net,rcu: convert call_rcu(ip_mc_list_reclaim) to kfree_rcu()

The rcu callback ip_mc_list_reclaim() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(ip_mc_list_reclaim).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

net/ipv4/igmp.c

@@ -149,17 +149,11 @@ static void ip_mc_clear_src(struct ip_mc_list *pmc);
 static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode,
 			 int sfcount, __be32 *psfsrc, int delta);
 
-
-static void ip_mc_list_reclaim(struct rcu_head *head)
-{
-	kfree(container_of(head, struct ip_mc_list, rcu));
-}
-
 static void ip_ma_put(struct ip_mc_list *im)
 {
 	if (atomic_dec_and_test(&im->refcnt)) {
 		in_dev_put(im->interface);
-		call_rcu(&im->rcu, ip_mc_list_reclaim);
+		kfree_rcu(im, rcu);
 	}
 }