[PATCH] Only the first two bits in bio->bi_rw and rq->flags match
Not three, as assumed. This causes the barrier bit to be needlessly set
for some IO.
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index ab17c72..61d6b3c 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -3491,8 +3491,8 @@
void blk_rq_bio_prep(request_queue_t *q, struct request *rq, struct bio *bio)
{
- /* first three bits are identical in rq->flags and bio->bi_rw */
- rq->flags |= (bio->bi_rw & 7);
+ /* first two bits are identical in rq->flags and bio->bi_rw */
+ rq->flags |= (bio->bi_rw & 3);
rq->nr_phys_segments = bio_phys_segments(q, bio);
rq->nr_hw_segments = bio_hw_segments(q, bio);
