* mac80211 flush callback
@ 2012-08-29 11:32 Arend van Spriel
2012-09-05 13:53 ` Johannes Berg
0 siblings, 1 reply; 4+ messages in thread
From: Arend van Spriel @ 2012-08-29 11:32 UTC (permalink / raw)
To: Johannes Berg; +Cc: linux-wireless@vger.kernel.org, John W. Linville
Hoi Johannes,
I ma currently looking into a long standing issue with flush callback in
brcmsmac. After some debugging I found out that mac80211 keeps pushing
packets to brcmsmac during the flush. Is that correct? Should brcmsmac
(or any other driver) stop the mac80211 queues during the flush? My
assumption was that mac80211 would not do transmits during the flush,
but it probably comes from another worker thread.
Gr. AvS
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: mac80211 flush callback
2012-08-29 11:32 mac80211 flush callback Arend van Spriel
@ 2012-09-05 13:53 ` Johannes Berg
2012-09-05 16:27 ` Arend van Spriel
0 siblings, 1 reply; 4+ messages in thread
From: Johannes Berg @ 2012-09-05 13:53 UTC (permalink / raw)
To: Arend van Spriel; +Cc: linux-wireless@vger.kernel.org, John W. Linville
Hi Arend,
> I ma currently looking into a long standing issue with flush callback in
> brcmsmac. After some debugging I found out that mac80211 keeps pushing
> packets to brcmsmac during the flush. Is that correct? Should brcmsmac
> (or any other driver) stop the mac80211 queues during the flush? My
> assumption was that mac80211 would not do transmits during the flush,
> but it probably comes from another worker thread.
Hmm, good question, this area isn't quite fully worked out yet I
think ... probably better to stop queues yourself for now, although I
guess mac80211 should really take care to do it ...
johannes
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: mac80211 flush callback
2012-09-05 13:53 ` Johannes Berg
@ 2012-09-05 16:27 ` Arend van Spriel
2012-09-05 16:34 ` Johannes Berg
0 siblings, 1 reply; 4+ messages in thread
From: Arend van Spriel @ 2012-09-05 16:27 UTC (permalink / raw)
To: Johannes Berg; +Cc: linux-wireless@vger.kernel.org, John W. Linville
On 09/05/2012 03:53 PM, Johannes Berg wrote:
> Hi Arend,
>
>> I ma currently looking into a long standing issue with flush callback in
>> brcmsmac. After some debugging I found out that mac80211 keeps pushing
>> packets to brcmsmac during the flush. Is that correct? Should brcmsmac
>> (or any other driver) stop the mac80211 queues during the flush? My
>> assumption was that mac80211 would not do transmits during the flush,
>> but it probably comes from another worker thread.
>
> Hmm, good question, this area isn't quite fully worked out yet I
> think ... probably better to stop queues yourself for now, although I
> guess mac80211 should really take care to do it ...
>
Thanks, Johannes
I did look at some other driver and it seems they grab a mutex in the
flush that is (probably?) also grabbed in the tx path thus blocking it.
For brcmsmac I submitted a patch to explicitly stop the queues in the flush.
Gr. AvS
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: mac80211 flush callback
2012-09-05 16:27 ` Arend van Spriel
@ 2012-09-05 16:34 ` Johannes Berg
0 siblings, 0 replies; 4+ messages in thread
From: Johannes Berg @ 2012-09-05 16:34 UTC (permalink / raw)
To: Arend van Spriel; +Cc: linux-wireless@vger.kernel.org, John W. Linville
On Wed, 2012-09-05 at 18:27 +0200, Arend van Spriel wrote:
> On 09/05/2012 03:53 PM, Johannes Berg wrote:
> > Hi Arend,
> >
> >> I ma currently looking into a long standing issue with flush callback in
> >> brcmsmac. After some debugging I found out that mac80211 keeps pushing
> >> packets to brcmsmac during the flush. Is that correct? Should brcmsmac
> >> (or any other driver) stop the mac80211 queues during the flush? My
> >> assumption was that mac80211 would not do transmits during the flush,
> >> but it probably comes from another worker thread.
> >
> > Hmm, good question, this area isn't quite fully worked out yet I
> > think ... probably better to stop queues yourself for now, although I
> > guess mac80211 should really take care to do it ...
> >
>
> Thanks, Johannes
>
> I did look at some other driver and it seems they grab a mutex in the
> flush that is (probably?) also grabbed in the tx path thus blocking it.
> For brcmsmac I submitted a patch to explicitly stop the queues in the flush.
I don't think any driver could possibly grab a mutex in the TX path
since it needs to be atomic? :)
johannes
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-09-05 16:33 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2012-08-29 11:32 mac80211 flush callback Arend van Spriel
2012-09-05 13:53 ` Johannes Berg
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2012-09-05 16:34 ` Johannes Berg
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