[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/sctp/ipv6.c b/net/sctp/ipv6.c
index fd87e3c..249e503 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -321,9 +321,9 @@
 	struct inet6_ifaddr *ifp;
 	struct sctp_sockaddr_entry *addr;
 
-	read_lock(&addrconf_lock);
+	rcu_read_lock();
 	if ((in6_dev = __in6_dev_get(dev)) == NULL) {
-		read_unlock(&addrconf_lock);
+		rcu_read_unlock();
 		return;
 	}
 
@@ -342,7 +342,7 @@
 	}
 
 	read_unlock(&in6_dev->lock);
-	read_unlock(&addrconf_lock);
+	rcu_read_unlock();
 }
 
 /* Initialize a sockaddr_storage from in incoming skb. */