[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/include/net/addrconf.h b/include/net/addrconf.h
index 5fc8627..aa2ed8f 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -133,20 +133,18 @@
 static inline struct inet6_dev *
 __in6_dev_get(struct net_device *dev)
 {
-	return (struct inet6_dev *)dev->ip6_ptr;
+	return rcu_dereference(dev->ip6_ptr);
 }
 
-extern rwlock_t addrconf_lock;
-
 static inline struct inet6_dev *
 in6_dev_get(struct net_device *dev)
 {
 	struct inet6_dev *idev = NULL;
-	read_lock(&addrconf_lock);
-	idev = dev->ip6_ptr;
+	rcu_read_lock();
+	idev = __in6_dev_get(dev);
 	if (idev)
 		atomic_inc(&idev->refcnt);
-	read_unlock(&addrconf_lock);
+	rcu_read_unlock();
 	return idev;
 }