Re: [RESEND PATCH] nl80211: Allow GET_INTERFACE dumps to be filtered

[Denis Kenzior <denkenz@gmail.com>]

Hi Johannes,

 >
> No, I don't see a fault in the logic. I just think it's misleading. You
> make the code look like it relies on filter_wiphy != 0, but then you go
> and treat filter_wiphy==0 as a valid case.

It relies on a sentry condition with all 3 variables being zero, not 
just filter_wiphy.  The original patch is about the most non-invasive 
one I can come up with.  Maybe a comment will alleviate any concerns? 
Anyway, if you feel this is misleading, fair enough.

>
> In other places, like nl80211_prepare_wdev_dump(), we add 1 to the
> wiphy and subtract it again later to avoid exactly this. Perhaps you
> could do the same, and rely only on filter_wiphy instead of really
> relying only on wp_start/if_start.

Having looked at that particular piece of code, I ran away scared with 
the conclusion that the cure is probably much worse than the disease :)

I posted a slightly different solution in v2.  It is a bit more 
invasive, but is more explicit in what is going on.  I ran sanity checks 
on it and it works as expected.

Regards,
-Denis