net: treewide use of RCU_INIT_POINTER

rcu_assign_pointer(ptr, NULL) can be safely replaced by
RCU_INIT_POINTER(ptr, NULL)

(old rcu_assign_pointer() macro was testing the NULL value and could
omit the smp_wmb(), but this had to be removed because of compiler
warnings)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 1b7082d..7c88d13 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -145,8 +145,8 @@
 	if (vlan) {
 		int index = get_slot(vlan, q);
 
-		rcu_assign_pointer(vlan->taps[index], NULL);
-		rcu_assign_pointer(q->vlan, NULL);
+		RCU_INIT_POINTER(vlan->taps[index], NULL);
+		RCU_INIT_POINTER(q->vlan, NULL);
 		sock_put(&q->sk);
 		--vlan->numvtaps;
 	}
@@ -223,8 +223,8 @@
 					      lockdep_is_held(&macvtap_lock));
 		if (q) {
 			qlist[j++] = q;
-			rcu_assign_pointer(vlan->taps[i], NULL);
-			rcu_assign_pointer(q->vlan, NULL);
+			RCU_INIT_POINTER(vlan->taps[i], NULL);
+			RCU_INIT_POINTER(q->vlan, NULL);
 			vlan->numvtaps--;
 		}
 	}