linux-kernel - Re: [PATCH V2] cpufreq: kyro: Release OPP tables on module removal

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Date:   Wed, 27 Feb 2019 15:10:18 +0200
From:   Georgi Djakov <georgi.djakov@...aro.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, Ilia Lin <ilia.lin@...nel.org>,
        linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Arnd Bergmann <arnd@...db.de>, amit.kucheria@...aro.org,
        stable@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2] cpufreq: kyro: Release OPP tables on module removal

On 2/27/19 12:04, Viresh Kumar wrote:
> Commit 5ad7346b4ae2 ("cpufreq: kryo: Add module remove and exit") made
> it possible to build the kyro cpufreq driver as a module, but it failed

Nit: s/kyro/kryo/ above and in the subject

> to release all the resources, i.e. OPP tables, when the module is
> unloaded.
> 
> This patch fixes it by releasing the OPP tables, by calling
> dev_pm_opp_put_supported_hw() for them, from the
> qcom_cpufreq_kryo_remove() routine. The array of pointers to the OPP
> tables is also allocated dynamically now in qcom_cpufreq_kryo_probe(),
> as the pointers will be required while releasing the resources.
> 
> Compile tested only.
> 
> Cc: 4.18+ <stable@...r.kernel.org> # v4.18+
> Fixes: 5ad7346b4ae2 ("cpufreq: kryo: Add module remove and exit")
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
> V1->V2:
> - The previous version targeted a compile time issue of frame size but
>   this fixes a bug in the driver and needs to get applied to 4.18+
>   kernels.
> - This may go in 5.0 release.
> - Haven't included any Reviewed-by tags as there were many changes in
>   this version.
> 
>  drivers/cpufreq/qcom-cpufreq-kryo.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/qcom-cpufreq-kryo.c b/drivers/cpufreq/qcom-cpufreq-kryo.c
> index 2a3675c24032..65edbfd4d4a5 100644
> --- a/drivers/cpufreq/qcom-cpufreq-kryo.c
> +++ b/drivers/cpufreq/qcom-cpufreq-kryo.c
> @@ -75,7 +75,7 @@ static enum _msm8996_version qcom_cpufreq_kryo_get_msm_id(void)
>  
>  static int qcom_cpufreq_kryo_probe(struct platform_device *pdev)
>  {
> -	struct opp_table *opp_tables[NR_CPUS] = {0};
> +	struct opp_table **opp_tables;
>  	enum _msm8996_version msm8996_version;
>  	struct nvmem_cell *speedbin_nvmem;
>  	struct device_node *np;
> @@ -133,6 +133,10 @@ static int qcom_cpufreq_kryo_probe(struct platform_device *pdev)
>  	}
>  	kfree(speedbin);
>  
> +	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables), GFP_KERNEL);
> +	if (!opp_tables)
> +		return -ENOMEM;
> +
>  	for_each_possible_cpu(cpu) {
>  		cpu_dev = get_cpu_device(cpu);
>  		if (NULL == cpu_dev) {
> @@ -151,8 +155,10 @@ static int qcom_cpufreq_kryo_probe(struct platform_device *pdev)
>  
>  	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
>  							  NULL, 0);
> -	if (!IS_ERR(cpufreq_dt_pdev))
> +	if (!IS_ERR(cpufreq_dt_pdev)) {
> +		platform_set_drvdata(pdev, opp_tables);
>  		return 0;
> +	}
>  
>  	ret = PTR_ERR(cpufreq_dt_pdev);
>  	dev_err(cpu_dev, "Failed to register platform device\n");
> @@ -163,13 +169,23 @@ static int qcom_cpufreq_kryo_probe(struct platform_device *pdev)
>  			break;
>  		dev_pm_opp_put_supported_hw(opp_tables[cpu]);
>  	}
> +	kfree(opp_tables);
>  
>  	return ret;
>  }
>  
>  static int qcom_cpufreq_kryo_remove(struct platform_device *pdev)
>  {
> +	struct opp_table **opp_tables = platform_get_drvdata(pdev);
> +	unsigned cpu;

Nit: unsigned int

> +
>  	platform_device_unregister(cpufreq_dt_pdev);
> +
> +	for_each_possible_cpu(cpu)
> +		dev_pm_opp_put_supported_hw(opp_tables[cpu]);
> +
> +	kfree(opp_tables);
> +
>  	return 0;
>  }
>  

Reviewed-by: Georgi Djakov <georgi.djakov@...aro.org>

Thanks,
Georgi