linux-kernel - RE: [PATCH 02/12] PM / devfreq: Fix locking range for making the frequency table

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Date:   Mon, 28 Aug 2017 00:25:51 +0000
From:   MyungJoo Ham <myungjoo.ham@...sung.com>
To:     Chanwoo Choi <cw00.choi@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>
CC:     "rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
        "chanwoo@...nel.org" <chanwoo@...nel.org>,
        Inki Dae <inki.dae@...sung.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH 02/12] PM / devfreq: Fix locking range for making the
 frequency table

> Even if the freq_table is included in the struct devfreq,
> the commit 0ec09ac2cebe ("PM / devfreq: Set the freq_table
> of devfreq device") set the frequency table outside the mutex locking.
> 
> So, this patch initializes the frequency table within the mutex locking.
> 
> Cc: stable@...r.kernel.org
> Fixes: 0ec09ac2cebe ("PM / devfreq: Set the freq_table of devfreq device")
> Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>

Is this because you do not have locks inside
devfreq_set_freq_table() anymore?

> ---
>  drivers/devfreq/devfreq.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index a1c4ee818614..3c5ccb96e165 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -553,11 +553,8 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  	devfreq->data = data;
>  	devfreq->nb.notifier_call = devfreq_notifier_call;
>  
> -	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
> -		mutex_unlock(&devfreq->lock);
> +	if (!devfreq->profile->max_state && !devfreq->profile->freq_table)
>  		devfreq_set_freq_table(devfreq);
> -		mutex_lock(&devfreq->lock);
> -	}
>  
>  	dev_set_name(&devfreq->dev, "devfreq%d",
>  				atomic_inc_return(&devfreq_no));