Re: [PATCH-v2 1/2] mac80211: Take bitrates into account when building IEs.

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2016-03-10 at 09:56 -0800, Ben Greear wrote:

> First, are you proposing that I make a copy of the entire  local-
> >hw.wiphy->bands array and store it locally in sdata?

No, I think it should be pointers there, say

sdata->bands[X] pointing to the same thing as local->hw.wiphy->bands[X] 
is pointing to.

So the first patch would introduce that, and replace each and every use
of local->hw.wiphy->bands[] with sdata->bands[], if necessary
annotating the remaining ones with why they're OK and should stay.

> And then, I would provide some API to modify the bands[i]->bitrates
> and other variables to properly select the advertised features?

Kinda. You'd provide some kind of helper function or API to take the
local->hw.wiphy->bands[X] and duplicate it into a newly allocated
buffer, modifying it along the way, before assigning it to the per-
sdata stuff in sdata->bands[X].

> I am a bit concerned about making copies (and then changing) the
> driver's bitrates array.  Likely it will work with ath10k, but it
> seems fragile at best.

That's an interesting point, we currently use the rate *index* a lot,
so we have to find some way of preserving that. Perhaps we need to
introduce a flag indicating a given rate is disabled?


johannes