linux-kernel - Re: [PATCH v3 13/79] media: s5p: fix pm_runtime_get

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Message-ID: <ae9e751a-be29-4ff8-b566-73c4f258d5b8@samsung.com>
Date:   Tue, 27 Apr 2021 12:51:45 +0200
From:   Sylwester Nawrocki <s.nawrocki@...sung.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH v3 13/79] media: s5p: fix pm_runtime_get_sync() usage
 count

On 27.04.2021 12:26, 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:
> 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 error was caught at
> s5p_cec_adap_enable().
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> ---
>  drivers/media/cec/platform/s5p/s5p_cec.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/cec/platform/s5p/s5p_cec.c b/drivers/media/cec/platform/s5p/s5p_cec.c
> index 2a3e7ffefe0a..2250c1cbc64e 100644
> --- a/drivers/media/cec/platform/s5p/s5p_cec.c
> +++ b/drivers/media/cec/platform/s5p/s5p_cec.c
> @@ -35,10 +35,13 @@ MODULE_PARM_DESC(debug, "debug level (0-2)");
>  
>  static int s5p_cec_adap_enable(struct cec_adapter *adap, bool enable)
>  {
> +	int ret;
>  	struct s5p_cec_dev *cec = cec_get_drvdata(adap);
>  
>  	if (enable) {
> -		pm_runtime_get_sync(cec->dev);
> +		ret = pm_runtime_resume_and_get(cec->dev);
> +		if (ret < 0)
> +			return ret;
>  
>  		s5p_cec_reset(cec);

Reviewed-by: Sylwester Nawrocki <s.nawrocki@...sung.com>

Not related to this patch, it seems there is bug in the second
'if (enable)' branch, where pm_runtime_disable() is used
instead of pm_runtime_put(_sync)().