Re: [PATCH 2/4] drm/virtio: resource teardown tweaks

[Chia-I Wu]

On Wed, Feb 5, 2020 at 10:43 PM Gerd Hoffmann  wrote:
>
> > > -
> > > -   drm_gem_shmem_free_object(obj);
> > > +   if (bo->created) {
> > > +   virtio_gpu_cmd_unref_resource(vgdev, bo);
> > > +   /* completion handler calls virtio_gpu_cleanup_object() */
> > nitpick: we don't need this comment when virtio_gpu_cmd_unref_cb is
> > defined by this file and passed to virtio_gpu_cmd_unref_resource.
>
> I want virtio_gpu_cmd_unref_cb + virtio_gpu_cmd_unref_resource being
> placed next to each other so it is easier to see how they work hand in
> hand.
>
> > I happen to be looking at our error handling paths.  I think we want
> > virtio_gpu_queue_fenced_ctrl_buffer to call vbuf->resp_cb on errors.
>
> /me was thinking about that too.  Yes, we will need either that,
> or a separate vbuf->error_cb callback.  That'll be another patch
> though.
Or the new virtio_gpu_queue_ctrl_sgs can return errors rather than
eating errors.

Yeah, that should be another patch.
>
> > > +   /*
> > > +* We are in the release callback and do NOT want refcount
> > > +* bo, so do NOT use virtio_gpu_array_add_obj().
> > > +*/
> > > +   vbuf->objs = virtio_gpu_array_alloc(1);
> > > +   vbuf->objs->objs[0] = >base.base
> > This is an abuse of obj array.  Add "void *private_data;" to
> > virtio_gpu_vbuffer and use that maybe?
>
> I'd name that *cb_data, but yes, that makes sense.
Sounds great.
>
> cheers,
>   Gerd
>
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Re: [PATCH 2/4] drm/virtio: resource teardown tweaks

[Gerd Hoffmann]

> > -
> > -   drm_gem_shmem_free_object(obj);
> > +   if (bo->created) {
> > +   virtio_gpu_cmd_unref_resource(vgdev, bo);
> > +   /* completion handler calls virtio_gpu_cleanup_object() */
> nitpick: we don't need this comment when virtio_gpu_cmd_unref_cb is
> defined by this file and passed to virtio_gpu_cmd_unref_resource.

I want virtio_gpu_cmd_unref_cb + virtio_gpu_cmd_unref_resource being
placed next to each other so it is easier to see how they work hand in
hand.

> I happen to be looking at our error handling paths.  I think we want
> virtio_gpu_queue_fenced_ctrl_buffer to call vbuf->resp_cb on errors.

/me was thinking about that too.  Yes, we will need either that,
or a separate vbuf->error_cb callback.  That'll be another patch
though.

> > +   /*
> > +* We are in the release callback and do NOT want refcount
> > +* bo, so do NOT use virtio_gpu_array_add_obj().
> > +*/
> > +   vbuf->objs = virtio_gpu_array_alloc(1);
> > +   vbuf->objs->objs[0] = >base.base
> This is an abuse of obj array.  Add "void *private_data;" to
> virtio_gpu_vbuffer and use that maybe?

I'd name that *cb_data, but yes, that makes sense.

cheers,
  Gerd

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Re: [PATCH 2/4] drm/virtio: resource teardown tweaks

[Chia-I Wu]

On Wed, Feb 5, 2020 at 3:00 AM Gerd Hoffmann  wrote:
>
> Add new virtio_gpu_cleanup_object() helper function for object cleanup.
> Wire up callback function for resource unref, do cleanup from callback
> when we know the host stopped using the resource.
>
> Signed-off-by: Gerd Hoffmann 
> ---
>  drivers/gpu/drm/virtio/virtgpu_drv.h|  3 ++-
>  drivers/gpu/drm/virtio/virtgpu_object.c | 19 ++
>  drivers/gpu/drm/virtio/virtgpu_vq.c | 35 ++---
>  3 files changed, 48 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h 
> b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 7e69c06e168e..372dd248cf02 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -262,7 +262,7 @@ void virtio_gpu_cmd_create_resource(struct 
> virtio_gpu_device *vgdev,
> struct virtio_gpu_object_array *objs,
> struct virtio_gpu_fence *fence);
>  void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
> -  uint32_t resource_id);
> +  struct virtio_gpu_object *bo);
>  void virtio_gpu_cmd_transfer_to_host_2d(struct virtio_gpu_device *vgdev,
> uint64_t offset,
> uint32_t width, uint32_t height,
> @@ -355,6 +355,7 @@ void virtio_gpu_fence_event_process(struct 
> virtio_gpu_device *vdev,
> u64 last_seq);
>
>  /* virtio_gpu_object */
> +void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo);
>  struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
> size_t size);
>  int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c 
> b/drivers/gpu/drm/virtio/virtgpu_object.c
> index 017a9e0fc3bb..28a161af7503 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -61,6 +61,14 @@ static void virtio_gpu_resource_id_put(struct 
> virtio_gpu_device *vgdev, uint32_t
> }
>  }
>
> +void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
> +{
> +   struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
> +
> +   virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
> +   drm_gem_shmem_free_object(>base.base);
> +}
> +
>  static void virtio_gpu_free_object(struct drm_gem_object *obj)
>  {
> struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
> @@ -68,11 +76,12 @@ static void virtio_gpu_free_object(struct drm_gem_object 
> *obj)
>
> if (bo->pages)
> virtio_gpu_object_detach(vgdev, bo);
> -   if (bo->created)
> -   virtio_gpu_cmd_unref_resource(vgdev, bo->hw_res_handle);
> -   virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
> -
> -   drm_gem_shmem_free_object(obj);
> +   if (bo->created) {
> +   virtio_gpu_cmd_unref_resource(vgdev, bo);
> +   /* completion handler calls virtio_gpu_cleanup_object() */
nitpick: we don't need this comment when virtio_gpu_cmd_unref_cb is
defined by this file and passed to virtio_gpu_cmd_unref_resource.

I happen to be looking at our error handling paths.  I think we want
virtio_gpu_queue_fenced_ctrl_buffer to call vbuf->resp_cb on errors.


> +   return;
> +   }
> +   virtio_gpu_cleanup_object(bo);
>  }
>
>  static const struct drm_gem_object_funcs virtio_gpu_gem_funcs = {
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c 
> b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index 6d6d55dc384e..6e8097e4c214 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -152,6 +152,15 @@ static void *virtio_gpu_alloc_cmd(struct 
> virtio_gpu_device *vgdev,
>  sizeof(struct virtio_gpu_ctrl_hdr), 
> NULL);
>  }
>
> +static void *virtio_gpu_alloc_cmd_cb(struct virtio_gpu_device *vgdev,
> +struct virtio_gpu_vbuffer **vbuffer_p,
> +int size,
> +virtio_gpu_resp_cb cb)
> +{
> +   return virtio_gpu_alloc_cmd_resp(vgdev, cb, vbuffer_p, size,
> +sizeof(struct virtio_gpu_ctrl_hdr), 
> NULL);
> +}
> +
>  static void free_vbuf(struct virtio_gpu_device *vgdev,
>   struct virtio_gpu_vbuffer *vbuf)
>  {
> @@ -494,17 +503,37 @@ void virtio_gpu_cmd_create_resource(struct 
> virtio_gpu_device *vgdev,
> bo->created = true;
>  }
>
> +static void virtio_gpu_cmd_unref_cb(struct virtio_gpu_device *vgdev,
> +   struct virtio_gpu_vbuffer *vbuf)
> +{
> +   struct virtio_gpu_object *bo;
> +
> +   bo = gem_to_virtio_gpu_obj(vbuf->objs->objs[0]);
> +   kfree(vbuf->objs);
> +