block: change the request allocation/congestion logic to be sync/async based

This makes sure that we never wait on async IO for sync requests, instead
of doing the split on writes vs reads.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/elevator.c b/block/elevator.c
index 98259eda0ef6..ca6788a0195a 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -677,7 +677,7 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
         }
 
         if (unplug_it && blk_queue_plugged(q)) {
-                int nrq = q->rq.count[READ] + q->rq.count[WRITE]
+                int nrq = q->rq.count[BLK_RW_SYNC] + q->rq.count[BLK_RW_ASYNC]
                         - q->in_flight;
 
                 if (nrq >= q->unplug_thresh)