pkt_sched: Fix sch_tree_lock()

Use new qdisc_root_sleeping_lock() instead of qdisc_root_lock() as
sch_tree_lock() because this lock could be used while dev is
deactivated, but we never need to use this with noop_qdisc as a root.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index ef8a7e2..e556962 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -232,12 +232,12 @@
 
 static inline void sch_tree_lock(struct Qdisc *q)
 {
-	spin_lock_bh(qdisc_root_lock(q));
+	spin_lock_bh(qdisc_root_sleeping_lock(q));
 }
 
 static inline void sch_tree_unlock(struct Qdisc *q)
 {
-	spin_unlock_bh(qdisc_root_lock(q));
+	spin_unlock_bh(qdisc_root_sleeping_lock(q));
 }
 
 #define tcf_tree_lock(tp)	sch_tree_lock((tp)->q)