Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index f84f167..cfce186 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -17,8 +17,8 @@
 #ifdef CONFIG_PAGE_EXTENSION
 
 enum page_ext_flags {
-	PAGE_EXT_DEBUG_GUARD,
 	PAGE_EXT_OWNER,
+	PAGE_EXT_OWNER_ALLOCATED,
 #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
 	PAGE_EXT_YOUNG,
 	PAGE_EXT_IDLE,
@@ -36,6 +36,7 @@
 	unsigned long flags;
 };
 
+extern unsigned long page_ext_size;
 extern void pgdat_page_ext_init(struct pglist_data *pgdat);
 
 #ifdef CONFIG_SPARSEMEM
@@ -52,6 +53,13 @@
 
 struct page_ext *lookup_page_ext(const struct page *page);
 
+static inline struct page_ext *page_ext_next(struct page_ext *curr)
+{
+	void *next = curr;
+	next += page_ext_size;
+	return next;
+}
+
 #else /* !CONFIG_PAGE_EXTENSION */
 struct page_ext;