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

[Dafna Hirschfeld <dafna@fastmail.com>]

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
> 

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