On Thu, 2013-11-14 at 15:53 +0100, Simon Wunderlich wrote:
> > @@ -3122,9 +3158,16 @@ int ieee80211_channel_switch(struct wiphy *wiphy,
> > struct net_device *dev, params->chandef.chan->band)
> > return -EINVAL;
> >
> > - err = ieee80211_ibss_csa_beacon(sdata, params);
> > - if (err < 0)
> > - return err;
> > + /* see comments and TODO in the NL80211_IFTYPE_AP block */
>
> Since you are sending an action frame below, this TODO appears to be obsolete?
Right... The comments are still valid, but the TODO only applies to AP,
since IBSS and MESH send the action frame, as you pointed out.
I'll fix it.
> > @@ -3173,8 +3220,13 @@ int ieee80211_channel_switch(struct wiphy *wiphy,
> > struct net_device *dev, sdata->csa_chandef = params->chandef;
> > sdata->vif.csa_active = true;
> >
> > - ieee80211_bss_info_change_notify(sdata, err);
> > - drv_channel_switch_beacon(sdata, ¶ms->chandef);
> > + if (changed) {
> > + ieee80211_bss_info_change_notify(sdata, changed);
> > + drv_channel_switch_beacon(sdata, ¶ms->chandef);
> > + } else {
> > + /* if the beacon didn't change, we can finalize immediately */
> > + ieee80211_csa_finalize(sdata);
> > + }
>
> I think setting csa_active == true for count 0 or 1 is wrong.
>
> When a beacon is generated/updated in ieee80211_beacon_get_tim(), it wil call
> ieee80211_update_csa() which will throw a warning in best case, but also
> modifies random data in the beacon/presp at the position where the count offset
> points to (we have no CSA IE in this case).
Hmmm... I guess you're right. I was setting the csa_active to true at
first because I was putting the work in a workqueue, so I was trying to
avoid potential races. I'll inspect this more carefully and fix it.
> I've also seen warnings in my IBSS tests (WARNING: CPU: 0 PID: 0 at
> net/mac80211/tx.c:2408 ieee80211_update_csa), when doing a CSA with count 0
> from userspace. Although likely, I'm not sure if this is related to the
> problem described above, but this function shouldn't be called at all in the
> count=0 case.
Yes, this is most likely related. I'll try to figure out what is going
wrong here.
Thanks a lot for your tests!
--
Cheers,
Luca.
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