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authorMing Lei <ming.lei@canonical.com>2015-10-20 23:13:52 +0800
committerJens Axboe <axboe@fb.com>2015-10-21 15:00:50 -0600
commitbdced438acd83ad83a6c6fc7f50099b820245ddb (patch)
tree441b9c9b16d55c157db90c499ba4fd2821bfe60b /block/blk-merge.c
parent0809e3ac62319dc7534b64f95ac37e230d740e8a (diff)
downloadlinux-bdced438acd83ad83a6c6fc7f50099b820245ddb.tar.bz2
block: setup bi_phys_segments after splitting
The number of bio->bi_phys_segments is always obtained during bio splitting, so it is natural to setup it just after bio splitting, then we can avoid to compute nr_segment again during merge. Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-merge.c')
-rw-r--r--block/blk-merge.c29
1 files changed, 22 insertions, 7 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index c4e9c37f3e38..22293fdf6514 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -11,13 +11,16 @@
static struct bio *blk_bio_discard_split(struct request_queue *q,
struct bio *bio,
- struct bio_set *bs)
+ struct bio_set *bs,
+ unsigned *nsegs)
{
unsigned int max_discard_sectors, granularity;
int alignment;
sector_t tmp;
unsigned split_sectors;
+ *nsegs = 1;
+
/* Zero-sector (unknown) and one-sector granularities are the same. */
granularity = max(q->limits.discard_granularity >> 9, 1U);
@@ -51,8 +54,11 @@ static struct bio *blk_bio_discard_split(struct request_queue *q,
static struct bio *blk_bio_write_same_split(struct request_queue *q,
struct bio *bio,
- struct bio_set *bs)
+ struct bio_set *bs,
+ unsigned *nsegs)
{
+ *nsegs = 1;
+
if (!q->limits.max_write_same_sectors)
return NULL;
@@ -64,7 +70,8 @@ static struct bio *blk_bio_write_same_split(struct request_queue *q,
static struct bio *blk_bio_segment_split(struct request_queue *q,
struct bio *bio,
- struct bio_set *bs)
+ struct bio_set *bs,
+ unsigned *segs)
{
struct bio_vec bv, bvprv, *bvprvp = NULL;
struct bvec_iter iter;
@@ -106,22 +113,30 @@ new_segment:
sectors += bv.bv_len >> 9;
}
+ *segs = nsegs;
return NULL;
split:
+ *segs = nsegs;
return bio_split(bio, sectors, GFP_NOIO, bs);
}
void blk_queue_split(struct request_queue *q, struct bio **bio,
struct bio_set *bs)
{
- struct bio *split;
+ struct bio *split, *res;
+ unsigned nsegs;
if ((*bio)->bi_rw & REQ_DISCARD)
- split = blk_bio_discard_split(q, *bio, bs);
+ split = blk_bio_discard_split(q, *bio, bs, &nsegs);
else if ((*bio)->bi_rw & REQ_WRITE_SAME)
- split = blk_bio_write_same_split(q, *bio, bs);
+ split = blk_bio_write_same_split(q, *bio, bs, &nsegs);
else
- split = blk_bio_segment_split(q, *bio, q->bio_split);
+ split = blk_bio_segment_split(q, *bio, q->bio_split, &nsegs);
+
+ /* physical segments can be figured out during splitting */
+ res = split ? split : *bio;
+ res->bi_phys_segments = nsegs;
+ bio_set_flag(res, BIO_SEG_VALID);
if (split) {
bio_chain(split, *bio);