i915 utils: range_overflows*()

[Jani Nikula]

On Fri, 30 May 2025, Kees Cook <kees at kernel.org> wrote:
> On Fri, May 30, 2025 at 10:44:31AM +0300, Jani Nikula wrote:
>> 
>> Hi Kees -
>> 
>> drivers/gpu/drm/i915/i915_utils.h has a handful of helper macros for
>> checking range overflows: range_overflows(), range_overflows_t(),
>> range_overflows_end(), and range_overflows_end_t().
>> 
>> Looks like the first one has also been copy-pasted to
>> include/drm/drm_buddy.h.
>> 
>> Feels like include/linux/overflow.h would be the right place for (some
>> version of) them.
>> 
>> Thoughts?
>
> Sure, yes! They need some documentation too. :) And probably some
> renaming. It looks like range_overflows() is not end-inclusive, but
> range_overflows_end() is? And the _t variants are forcing explicit
> types (like max_t, but unlike struct_size_t).

Ah, naming.

As we all know, NP in NP-complete actually stands for "naming
problem". It's hard to come up with a good name, but presented with one,
it's quick to verify it is indeed good.

Ideas for the hard part?


BR,
Jani.


-- 
Jani Nikula, Intel