Re: [PATCH 2/7] drm/client: Move dumb-buffer handling to drm_client_framebuffer_create()

[Jocelyn Falempe <jfalempe@redhat.com>]

On 20/10/2025 17:04, Thomas Zimmermann wrote:
> Dumb-buffer creation within the client code is asymetrically balanced
> across drm_client_buffer_create() and drm_client_framebuffer_create().
> Put all dumb-buffer code into drm_client_framebuffer_create() and leave
> client-buffer initialization to drm_client_buffer_create(). Clarifies
> responsibility between these functions.
> 
> Apart form the architectural improvements, drm_client_buffer_create()
> can now be exported if needed by clients. The client will be able to
> initialize buffers that have been created from other interfaces than
> dumb buffers.

Thanks, it looks good to me.

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>

> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>   drivers/gpu/drm/drm_client.c | 56 +++++++++++++++++++-----------------
>   1 file changed, 29 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
> index 5fa8a1628563..9bf2edfb7b64 100644
> --- a/drivers/gpu/drm/drm_client.c
> +++ b/drivers/gpu/drm/drm_client.c
> @@ -184,11 +184,8 @@ static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
>   
>   static struct drm_client_buffer *
>   drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
> -			 u32 format, u32 *handle, u32 *pitch)
> +			 u32 format, u32 handle, u32 pitch)
>   {
> -	const struct drm_format_info *info = drm_format_info(format);
> -	struct drm_mode_create_dumb dumb_args = { };
> -	struct drm_device *dev = client->dev;
>   	struct drm_client_buffer *buffer;
>   	struct drm_gem_object *obj;
>   	int ret;
> @@ -199,28 +196,18 @@ drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
>   
>   	buffer->client = client;
>   
> -	dumb_args.width = width;
> -	dumb_args.height = height;
> -	dumb_args.bpp = drm_format_info_bpp(info, 0);
> -	ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
> -	if (ret)
> -		goto err_delete;
> -
> -	obj = drm_gem_object_lookup(client->file, dumb_args.handle);
> +	obj = drm_gem_object_lookup(client->file, handle);
>   	if (!obj)  {
>   		ret = -ENOENT;
>   		goto err_delete;
>   	}
>   
>   	buffer->gem = obj;
> -	*handle = dumb_args.handle;
> -	*pitch = dumb_args.pitch;
>   
>   	return buffer;
>   
>   err_delete:
> -	drm_client_buffer_delete(buffer);
> -
> +	kfree(buffer);
>   	return ERR_PTR(ret);
>   }
>   
> @@ -394,16 +381,30 @@ static int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
>   struct drm_client_buffer *
>   drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format)
>   {
> +	const struct drm_format_info *info = drm_format_info(format);
> +	struct drm_device *dev = client->dev;
> +	struct drm_mode_create_dumb dumb_args = { };
>   	struct drm_client_buffer *buffer;
> -	u32 handle, pitch;
>   	int ret;
>   
> +	dumb_args.width = width;
> +	dumb_args.height = height;
> +	dumb_args.bpp = drm_format_info_bpp(info, 0);
> +	ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
>   	buffer = drm_client_buffer_create(client, width, height, format,
> -					  &handle, &pitch);
> -	if (IS_ERR(buffer))
> -		return buffer;
> +					  dumb_args.handle, dumb_args.pitch);
> +	if (IS_ERR(buffer)) {
> +		ret = PTR_ERR(buffer);
> +		goto err_drm_mode_destroy_dumb;
> +	}
>   
> -	ret = drm_client_buffer_addfb(buffer, width, height, format, handle, pitch);
> +	ret = drm_client_buffer_addfb(buffer, width, height, format,
> +				      dumb_args.handle, dumb_args.pitch);
> +	if (ret)
> +		goto err_drm_client_buffer_delete;
>   
>   	/*
>   	 * The handle is only needed for creating the framebuffer, destroy it
> @@ -411,14 +412,15 @@ drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 heig
>   	 * object as DMA-buf. The framebuffer and our buffer structure are still
>   	 * holding references to the GEM object to prevent its destruction.
>   	 */
> -	drm_mode_destroy_dumb(client->dev, handle, client->file);
> -
> -	if (ret) {
> -		drm_client_buffer_delete(buffer);
> -		return ERR_PTR(ret);
> -	}
> +	drm_mode_destroy_dumb(client->dev, dumb_args.handle, client->file);
>   
>   	return buffer;
> +
> +err_drm_client_buffer_delete:
> +	drm_client_buffer_delete(buffer);
> +err_drm_mode_destroy_dumb:
> +	drm_mode_destroy_dumb(client->dev, dumb_args.handle, client->file);
> +	return ERR_PTR(ret);
>   }
>   EXPORT_SYMBOL(drm_client_framebuffer_create);
>