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[71.255.245.97]) by smtp.gmail.com with ESMTPSA id v1sm25458220qtj.68.2019.01.02.18.29.11 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Jan 2019 18:29:11 -0800 (PST) Subject: Re: [PATCH V2] thermal: Fix locking in cooling device sysfs update cur_state To: rui.zhang@intel.com, edubezval@gmail.com, daniel.lezcano@linaro.org References: <1543358591-25189-1-git-send-email-thara.gopinath@linaro.org> Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org From: Thara Gopinath Message-ID: <5C2D7376.3010408@linaro.org> Date: Wed, 2 Jan 2019 21:29:10 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1543358591-25189-1-git-send-email-thara.gopinath@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/27/2018 05:43 PM, Thara Gopinath wrote: > Sysfs interface to update cooling device cur_state does not > currently holding cooling device lock sometimes leading to > stale values in cur_state if getting updated simultanelously > from user space and thermal framework. Adding the proper locking > code fixes this issue. > > Signed-off-by: Thara Gopinath > --- > > V1->V2: Rearranged the code as per Daniel's review comment Hi Eduardo, Daniel Any comments on this ? Regards Thara > > drivers/thermal/thermal_sysfs.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c > index 2241cea..aa99edb 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -712,11 +712,14 @@ cur_state_store(struct device *dev, struct device_attribute *attr, > if ((long)state < 0) > return -EINVAL; > > + mutex_lock(&cdev->lock); > + > result = cdev->ops->set_cur_state(cdev, state); > - if (result) > - return result; > - thermal_cooling_device_stats_update(cdev, state); > - return count; > + if (!result) > + thermal_cooling_device_stats_update(cdev, state); > + > + mutex_unlock(&cdev->lock); > + return result ? result : count; > } > > static struct device_attribute >