shmem_create_from_object

struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
{
	struct drm_i915_private *i915 = to_i915(obj->base.dev);
	struct file *file;
	void *ptr;
	int err;

	if (obj->base.import_attach) {
		file = obj->base.filp;
		atomic_long_inc(&file->f_count);

	} else if (i915_gem_object_is_shmem(obj)) {

		err = i915_gem_object_pin_pages_unlocked(obj);
		if (err) {
			drm_dbg(&i915->drm, "%s pin-pages err=%d\n", __func__, err);
			return ERR_PTR(err);
		}

		file = i915_gem_ttm_get_filep(obj);
		GEM_BUG_ON(!file);
		atomic_long_inc(&file->f_count);

		i915_gem_clflush_object(obj, I915_CLFLUSH_FORCE | I915_CLFLUSH_SYNC);
		i915_gem_object_unpin_pages(obj);

	} else {
		ptr = i915_gem_object_pin_map_unlocked(obj, i915_gem_object_is_lmem(obj) ?
						       I915_MAP_WC : I915_MAP_WB);
		if (IS_ERR(ptr)) {
			i915_gem_object_unpin_pages(obj);
			return ERR_CAST(ptr);
		}

		file = shmem_create_from_data("", ptr, obj->base.size);
		i915_gem_object_unpin_map(obj);
	}

	return file;
}