On 12/13/2012 10:41 AM, Johannes Berg wrote:
On Thu, 2012-12-13 at 10:39 -0800, Ben Greear wrote:
So, near where we currently call cancel_work_sync(&sdata->work), I
think we'd also need to cancel things like the sta->ampdu_mlme.work,
and probably others as well.
Then, when we're sure there are no more references to sdata on the
main-work-queue, it would be safe to flush the destructor-workqueue
(which would have the fre_sta_work() on it).
Maybe?
Huh, ok, but I don't think you'll find much that doesn't reference an
sdata?
I think you are right...so just need to find all of those work items
and call cancel_work_sync() on them, just like we are currently cancelling
the sdata->work....
Well the concern there is that we expose the workqueue to the driver,
and it might even put sdata-referencing work items on it and expect them
to be flushed out before stop_interface() is called?
You'd be welcome to change the API so that isn't true, or things are
different, or whatever, but it'd be a lot of careful auditing (and
probably fixing) of drivers.
So, maybe a new driver api call to 'cancel_all_work_items(sdata)',
and if the driver does not implement this, then we stick with the
full flush_workqueue() in mac80211_do_stop(). But, if the driver
does implement it, and we add code there to flush any mac80211 related
work-items, then we could skip the flush_workqueue() call....
I'll go looking in ath9k to see how much it uses the work-queue...that
driver is my only real concern at the moment.
Thanks,
Ben
johannes
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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