Re: [ath9k-devel] [RFC] ath9k: fix tx queue selection

[Felix Fietkau <nbd@openwrt.org>]

On 2010-11-02 7:20 PM, Björn Smedman wrote:
> 2010/11/2 Felix Fietkau <nbd@openwrt.org>:
>> +       q = ath_get_mac80211_qnum(txq->axq_class, sc);
>>        r = ath_tx_setup_buffer(hw, bf, skb, txctl);
>>        if (unlikely(r)) {
>>                ath_print(common, ATH_DBG_FATAL, "TX mem alloc failure\n");
>> @@ -1756,8 +1757,8 @@ int ath_tx_start(struct ieee80211_hw *hw
>>                 * we will at least have to run TX completionon one buffer
>>                 * on the queue */
>>                spin_lock_bh(&txq->axq_lock);
>> -               if (!txq->stopped && txq->axq_depth > 1) {
>> -                       ath_mac80211_stop_queue(sc, skb_get_queue_mapping(skb));
>> +               if (q >= 0 && !txq->stopped && txq->axq_depth > 1) {
>> +                       ath_mac80211_stop_queue(sc, q);
>>                        txq->stopped = 1;
>>                }
> 
> You cannot be sure that you are stopping the queue that the skb
> actually came in on here since mac80211 queues are mapped to hw queues
> by ath_get_hal_qnum() and that mapping is not reversible (due to the
> default statement):
How does the default statement matter here? The queue number always
comes from an index of the ieee802_1d_to_ac[] array, which only contains
numbers from 0 to 3. That should make the conversion reversible.

- Felix