linux-kernel - Re: [PATCH] cpufreq: stats: do cpufreq_cpu_put() corresponding to cpufreq_cpu

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Date:	Fri, 22 Mar 2013 16:42:57 +0530
From:	Amit Kucheria <amit.kucheria@...aro.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Robin Randhawa <robin.randhawa@....com>,
	linux-pm@...r.kernel.org, Liviu Dudau <Liviu.Dudau@....com>,
	linux-kernel@...r.kernel.org, cpufreq@...r.kernel.org,
	Steve Bannister <Steve.Bannister@....com>,
	Arvind Chauhan <arvind.chauhan@....com>,
	Lists linaro-kernel <linaro-kernel@...ts.linaro.org>,
	Charles Garcia-Tobin <charles.garcia-tobin@....com>
Subject: Re: [PATCH] cpufreq: stats: do cpufreq_cpu_put() corresponding to cpufreq_cpu_get

On Fri, Mar 22, 2013 at 3:43 PM, Viresh Kumar <viresh.kumar@...aro.org> wrote:
> In cpufreq_stats_free_sysfs() we aren't balancing calls to cpufreq_cpu_get()
> with cpufreq_cpu_put(). This will never let us have ref count to policy->kobj as
> zero.

Rafael,

Since this prevents booting on our hardware (we unregister and
re-register the cpufreq driver to account for virtual cores), will
this be considered as a hotfix for 3.9?

> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>

Acked-by: Amit Kucheria <amit.kucheria@...aro.org>

> ---
>  drivers/cpufreq/cpufreq_stats.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
> index 2fd779e..bfd6273 100644
> --- a/drivers/cpufreq/cpufreq_stats.c
> +++ b/drivers/cpufreq/cpufreq_stats.c
> @@ -180,15 +180,19 @@ static void cpufreq_stats_free_sysfs(unsigned int cpu)
>  {
>         struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
>
> -       if (!cpufreq_frequency_get_table(cpu))
> +       if (!policy)
>                 return;
>
> -       if (policy && !policy_is_shared(policy)) {
> +       if (!cpufreq_frequency_get_table(cpu))
> +               goto put_ref;
> +
> +       if (!policy_is_shared(policy)) {
>                 pr_debug("%s: Free sysfs stat\n", __func__);
>                 sysfs_remove_group(&policy->kobj, &stats_attr_group);
>         }
> -       if (policy)
> -               cpufreq_cpu_put(policy);
> +
> +put_ref:
> +       cpufreq_cpu_put(policy);
>  }
>
>  static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
> --
> 1.7.12.rc2.18.g61b472e
>
--
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