[PKT_SCHED]: Fix double locking in tcindex destroy path.

tcindex's destroy uses its own delete functions to destroy its
configuration. The delete function (correctly) takes the qdisc_tree_lock
to prevent list walkings from happening while removing from the list.
The qdisc_tree_lock is already held if we're comming via the destroy
path and thus a double locking takes place.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_tcindex.c

@@ -160,7 +160,8 @@ static int tcindex_init(struct tcf_proto *tp)
 }
 
 
-static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
+static int
+__tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
 {
 	struct tcindex_data *p = PRIV(tp);
 	struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
@@ -182,8 +183,10 @@ static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
 
 found:
 		f = *walk;
+		if (lock)
 			tcf_tree_lock(tp);
 		*walk = f->next;
+		if (lock)
 			tcf_tree_unlock(tp);
 	}
 	tcf_unbind_filter(tp, &r->res);
@@ -195,6 +198,10 @@ static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
 	return 0;
 }
 
+static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
+{
+	return __tcindex_delete(tp, arg, 1);
+}
 
 /*
  * There are no parameters for tcindex_init, so we overload tcindex_change
@@ -384,7 +391,7 @@ static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
 static int tcindex_destroy_element(struct tcf_proto *tp,
     unsigned long arg, struct tcf_walker *walker)
 {
-	return tcindex_delete(tp,arg);
+	return __tcindex_delete(tp, arg, 0);
 }