block: Introduce new bio_split()
The new bio_split() can split arbitrary bios - it's not restricted to
single page bios, like the old bio_split() (previously renamed to
bio_pair_split()). It also has different semantics - it doesn't allocate
a struct bio_pair, leaving it up to the caller to handle completions.
Then convert the existing bio_pair_split() users to the new bio_split()
- and also nvme, which was open coding bio splitting.
(We have to take that BUG_ON() out of bio_integrity_trim() because this
bio_split() needs to use it, and there's no reason it has to be used on
bios marked as cloned; BIO_CLONED doesn't seem to have clearly
documented semantics anyways.)
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Neil Brown <neilb@suse.de>
diff --git a/drivers/md/bcache/io.c b/drivers/md/bcache/io.c
index 522f957..fa028fa 100644
--- a/drivers/md/bcache/io.c
+++ b/drivers/md/bcache/io.c
@@ -11,84 +11,6 @@
#include <linux/blkdev.h>
-/**
- * bch_bio_split - split a bio
- * @bio: bio to split
- * @sectors: number of sectors to split from the front of @bio
- * @gfp: gfp mask
- * @bs: bio set to allocate from
- *
- * Allocates and returns a new bio which represents @sectors from the start of
- * @bio, and updates @bio to represent the remaining sectors.
- *
- * If bio_sectors(@bio) was less than or equal to @sectors, returns @bio
- * unchanged.
- *
- * The newly allocated bio will point to @bio's bi_io_vec, if the split was on a
- * bvec boundry; it is the caller's responsibility to ensure that @bio is not
- * freed before the split.
- */
-struct bio *bch_bio_split(struct bio *bio, int sectors,
- gfp_t gfp, struct bio_set *bs)
-{
- unsigned vcnt = 0, nbytes = sectors << 9;
- struct bio_vec bv;
- struct bvec_iter iter;
- struct bio *ret = NULL;
-
- BUG_ON(sectors <= 0);
-
- if (sectors >= bio_sectors(bio))
- return bio;
-
- if (bio->bi_rw & REQ_DISCARD) {
- ret = bio_alloc_bioset(gfp, 1, bs);
- if (!ret)
- return NULL;
- goto out;
- }
-
- bio_for_each_segment(bv, bio, iter) {
- vcnt++;
-
- if (nbytes <= bv.bv_len)
- break;
-
- nbytes -= bv.bv_len;
- }
-
- ret = bio_alloc_bioset(gfp, vcnt, bs);
- if (!ret)
- return NULL;
-
- bio_for_each_segment(bv, bio, iter) {
- ret->bi_io_vec[ret->bi_vcnt++] = bv;
-
- if (ret->bi_vcnt == vcnt)
- break;
- }
-
- ret->bi_io_vec[ret->bi_vcnt - 1].bv_len = nbytes;
-out:
- ret->bi_bdev = bio->bi_bdev;
- ret->bi_iter.bi_sector = bio->bi_iter.bi_sector;
- ret->bi_iter.bi_size = sectors << 9;
- ret->bi_rw = bio->bi_rw;
-
- if (bio_integrity(bio)) {
- if (bio_integrity_clone(ret, bio, gfp)) {
- bio_put(ret);
- return NULL;
- }
-
- bio_integrity_trim(ret, 0, bio_sectors(ret));
- }
-
- bio_advance(bio, ret->bi_iter.bi_size);
-
- return ret;
-}
-
static unsigned bch_bio_max_sectors(struct bio *bio)
{
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
@@ -172,8 +94,8 @@
bio_get(bio);
do {
- n = bch_bio_split(bio, bch_bio_max_sectors(bio),
- GFP_NOIO, s->p->bio_split);
+ n = bio_next_split(bio, bch_bio_max_sectors(bio),
+ GFP_NOIO, s->p->bio_split);
n->bi_end_io = bch_bio_submit_split_endio;
n->bi_private = &s->cl;