cfq: fix IOPRIO_CLASS_IDLE accounting

Spotted by Nick <gentuu@gmail.com>, hopefully can explain the second trace in
http://bugzilla.kernel.org/show_bug.cgi?id=9180.

If ->async_idle_cfqq != NULL cfq_put_async_queues() puts it IOPRIO_BE_NR times
in a loop. Fix this.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index e47a9309eb4..61a3f22eee2 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2068,9 +2068,10 @@ static void cfq_put_async_queues(struct cfq_data *cfqd)
                         cfq_put_queue(cfqd->async_cfqq[0][i]);
                 if (cfqd->async_cfqq[1][i])
                         cfq_put_queue(cfqd->async_cfqq[1][i]);
-                if (cfqd->async_idle_cfqq)
-                        cfq_put_queue(cfqd->async_idle_cfqq);
         }
+
+        if (cfqd->async_idle_cfqq)
+                cfq_put_queue(cfqd->async_idle_cfqq);
 }
 
 static void cfq_exit_queue(elevator_t *e)