X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=block%2Fblk-cgroup.c;h=8c4e81ac5e75432c1e29917dd6bf0305505ad7a6;hb=f399038b276db24cccb6f97654214ba81c2d09a5;hp=b95219d2168d0957eb2a537c920cac531d7238d7;hpb=35dfcefb1a05f270bea4e62844799286b4eb6b91;p=firefly-linux-kernel-4.4.55.git

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index b95219d2168d..8c4e81ac5e75 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -720,8 +720,12 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 		return -EINVAL;
 
 	disk = get_gendisk(MKDEV(major, minor), &part);
-	if (!disk || part)
+	if (!disk)
 		return -EINVAL;
+	if (part) {
+		put_disk(disk);
+		return -EINVAL;
+	}
 
 	rcu_read_lock();
 	spin_lock_irq(disk->queue->queue_lock);
@@ -876,6 +880,13 @@ void blkcg_drain_queue(struct request_queue *q)
 {
 	lockdep_assert_held(q->queue_lock);
 
+	/*
+	 * @q could be exiting and already have destroyed all blkgs as
+	 * indicated by NULL root_blkg.  If so, don't confuse policies.
+	 */
+	if (!q->root_blkg)
+		return;
+
 	/*
 	 * @q could be exiting and already have destroyed all blkgs as
 	 * indicated by NULL root_blkg.  If so, don't confuse policies.