Re: [PATCH] pwm: omap-dmtimer: Add missing put_device() call in pwm_omap_dmtimer_probe() - Uwe Kleine-König

From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Markus Elfring <Markus.Elfring@web.de>
Cc: linux-pwm@vger.kernel.org,
	Claudiu Beznea <claudiu.beznea@microchip.com>,
	Keerthy <j-keerthy@ti.com>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Tony Lindgren <tony@atomide.com>,
	LKML <linux-kernel@vger.kernel.org>,
	kernel-janitors@vger.kernel.org,
	Grant Erickson <marathon96@gmail.com>,
	Joachim Eastwood <manabian@gmail.com>, Neil Brown <neilb@suse.de>,
	Wen Yang <wen.yang99@zte.com.cn>
Subject: Re: [PATCH] pwm: omap-dmtimer: Add missing put_device() call in pwm_omap_dmtimer_probe()
Date: Mon, 11 Nov 2019 08:19:52 +0100	[thread overview]
Message-ID: <20191111071952.6pbswbboqreen6im@pengutronix.de> (raw)
In-Reply-To: <fd7a56e4-2a35-a6c4-e5bd-1e53a6c48687@web.de>

Hello Markus,

On Sat, Nov 09, 2019 at 01:26:50PM +0100, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sat, 9 Nov 2019 13:09:42 +0100
> 
> A coccicheck run provided information like the following.
> 
> drivers/pwm/pwm-omap-dmtimer.c:304:2-8: ERROR: missing put_device;
> call of_find_device_by_node on line 255, but without a corresponding
> object release within this function.
> 
> Generated by: scripts/coccinelle/free/put_device.cocci
> 
> Thus add jump targets to fix the exception handling for this
> function implementation.
> 
> Fixes: b7290cf6ff7869ec12070aa146c370728cab62c2 ("pwm: pwm-omap-dmtimer: Adapt driver to utilize dmtimer pdata ops")
> Fixes: 6604c6556db9e41c85f2839f66bd9d617bcf9f87 ("pwm: Add PWM driver for OMAP using dual-mode timers")
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  drivers/pwm/pwm-omap-dmtimer.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
> index 00772fc53490..958854213786 100644
> --- a/drivers/pwm/pwm-omap-dmtimer.c
> +++ b/drivers/pwm/pwm-omap-dmtimer.c
> @@ -301,12 +301,13 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>  put:
>  	of_node_put(timer);
>  	if (ret < 0)
> -		return ret;
> +		goto check_timer_pdev;
> 
>  	omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL);
>  	if (!omap) {
>  		pdata->free(dm_timer);
> -		return -ENOMEM;
> +		ret = -ENOMEM;
> +		goto put_device;
>  	}
> 
>  	omap->pdata = pdata;
> @@ -340,12 +341,19 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "failed to register PWM\n");
>  		omap->pdata->free(omap->dm_timer);
> -		return ret;
> +		goto put_device;
>  	}
> 
>  	platform_set_drvdata(pdev, omap);
> 
>  	return 0;
> +
> +check_timer_pdev:
> +	if (timer_pdev)
> +put_device:
> +		put_device(&timer_pdev->dev);

This is ugly but necessary with the driver as is because the error
handling is interwinded within the normal path through this function.

I would prefer to clean this up first, then this fix gets a bit nicer.
Will send a patch in reply to this mail.

Best regards
Uwe

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Pengutronix e.K.                           | Uwe Kleine-König            |
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