tcp: share code through function, not through copy-paste. :-)

Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_input.c

@@ -3052,6 +3052,13 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, int flag)
 	tcp_xmit_retransmit_queue(sk);
 }
 
+static void tcp_valid_rtt_meas(struct sock *sk, u32 seq_rtt)
+{
+	tcp_rtt_estimator(sk, seq_rtt);
+	tcp_set_rto(sk);
+	inet_csk(sk)->icsk_backoff = 0;
+}
+
 /* Read draft-ietf-tcplw-high-performance before mucking
  * with this code. (Supersedes RFC1323)
  */
@@ -3073,10 +3080,8 @@ static void tcp_ack_saw_tstamp(struct sock *sk, int flag)
 	 * in window is lost... Voila.	 			--ANK (010210)
 	 */
 	struct tcp_sock *tp = tcp_sk(sk);
-	const __u32 seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
-	tcp_rtt_estimator(sk, seq_rtt);
-	tcp_set_rto(sk);
-	inet_csk(sk)->icsk_backoff = 0;
+
+	tcp_valid_rtt_meas(sk, tcp_time_stamp - tp->rx_opt.rcv_tsecr);
 }
 
 static void tcp_ack_no_tstamp(struct sock *sk, u32 seq_rtt, int flag)
@@ -3093,9 +3098,7 @@ static void tcp_ack_no_tstamp(struct sock *sk, u32 seq_rtt, int flag)
 	if (flag & FLAG_RETRANS_DATA_ACKED)
 		return;
 
-	tcp_rtt_estimator(sk, seq_rtt);
-	tcp_set_rto(sk);
-	inet_csk(sk)->icsk_backoff = 0;
+	tcp_valid_rtt_meas(sk, seq_rtt);
 }
 
 static inline void tcp_ack_update_rtt(struct sock *sk, const int flag,