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Commit 5323fd04 authored by Eric Anholt's avatar Eric Anholt
Browse files

drm/i915: Zap mmaps of objects before unbinding them from the GTT. 



Otherwise, some other userland writing into its buffer may race to land
writes either after the CPU thinks it's got a coherent view, or after its
GTT entries have been redirected to point at the scratch page.  Either
result is unpleasant.

Signed-off-by: default avatarEric Anholt <eric@anholt.net>
parent 7839c5d5

drivers/gpu/drm/i915/i915_gem.c

+8 −8
Original line number Diff line number Diff line
@@ -1915,6 +1915,12 @@ i915_gem_object_unbind(struct drm_gem_object *obj) 
		return -EINVAL;

	}



	/* blow away mappings if mapped through GTT */

	i915_gem_release_mmap(obj);



	if (obj_priv->fence_reg != I915_FENCE_REG_NONE)

		i915_gem_clear_fence_reg(obj);



	/* Move the object to the CPU domain to ensure that

	 * any possible CPU writes while it's not in the GTT

	 * are flushed when we go to remap it. This will
@@ -1928,20 +1934,14 @@ i915_gem_object_unbind(struct drm_gem_object *obj) 
		return ret;

	}



	BUG_ON(obj_priv->active);



	if (obj_priv->agp_mem != NULL) {

		drm_unbind_agp(obj_priv->agp_mem);

		drm_free_agp(obj_priv->agp_mem, obj->size / PAGE_SIZE);

		obj_priv->agp_mem = NULL;

	}



	BUG_ON(obj_priv->active);



	/* blow away mappings if mapped through GTT */

	i915_gem_release_mmap(obj);



	if (obj_priv->fence_reg != I915_FENCE_REG_NONE)

		i915_gem_clear_fence_reg(obj);



	i915_gem_object_put_pages(obj);



	if (obj_priv->gtt_space) {