net: reintroduce missing rcu_assign_pointer() calls

commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index a4894f4..d02f7e4 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -131,7 +131,7 @@
 
 int rawv6_mh_filter_register(mh_filter_t filter)
 {
-	RCU_INIT_POINTER(mh_filter, filter);
+	rcu_assign_pointer(mh_filter, filter);
 	return 0;
 }
 EXPORT_SYMBOL(rawv6_mh_filter_register);