ALSA: usb-audio: Fix missing autopm for MIDI input

[pandora-kernel.git] / block / blk-cgroup.c

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index cafcd74..d0b7703 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -285,6 +285,13 @@ static void blkg_destroy_all(struct request_queue *q)
                blkg_destroy(blkg);
                spin_unlock(&blkcg->lock);
        }
+
+       /*
+        * root blkg is destroyed.  Just clear the pointer since
+        * root_rl does not take reference on root blkg.
+        */
+       q->root_blkg = NULL;
+       q->root_rl.blkg = NULL;
 }
 
 static void blkg_rcu_free(struct rcu_head *rcu_head)
@@ -326,6 +333,9 @@ struct request_list *__blk_queue_next_rl(struct request_list *rl,
         */
        if (rl == &q->root_rl) {
                ent = &q->blkg_list;
+               /* There are no more block groups, hence no request lists */
+               if (list_empty(ent))
+                       return NULL;
        } else {
                blkg = container_of(rl, struct blkcg_gq, rl);
                ent = &blkg->q_node;