[PATCH v3 1/4] devfreq: Use mutex guard in governor_store()

[Jie Zhan]

Use mutex guard in governor_store() so as to simplify the locking logic.

No functional impact intended.

Reviewed-by: Yaxiong Tian <tianyaxiong at kylinos.cn>
Signed-off-by: Jie Zhan <zhanjie9 at hisilicon.com>
---
 drivers/devfreq/devfreq.c | 38 ++++++++++++++++----------------------
 1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index f08fc6966eae..7a70dd051644 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1394,23 +1394,20 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 	if (ret != 1)
 		return -EINVAL;
 
-	mutex_lock(&devfreq_list_lock);
+	guard(mutex)(&devfreq_list_lock);
 	governor = try_then_request_governor(str_governor);
-	if (IS_ERR(governor)) {
-		ret = PTR_ERR(governor);
-		goto out;
-	}
+	if (IS_ERR(governor))
+		return PTR_ERR(governor);
+
 	if (!df->governor)
 		goto start_new_governor;
 
-	if (df->governor == governor) {
-		ret = 0;
-		goto out;
-	} else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
-		|| IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (df->governor == governor)
+		return count;
+
+	if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE) ||
+	    IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
+		return -EINVAL;
 
 	/*
 	 * Stop the current governor and remove the specific sysfs files
@@ -1420,7 +1417,7 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 	if (ret) {
 		dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
 			 __func__, df->governor->name, ret);
-		goto out;
+		return ret;
 	}
 
 start_new_governor:
@@ -1438,7 +1435,7 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 		/* Restore previous governor */
 		df->governor = prev_governor;
 		if (!df->governor)
-			goto out;
+			return ret;
 
 		ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
 		if (ret) {
@@ -1446,7 +1443,7 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 				"%s: reverting to Governor %s failed (%d)\n",
 				__func__, prev_governor->name, ret);
 			df->governor = NULL;
-			goto out;
+			return ret;
 		}
 	}
 
@@ -1455,13 +1452,10 @@ static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
 	 * the new governor, restore the sysfs files of previous governor.
 	 */
 	ret = sysfs_update_group(&df->dev.kobj, &gov_attr_group);
+	if (ret)
+		return ret;
 
-out:
-	mutex_unlock(&devfreq_list_lock);
-
-	if (!ret)
-		ret = count;
-	return ret;
+	return count;
 }
 static DEVICE_ATTR_RW(governor);
 
-- 
2.43.0