Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 371b3b4..8955460 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * NET		Generic infrastructure for INET connection oriented protocols.
  *
@@ -6,11 +7,6 @@
  * Authors:	Many people, see the TCP sources
  *
  * 		From code originally in TCP
- *
- *		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.
  */
 #ifndef _INET_CONNECTION_SOCK_H
 #define _INET_CONNECTION_SOCK_H
@@ -101,7 +97,7 @@
 	const struct tcp_congestion_ops *icsk_ca_ops;
 	const struct inet_connection_sock_af_ops *icsk_af_ops;
 	const struct tcp_ulp_ops  *icsk_ulp_ops;
-	void			  *icsk_ulp_data;
+	void __rcu		  *icsk_ulp_data;
 	void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
 	struct hlist_node         icsk_listen_portaddr_node;
 	unsigned int		  (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
@@ -139,8 +135,8 @@
 	} icsk_mtup;
 	u32			  icsk_user_timeout;
 
-	u64			  icsk_ca_priv[88 / sizeof(u64)];
-#define ICSK_CA_PRIV_SIZE      (11 * sizeof(u64))
+	u64			  icsk_ca_priv[104 / sizeof(u64)];
+#define ICSK_CA_PRIV_SIZE      (13 * sizeof(u64))
 };
 
 #define ICSK_TIME_RETRANS	1	/* Retransmit timer */
@@ -314,4 +310,29 @@
 			       char __user *optval, unsigned int optlen);
 
 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
+
+#define TCP_PINGPONG_THRESH	3
+
+static inline void inet_csk_enter_pingpong_mode(struct sock *sk)
+{
+	inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;
+}
+
+static inline void inet_csk_exit_pingpong_mode(struct sock *sk)
+{
+	inet_csk(sk)->icsk_ack.pingpong = 0;
+}
+
+static inline bool inet_csk_in_pingpong_mode(struct sock *sk)
+{
+	return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
+}
+
+static inline void inet_csk_inc_pingpong_cnt(struct sock *sk)
+{
+	struct inet_connection_sock *icsk = inet_csk(sk);
+
+	if (icsk->icsk_ack.pingpong < U8_MAX)
+		icsk->icsk_ack.pingpong++;
+}
 #endif /* _INET_CONNECTION_SOCK_H */