net: sched: route: don't set arg->stop in route4_walk() when empty

Some classifiers set arg->stop in their implementation of tp->walk() API
when empty. Most of classifiers do not adhere to that convention. Do not
set arg->stop in route4_walk() to unify tp->walk() behavior among
classifier implementations.

Fixes: ed76f5ed ("net: sched: protect filter_chain list with filter_chain_lock mutex")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_route.c

@@ -567,10 +567,7 @@ static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 	struct route4_head *head = rtnl_dereference(tp->root);
 	unsigned int h, h1;
 
-	if (head == NULL)
-		arg->stop = 1;
-
-	if (arg->stop)
+	if (head == NULL || arg->stop)
 		return;
 
 	for (h = 0; h <= 256; h++) {