net: unify for_each_ip_tunnel_rcu()

The defitions of for_each_ip_tunnel_rcu() are same,
so unify it. Also, don't hide the parameter 't'.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/if_tunnel.h b/include/linux/if_tunnel.h
index 06d1d5b..f4e56ec 100644
--- a/include/linux/if_tunnel.h
+++ b/include/linux/if_tunnel.h
@@ -6,6 +6,13 @@
 #include <uapi/linux/if_tunnel.h>
 #include <linux/u64_stats_sync.h>
 
+/*
+ * Locking : hash tables are protected by RCU and RTNL
+ */
+
+#define for_each_ip_tunnel_rcu(pos, start) \
+	for (pos = rcu_dereference(start); pos; pos = rcu_dereference(pos->next))
+
 /* often modified stats are per cpu, other are shared (netdev->stats) */
 struct pcpu_tstats {
 	u64	rx_packets;