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

Eric Dumazet · davem330 · commit 4eaa0e3c869a · 2010-04-14T16:13:29.000-07:00
Followup of commit 634a4b2 Allow tnode_get_child_rcu() to be called either under rcu_read_lock() protection or with RTNL held. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
@@ -209,7 +209,9 @@ static inline struct node *tnode_get_child_rcu(struct tnode *tn, unsigned int i)
 {
 	struct node *ret = tnode_get_child(tn, i);
 
-	return rcu_dereference(ret);
+	return rcu_dereference_check(ret,
+				     rcu_read_lock_held() ||
+				     lockdep_rtnl_is_held());
 }
 
 static inline int tnode_child_length(const struct tnode *tn)

Original file line number	Diff line number	Diff line change
`@@ -209,7 +209,9 @@ static inline struct node tnode_get_child_rcu(struct tnode tn, unsigned int i)`
`209`	`209`	`{`
`210`	`210`	`struct node *ret = tnode_get_child(tn, i);`
`211`	`211`
`212`		`- return rcu_dereference(ret);`
	`212`	`+ return rcu_dereference_check(ret,`
	`213`	`+ rcu_read_lock_held() \|\|`
	`214`	`+ lockdep_rtnl_is_held());`
`213`	`215`	`}`
`214`	`216`
`215`	`217`	`static inline int tnode_child_length(const struct tnode *tn)`