openvswitch: using kfree_rcu() to simplify the code

The callback function of call_rcu() just calls a kfree(), so we
can use kfree_rcu() instead of call_rcu() + callback function.

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/flow.c

@@ -427,19 +427,11 @@ void ovs_flow_deferred_free(struct sw_flow *flow)
 	call_rcu(&flow->rcu, rcu_free_flow_callback);
 }
 
-/* RCU callback used by ovs_flow_deferred_free_acts. */
-static void rcu_free_acts_callback(struct rcu_head *rcu)
-{
-	struct sw_flow_actions *sf_acts = container_of(rcu,
-			struct sw_flow_actions, rcu);
-	kfree(sf_acts);
-}
-
 /* Schedules 'sf_acts' to be freed after the next RCU grace period.
  * The caller must hold rcu_read_lock for this to be sensible. */
 void ovs_flow_deferred_free_acts(struct sw_flow_actions *sf_acts)
 {
-	call_rcu(&sf_acts->rcu, rcu_free_acts_callback);
+	kfree_rcu(sf_acts, rcu);
 }
 
 static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)