block: don't set REQ_NOMERGE unnecessarily
Tejun Heo [Thu, 23 Apr 2009 02:05:17 +0000 (11:05 +0900)]
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.

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>

block/blk-core.c
block/blk-exec.c

index 8b4a0af..7e0fab5 100644 (file)
@@ -1082,16 +1082,13 @@ 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;
index 6af716d..49557e9 100644 (file)
@@ -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);