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: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -475,7 +475,7 @@ int br_del_if(struct net_bridge *br, struct net_device *dev)
 {
 	struct net_bridge_port *p;
 
-	p = br_port_get(dev);
+	p = br_port_get_rtnl(dev);
 	if (!p || p->br != br)
 		return -EINVAL;
 

net/bridge/br_netlink.c

@@ -119,7 +119,7 @@ static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 
 	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 @@ static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 	if (!dev)
 		return -ENODEV;
 
-	p = br_port_get(dev);
+	p = br_port_get_rtnl(dev);
 	if (!p)
 		return -EINVAL;
 

net/bridge/br_notify.c

@@ -37,10 +37,10 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
 	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) {

net/bridge/br_private.h

@@ -159,9 +159,10 @@ static inline struct net_bridge_port *br_port_get_rcu(const struct net_device *d
 	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 {