Re: [PATCH v3 03/17] media: rkisp1: isp: Fix and simplify (un)registration

Dafna Hirschfeld
2022-03-22T04:23:18Z

On 19.03.2022 18:30, Laurent Pinchart wrote:
> The rkisp1_isp_register() and rkisp1_isp_unregister() functions don't
> destroy the mutex (in the error path for the former). Fix this, simplify
> error handling at registration time as media_entity_cleanup() can be
> called on an uninitialized entity, and make rkisp1_isp_unregister() and
> safe to be called on an unregistered isp subdev to prepare for
> simplification of error handling at probe time.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
> .../platform/rockchip/rkisp1/rkisp1-isp.c | 20 ++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> index 2a35bf24e54e..f84e53b60ee1 100644
> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> @@ -1090,29 +1090,35 @@ int rkisp1_isp_register(struct rkisp1_device *rkisp1)
> mutex_init(&isp->ops_lock);
> ret = media_entity_pads_init(&sd->entity, RKISP1_ISP_PAD_MAX, pads);
> if (ret)
> - return ret;
> + goto error;
>
> ret = v4l2_device_register_subdev(&rkisp1->v4l2_dev, sd);
> if (ret) {
> dev_err(rkisp1->dev, "Failed to register isp subdev\n");
> - goto err_cleanup_media_entity;
> + goto error;
> }
>
> rkisp1_isp_init_config(sd, &state);
> +
> return 0;
>
> -err_cleanup_media_entity:
> +error:
> media_entity_cleanup(&sd->entity);

I remember long ago that Ezequiel suggested removing that
'media_entity_cleanup' since it was never implemented which
indicates there is probably no need for it.

> -
> + mutex_destroy(&isp->ops_lock);
> + isp->sd.flags = 0;
> return ret;
> }
>
> void rkisp1_isp_unregister(struct rkisp1_device *rkisp1)
> {
> - struct v4l2_subdev *sd = &rkisp1->isp.sd;
> + struct rkisp1_isp *isp = &rkisp1->isp;
>
> - v4l2_device_unregister_subdev(sd);
> - media_entity_cleanup(&sd->entity);
> + if (!isp->sd.flags)

We assume no flags means that the device is not registered. This might
stop working if we ever decide to remove the existing flags.
So better "if (!isp->sd.v4l2_dev)" ?

Thanks,
Dafna

> + return;
> +
> + v4l2_device_unregister_subdev(&isp->sd);
> + media_entity_cleanup(&isp->sd.entity);
> + mutex_destroy(&isp->ops_lock);
> }
>
> /* ----------------------------------------------------------------------------
> --
> Regards,
>
> Laurent Pinchart
>