linux-kernel - Re: [PATCH v4 08/10] thermal: imx: Use scope-based cleanup helper

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Message-ID: <20250905110551.00006588@huawei.com>
Date: Fri, 5 Sep 2025 11:05:51 +0100
From: Jonathan Cameron <jonathan.cameron@...wei.com>
To: Zihuan Zhang <zhangzihuan@...inos.cn>
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Subject: Re: [PATCH v4 08/10] thermal: imx: Use scope-based cleanup helper

On Wed,  3 Sep 2025 21:17:31 +0800
Zihuan Zhang <zhangzihuan@...inos.cn> wrote:

> Replace the manual cpufreq_cpu_put() with __free(put_cpufreq_policy)
> annotation for policy references. This reduces the risk of reference
> counting mistakes and aligns the code with the latest kernel style.
> 
> No functional change intended.
> 
> Signed-off-by: Zihuan Zhang <zhangzihuan@...inos.cn>

This radically changes the lifetime of the reference to policy.
If that is valid, then I'd expect a lot more description of why!

> ---
>  drivers/thermal/imx_thermal.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> index 38c993d1bcb3..cd1d9d419275 100644
> --- a/drivers/thermal/imx_thermal.c
> +++ b/drivers/thermal/imx_thermal.c
> @@ -201,7 +201,6 @@ static struct thermal_soc_data thermal_imx7d_data = {
>  
>  struct imx_thermal_data {
>  	struct device *dev;
> -	struct cpufreq_policy *policy;
>  	struct thermal_zone_device *tz;
>  	struct thermal_cooling_device *cdev;
>  	struct regmap *tempmon;
> @@ -541,22 +540,20 @@ MODULE_DEVICE_TABLE(of, of_imx_thermal_match);
>  static int imx_thermal_register_legacy_cooling(struct imx_thermal_data *data)
>  {
>  	struct device_node *np;
> +	struct cpufreq_policy *policy __free(put_cpufreq_policy) = cpufreq_cpu_get(0);
>  	int ret = 0;
>  
> -	data->policy = cpufreq_cpu_get(0);
> -	if (!data->policy) {
> +	if (!policy) {
>  		pr_debug("%s: CPUFreq policy not found\n", __func__);
>  		return -EPROBE_DEFER;
>  	}
>  
> -	np = of_get_cpu_node(data->policy->cpu, NULL);
> +	np = of_get_cpu_node(policy->cpu, NULL);
>  
>  	if (!np || !of_property_present(np, "#cooling-cells")) {
> -		data->cdev = cpufreq_cooling_register(data->policy);
> -		if (IS_ERR(data->cdev)) {
> +		data->cdev = cpufreq_cooling_register(policy);
> +		if (IS_ERR(data->cdev))
>  			ret = PTR_ERR(data->cdev);
> -			cpufreq_cpu_put(data->policy);
> -		}
>  	}
>  
>  	of_node_put(np);
> @@ -567,7 +564,6 @@ static int imx_thermal_register_legacy_cooling(struct imx_thermal_data *data)
>  static void imx_thermal_unregister_legacy_cooling(struct imx_thermal_data *data)
>  {
>  	cpufreq_cooling_unregister(data->cdev);
> -	cpufreq_cpu_put(data->policy);
>  }
>  
>  #else