net: use indirect call helpers for dst_input

This patch avoids the indirect call for the common case:
ip_local_deliver and ip6_input

Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/dst.h

@@ -18,6 +18,7 @@
 #include <linux/refcount.h>
 #include <net/neighbour.h>
 #include <asm/processor.h>
+#include <linux/indirect_call_wrapper.h>
 
 struct sk_buff;
 
@@ -441,10 +442,13 @@ static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *s
 	return skb_dst(skb)->output(net, sk, skb);
 }
 
+INDIRECT_CALLABLE_DECLARE(int ip6_input(struct sk_buff *));
+INDIRECT_CALLABLE_DECLARE(int ip_local_deliver(struct sk_buff *));
 /* Input packet from network to transport.  */
 static inline int dst_input(struct sk_buff *skb)
 {
-	return skb_dst(skb)->input(skb);
+	return INDIRECT_CALL_INET(skb_dst(skb)->input,
+				  ip6_input, ip_local_deliver, skb);
 }
 
 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)

net/ipv4/ip_input.c

@@ -253,6 +253,7 @@ int ip_local_deliver(struct sk_buff *skb)
 		       net, NULL, skb, skb->dev, NULL,
 		       ip_local_deliver_finish);
 }
+EXPORT_SYMBOL(ip_local_deliver);
 
 static inline bool ip_rcv_options(struct sk_buff *skb, struct net_device *dev)
 {