mac80211 flush callback

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.

Hi Arend,

Quoted 6 lines

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 ...

Quoted 9 lines · Johannes Berg

Hi Arend,

Quoted 6 lines

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.

Quoted 4 lines

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.