[PATCH] drm/virtio: delete notify in virtio_gpu_object_create

[Chia-I Wu]

On Wed, Mar 25, 2020 at 8:41 AM Gurchetan Singh
<gurchetansingh at chromium.org> wrote:
>
> For 3D buffers, virtio_gpu_gem_object_open notifies.
> We can have the same behavior for dumb buffer.  We just
> need to make sure the first open notifies the host for
> dumb buffers.
virtio_gpu_notify is cheap and does not kick unless there is a need.
I probably won't bother with adding `bool notified', which adds a
(harmless) data race.




>
> v2: virtio_gpu_gem_object_open always notifies
>
> Signed-off-by: Gurchetan Singh <gurchetansingh at chromium.org>
> ---
>  drivers/gpu/drm/virtio/virtgpu_drv.h    |  1 +
>  drivers/gpu/drm/virtio/virtgpu_gem.c    | 10 ++++++++--
>  drivers/gpu/drm/virtio/virtgpu_object.c |  1 -
>  3 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 79ad176aca5a8..842200e01d785 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -71,6 +71,7 @@ struct virtio_gpu_object {
>         uint32_t hw_res_handle;
>         bool dumb;
>         bool created;
> +       bool notified;
>  };
>  #define gem_to_virtio_gpu_obj(gobj) \
>         container_of((gobj), struct virtio_gpu_object, base.base)
> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
> index 90c0a8ea1708c..597ddb7391fb9 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> @@ -111,10 +111,13 @@ int virtio_gpu_gem_object_open(struct drm_gem_object *obj,
>  {
>         struct virtio_gpu_device *vgdev = obj->dev->dev_private;
>         struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
> +       struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
>         struct virtio_gpu_object_array *objs;
>
> -       if (!vgdev->has_virgl_3d)
> -               return 0;
> +       if (!vgdev->has_virgl_3d && !bo->notified)
> +               goto out_notify;
> +       else if (!vgdev->has_virgl_3d)
> +               goto out;
>
>         objs = virtio_gpu_array_alloc(1);
>         if (!objs)
> @@ -123,7 +126,10 @@ int virtio_gpu_gem_object_open(struct drm_gem_object *obj,
>
>         virtio_gpu_cmd_context_attach_resource(vgdev, vfpriv->ctx_id,
>                                                objs);
> +out_notify:
> +       bo->notified = true;
>         virtio_gpu_notify(vgdev);
> +out:
>         return 0;
>  }
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
> index d9039bb7c5e37..51a8da7d5ef3b 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -241,7 +241,6 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
>                 return ret;
>         }
>
> -       virtio_gpu_notify(vgdev);
>         *bo_ptr = bo;
>         return 0;
>
> --
> 2.24.1
>
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