driver: ipvlan: Free ipvl_port directly with kfree instead of kfree_rcu

There are two functions which would free the ipvl_port now. The first
is ipvlan_port_create. It frees the ipvl_port in the error handler,
so it could kfree it directly. The second is ipvlan_port_destroy. It
invokes netdev_rx_handler_unregister which enforces one grace period
by synchronize_net firstly, so it also could kfree the ipvl_port
directly and safely.

So it is unnecessary to use kfree_rcu to free ipvl_port.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipvlan/ipvlan.h

@@ -97,7 +97,6 @@ struct ipvl_port {
 	struct work_struct	wq;
 	struct sk_buff_head	backlog;
 	int			count;
-	struct rcu_head		rcu;
 };
 
 static inline struct ipvl_port *ipvlan_port_get_rcu(const struct net_device *d)

drivers/net/ipvlan/ipvlan_main.c

@@ -128,7 +128,7 @@ static int ipvlan_port_create(struct net_device *dev)
 	return 0;
 
 err:
-	kfree_rcu(port, rcu);
+	kfree(port);
 	return err;
 }
 
@@ -145,7 +145,7 @@ static void ipvlan_port_destroy(struct net_device *dev)
 	netdev_rx_handler_unregister(dev);
 	cancel_work_sync(&port->wq);
 	__skb_queue_purge(&port->backlog);
-	kfree_rcu(port, rcu);
+	kfree(port);
 }
 
 #define IPVLAN_FEATURES \