linux-kernel - Re: [PATCH V2] cpufreq: Always remove sysfs cpuX/cpufreq link on ->remove

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Date:	Sat, 21 Nov 2015 06:42:09 -0800
From:	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:	Viresh Kumar <viresh.kumar@...aro.org>,
	Rafael Wysocki <rjw@...ysocki.net>
Cc:	linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2] cpufreq: Always remove sysfs cpuX/cpufreq link on
 ->remove_dev()

On Sat, 2015-11-21 at 09:06 +0530, Viresh Kumar wrote:
> Subsys interface's ->remove_dev() is called when the cpufreq driver
> is
> unregistering or the CPU is getting physically removed. We keep
> removing
> the cpuX/cpufreq link for all CPUs except the last one, which is a
> mistake as all CPUs contain a link now.
> 
> Because of this, one CPU from each policy will still contain a link
> (to
> an already removed policyX directory), after the cpufreq driver is
> unregistered.
> 
> Fix that by removing the link first and then only see if the policy
> is
> required to be freed. That will make sure that no links are left out.
> 
> Fixes: 96bdda61f58b ("cpufreq: create cpu/cpufreq/policyX
> directories")
> Reported-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com

Tested-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com
> >
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
> [v2] Drop the unnecessary 'return', sorry about that :(
> 
>  drivers/cpufreq/cpufreq.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 7c48e7316d91..a83c995a62df 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1401,13 +1401,10 @@ static void cpufreq_remove_dev(struct device
> *dev, struct subsys_interface *sif)
>  	}
>  
>  	cpumask_clear_cpu(cpu, policy->real_cpus);
> +	remove_cpu_dev_symlink(policy, cpu);
>  
> -	if (cpumask_empty(policy->real_cpus)) {
> +	if (cpumask_empty(policy->real_cpus))
>  		cpufreq_policy_free(policy, true);
> -		return;
> -	}
> -
> -	remove_cpu_dev_symlink(policy, cpu);
>  }
>  
>  static void handle_update(struct work_struct *work)
--
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