This patch fixes q->unplug_thresh condition check in
__elv_add_request(). rq.count[READ] + rq.count[WRITE] can increase
more than one if another thread has allocated a request after the
current request is allocated or in_flight could have changed resulting
in larger-than-one change of nrq, thus breaking the threshold
mechanism.
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
index 98fcabb..8998292 100644
--- a/drivers/block/elevator.c
+++ b/drivers/block/elevator.c
@@ -317,7 +317,7 @@
int nrq = q->rq.count[READ] + q->rq.count[WRITE]
- q->in_flight;
- if (nrq == q->unplug_thresh)
+ if (nrq >= q->unplug_thresh)
__generic_unplug_device(q);
}
} else