bridge: add RCU annotations to bridge port lookup

br_port_get() renamed to br_port_get_rtnl() to make clear RTNL is held.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 427f90a..d9d1e2b 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -475,7 +475,7 @@
 {
 	struct net_bridge_port *p;
 
-	p = br_port_get(dev);
+	p = br_port_get_rtnl(dev);
 	if (!p || p->br != br)
 		return -EINVAL;
 
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index e3de0a4..f8bf4c7 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -119,7 +119,7 @@
 
 	idx = 0;
 	for_each_netdev(net, dev) {
-		struct net_bridge_port *port = br_port_get(dev);
+		struct net_bridge_port *port = br_port_get_rtnl(dev);
 
 		/* not a bridge port */
 		if (!port || idx < cb->args[0])
@@ -171,7 +171,7 @@
 	if (!dev)
 		return -ENODEV;
 
-	p = br_port_get(dev);
+	p = br_port_get_rtnl(dev);
 	if (!p)
 		return -EINVAL;
 
diff --git a/net/bridge/br_notify.c b/net/bridge/br_notify.c
index ef2175c..7d337c9 100644
--- a/net/bridge/br_notify.c
+++ b/net/bridge/br_notify.c
@@ -37,10 +37,10 @@
 	int err;
 
 	/* not a port of a bridge */
-	if (!br_port_exists(dev))
+	p = br_port_get_rtnl(dev);
+	if (!p)
 		return NOTIFY_DONE;
 
-	p = br_port_get(dev);
 	br = p->br;
 
 	switch (event) {
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 46e0bec..84aac77 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -159,9 +159,10 @@
 	return br_port_exists(dev) ? port : NULL;
 }
 
-static inline struct net_bridge_port *br_port_get(struct net_device *dev)
+static inline struct net_bridge_port *br_port_get_rtnl(struct net_device *dev)
 {
-	return br_port_exists(dev) ? dev->rx_handler_data : NULL;
+	return br_port_exists(dev) ?
+		rtnl_dereference(dev->rx_handler_data) : NULL;
 }
 
 struct br_cpu_netstats {