[NET] NETNS: Omit neigh_parms->net and pneigh_entry->net without CONFIG_NET_NS.

Introduce neigh_parms/pneigh_entry inlines: neigh_parms_net(), pneigh_net().
Without CONFIG_NET_NS, no namespace other than &init_net exists.
Let's explicitly define them to help compiler optimizations.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 0622818..8bec0d6 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -38,7 +38,9 @@
 
 struct neigh_parms
 {
+#ifdef CONFIG_NET_NS
 	struct net *net;
+#endif
 	struct net_device *dev;
 	struct neigh_parms *next;
 	int	(*neigh_setup)(struct neighbour *);
@@ -131,7 +133,9 @@
 struct pneigh_entry
 {
 	struct pneigh_entry	*next;
+#ifdef CONFIG_NET_NS
 	struct net		*net;
+#endif
 	struct net_device	*dev;
 	u8			flags;
 	u8			key[0];
@@ -213,6 +217,17 @@
 
 extern struct neigh_parms	*neigh_parms_alloc(struct net_device *dev, struct neigh_table *tbl);
 extern void			neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms);
+
+static inline
+struct net			*neigh_parms_net(const struct neigh_parms *parms)
+{
+#ifdef CONFIG_NET_NS
+	return parms->net;
+#else
+	return &init_net;
+#endif
+}
+
 extern unsigned long		neigh_rand_reach_time(unsigned long base);
 
 extern void			pneigh_enqueue(struct neigh_table *tbl, struct neigh_parms *p,
@@ -220,6 +235,16 @@
 extern struct pneigh_entry	*pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev, int creat);
 extern int			pneigh_delete(struct neigh_table *tbl, struct net *net, const void *key, struct net_device *dev);
 
+static inline
+struct net			*pneigh_net(const struct pneigh_entry *pneigh)
+{
+#ifdef CONFIG_NET_NS
+	return pneigh->net;
+#else
+	return &init_net;
+#endif
+}
+
 extern void neigh_app_ns(struct neighbour *n);
 extern void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void *), void *cookie);
 extern void __neigh_for_each_release(struct neigh_table *tbl, int (*cb)(struct neighbour *));