The strncpy_from_user() returns number of copied bytes and not zero on
success. The non-zero return value of ioctl is treated as error. Return
zero on success instead of the number of copied bytes.

Fixes: 7add80126bce ("drm/uapi: add explicit virtgpu context debug name")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 1e2042419f95..e4f76f315550 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -665,6 +665,7 @@ static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
 				goto out_unlock;
 
 			vfpriv->explicit_debug_name = true;
+			ret = 0;
 			break;
 		default:
 			ret = -EINVAL;
-- 
2.41.0

On 11/12/23 01:42, Dmitry Osipenko wrote:
> The strncpy_from_user() returns number of copied bytes and not zero on
> success. The non-zero return value of ioctl is treated as error. Return
> zero on success instead of the number of copied bytes.
> 
> Fixes: 7add80126bce ("drm/uapi: add explicit virtgpu context debug name")
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index 1e2042419f95..e4f76f315550 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -665,6 +665,7 @@ static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
>  				goto out_unlock;
>  
>  			vfpriv->explicit_debug_name = true;
> +			ret = 0;
>  			break;
>  		default:
>  			ret = -EINVAL;

Applied to misc-next

-- 
Best regards,
Dmitry