Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 7d6ff98..3349ea8 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 
 /*
  * DECnet       An implementation of the DECnet protocol suite for the LINUX
@@ -46,15 +47,6 @@
 /******************************************************************************
     (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
 
-    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
-    any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
 
 HISTORY:
 
@@ -192,7 +184,7 @@
 static unsigned short port_alloc(struct sock *sk)
 {
 	struct dn_scp *scp = DN_SK(sk);
-static unsigned short port = 0x2000;
+	static unsigned short port = 0x2000;
 	unsigned short i_port = port;
 
 	while(check_port(cpu_to_le16(++port)) != 0) {
@@ -444,7 +436,7 @@
 	skb_queue_purge(&scp->other_xmit_queue);
 	skb_queue_purge(&scp->other_receive_queue);
 
-	dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
+	dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));
 }
 
 static unsigned long dn_memory_pressure;
@@ -1213,7 +1205,7 @@
 	struct dn_scp *scp = DN_SK(sk);
 	__poll_t mask = datagram_poll(file, sock, wait);
 
-	if (!skb_queue_empty(&scp->other_receive_queue))
+	if (!skb_queue_empty_lockless(&scp->other_receive_queue))
 		mask |= EPOLLRDBAND;
 
 	return mask;
@@ -2405,7 +2397,7 @@
 
 	proto_unregister(&dn_proto);
 
-	rcu_barrier_bh(); /* Wait for completion of call_rcu_bh()'s */
+	rcu_barrier(); /* Wait for completion of call_rcu()'s */
 }
 module_exit(decnet_exit);
 #endif