Cc: Jeff Moyer <jmoyer@redhat.com>

Cc: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/direct-io.c

@@ -130,6 +130,12 @@ struct dio {
 	unsigned head;			/* next page to process */
 	unsigned tail;			/* last valid page + 1 */
 	int page_errors;		/* errno from get_user_pages() */
+
+	/*
+	 * pages[] (and any fields placed after it) are not zeroed out at
+	 * allocation time.  Don't add new fields after pages[] unless you
+	 * wish that they not be zeroed.
+	 */
 	struct page *pages[DIO_PAGES];	/* page buffer */
 };