linux-kernel - Re: [PATCH 5/6] remoteproc: da8xx: Use devm action to release reserved memory

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Date: Tue, 11 Jun 2024 11:58:21 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Andrew Davis <afd@...com>
Cc: Hari Nagalla <hnagalla@...com>, Bjorn Andersson <andersson@...nel.org>,
	linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] remoteproc: da8xx: Use devm action to release
 reserved memory

Hi Andrew,

On Mon, Jun 10, 2024 at 10:17:20AM -0500, Andrew Davis wrote:
> This helps prevent mistakes like freeing out of order in cleanup functions
> and forgetting to free on error paths.
> 
> Signed-off-by: Andrew Davis <afd@...com>
> ---
>  drivers/remoteproc/da8xx_remoteproc.c | 29 +++++++++++++--------------
>  1 file changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/remoteproc/da8xx_remoteproc.c b/drivers/remoteproc/da8xx_remoteproc.c
> index c8b7576937733..1ce91516fc6e5 100644
> --- a/drivers/remoteproc/da8xx_remoteproc.c
> +++ b/drivers/remoteproc/da8xx_remoteproc.c
> @@ -233,6 +233,13 @@ static int da8xx_rproc_get_internal_memories(struct platform_device *pdev,
>  	return 0;
>  }
>  
> +static void da8xx_rproc_mem_release(void *data)
> +{
> +	struct device *dev = data;
> +
> +	of_reserved_mem_device_release(dev);
> +}
> +
>  static int da8xx_rproc_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -293,14 +300,13 @@ static int da8xx_rproc_probe(struct platform_device *pdev)
>  				ret);
>  			return ret;
>  		}
> +		devm_add_action_or_reset(&pdev->dev, da8xx_rproc_mem_release, &pdev->dev);
>  	}
>  
>  	rproc = devm_rproc_alloc(dev, "dsp", &da8xx_rproc_ops, da8xx_fw_name,
>  				 sizeof(*drproc));
> -	if (!rproc) {
> -		ret = -ENOMEM;
> -		goto free_mem;
> -	}
> +	if (!rproc)
> +		return -ENOMEM;
>  
>  	/* error recovery is not supported at present */
>  	rproc->recovery_disabled = true;
> @@ -313,7 +319,7 @@ static int da8xx_rproc_probe(struct platform_device *pdev)
>  
>  	ret = da8xx_rproc_get_internal_memories(pdev, drproc);
>  	if (ret)
> -		goto free_mem;
> +		return ret;
>  
>  	platform_set_drvdata(pdev, rproc);
>  
> @@ -323,7 +329,7 @@ static int da8xx_rproc_probe(struct platform_device *pdev)
>  					rproc);
>  	if (ret) {
>  		dev_err(dev, "devm_request_threaded_irq error: %d\n", ret);
> -		goto free_mem;
> +		return ret;
>  	}
>  
>  	/*
> @@ -333,7 +339,7 @@ static int da8xx_rproc_probe(struct platform_device *pdev)
>  	 */
>  	ret = reset_control_assert(dsp_reset);
>  	if (ret)
> -		goto free_mem;
> +		return ret;
>  
>  	drproc->chipsig = chipsig;
>  	drproc->bootreg = bootreg;
> @@ -344,15 +350,10 @@ static int da8xx_rproc_probe(struct platform_device *pdev)
>  	ret = rproc_add(rproc);
>  	if (ret) {
>  		dev_err(dev, "rproc_add failed: %d\n", ret);
> -		goto free_mem;
> +		return ret;
>  	}
>  
>  	return 0;
> -
> -free_mem:
> -	if (dev->of_node)
> -		of_reserved_mem_device_release(dev);
> -	return ret;
>  }
>  
>  static void da8xx_rproc_remove(struct platform_device *pdev)
> @@ -369,8 +370,6 @@ static void da8xx_rproc_remove(struct platform_device *pdev)
>  	disable_irq(drproc->irq);
>  
>  	rproc_del(rproc);
> -	if (dev->of_node)
> -		of_reserved_mem_device_release(dev);


This patch gives me the following compilation warning:

  CC      kernel/module/main.o
  CC      drivers/remoteproc/da8xx_remoteproc.o
  AR      drivers/base/firmware_loader/built-in.a
  AR      drivers/base/built-in.a
remoteproc/kernel/drivers/remoteproc/da8xx_remoteproc.c: In function ‘da8xx_rproc_remove’:
remoteproc/kernel/drivers/remoteproc/da8xx_remoteproc.c:363:24: warning: unused variable ‘dev’ [-Wunused-variable]
  363 |         struct device *dev = &pdev->dev;
      |                        ^~~
  AR      drivers/remoteproc/built-in.a

which is then fixed in the following patch with the introduction of
devm_rproc_add().  I suggest doing the opposite, i.e introduce devm_rproc_add()
and then get rid of da8xx_rproc_remove() by introducing
da8xx_rproc_mem_release().

No need to resend the omap set, I have them.

Thanks,
Mathieu

>  }
>  
>  static const struct of_device_id davinci_rproc_of_match[] __maybe_unused = {
> -- 
> 2.39.2
>