ipv4: ip_route_output_key() is better as an inline.

This avoid a stack frame at zero cost.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/route.h

@@ -119,11 +119,15 @@ extern void		ip_rt_redirect(__be32 old_gw, __be32 dst, __be32 new_gw,
 extern void		rt_cache_flush(struct net *net, int how);
 extern void		rt_cache_flush_batch(struct net *net);
 extern struct rtable *__ip_route_output_key(struct net *, const struct flowi *flp);
-extern struct rtable *ip_route_output_key(struct net *, struct flowi *flp);
 extern struct rtable *ip_route_output_flow(struct net *, struct flowi *flp,
 					   struct sock *sk);
 extern struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig);
 
+static inline struct rtable *ip_route_output_key(struct net *net, struct flowi *flp)
+{
+	return ip_route_output_flow(net, flp, NULL);
+}
+
 extern int ip_route_input_common(struct sk_buff *skb, __be32 dst, __be32 src,
 				 u8 tos, struct net_device *devin, bool noref);
 

net/ipv4/route.c

@@ -2736,12 +2736,6 @@ struct rtable *ip_route_output_flow(struct net *net, struct flowi *flp,
 }
 EXPORT_SYMBOL_GPL(ip_route_output_flow);
 
-struct rtable *ip_route_output_key(struct net *net, struct flowi *flp)
-{
-	return ip_route_output_flow(net, flp, NULL);
-}
-EXPORT_SYMBOL(ip_route_output_key);
-
 static int rt_fill_info(struct net *net,
 			struct sk_buff *skb, u32 pid, u32 seq, int event,
 			int nowait, unsigned int flags)