ipv4: tcp: dont cache output dst for syncookies

Don't cache output dst for syncookies, as this adds pressure on IP route
cache and rcu subsystem for no gain.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index e1b7734..af3c743 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -251,7 +251,8 @@
 
 extern struct dst_entry* inet_csk_route_req(struct sock *sk,
 					    struct flowi4 *fl4,
-					    const struct request_sock *req);
+					    const struct request_sock *req,
+					    bool nocache);
 extern struct dst_entry* inet_csk_route_child_sock(struct sock *sk,
 						   struct sock *newsk,
 						   const struct request_sock *req);