ea47ab11 Tue Sep 07 15:14:05 CDT 2021 Al Viro <viro@zeniv.linux.org.uk> putname(): IS_ERR_OR_NULL() is wrong here
Mixing NULL and ERR_PTR() just in case is a Bad Idea(tm). For struct filename the former is wrong - failures are reported as ERR_PTR(...), not as NULL.