Re: [PATCH RFC] wext: Add event stream wrappers that return E2BIG when values don't fit

From: James Minor
Date: Thu Feb 19 2015 - 16:34:41 EST

On 01/29/2015 03:22 PM, Johannes Berg wrote:

> > What you mean is "with the wext (compatibility) code in cfg80211".

Comment fixed in the v2 of the patch (coming shortly).

> > Either way, I *strongly* recommend against using this in the first
> > place. There's an upper bound of 64k (I think) on the amount of memory
> > that can be used, and people have been known to run into this limit - at
> > which point you get absolutely no scan results back whatsoever. It's far
> > safer to use nl80211's scan dump, and if you're looking at this code in
> > particular then clearly you have it available.

Agreed, and we will be switching to nl80211 as soon as we can.

> > Regarding the patch itself, it seems to add a bit much code. Is there
> > really no better way to express this? Perhaps by checking that the
> > stream actually moved forward - which will *always* happen for any of
> > these functions if they actually did anything? Even maybe if the new
> > _check inlines were to do that it'd still make the code smaller.

I've shuffled some things around and will submit the v2 momentarily.


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