Re: [PATCH 10/10] drm/qxl: add lock asserts to qxl_bo_kmap_locked + qxl_bo_kunmap_locked

[Thomas Zimmermann]

Hi

Am 16.02.21 um 12:37 schrieb Gerd Hoffmann:
> Try avoid re-introducing locking bugs.
>
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>

Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

IMHO this should eventually be done in the rsp TTM functions. But so 
far, I'd expect this to break some drivers.

Best regards
Thomas

> ---
>   drivers/gpu/drm/qxl/qxl_object.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
> index 22748b9566af..90d5e5b7f927 100644
> --- a/drivers/gpu/drm/qxl/qxl_object.c
> +++ b/drivers/gpu/drm/qxl/qxl_object.c
> @@ -162,6 +162,8 @@ int qxl_bo_kmap_locked(struct qxl_bo *bo, struct dma_buf_map *map)
>   {
>   	int r;
>   
> +	dma_resv_assert_held(bo->tbo.base.resv);
> +
>   	if (bo->kptr) {
>   		bo->map_count++;
>   		goto out;
> @@ -236,6 +238,8 @@ void *qxl_bo_kmap_atomic_page(struct qxl_device *qdev,
>   
>   void qxl_bo_kunmap_locked(struct qxl_bo *bo)
>   {
> +	dma_resv_assert_held(bo->tbo.base.resv);
> +
>   	if (bo->kptr == NULL)
>   		return;
>   	bo->map_count--;

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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