tcp: move tp->rack init to tcp_disconnect()

If we make sure all listeners have proper tp->rack value,
then a clone will also inherit proper initial value.

Note that fresh sockets init tp->rack from tcp_init_sock()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

@@ -2611,6 +2611,12 @@ int tcp_disconnect(struct sock *sk, int flags)
 	tp->last_oow_ack_time = 0;
 	/* There's a bubble in the pipe until at least the first ACK. */
 	tp->app_limited = ~0U;
+	tp->rack.mstamp = 0;
+	tp->rack.advanced = 0;
+	tp->rack.reo_wnd_steps = 1;
+	tp->rack.last_delivered = 0;
+	tp->rack.reo_wnd_persist = 0;
+	tp->rack.dsack_seen = 0;
 
 
 	/* Clean up fastopen related fields */

net/ipv4/tcp_minisocks.c

@@ -535,12 +535,6 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
 	newtp->fastopen_req = NULL;
 	newtp->fastopen_rsk = NULL;
 	newtp->syn_data_acked = 0;
-	newtp->rack.mstamp = 0;
-	newtp->rack.advanced = 0;
-	newtp->rack.reo_wnd_steps = 1;
-	newtp->rack.last_delivered = 0;
-	newtp->rack.reo_wnd_persist = 0;
-	newtp->rack.dsack_seen = 0;
 
 	__TCP_INC_STATS(sock_net(sk), TCP_MIB_PASSIVEOPENS);