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: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 5f15fcc..2348199 100644
--- a/net/ipv4/tcp.c
+++ b/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 */