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Subject[PATCH 06/17] block: don't set REQ_NOMERGE unnecessarily
Date
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@kernel.org>
---
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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