diff --git a/include/net/tcp.h b/include/net/tcp.h
index 306580c..7de4ea3 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -786,27 +786,7 @@
 {
 	return tp->snd_una + tp->snd_wnd;
 }
-
-/* RFC2861 Check whether we are limited by application or congestion window
- * This is the inverse of cwnd check in tcp_tso_should_defer
- */
-static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
-{
-	const struct tcp_sock *tp = tcp_sk(sk);
-	u32 left;
-
-	if (in_flight >= tp->snd_cwnd)
-		return 1;
-
-	if (!sk_can_gso(sk))
-		return 0;
-
-	left = tp->snd_cwnd - in_flight;
-	if (sysctl_tcp_tso_win_divisor)
-		return left * sysctl_tcp_tso_win_divisor < tp->snd_cwnd;
-	else
-		return left <= tcp_max_burst(tp);
-}
+extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight);
 
 static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
 				       const struct sk_buff *skb)