Re: [PATCH] intel-iommu: fix build with CONFIG_BRANCH_TRACER=y

David Woodhouse
2009-04-07T12:45:20Z

On Tue, 2009-04-07 at 14:14 +0200, Ingo Molnar wrote:
> Well, i consider it a feature that it flags weird if (x, y)
> constructs: and yes, these iterators you introduced, while they are
> legit C, definitely count as 'weird'. If regular code was doing it,
> not a loop abstraction, i'd call it non-obvious and borderline
> broken straight away.
>
> We should _never ever_ put comma statements into if () constructs
> without a _really_ good reason - and if yes, we can flag that we
> know what we are doing, via extra parentheses.

I disagree. I don't think we should be declaring valid C syntax as 'off
limits', however rare it is.

_Especially_ if it only actually fails with a fairly esoteric config
option set. That's just asking for build breakage.

> and if yes, we can flag that we know what we are doing, via extra
> parentheses.

That's hardly much of a barrier. The requirement to sprinkle
gratuitous-looking extra parentheses around the place really isn't going
to give us much of a _benefit_ in return for the build breakage.

--
David Woodhouse Open Source Technology Centre
David.Woodhouse@intel.com Intel Corporation