962 for (i = 0; i < bio->bi_vcnt; i++) {
963 struct page *page = bvec[i].bv_page;
965 if (PageDirty(page) || PageCompound(page)) {
966 page_cache_release(page);
967 bvec[i].bv_page = NULL;
973 if (nr_clean_pages) {
976 spin_lock_irqsave(&bio_dirty_lock, flags);
977 bio->bi_private = bio_dirty_list;
978 bio_dirty_list = bio;
979 spin_unlock_irqrestore(&bio_dirty_lock, flags);
980 schedule_work(&bio_dirty_work);
987 * bio_endio - end I/O on a bio
989 * @error: error, if any
992 * bio_endio() will end I/O on the whole bio. bio_endio() is the
993 * preferred way to end I/O on a bio, it takes care of clearing
994 * BIO_UPTODATE on error. @error is 0 on success, and and one of the
995 * established -Exxxx (-EIO, for instance) error values in case
996 * something went wrong. Noone should call bi_end_io() directly on a
997 * bio unless they own it and thus know that it has an end_io
1000 void bio_endio(struct bio *bio, int error)
1003 clear_bit(BIO_UPTODATE, &bio->bi_flags);
1004 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
1008 bio->bi_end_io(bio, error);
1011 void bio_pair_release(struct bio_pair *bp)
1013 if (atomic_dec_and_test(&bp->cnt)) {
1014 struct bio *master = bp->bio1.bi_private;
1016 bio_endio(master, bp->error);
1017 mempool_free(bp, bp->bio2.bi_private);
1021 static void bio_pair_end_1(struct bio *bi, int err)
1023 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1);
1028 bio_pair_release(bp);
1031 static void bio_pair_end_2(struct bio *bi, int err)
1033 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2);
1038 bio_pair_release(bp);
1042 * split a bio - only worry about a bio with a single page
1045 struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
1047 struct bio_pair *bp = mempool_alloc(pool, GFP_NOIO);
1052 blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
1053 bi->bi_sector + first_sectors);
1055 BUG_ON(bi->bi_vcnt != 1);
1056 BUG_ON(bi->bi_idx != 0);
1057 atomic_set(&bp->cnt, 3);
1061 bp->bio2.bi_sector += first_sectors;
1062 bp->bio2.bi_size -= first_sectors << 9;
1063 bp->bio1.bi_size = first_sectors << 9;
1065 bp->bv1 = bi->bi_io_vec[0];
1066 bp->bv2 = bi->bi_io_vec[0];
1067 bp->bv2.bv_offset += first_sectors << 9;
1068 bp->bv2.bv_len -= first_sectors << 9;
1069 bp->bv1.bv_len = first_sectors << 9;
1071 bp->bio1.bi_io_vec = &bp->bv1;
1072 bp->bio2.bi_io_vec = &bp->bv2;
1074 bp->bio1.bi_max_vecs = 1;
1075 bp->bio2.bi_max_vecs = 1;
1077 bp->bio1.bi_end_io = bio_pair_end_1;
1078 bp->bio2.bi_end_io = bio_pair_end_2;
1080 bp->bio1.bi_private = bi;
1081 bp->bio2.bi_private = pool;
1088 * create memory pools for biovec's in a bio_set.
1089 * use the global biovec slabs created for general use.
1091 static int biovec_create_pools(struct bio_set *bs, int pool_entries)
1095 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1096 struct biovec_slab *bp = bvec_slabs + i;
1097 mempool_t **bvp = bs->bvec_pools + i;
1099 *bvp = mempool_create_slab_pool(pool_entries, bp->slab);
1106 static void biovec_free_pools(struct bio_set *bs)
1110 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1111 mempool_t *bvp = bs->bvec_pools[i];
1114 mempool_destroy(bvp);
1119 void bioset_free(struct bio_set *bs)
1122 mempool_destroy(bs->bio_pool);
1124 biovec_free_pools(bs);
1129 struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size)
1131 struct bio_set *bs = kzalloc(sizeof(*bs), GFP_KERNEL);
1136 bs->bio_pool = mempool_create_slab_pool(bio_pool_size, bio_slab);
1140 if (!biovec_create_pools(bs, bvec_pool_size))
1148 static void __init biovec_init_slabs(void)
1152 for (i = 0; i < BIOVEC_NR_POOLS; i++) {
1154 struct biovec_slab *bvs = bvec_slabs + i;
1156 size = bvs->nr_vecs * sizeof(struct bio_vec);
1157 bvs->slab = kmem_cache_create(bvs->name, size, 0,
1158 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
1162 static int __init init_bio(void)
1164 bio_slab = KMEM_CACHE(bio, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
1166 biovec_init_slabs();
1168 fs_bio_set = bioset_create(BIO_POOL_SIZE, 2);
1170 panic("bio: can't allocate bios\n");
1172 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
1173 sizeof(struct bio_pair));
1174 if (!bio_split_pool)
1175 panic("bio: can't create split pool\n");
1180 subsys_initcall(init_bio);
1182 EXPORT_SYMBOL(bio_alloc);
1183 EXPORT_SYMBOL(bio_put);
1184 EXPORT_SYMBOL(bio_free);
1185 EXPORT_SYMBOL(bio_endio);
1186 EXPORT_SYMBOL(bio_init);
1187 EXPORT_SYMBOL(__bio_clone);
1188 EXPORT_SYMBOL(bio_clone);
1189 EXPORT_SYMBOL(bio_phys_segments);
1190 EXPORT_SYMBOL(bio_hw_segments);
1191 EXPORT_SYMBOL(bio_add_page);
1192 EXPORT_SYMBOL(bio_add_pc_page);
1193 EXPORT_SYMBOL(bio_get_nr_vecs);
1194 EXPORT_SYMBOL(bio_map_kern);
1195 EXPORT_SYMBOL(bio_pair_release);
1196 EXPORT_SYMBOL(bio_split);
1197 EXPORT_SYMBOL(bio_split_pool);
1198 EXPORT_SYMBOL(bio_copy_user);
1199 EXPORT_SYMBOL(bio_uncopy_user);
1200 EXPORT_SYMBOL(bioset_create);
1201 EXPORT_SYMBOL(bioset_free);
1202 EXPORT_SYMBOL(bio_alloc_bioset);