[PATCH] cpufreq: mediatek: Fix potential deadlock problem in mtk_cpufreq_set_target

[Rex-BC Chen]

On Tue, 2022-05-10 at 16:01 +0800, Wan Jiabing wrote:
> Fix following coccichek error:
> ./drivers/cpufreq/mediatek-cpufreq.c:199:2-8: preceding lock on line
> ./drivers/cpufreq/mediatek-cpufreq.c:208:2-8: preceding lock on line
> 
> mutex_lock is acquired but not released before return.
> Use 'goto out' to help releasing the mutex_lock.
> 
> Fixes: c210063b40ac ("cupful: mediatek: Add opp notification
> support")
> Signed-off-by: Wan Jiabing <wanjiabing at vivo.com>
> ---
>  drivers/cpufreq/mediatek-cpufreq.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c
> b/drivers/cpufreq/mediatek-cpufreq.c
> index 75bf21ddf61f..4c6d53c99d79 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c
> @@ -196,7 +196,8 @@ static int mtk_cpufreq_set_target(struct
> cpufreq_policy *policy,
>  
>  	if (pre_vproc < 0) {
>  		dev_err(cpu_dev, "invalid Vproc value: %d\n",
> pre_vproc);
> -		return pre_vproc;
> +		ret = pre_vproc;
> +		goto out;
>  	}
>  
>  	freq_hz = freq_table[index].frequency * 1000;
> @@ -205,7 +206,8 @@ static int mtk_cpufreq_set_target(struct
> cpufreq_policy *policy,
>  	if (IS_ERR(opp)) {
>  		dev_err(cpu_dev, "cpu%d: failed to find OPP for %ld\n",
>  			policy->cpu, freq_hz);
> -		return PTR_ERR(opp);
> +		ret = PTR_ERR(opp);
> +		goto out;
>  	}
>  	vproc = dev_pm_opp_get_voltage(opp);
>  	dev_pm_opp_put(opp);

Hello Wan,

Thanks for checking this issue.
I did not notice this issue when I am asked to move the mutex lock here
in my patch.

Reviewed-by: Rex-BC Chen <rex-bc.chen at mediatek.com>

BRs,
Rex