[PATCH v4] soc: qcom: apr: Add check for idr_alloc and of_property_read_string_index

[PATCH v4] soc: qcom: apr: Add check for idr_alloc and of_property_read_string_index

[Jiasheng Jiang]

As idr_alloc() and of_property_read_string_index() can return negative
numbers, it should be better to check the return value and deal with
the exception.
Therefore, it should be better to use goto statement to deal with the
exception.

Fixes: 6adba21eb434 ("soc: qcom: Add APR bus driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
Changelog:

v3 -> v4:

1. Change the title and remove the kfree.

v2 -> v3:

1. Change the title and use goto statement to deal with the exception.

v1 -> v2:

1. Add dev_err and put_device in order to maintain the code consistency.
---
 drivers/soc/qcom/apr.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/qcom/apr.c b/drivers/soc/qcom/apr.c
index b4046f393575..8101b92e352c 100644
--- a/drivers/soc/qcom/apr.c
+++ b/drivers/soc/qcom/apr.c
@@ -454,20 +454,33 @@ static int apr_add_device(struct device *dev, struct device_node *np,
 	adev->dev.driver = NULL;
 
 	spin_lock(&apr->svcs_lock);
-	idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
+	ret = idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
 	spin_unlock(&apr->svcs_lock);
+	if (ret < 0) {
+		dev_err(dev, "idr_alloc failed: %d\n", ret);
+		goto error;
+	}
 
-	of_property_read_string_index(np, "qcom,protection-domain",
-				      1, &adev->service_path);
+	ret = of_property_read_string_index(np, "qcom,protection-domain",
+					    1, &adev->service_path);
+	if (ret < 0) {
+		dev_err(dev, "of_property_read_string_index failed: %d\n", ret);
+		goto error;
+	}
 
 	dev_info(dev, "Adding APR/GPR dev: %s\n", dev_name(&adev->dev));
 
 	ret = device_register(&adev->dev);
 	if (ret) {
 		dev_err(dev, "device_register failed: %d\n", ret);
-		put_device(&adev->dev);
+		goto error;
 	}
 
+	goto end;
+
+error:
+	put_device(&adev->dev);
+end:
 	return ret;
 }
 
-- 
2.25.1

Re: [PATCH v4] soc: qcom: apr: Add check for idr_alloc and of_property_read_string_index

[Bjorn Andersson]

On Wed, Sep 14, 2022 at 09:22:52AM +0800, Jiasheng Jiang wrote:
> As idr_alloc() and of_property_read_string_index() can return negative
> numbers, it should be better to check the return value and deal with
> the exception.
> Therefore, it should be better to use goto statement to deal with the
> exception.
> 

Thank you for your patch Jiasheng, just a few small requests below.

> Fixes: 6adba21eb434 ("soc: qcom: Add APR bus driver")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> ---
> Changelog:
> 
> v3 -> v4:
> 
> 1. Change the title and remove the kfree.
> 
> v2 -> v3:
> 
> 1. Change the title and use goto statement to deal with the exception.
> 
> v1 -> v2:
> 
> 1. Add dev_err and put_device in order to maintain the code consistency.
> ---
>  drivers/soc/qcom/apr.c | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/soc/qcom/apr.c b/drivers/soc/qcom/apr.c
> index b4046f393575..8101b92e352c 100644
> --- a/drivers/soc/qcom/apr.c
> +++ b/drivers/soc/qcom/apr.c
> @@ -454,20 +454,33 @@ static int apr_add_device(struct device *dev, struct device_node *np,
>  	adev->dev.driver = NULL;
>  
>  	spin_lock(&apr->svcs_lock);
> -	idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
> +	ret = idr_alloc(&apr->svcs_idr, svc, svc_id, svc_id + 1, GFP_ATOMIC);
>  	spin_unlock(&apr->svcs_lock);
> +	if (ret < 0) {
> +		dev_err(dev, "idr_alloc failed: %d\n", ret);
> +		goto error;
> +	}
>  
> -	of_property_read_string_index(np, "qcom,protection-domain",
> -				      1, &adev->service_path);
> +	ret = of_property_read_string_index(np, "qcom,protection-domain",
> +					    1, &adev->service_path);
> +	if (ret < 0) {
> +		dev_err(dev, "of_property_read_string_index failed: %d\n", ret);

I think "Failed to read second value of qcom,protection-domain" would be
more useful. Probably no need to include "ret".

> +		goto error;
> +	}
>  
>  	dev_info(dev, "Adding APR/GPR dev: %s\n", dev_name(&adev->dev));
>  
>  	ret = device_register(&adev->dev);
>  	if (ret) {
>  		dev_err(dev, "device_register failed: %d\n", ret);
> -		put_device(&adev->dev);
> +		goto error;
>  	}
>  
> +	goto end;

I unfortunately do not fancy the goto dance here. Please add
put_device() in each of the error cases above.

> +
> +error:
> +	put_device(&adev->dev);
> +end:

I would prefer this label to be named "out".

Thanks,
Bjorn

>  	return ret;
>  }
>  
> -- 
> 2.25.1
>