[PATCH 1/2] drm/ttm: make unlocking in ttm_bo_cleanup_refs optional v2

[Michel Dänzer]

On 13/11/17 10:54 AM, Christian König wrote:
> Needed for the next patch.
> 
> v2: actually predicate all unlocks
> 
> Signed-off-by: Christian König <christian.koenig at amd.com>

[...]

> @@ -531,24 +533,28 @@ static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo,
>  			return -EBUSY;
>  
>  		spin_lock(&glob->lru_lock);
> -		ret = reservation_object_trylock(bo->resv) ? 0 : -EBUSY;
> -
> -		/*
> -		 * We raced, and lost, someone else holds the reservation now,
> -		 * and is probably busy in ttm_bo_cleanup_memtype_use.
> -		 *
> -		 * Even if it's not the case, because we finished waiting any
> -		 * delayed destruction would succeed, so just return success
> -		 * here.
> -		 */
> -		if (ret) {
> -			spin_unlock(&glob->lru_lock);
> -			return 0;
> +		if (unlock_resv) {
> +			ret = reservation_object_trylock(bo->resv) ? 0 : -EBUSY;
> +			/*
> +			 * We raced, and lost, someone else holds the reservation now,
> +			 * and is probably busy in ttm_bo_cleanup_memtype_use.
> +			 *
> +			 * Even if it's not the case, because we finished waiting any
> +			 * delayed destruction would succeed, so just return success
> +			 * here.
> +			 */
> +			if (ret) {
> +				spin_unlock(&glob->lru_lock);
> +				return 0;
> +			}
> +		} else {
> +			ret = 0;
>  		}
>  	}

This could be simplified slightly:

		if (unlock_resv && !reservation_object_trylock(bo->resv)) {
			/*
			 * We raced, and lost, someone else holds the reservation now,
			 * and is probably busy in ttm_bo_cleanup_memtype_use.
			 *
			 * Even if it's not the case, because we finished waiting any
			 * delayed destruction would succeed, so just return success
			 * here.
			 */
			spin_unlock(&glob->lru_lock);
			return 0;
		}

		ret = 0;
	}


Either way, this patch is


Reviewed-and-Tested-by: Michel Dänzer <michel.daenzer at amd.com>


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer