drm/vmwgfx: Detach backing store from its resources when it is evicted

 * @mem:            The truct ttm_mem_reg indicating to what memory

 *                  region the move is taking place.

 *

 * For now does nothing.

 * Evicts the Guest Backed hardware resource if the backup

 * buffer is being moved out of MOB memory.

 * Note that this function should not race with the resource

 * validation code as long as it accesses only members of struct

 * resource that remain static while bo::res is !NULL and

 * while we have @bo reserved. struct resource::backup is *not* a

 * static member. The resource validation code will take care

 * to set @bo::res to NULL, while having @bo reserved when the

 * buffer is no longer bound to the resource, so @bo:res can be

 * used to determine whether there is a need to unbind and whether

 * it is safe to unbind.

 */

void vmw_resource_move_notify(struct ttm_buffer_object *bo,

			      struct ttm_mem_reg *mem)

{

	struct vmw_dma_buffer *dma_buf;

	if (mem == NULL)

		return;

	if (bo->destroy != vmw_dmabuf_bo_free &&

	    bo->destroy != vmw_user_dmabuf_destroy)

		return;

	dma_buf = container_of(bo, struct vmw_dma_buffer, base);

	if (mem->mem_type != VMW_PL_MOB) {

		struct vmw_resource *res, *n;

		struct ttm_bo_device *bdev = bo->bdev;

		struct ttm_validate_buffer val_buf;

		val_buf.bo = bo;

		list_for_each_entry_safe(res, n, &dma_buf->res_list, mob_head) {

			if (unlikely(res->func->unbind == NULL))

				continue;

			(void) res->func->unbind(res, true, &val_buf);

			res->backup_dirty = true;

			res->res_dirty = false;

			list_del_init(&res->mob_head);

		}

		spin_lock(&bdev->fence_lock);

		(void) ttm_bo_wait(bo, false, false, false);

		spin_unlock(&bdev->fence_lock);

	}

}

/**