linux-kernel - Re: [PATCH 1/4] pwm: omap-dmtimer: remove pwmchip in .remove before making it unfunctional

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Date:   Mon, 11 Nov 2019 21:00:05 +0100
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     Markus Elfring <Markus.Elfring@....de>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        linux-pwm@...r.kernel.org, Neil Brown <neilb@...e.de>,
        kernel-janitors@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>, kernel@...gutronix.de,
        Neil Armstrong <narmstrong@...libre.com>
Subject: Re: [PATCH 1/4] pwm: omap-dmtimer: remove pwmchip in .remove before
 making it unfunctional

Hello Markus,

On Mon, Nov 11, 2019 at 02:30:42PM +0100, Markus Elfring wrote:
> > In the old code (e.g.) mutex_destroy() was called before
> > pwmchip_remove(). Between these two calls it is possible that a pwm
> > callback is used which tries to grab the mutex.
> 
> How do you think about to add a more “imperative mood” for your
> change description?
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=31f4f5b495a62c9a8b15b1c3581acd5efeb9af8c#n151

I described the old behaviour and like my wording.

> > +++ b/drivers/pwm/pwm-omap-dmtimer.c
> > @@ -351,6 +351,11 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
> >  static int pwm_omap_dmtimer_remove(struct platform_device *pdev)
> >  {
> >  	struct pwm_omap_dmtimer_chip *omap = platform_get_drvdata(pdev);
> > +	int ret;
> > +
> > +	ret = pwmchip_remove(&omap->chip);
> > +	if (ret)
> > +		return ret;
> >
> >  	if (pm_runtime_active(&omap->dm_timer_pdev->dev))
> >  		omap->pdata->stop(omap->dm_timer);
> 
> How do you think about to use the following statement variant?
> 
> +	int ret = pwmchip_remove(&omap->chip);

I think that between the declarations and code should be an empty line
and between the assignment to ret and the respective check there
shouldn't be one.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |