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Message-ID: <58fdd62041c0388740cabea5a421c5417f959124.camel@sipsolutions.net>
Subject: Re: [PATCH 2/3] cfg80211: validate RU puncturing bitmap
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Aloka Dixit <quic_alokad@quicinc.com>,
        linux-wireless@vger.kernel.org
Date:   Wed, 04 May 2022 14:08:16 +0200
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On Tue, 2022-02-15 at 16:37 -0800, Aloka Dixit wrote:
> > 
> > Conceptually, I'm wondering if it really belongs into the chandef? Can
> > you explain why it's part of the channel configuration? If you've got
> > two chandefs with the same control channel, CCFS and bandwidth, but
> > different puncturing, does it really make sense to treat them as two
> > separate channel contexts, e.g. in mac80211? It seems strange to do
> > that.
> 
> Added it here so that any command working with chandef will be updated 
> without any other change.
> Example: During channel switch, user can provide a puncturing bitmap 
> with a new option I added in userspace, and because it is part of 
> chandef, the same code path validates it for that command automatically.

Yeah but is it really a CSA/chanswitch if the puncturing changes? I
don't think so?

> Regarding if different puncturing pattern should be considered as a new 
> context - yes, depending on if it is HE or non-HE mode, the new bitmap 
> may be invalid and the operation should fail.
> 

That wasn't really the question though. Consider this:

Say you have STA + STA, if the first STA is connected to an AP with no
puncturing, and the second STA is connected to an AP where the channel
and bandwidth are the same, but some puncturing is done, should that
really be two channel contexts as far as mac80211 is concerned, and thus
require channels=2 in the interface combinations etc.? It doesn't seem
right to me.

Or consider AP + STA, where the AP is set up for some channel but the
STA is connecting to an AP on the exact same channel, but with
puncturing... Again, same thing, I don't think it should consume two
channel resources.

johannes