[Intel-gfx] [PATCH 12/12] drm/i915: Add BKL asserts to get page helpers

[Chris Wilson]

On Tue, Feb 02, 2016 at 11:06:30AM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Purpose is catching illegal callers.
> 
> v2: Replace WARN_ON with lockdep_assert_held. (Chris Wilson, Daniel Vetter)
> v3: Moved under dedicated CONFIG_DRM_I915_DEBUG and back to WARN_ON.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_drv.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 4ad025210416..6d34f74a5919 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2933,6 +2933,9 @@ i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj, int n);
>  static inline struct page *
>  i915_gem_object_get_page(struct drm_i915_gem_object *obj, int n)
>  {
> +#ifdef CONFIG_DRM_I915_DEBUG
> +	WARN_ON_ONCE(!mutex_is_locked(&obj->base.dev->struct_mutex));
> +#endif

But lockdep gives us useful debug information!
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre