vlan: rcu annotations

(struct net_device)->vlgrp is rcu protected :

add __rcu annotation and proper rcu primitives.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index fcd3dda..ceefb441 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -944,7 +944,7 @@
 	/* Protocol specific pointers */
 
 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
-	struct vlan_group	*vlgrp;		/* VLAN group */
+	struct vlan_group __rcu	*vlgrp;		/* VLAN group */
 #endif
 #ifdef CONFIG_NET_DSA
 	void			*dsa_ptr;	/* dsa specific data */