tcp: cleanup of cwnd initialization in tcp_init_metrics()

Commit 86bcebafc5e7f5 ("tcp: fix >2 iw selection") fixed a case
when congestion window initialization has been mistakenly omitted
by introducing cwnd label and putting backwards goto from the
end of the function.

This makes the code unnecessarily tricky to read and understand
on a first sight.

Shuffle the code around a little bit to make it more obvious.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp_input.c

@@ -916,25 +916,20 @@ static void tcp_init_metrics(struct sock *sk)
 		tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk));
 	}
 	tcp_set_rto(sk);
-	if (inet_csk(sk)->icsk_rto < TCP_TIMEOUT_INIT && !tp->rx_opt.saw_tstamp)
-		goto reset;
-
-cwnd:
-	tp->snd_cwnd = tcp_init_cwnd(tp, dst);
-	tp->snd_cwnd_stamp = tcp_time_stamp;
-	return;
-
+	if (inet_csk(sk)->icsk_rto < TCP_TIMEOUT_INIT && !tp->rx_opt.saw_tstamp) {
 reset:
-	/* Play conservative. If timestamps are not
-	 * supported, TCP will fail to recalculate correct
-	 * rtt, if initial rto is too small. FORGET ALL AND RESET!
-	 */
-	if (!tp->rx_opt.saw_tstamp && tp->srtt) {
-		tp->srtt = 0;
-		tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_INIT;
-		inet_csk(sk)->icsk_rto = TCP_TIMEOUT_INIT;
+		/* Play conservative. If timestamps are not
+		 * supported, TCP will fail to recalculate correct
+		 * rtt, if initial rto is too small. FORGET ALL AND RESET!
+		 */
+		if (!tp->rx_opt.saw_tstamp && tp->srtt) {
+			tp->srtt = 0;
+			tp->mdev = tp->mdev_max = tp->rttvar = TCP_TIMEOUT_INIT;
+			inet_csk(sk)->icsk_rto = TCP_TIMEOUT_INIT;
+		}
 	}
-	goto cwnd;
+	tp->snd_cwnd = tcp_init_cwnd(tp, dst);
+	tp->snd_cwnd_stamp = tcp_time_stamp;
 }
 
 static void tcp_update_reordering(struct sock *sk, const int metric,