neigh: use NEIGH_VAR_INIT in ndo_neigh_setup functions.

When ndo_neigh_setup is called, the bitfield used by NEIGH_VAR_SET is
not initialized yet. This might cause confusion for the people who use
NEIGH_VAR_SET in ndo_neigh_setup. So rather introduce NEIGH_VAR_INIT for
usage in ndo_neigh_setup.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 4c09bd2..7277caf 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -92,6 +92,11 @@
 }
 
 #define NEIGH_VAR(p, attr) ((p)->data[NEIGH_VAR_ ## attr])
+
+/* In ndo_neigh_setup, NEIGH_VAR_INIT should be used.
+ * In other cases, NEIGH_VAR_SET should be used.
+ */
+#define NEIGH_VAR_INIT(p, attr, val) (NEIGH_VAR(p, attr) = val)
 #define NEIGH_VAR_SET(p, attr, val) neigh_var_set(p, NEIGH_VAR_ ## attr, val)
 
 static inline void neigh_parms_data_state_setall(struct neigh_parms *p)