linux-kernel - Re: [PATCH] media: platform: s3c-camif: Fix runtime PM imbalance in s3c_camif

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Message-ID: <611ffe6a-c4ef-d23c-4d3f-a7771ce56bab@xs4all.nl>
Date:   Thu, 17 Sep 2020 13:26:46 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Dinghao Liu <dinghao.liu@....edu.cn>, kjlu@....edu
Cc:     Sylwester Nawrocki <sylvester.nawrocki@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: platform: s3c-camif: Fix runtime PM imbalance in
 s3c_camif_open

On 22/05/2020 10:29, Dinghao Liu wrote:
> pm_runtime_get_sync() increments the runtime PM usage counter even
> when it returns an error code. Thus a pairing decrement is needed on
> the error handling path to keep the counter balanced.
> 
> Also, call pm_runtime_put() and v4l2_fh_release() when sensor_set_power()
> returns an error code.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
> ---
>  drivers/media/platform/s3c-camif/camif-capture.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/media/platform/s3c-camif/camif-capture.c b/drivers/media/platform/s3c-camif/camif-capture.c
> index 9ca49af29542..d42d9cfaf674 100644
> --- a/drivers/media/platform/s3c-camif/camif-capture.c
> +++ b/drivers/media/platform/s3c-camif/camif-capture.c
> @@ -552,11 +552,9 @@ static int s3c_camif_open(struct file *file)
>  		goto err_pm;
>  
>  	ret = sensor_set_power(camif, 1);
> -	if (!ret)
> -		goto unlock;

This is wrong, now this will call v4l2_fh_release() as well on success.

This needs to be reworked.

Regards,

	Hans

>  
> -	pm_runtime_put(camif->dev);
>  err_pm:
> +	pm_runtime_put(camif->dev);
>  	v4l2_fh_release(file);
>  unlock:
>  	mutex_unlock(&camif->lock);
>