tcp: clear tp->delivered in tcp_disconnect()

tp->delivered needs to be cleared in tcp_disconnect().

tcp_disconnect() is rarely used, but it is worth fixing it.

Fixes: ddf1af6 ("tcp: new delivery accounting")
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Yuchung Cheng <[email protected]>
Cc: Neal Cardwell <[email protected]>
Acked-by: Yuchung Cheng <[email protected]>
Acked-by: Neal Cardwell <[email protected]>
Acked-by: Soheil Hassas Yeganeh <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

Author: edumazet

net/ipv4/tcp.c

@@ -2622,6 +2622,7 @@ int tcp_disconnect(struct sock *sk, int flags)
 	tp->snd_cwnd = TCP_INIT_CWND;
 	tp->snd_cwnd_cnt = 0;
 	tp->window_clamp = 0;
+	tp->delivered = 0;
 	tp->delivered_ce = 0;
 	tcp_set_ca_state(sk, TCP_CA_Open);
 	tp->is_sack_reneg = 0;