net/802: add __rcu annotations

(struct net_device)->garp_port is rcu protected :
(struct garp_port)->applicants 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/net/802/garp.c b/net/802/garp.c
index 941f2a3..c1df2da 100644
--- a/net/802/garp.c
+++ b/net/802/garp.c
@@ -346,8 +346,8 @@
 		      const struct garp_application *appl,
 		      const void *data, u8 len, u8 type)
 {
-	struct garp_port *port = dev->garp_port;
-	struct garp_applicant *app = port->applicants[appl->type];
+	struct garp_port *port = rtnl_dereference(dev->garp_port);
+	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
 	struct garp_attr *attr;
 
 	spin_lock_bh(&app->lock);
@@ -366,8 +366,8 @@
 			const struct garp_application *appl,
 			const void *data, u8 len, u8 type)
 {
-	struct garp_port *port = dev->garp_port;
-	struct garp_applicant *app = port->applicants[appl->type];
+	struct garp_port *port = rtnl_dereference(dev->garp_port);
+	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
 	struct garp_attr *attr;
 
 	spin_lock_bh(&app->lock);
@@ -546,11 +546,11 @@
 
 static void garp_release_port(struct net_device *dev)
 {
-	struct garp_port *port = dev->garp_port;
+	struct garp_port *port = rtnl_dereference(dev->garp_port);
 	unsigned int i;
 
 	for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
-		if (port->applicants[i])
+		if (rtnl_dereference(port->applicants[i]))
 			return;
 	}
 	rcu_assign_pointer(dev->garp_port, NULL);
@@ -565,7 +565,7 @@
 
 	ASSERT_RTNL();
 
-	if (!dev->garp_port) {
+	if (!rtnl_dereference(dev->garp_port)) {
 		err = garp_init_port(dev);
 		if (err < 0)
 			goto err1;
@@ -601,8 +601,8 @@
 
 void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)
 {
-	struct garp_port *port = dev->garp_port;
-	struct garp_applicant *app = port->applicants[appl->type];
+	struct garp_port *port = rtnl_dereference(dev->garp_port);
+	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
 
 	ASSERT_RTNL();