Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/lib/assoc_array.c b/lib/assoc_array.c
index c6659cb..6f4bcf5 100644
--- a/lib/assoc_array.c
+++ b/lib/assoc_array.c
@@ -1,14 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* Generic associative array implementation.
  *
  * See Documentation/core-api/assoc_array.rst for information.
  *
  * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
  */
 //#define DEBUG
 #include <linux/rcupdate.h>
@@ -768,9 +764,11 @@
 		new_s0->index_key[i] =
 			ops->get_key_chunk(index_key, i * ASSOC_ARRAY_KEY_CHUNK_SIZE);
 
-	blank = ULONG_MAX << (level & ASSOC_ARRAY_KEY_CHUNK_MASK);
-	pr_devel("blank off [%zu] %d: %lx\n", keylen - 1, level, blank);
-	new_s0->index_key[keylen - 1] &= ~blank;
+	if (level & ASSOC_ARRAY_KEY_CHUNK_MASK) {
+		blank = ULONG_MAX << (level & ASSOC_ARRAY_KEY_CHUNK_MASK);
+		pr_devel("blank off [%zu] %d: %lx\n", keylen - 1, level, blank);
+		new_s0->index_key[keylen - 1] &= ~blank;
+	}
 
 	/* This now reduces to a node splitting exercise for which we'll need
 	 * to regenerate the disparity table.
@@ -1115,6 +1113,7 @@
 						index_key))
 				goto found_leaf;
 		}
+		/* fall through */
 	case assoc_array_walk_tree_empty:
 	case assoc_array_walk_found_wrong_shortcut:
 	default: