rcu: convert uses of rcu_assign_pointer(x, NULL) to RCU_INIT_POINTER

When assigning a NULL value to an RCU protected pointer, no barrier
is needed. The rcu_assign_pointer, used to handle that but will soon
change to not handle the special case.

Convert all rcu_assign_pointer of NULL value.

//smpl
@@ expression P; @@

- rcu_assign_pointer(P, NULL)
+ RCU_INIT_POINTER(P, NULL)

// </smpl>

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 07bf108..e48a41c 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -182,7 +182,7 @@
 	     (iter = rtnl_dereference(*tp)) != NULL;
 	     tp = &iter->next) {
 		if (t == iter) {
-			rcu_assign_pointer(*tp, t->next);
+			RCU_INIT_POINTER(*tp, t->next);
 			break;
 		}
 	}
@@ -192,8 +192,8 @@
 {
 	struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 
-	rcu_assign_pointer(t->next, rtnl_dereference(*tp));
-	rcu_assign_pointer(*tp, t);
+	RCU_INIT_POINTER(t->next, rtnl_dereference(*tp));
+	RCU_INIT_POINTER(*tp, t);
 }
 
 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
@@ -391,7 +391,7 @@
 	p->addr = a->addr;
 	p->flags = a->flags;
 	t->prl_count++;
-	rcu_assign_pointer(t->prl, p);
+	RCU_INIT_POINTER(t->prl, p);
 out:
 	return err;
 }
@@ -474,7 +474,7 @@
 	struct sit_net *sitn = net_generic(net, sit_net_id);
 
 	if (dev == sitn->fb_tunnel_dev) {
-		rcu_assign_pointer(sitn->tunnels_wc[0], NULL);
+		RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 	} else {
 		ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 		ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
@@ -1173,7 +1173,7 @@
 	if (!dev->tstats)
 		return -ENOMEM;
 	dev_hold(dev);
-	rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
+	RCU_INIT_POINTER(sitn->tunnels_wc[0], tunnel);
 	return 0;
 }