Re: [ath9k-devel] ath9k, multiple stations, and AMPDUs

[Ben Greear <greearb@candelatech.com>]

On 09/21/2010 12:32 PM, Felix Fietkau wrote:
> On 2010-09-21 9:28 PM, Johannes Berg wrote:
>> On Tue, 2010-09-21 at 20:00 +0200, Felix Fietkau wrote:
>>
>>>> Could we just poke a pointer to the STA into the ath_buf structure?
>>
>>> No, that doesn't work because of RCU.
>>
>> Well, it could work, if you walk all the structures upon sta_notify and
>> remove now stale pointers (or just drop the frames or something).
> I think it would be much better to just add the helper function that
> checks the RA on STA lookup. Keeps things simple, especially since
> nothing else in the tx path needs the vif.

How about this.  Seems to do the trick on my system:


diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 85a7323..09815a1 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -328,8 +328,7 @@ static void ath_tx_complete_aggr(struct ath_softc *sc, struct ath_txq *txq,

         rcu_read_lock();

-       /* XXX: use ieee80211_find_sta! */
-       sta = ieee80211_find_sta_by_hw(hw, hdr->addr1);
+       sta = tx_info->control.sta;
         if (!sta) {
                 rcu_read_unlock();

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com