linux-kernel - Re: [PATCH 06/78] media: renesas-ceu: fix pm_runtime_get

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Date:   Sat, 24 Apr 2021 10:11:21 +0200
From:   Jacopo Mondi <jacopo@...ndi.org>
To:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH 06/78] media: renesas-ceu: fix pm_runtime_get_sync()
 usage count

Hi Mauro,

On Sat, Apr 24, 2021 at 08:44:16AM +0200, Mauro Carvalho Chehab wrote:
> The pm_runtime_get_sync() internally increments the
> dev->power.usage_count without decrementing it, even on errors.
> replace it by the new pm_runtime_resume_and_get(), introduced by:

Nit: 'Replace' as it follows a full stop ?

> commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> in order to properly decrement the usage counter and avoid memory
> leaks.
>
> While here, check if the PM runtime was caught at open time.

Nit: Maybe "PM runtime error ..." or something similar as I'm missing the
subject of the phrase.

>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> ---
>  drivers/media/platform/renesas-ceu.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/renesas-ceu.c b/drivers/media/platform/renesas-ceu.c
> index cd137101d41e..965a7259e707 100644
> --- a/drivers/media/platform/renesas-ceu.c
> +++ b/drivers/media/platform/renesas-ceu.c
> @@ -1099,7 +1099,10 @@ static int ceu_open(struct file *file)
>
>  	mutex_lock(&ceudev->mlock);
>  	/* Causes soft-reset and sensor power on on first open */
> -	pm_runtime_get_sync(ceudev->dev);
> +	ret = pm_runtime_resume_and_get(ceudev->dev);
> +	if (ret < 0)
> +		return ret;

The mutex should be released before returning

> +
>  	mutex_unlock(&ceudev->mlock);
>
>  	return 0;
> --
> 2.30.2
>