[Intel-gfx] [PATCH] drm/i915: make GEM_WARN_ON less terrible

[Matthew Auld]

On 19 March 2018 at 18:17, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Quoting Matthew Auld (2018-03-19 18:08:54)
>> GEM_WARN_ON() was originally intended to be used only as:
>>
>>    if (GEM_WARN_ON(expr))
>>         ...
>>
>> but it just so happens to also work as simply:
>>
>>    GEM_WARN_ON(expr);
>>
>> since it just wraps WARN_ON, which is a little misleading since for
>> !DRM_I915_DEBUG_GEM builds the second case will actually break the
>> build. Given that there are some patches floating around which seem to
>> miss this, it probably makes sense to just make it work for both cases.
>
> That really was quite intentional. The only time to use GEM_WARN_ON() is
> inside an if, otherwise what's the point?

Why wouldn't we want it to behave like WARN_ON? That seems to be what
people expect, since it does wrap WARN_ON, and we don't always use
WARN_ON in an if...