_cpu_down() acquires `workqueue_mutex' on its process, but doen't release it
if __cpu_disable() fails.
Signed-off-by: NSatoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>