On 6/23/08, Michael Buesch <mb@xxxxxxxxx> wrote:
> On Monday 23 June 2008 10:30:47 Ivo Van Doorn wrote:
>> On 6/23/08, Michael Buesch <mb@xxxxxxxxx> wrote:
>> > On Monday 23 June 2008 00:42:41 Ivo van Doorn wrote:
>> >> That function calls flush_workqueue()
>> >
>> > Uh wait. It shouldn't call that. Where exactly is this function called?
>>
>> It is called right before local->ops->remove_interface() which means the
>> workqueue is flushed when it isn't even guaranteed that all interfaces are
>> gone.
>>
>> net/mac80211/main.c:553
>>
>> static int ieee80211_stop(struct net_device *dev)
>> {
>> <snip>
>> switch (sdata->vif.type) {
>> case IEEE80211_IF_TYPE_MESH_POINT:
>> case IEEE80211_IF_TYPE_STA:
>> case IEEE80211_IF_TYPE_IBSS:
>> <snip>
>> flush_workqueue(local->hw.workqueue);
>> <snip>
>> }
>> <snip>
>> }
>
> Oh right. I see. This is actually OK. I thought it would flush the global
> wq.
> The local mac80211 wq was introduced to workaround this rtnl deadlock,
> so I'm surprised it happens again.
Well it was caused by the recent introduction of the interface iterator.
Question now is if we need to restrict the usage, remove the flush_workqueue,
or change the locking in the interface iterator. :S
Ivo
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