Sender: Guenter Roeck <groeck7@gmail.com>
Date:   Mon, 20 Feb 2023 06:11:54 -0800
From:   Guenter Roeck <linux@roeck-us.net>
To:     Daniel Lezcano <daniel.lezcano@linaro.org>
Cc:     linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Amit Kucheria <amitk@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>, rafael@kernel.org
Subject: Re: [PATCH v1 07/17] thermal/hwmon: Use the thermal API instead
 tampering the internals
Message-ID: <20230220141154.GB4009286@roeck-us.net>
References: <20230219143657.241542-1-daniel.lezcano@linaro.org>
 <20230219143657.241542-8-daniel.lezcano@linaro.org>
 <9ac3a59f-a3b7-4128-87d0-7b3310ce7828@linaro.org>
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On Mon, Feb 20, 2023 at 02:34:08PM +0100, Daniel Lezcano wrote:
> Hi Guenter,
> 
> my script should have Cc'ed you but it didn't, so just a heads up this patch
> ;)
> 
> On 19/02/2023 15:36, Daniel Lezcano wrote:
> > In this function, there is a guarantee the thermal zone is registered.
> > 
> > The sysfs hwmon unregistering will be blocked until we exit the
> > function. The thermal zone is unregistered after the sysfs hwmon is
> > unregistered.
> > 
> > When we are in this function, the thermal zone is registered.
> > 
> > We can call the thermal_zone_get_crit_temp() function safely and let
> > the function use the lock which is private the thermal core code.
> > 

Hmm, if you say so. That very same call used to cause a crash in
Chromebooks, which is why I had added the locking.

Guenter

> > Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> > ---
> >   drivers/thermal/thermal_hwmon.c | 10 +---------
> >   1 file changed, 1 insertion(+), 9 deletions(-)
> > 
> > diff --git a/drivers/thermal/thermal_hwmon.c b/drivers/thermal/thermal_hwmon.c
> > index bc02095b314c..15158715b967 100644
> > --- a/drivers/thermal/thermal_hwmon.c
> > +++ b/drivers/thermal/thermal_hwmon.c
> > @@ -77,15 +77,7 @@ temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
> >   	int temperature;
> >   	int ret;
> > -	mutex_lock(&tz->lock);
> > -
> > -	if (device_is_registered(&tz->device))
> > -		ret = tz->ops->get_crit_temp(tz, &temperature);
> > -	else
> > -		ret = -ENODEV;
> > -
> > -	mutex_unlock(&tz->lock);
> > -
> > +	ret = thermal_zone_get_crit_temp(tz, &temperature);
> >   	if (ret)
> >   		return ret;
> 
> -- 
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