[PATCHSET] dm: update workqueue usages

[Tejun Heo <tj@kernel.org>]

Hello,

This patchset updates workqueue usages in dm and contains the
following six patches.

 0001-dm-stripe-drop-kstriped.patch
 0002-dm-snap-kill-unused-dm_snapshot-queued_bios_work-and.patch
 0003-dm-snap-convert-to-alloc-_ordered-_workqueue.patch
 0004-dm-don-t-use-flush_scheduled_work.patch
 0005-dm-use-non-reentrant-workqueues-if-equivalent.patch
 0006-dm-snap-persistent-make-metadata_wq-multithreaded.patch

0001-0002 drop unnecessary workqueues.  0003-0004 conver to the new
APIs.  0005-0006 relax ordering requirement of some workqueues.

All patches in this series shouldn't introduce any noticeable
difference in work execution ordering.  I stayed away from more
difficult ones like...

* Can the workqueues converted by 0005 be multithreaded instead of
  non-reentrant?

* Does dm-mpath::kmpath_handlerd need WQ_RESCUER?  I suspect not but
  not sure.  If not, it can be dropped and system_wq or kmultipathd
  can be used instead.  Another curious thing here is that while
  activate_path work is queued to kmpath_handlerd, deactivate_path is
  queued to kmultipathd.  Is this intentional?  If so, it might be a
  good idea to comment why it's done that way as it's a bit confusing.

* I'm pretty sure workqueues in dm-crypt would benefit from using
  multithreaded workqueue but people already seem to be working on it
  so I left it alone.

This patchset is on top of 2.6.37-rc5 (6313e3c2).  If it needs to be
against a different tree, please let me know.  The patches are also
available in the following git tree.

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git update-dm

and contains the following changes.  Thanks.

 drivers/md/dm-crypt.c           |    4 ++--
 drivers/md/dm-delay.c           |    2 +-
 drivers/md/dm-kcopyd.c          |    3 ++-
 drivers/md/dm-mpath.c           |    7 ++++---
 drivers/md/dm-raid1.c           |    5 +++--
 drivers/md/dm-snap-persistent.c |    4 ++--
 drivers/md/dm-snap.c            |   38 --------------------------------------
 drivers/md/dm-stripe.c          |   25 ++++++-------------------
 drivers/md/dm.c                 |    3 ++-
 9 files changed, 22 insertions(+), 69 deletions(-)

--
tejun