dlm: recheck kthread_should_stop() before schedule()
Call schedule() here could make the thread miss wake
up from kthread_stop(), so it is better to recheck
kthread_should_stop() before call schedule(), a symptom
happened when I run indefinite test (which mostly created
clustered raid1, assemble it in other nodes, then stop
them) of clustered raid.
This maybe not resolve the issue completely since the
KTHREAD_SHOULD_STOP flag could be set between "break"
and "schedule", but at least the chance for the symptom
happen could be reduce a lot (The indefinite test runs
more than 20 hours without problem and it happens easily
without the change).
Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: David Teigland <teigland@redhat.com>