[Intel-gfx] [PATCH v30 4/5] drm/i915: Expose RPCS (SSEU) configuration to userspace (Gen11 only)

[Tvrtko Ursulin]

On 31/01/2019 09:15, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2019-01-31 08:47:37)
>> +       /*
>> +        * Some future proofing on the types since the uAPI is wider than the
>> +        * current internal implementation.
>> +        */
>> +       if (WARN_ON((fls(user->slice_mask) >
>> +                    sizeof(context->slice_mask) * BITS_PER_BYTE) ||
>> +                   (fls(user->subslice_mask) >
>> +                    sizeof(context->subslice_mask) * BITS_PER_BYTE) ||
>> +                   overflows_type(user->min_eus_per_subslice,
>> +                                  context->min_eus_per_subslice) ||
>> +                   overflows_type(user->max_eus_per_subslice,
>> +                                  context->max_eus_per_subslice)))
> 
> fls(0) is not well-defined, so
> 
> if (order_base_2(user->slice_mask) > BITS_PER_TYPE(context->slice_mask))
> 	return -EINVAL;
> 
> etc
> 
> Don't WARN_ON() for user controlled variables.

Looks I was thinking it is not user controllable eg. was supposed to be 
the reminder of a too narrow internal type. But that is obviously not 
true.. Also not sure why I did not use overflows_type for all.

Thanks,

Tvrtko