Fix a CFQ crash in "for-2.6.33" branch of block tree

[safe/jmp/linux-2.6] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 96f59ae..f3f6239 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2151,10 +2151,11 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
                 * have been idling all along on this queue and it should be
                 * ok to wait for this request to complete.
                 */
-               if (cfqq->cfqg->nr_cfqq == 1 && cfqq->dispatched
-                   && cfq_should_idle(cfqd, cfqq))
+               if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list)
+                   && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
+                       cfqq = NULL;
                        goto keep_queue;
-               else
+               } else
                        goto expire;
        }