[PATCH 2/2] drm/ttm: fix ttm_bo_cleanup_refs_or_queue once more

[zhoucm1]

Acked-by: Chunming Zhou <david1.zhou at amd.com>


On 2017年09月05日 03:02, Christian König wrote:
> From: Christian König <christian.koenig at amd.com>
>
> With shared reservation objects __ttm_bo_reserve() can easily fail even on
> destroyed BOs. This prevents correct handling when we need to individualize
> the reservation object.
>
> Fix this by individualizing the object before even trying to reserve it.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>   drivers/gpu/drm/ttm/ttm_bo.c | 32 +++++++++++++++++---------------
>   1 file changed, 17 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 180ce62..bee77d3 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -440,28 +440,29 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
>   	struct ttm_bo_global *glob = bo->glob;
>   	int ret;
>   
> +	ret = ttm_bo_individualize_resv(bo);
> +	if (ret) {
> +		/* Last resort, if we fail to allocate memory for the
> +		 * fences block for the BO to become idle
> +		 */
> +		reservation_object_wait_timeout_rcu(bo->resv, true, false,
> +						    30 * HZ);
> +		spin_lock(&glob->lru_lock);
> +		goto error;
> +	}
> +
>   	spin_lock(&glob->lru_lock);
>   	ret = __ttm_bo_reserve(bo, false, true, NULL);
> -
>   	if (!ret) {
> -		if (!ttm_bo_wait(bo, false, true)) {
> +		if (reservation_object_test_signaled_rcu(&bo->ttm_resv, true)) {
>   			ttm_bo_del_from_lru(bo);
>   			spin_unlock(&glob->lru_lock);
> +			if (bo->resv != &bo->ttm_resv)
> +				reservation_object_unlock(&bo->ttm_resv);
>   			ttm_bo_cleanup_memtype_use(bo);
> -
>   			return;
>   		}
>   
> -		ret = ttm_bo_individualize_resv(bo);
> -		if (ret) {
> -			/* Last resort, if we fail to allocate memory for the
> -			 * fences block for the BO to become idle and free it.
> -			 */
> -			spin_unlock(&glob->lru_lock);
> -			ttm_bo_wait(bo, true, true);
> -			ttm_bo_cleanup_memtype_use(bo);
> -			return;
> -		}
>   		ttm_bo_flush_all_fences(bo);
>   
>   		/*
> @@ -474,11 +475,12 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
>   			ttm_bo_add_to_lru(bo);
>   		}
>   
> -		if (bo->resv != &bo->ttm_resv)
> -			reservation_object_unlock(&bo->ttm_resv);
>   		__ttm_bo_unreserve(bo);
>   	}
> +	if (bo->resv != &bo->ttm_resv)
> +		reservation_object_unlock(&bo->ttm_resv);
>   
> +error:
>   	kref_get(&bo->list_kref);
>   	list_add_tail(&bo->ddestroy, &bdev->ddestroy);
>   	spin_unlock(&glob->lru_lock);