Re: [PATCH 4/9] firewire: don't use PREPARE_DELAYED_WORK

From: Stefan Richter
Date: Wed Mar 05 2014 - 16:34:59 EST


On Feb 21 Stefan Richter wrote:
> On Feb 20 Tejun Heo wrote:
> > PREPARE_[DELAYED_]WORK() are being phased out. They have few users
> > and a nasty surprise in terms of reentrancy guarantee as workqueue
> > considers work items to be different if they don't have the same work
> > function.
> >
> > firewire core-device and sbp2 have been been multiplexing work items
> > with multiple work functions. Introduce fw_device_workfn() and
> > sbp2_lu_workfn() which invoke fw_device->workfn and
> > sbp2_logical_unit->workfn respectively and always use the two
> > functions as the work functions and update the users to set the
> > ->workfn fields instead of overriding work functions using
> > PREPARE_DELAYED_WORK().
> >
> > It would probably be best to route this with other related updates
> > through the workqueue tree.
> >
> > Compile tested.
> >
> > Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> > Cc: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
> > Cc: linux1394-devel@xxxxxxxxxxxxxxxxxxxxx
>
> Acked-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>

Actually, there is something missing in the changelog:

This fixes a variety of possible regressions since a2c1c57be8d9
"workqueue: consider work function when searching for busy work items"
due to which fw_workqueue lost its required non-reentrancy property.

Cc: stable@xxxxxxxxxx # v3.9+
Cc: stable@xxxxxxxxxx # v3.8.2+
Cc: stable@xxxxxxxxxx # v3.4.60+
Cc: stable@xxxxxxxxxx # v3.2.40+

Tejun, will you be adding these and push the patch at the latest before
v3.15-rc1? Otherwise, I will take over the patch and push it still this
week, i.e. before v3.14-rc6.
--
Stefan Richter
-=====-====- --== --=-=
http://arcgraph.de/sr/
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