diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 2330c7b..97bc26e 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -689,7 +689,8 @@
 	}
 }
 
-static struct dst_entry *tcp_v6_route_req(struct sock *sk, struct flowi *fl,
+static struct dst_entry *tcp_v6_route_req(const struct sock *sk,
+					  struct flowi *fl,
 					  const struct request_sock *req,
 					  bool *strict)
 {