Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/samples/bpf/hbm.h b/samples/bpf/hbm.h
new file mode 100644
index 0000000..f0963ed
--- /dev/null
+++ b/samples/bpf/hbm.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (c) 2019 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * Include file for Host Bandwidth Management (HBM) programs
+ */
+struct hbm_vqueue {
+	struct bpf_spin_lock lock;
+	/* 4 byte hole */
+	unsigned long long lasttime;	/* In ns */
+	int credit;			/* In bytes */
+	unsigned int rate;		/* In bytes per NS << 20 */
+};
+
+struct hbm_queue_stats {
+	unsigned long rate;		/* in Mbps*/
+	unsigned long stats:1,		/* get HBM stats (marked, dropped,..) */
+		loopback:1,		/* also limit flows using loopback */
+		no_cn:1;		/* do not use cn flags */
+	unsigned long long pkts_marked;
+	unsigned long long bytes_marked;
+	unsigned long long pkts_dropped;
+	unsigned long long bytes_dropped;
+	unsigned long long pkts_total;
+	unsigned long long bytes_total;
+	unsigned long long firstPacketTime;
+	unsigned long long lastPacketTime;
+	unsigned long long pkts_ecn_ce;
+	unsigned long long returnValCount[4];
+	unsigned long long sum_cwnd;
+	unsigned long long sum_rtt;
+	unsigned long long sum_cwnd_cnt;
+	long long sum_credit;
+};