Notifier callbacks have to return either one of NOTIFY_* codes or a negative
errno, converted to a suitable value by the notifier_from_errno() inline, if
the notifier chain shall not be continued.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Paul Mundt <lethal@linux-sh.org>