net: sched: fw: don't set arg->stop in fw_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 fw_walk() to unify tp->walk() behavior among classifier
implementations.

Fixes: ed76f5e ("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_fw.c

@@ -362,10 +362,7 @@ static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg,
 	struct fw_head *head = rtnl_dereference(tp->root);
 	int h;
 
-	if (head == NULL)
-		arg->stop = 1;
-
-	if (arg->stop)
+	if (head == NULL || arg->stop)
 		return;
 
 	for (h = 0; h < HTSIZE; h++) {