[IPV6] ADDRCONF: Convert addrconf_lock to RCU.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index b80fc50..a960476 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -56,7 +56,7 @@
 	int	onlink;
 
 	onlink = 0;
-	read_lock(&addrconf_lock);
+	rcu_read_lock();
 	idev = __in6_dev_get(dev);
 	if (idev) {
 		read_lock_bh(&idev->lock);
@@ -68,7 +68,7 @@
 		}
 		read_unlock_bh(&idev->lock);
 	}
-	read_unlock(&addrconf_lock);
+	rcu_read_unlock();
 	return onlink;
 }