Changes:
[PATCH 1/2] reimplement flush_workqueue()
Not changed, just re-diff against 2.6.20-rc2-mm1
[PATCH 2/2] implement flush_work()
Fix a race vs cpu-hotplug. The work should be dequeued before
we check any CPU for ->current_work == work, otherwise the work
can migrate to already checked CPU.
Oleg.