[PATCH 03/14] block: don't set REQ_NOMERGE unnecessarily

[Tejun Heo]

Impact: cleanup

RQ_NOMERGE_FLAGS already clears defines which REQ flags aren't
mergeable.  There is no reason to specify it superflously.  It only
adds to confusion.  Don't set REQ_NOMERGE for barriers and requests
with specific queueing directive.  REQ_NOMERGE is now exclusively used
by the merging code.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
 block/blk-core.c |    5 +----
 block/blk-exec.c |    1 -
 2 files changed, 1 insertions(+), 5 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 7c2d836..d7b2cc9 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1077,16 +1077,13 @@ void init_request_from_bio(struct request *req, struct bio *bio)
 	if (bio_failfast_driver(bio))
 		req->cmd_flags |= REQ_FAILFAST_DRIVER;
 
-	/*
-	 * REQ_BARRIER implies no merging, but lets make it explicit
-	 */
 	if (unlikely(bio_discard(bio))) {
 		req->cmd_flags |= REQ_DISCARD;
 		if (bio_barrier(bio))
 			req->cmd_flags |= REQ_SOFTBARRIER;
 		req->q->prepare_discard_fn(req->q, req);
 	} else if (unlikely(bio_barrier(bio)))
-		req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
+		req->cmd_flags |= REQ_HARDBARRIER;
 
 	if (bio_sync(bio))
 		req->cmd_flags |= REQ_RW_SYNC;
diff --git a/block/blk-exec.c b/block/blk-exec.c
index 6af716d..49557e9 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -51,7 +51,6 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
 	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
 
 	rq->rq_disk = bd_disk;
-	rq->cmd_flags |= REQ_NOMERGE;
 	rq->end_io = done;
 	WARN_ON(irqs_disabled());
 	spin_lock_irq(q->queue_lock);
-- 
1.6.0.2

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