[PATCHSET] workqueue: implement alloc_ordered_workqueue() and flush[_delayed]_work_sync()

[Tejun Heo <tj@kernel.org>]

Hello,

This patchset implements new workqueue API fucntions -
alloc_ordered_workqueue() and flush[_delayed]_work_sync().

The former is rather straight-forward replacement for
alloc_singlethread/frozen_workqueue().

The latter two are similar to cancel[_delayed]_work_sync() but wait
for the work to finish execution rather than cancelling them.  These
syncing flushes make sure that works which were queued on multiple
workqueues or a reentrant workqueues have finished execution on all
CPUs.  One usage of these new flushes is replacing
flush_scheduled_works() with finer scoped flushes.

This patchset contains the following four patches.

 0001-workqueue-implement-alloc_ordered_workqueue.patch
 0002-workqueue-cleanup-flush-cancel-functions.patch
 0003-workqueue-factor-out-start_flush_work.patch
 0004-workqueue-implement-flush-_delayed-_work_sync.patch

0001 adds alloc_ordered_workqueue().  0002-0003 prepare for syncing
flushes.  0004 implements them.

Dmitry, as I wrote before, I think serio should be able to simply use
schedule_work() combined with flush_work_sync() implemented by this
patchset.  Would this work for you?

The patches are available in the following git tree.

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git review-flush_sync

and contains the following changes.

 include/linux/workqueue.h |   38 +++++-
 kernel/workqueue.c        |  265 +++++++++++++++++++++++++++++-----------------
 2 files changed, 201 insertions(+), 102 deletions(-)

Thanks.

--
tejun