[Intel-gfx] [PATCH] drm/i915: allow GEM_BUG_ON expr checking with !DEBUG_GEM

[Chris Wilson]

On Fri, Dec 02, 2016 at 06:47:50PM +0000, Matthew Auld wrote:
> Use BUILD_BUG_ON_INVALID(expr) in GEM_BUG_ON when building without
> DEBUG_GEM. This means the compiler can now check the validity of expr
> without generating any code, in turn preventing us from inadvertently
> breaking the build when DEBUG_GEM is not enabled.
> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
> index 51ec793f2e20..8801a14a78a2 100644
> --- a/drivers/gpu/drm/i915/i915_gem.h
> +++ b/drivers/gpu/drm/i915/i915_gem.h
> @@ -28,7 +28,7 @@
>  #ifdef CONFIG_DRM_I915_DEBUG_GEM
>  #define GEM_BUG_ON(expr) BUG_ON(expr)
>  #else
> -#define GEM_BUG_ON(expr) do { } while (0)
> +#define GEM_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
>  #endif

Lgtm, compiles both ways and picks up an error when DEBUG_GEM is disabled.
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre