net: suppress lockdep-RCU false positive in FIB trie.

paulmck · davem330 · commit 634a4b2038a6 · 2010-03-21T18:01:05.000-07:00
Allow fib_find_node() to be called either under rcu_read_lock()
protection or with RTNL held.

Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Signed-off-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
@@ -961,7 +961,9 @@ fib_find_node(struct trie *t, u32 key)
 	struct node *n;
 
 	pos = 0;
-	n = rcu_dereference(t->trie);
+	n = rcu_dereference_check(t->trie,
+				  rcu_read_lock_held() ||
+				  lockdep_rtnl_is_held());
 
 	while (n != NULL &&  NODE_TYPE(n) == T_TNODE) {
 		tn = (struct tnode *) n;
