linux-kernel - [PATCH V2 06/13] thermal/drivers/hisi: Remove pointless lock

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Message-Id: <1504554972-2624-6-git-send-email-daniel.lezcano@linaro.org>
Date:   Mon,  4 Sep 2017 21:56:05 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     rui.zhang@...el.com, edubezval@...il.com
Cc:     daniel.lezcano@...aro.org, linux-pm@...r.kernel.org,
        kevin.wangtao@...aro.org, leo.yan@...aro.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH V2 06/13] thermal/drivers/hisi: Remove pointless lock

The threaded interrupt inspect the sensors structure to look in the temp
threshold field, but this field is read-only in all the code, except in the
probe function before the threaded interrupt is set. In other words there
is not race window in the threaded interrupt when reading the field value.

Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
Reviewed-by: Leo Yan <leo.yan@...aro.org>
---
 drivers/thermal/hisi_thermal.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c
index f523197..9ec5f29 100644
--- a/drivers/thermal/hisi_thermal.c
+++ b/drivers/thermal/hisi_thermal.c
@@ -221,14 +221,10 @@ static irqreturn_t hisi_thermal_alarm_irq(int irq, void *dev)
 static irqreturn_t hisi_thermal_alarm_irq_thread(int irq, void *dev)
 {
 	struct hisi_thermal_data *data = dev;
-	struct hisi_thermal_sensor *sensor;
-
-	mutex_lock(&data->thermal_lock);
-	sensor = &data->sensors;
+	struct hisi_thermal_sensor *sensor = &data->sensors;
 
 	dev_crit(&data->pdev->dev, "THERMAL ALARM: T > %d\n",
 		 sensor->thres_temp);
-	mutex_unlock(&data->thermal_lock);
 
 	thermal_zone_device_update(data->sensors.tzd,
 				   THERMAL_EVENT_UNSPECIFIED);
-- 
2.7.4