Re: [Intel-gfx] [PATCH v2 7/7] drm/i915: Remove truncation warning for large objects

[Mauro Carvalho Chehab <mauro.chehab@linux.intel.com>]

On Tue,  5 Jul 2022 15:24:55 +0300
Gwan-gyeong Mun <gwan-gyeong.mun@intel.com> wrote:

> From: Chris Wilson <chris@chris-wilson.co.uk>
> 
> Having addressed the issues surrounding incorrect types for local
> variables and potential integer truncation in using the scatterlist API,
> we have closed all the loop holes we had previously identified with
> dangerously large object creation. As such, we can eliminate the warning
> put in place to remind us to complete the review.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Cc: Brian Welty <brian.welty@intel.com>
> Cc: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Testcase: igt@gem_create@create-massive
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4991
> Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>

Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org>

> ---
>  drivers/gpu/drm/i915/gem/i915_gem_object.h | 15 ---------------
>  1 file changed, 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index 31bb09dccf2f..4d614e4c1c4e 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -20,25 +20,10 @@
>  
>  enum intel_region_id;
>  
> -/*
> - * XXX: There is a prevalence of the assumption that we fit the
> - * object's page count inside a 32bit _signed_ variable. Let's document
> - * this and catch if we ever need to fix it. In the meantime, if you do
> - * spot such a local variable, please consider fixing!
> - *
> - * We can check for invalidly typed locals with typecheck(), see for example
> - * i915_gem_object_get_sg().
> - */
> -#define GEM_CHECK_SIZE_OVERFLOW(sz) \
> -	GEM_WARN_ON((sz) >> PAGE_SHIFT > INT_MAX)
> -
>  static inline bool i915_gem_object_size_2big(u64 size)
>  {
>  	struct drm_i915_gem_object *obj;
>  
> -	if (GEM_CHECK_SIZE_OVERFLOW(size))
> -		return true;
> -
>  	if (overflows_type(size, obj->base.size))
>  		return true;
>