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authorMing Lei <ming.lei@redhat.com>2017-12-18 20:22:14 +0800
committerJens Axboe <axboe@kernel.dk>2018-01-06 09:18:00 -0700
commit6a501bf0807b5dc024fe52a4f956800a352c39ab (patch)
treecc869dfac6aaf6205896fd1e2adf9631f4d75b70
parent92681eca6104d2ec2fdf9fc65f529deb226ab0a1 (diff)
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blk-merge: compute bio->bi_seg_front_size efficiently
It is enough to check and compute bio->bi_seg_front_size just after the 1st segment is found, but current code checks that for each bvec, which is inefficient. This patch follows the way in __blk_recalc_rq_segments() for computing bio->bi_seg_front_size, and it is more efficient and code becomes more readable too. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/blk-merge.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index f5dedd57dff6..a476337a8ff4 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -146,22 +146,21 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
bvprvp = &bvprv;
sectors += bv.bv_len >> 9;
- if (nsegs == 1 && seg_size > front_seg_size)
- front_seg_size = seg_size;
continue;
}
new_segment:
if (nsegs == queue_max_segments(q))
goto split;
+ if (nsegs == 1 && seg_size > front_seg_size)
+ front_seg_size = seg_size;
+
nsegs++;
bvprv = bv;
bvprvp = &bvprv;
seg_size = bv.bv_len;
sectors += bv.bv_len >> 9;
- if (nsegs == 1 && seg_size > front_seg_size)
- front_seg_size = seg_size;
}
do_split = false;
@@ -174,6 +173,8 @@ split:
bio = new;
}
+ if (nsegs == 1 && seg_size > front_seg_size)
+ front_seg_size = seg_size;
bio->bi_seg_front_size = front_seg_size;
if (seg_size > bio->bi_seg_back_size)
bio->bi_seg_back_size = seg_size;