Messages in this thread | | | Date | Fri, 26 Jun 2009 17:13:29 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [patch update] PM: Introduce core framework for run-time PM of I/O devices (rev. 6) |
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On Fri, 26 Jun 2009, Rafael J. Wysocki wrote:
> > It occurs to me that the problem would be solved if were a cancel_work > > routine. In the same vein, it ought to be possible for > > cancel_delayed_work to run in interrupt context. I'll see what can be > > done. > > Having looked at the workqueue code I'm not sure if there's a way to implement > that in a non-racy way. Which may be the reason why there are no such > functions already. :-)
Well, I'll give it a try.
Speaking of races, have you noticed that the way power.work_done gets used is racy? You can't wait for the completion before releasing the lock, but then anything could happen.
A safer approach would be to use a wait_queue.
> In the meantime I reworked the patch (below) to use more RPM_* flags and I > removed the runtime_break and runtime_notify bits from it. Also added some > comments to explain some non-obvious steps (hope that helps). > > I also added the pm_runtime_put_atomic() and pm_runtime_put() as per the > comment above. > > It seems to be a bit cleaner this way, but that's my personal view. :-)
I'll look at it over the weekend. And I'll try to see if proper cancel_work and cancel_delayed_work functions can help clean it up.
Alan Stern
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