Re: [PATCH] mac80211: Call mgd_prepare_tx before deauthentication

[Sujith Manoharan <sujith@msujith.org>]

Emmanuel Grumbach wrote:
> I still think it does not match the original intent of mgd_prepare_tx().
> The way I see it, mgd_prepare_tx() ensures that the Tx *will* happen
> in cases the driver has no specific reason to be on channel, mainly
> because the context is not associated yet. Note that after association
> mac80211 does not interfere with the context switches. The driver is in
> charge of all this - why would it be different in this case?
> flush() makes sure that the Tx *has* happened before destroying things.
> The context switches from association until destruction are under the driver's
> responsibility.
> 
> At least this is the way I see it.
> We (Intel) will not break if you add this call, but in my eyes this does not
> comply with the design. I guess you can always send a patch to add it and
> see what others will say, but Johannes is away right now.
> If you choose to do that, please add a reason as a parameter to mgd_prepare_tx()
> so that we can ignore it when it is called before sending a frame that
> is flush()'ed.
> I still prefer to rely on flush(). And I agree that flush() isn't a
> trivial implementation.

I can see your point and agree that the original intention of the mgd_prepare_tx()
callback is as described in the documentation. But with multiple active
contexts, flush() becomes a big hammer rather than a simple emptying of
the queues. :-)

I think we can extend the intention of the API and use mgd_prepare_tx()
for deauth/disassoc too. And this was done in the original patch, anyway.
This would greatly reduce driver complexity.

I'll send a patch including your suggestion about adding a parameter
to mgd_prepare_tx() which iwlwifi can use.

Sujith