Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/dccp/timer.c b/net/dccp/timer.c
index 1501a20..c0b3672 100644
--- a/net/dccp/timer.c
+++ b/net/dccp/timer.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  net/dccp/timer.c
  *
  *  An implementation of the DCCP protocol
  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
- *
- *	This program is free software; you can redistribute it and/or
- *	modify it under the terms of the GNU General Public License
- *	as published by the Free Software Foundation; either version
- *	2 of the License, or (at your option) any later version.
  */
 
 #include <linux/dccp.h>
@@ -199,7 +195,7 @@
 	icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
 
 	if (inet_csk_ack_scheduled(sk)) {
-		if (!icsk->icsk_ack.pingpong) {
+		if (!inet_csk_in_pingpong_mode(sk)) {
 			/* Delayed ACK missed: inflate ATO. */
 			icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
 						 icsk->icsk_rto);
@@ -207,7 +203,7 @@
 			/* Delayed ACK missed: leave pingpong mode and
 			 * deflate ATO.
 			 */
-			icsk->icsk_ack.pingpong = 0;
+			inet_csk_exit_pingpong_mode(sk);
 			icsk->icsk_ack.ato = TCP_ATO_MIN;
 		}
 		dccp_send_ack(sk);