such expression:
	if (err)
		return err;
	return 0;
can simplify to:
	return err;
Signed-off-by: William Dean <williamsukatube@163.com>
Link: https://lore.kernel.org/r/20220917063556.2673-1-williamsukatube@163.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>