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 <tom.leiming@xxxxxxxxx> --- block/blk-merge.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 182398cb1524..e3abc835e4b7 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -153,22 +153,21 @@ 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; @@ -181,6 +180,8 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, 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; -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
