[PKT_SCHED]: Disable local bh's when grabbing qdisc_tree_lock in tc_dump_tfilter.

I missed this one when fixing locking in __qdisc_destroy.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@redhat.com>

net/sched/cls_api.c

@@ -387,7 +387,7 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 	if ((dev = dev_get_by_index(tcm->tcm_ifindex)) == NULL)
 		return skb->len;
 
-	read_lock(&qdisc_tree_lock);
+	read_lock_bh(&qdisc_tree_lock);
 	if (!tcm->tcm_parent)
 		q = dev->qdisc_sleeping;
 	else
@@ -444,7 +444,7 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 	if (cl)
 		cops->put(q, cl);
 out:
-	read_unlock(&qdisc_tree_lock);
+	read_unlock_bh(&qdisc_tree_lock);
 	dev_put(dev);
 	return skb->len;
 }