Re: [PATCH v5] mac80211: implement multi-vif in-place reservations

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2014-05-14 at 07:14 +0200, Michal Kazior wrote:

> Hmm.. I thought of it more as a theoretical appliance of the transaction API.
> 
> Let me re-post his example:
> 
> > With the generic transactions you could do:
> >  - new chanctx2
> >  - new chanctx3
> >  - switch vif1 chanctx1->chanctx2
> >  - switch vif2 chanctx1->chanctx3
> >  - del chanctx1
> 
> From this I infer you can run at least 2 chanctx since that's what you
> end up with. This means you can perform one of the switches separately
> because only 1 chanctx was used (that's the easy part that never
> really required transactions or multi-vif-chanctx-assign to begin
> with). The other switch would fall into the "incompat case" where you
> need to basically swap chanctx for one of the vifs in the example.
> 
> So I fail to see why we would need to have a list of old/new contexts
> in the proposed switch_vif_chanctx(), at least for now.

Further down the thread there was a discussion about e.g. radar
detection with the combinations, when one needs radar and the other
doesn't or something, then maybe you're running into a situation where
some interface combination allows more than 2 channels and the other
doesn't, or such.

johannes