[CC'ed Johannes & linux-wireless]
Am Sonntag, 29. Mai 2011 schrieb Gertjan van Wingerde:
> On 05/28/11 16:47, Helmut Schaa wrote:
> > Am Samstag, 28. Mai 2011 schrieb Gertjan van Wingerde:
> >>>> diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
> >>>> index f1e1381..2ace0f9 100644
> >>>> --- a/drivers/net/wireless/rt2x00/rt2x00queue.c
> >>>> +++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
> >>>> @@ -555,15 +555,21 @@ int rt2x00queue_write_tx_frame(struct data_queue *queue, struct sk_buff *skb,
> >>>> bool local)
> >>>> {
> >>>> struct ieee80211_tx_info *tx_info;
> >>>> - struct queue_entry *entry = rt2x00queue_get_entry(queue, Q_INDEX);
> >>>> + struct queue_entry *entry;
> >>>> struct txentry_desc txdesc;
> >>>> struct skb_frame_desc *skbdesc;
> >>>> u8 rate_idx, rate_flags;
> >>>> + int ret = 0;
> >>>> +
> >>>> + spin_lock_bh(&queue->tx_lock);
> >>>> +
> >>>
> >>> Shouldn't spin_lock be enough already? All tx calls from mac80211 are already
> >>> done in softirq context or protected by local_bh_disable/enable. This would be
> >>> especially useful on single CPU machines since spin_lock (without _bh) can be
> >>> optimized out on these.
> >>
> >> AFAICT not all tx calls from mac80211 are protected by local_bh_disable/enable. I believe
> >> that this is the case for the "process" context tx calls from
> >
> >> ieee80211_subif_start_xmit
> >
> > This should only be called from the network softirq and thus doesn't require bottom halves
> > to be disabled (AFAIK).
> >
> >> and
> >> ieee80211_monitor_start_xmit.
> >
> > Same here.
>
> Hmm, are you sure about this?
Maybe Johannes can clarify this for us ;)
Johannes, are all calls to the drivers tx callback done in softirq context or
adequately protected by local_bh_disable/enable? Or is this presumption wrong?
Thanks,
Helmut
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