linux-kernel - [RFC PATCH for 6.13 v1 20/20] thermal: core: Manage thermal_governor

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Message-ID: <863177860.0ifERbkFSE@rjwysocki.net>
Date: Sat, 14 Sep 2024 12:50:15 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Lukasz Luba <lukasz.luba@....com>, Zhang Rui <rui.zhang@...el.com>
Subject:
 [RFC PATCH for 6.13 v1 20/20] thermal: core: Manage thermal_governor_lock
 using a mutex guard

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Switch over the thermal core to using a mutex guard for
thermal_governor_lock management.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/thermal/thermal_core.c |   40 +++++++++++++---------------------------
 1 file changed, 13 insertions(+), 27 deletions(-)

Index: linux-pm/drivers/thermal/thermal_core.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.c
+++ linux-pm/drivers/thermal/thermal_core.c
@@ -123,7 +123,7 @@ int thermal_register_governor(struct the
 	if (!governor)
 		return -EINVAL;
 
-	mutex_lock(&thermal_governor_lock);
+	guard(mutex)(&thermal_governor_lock);
 
 	err = -EBUSY;
 	if (!__find_governor(governor->name)) {
@@ -162,8 +162,6 @@ int thermal_register_governor(struct the
 		}
 	}
 
-	mutex_unlock(&thermal_governor_lock);
-
 	return err;
 }
 
@@ -174,10 +172,10 @@ void thermal_unregister_governor(struct
 	if (!governor)
 		return;
 
-	mutex_lock(&thermal_governor_lock);
+	guard(mutex)(&thermal_governor_lock);
 
 	if (!__find_governor(governor->name))
-		goto exit;
+		return;
 
 	list_del(&governor->governor_list);
 
@@ -188,9 +186,6 @@ void thermal_unregister_governor(struct
 				 THERMAL_NAME_LENGTH))
 			thermal_set_governor(pos, NULL);
 	}
-
-exit:
-	mutex_unlock(&thermal_governor_lock);
 }
 
 int thermal_zone_device_set_policy(struct thermal_zone_device *tz,
@@ -199,16 +194,13 @@ int thermal_zone_device_set_policy(struc
 	struct thermal_governor *gov;
 	int ret = -EINVAL;
 
-	mutex_lock(&thermal_governor_lock);
-
+	guard(mutex)(&thermal_governor_lock);
 	guard(thermal_zone)(tz);
 
 	gov = __find_governor(strim(policy));
 	if (gov)
 		ret = thermal_set_governor(tz, gov);
 
-	mutex_unlock(&thermal_governor_lock);
-
 	thermal_notify_tz_gov_change(tz, policy);
 
 	return ret;
@@ -219,15 +211,13 @@ int thermal_build_list_of_policies(char
 	struct thermal_governor *pos;
 	ssize_t count = 0;
 
-	mutex_lock(&thermal_governor_lock);
+	guard(mutex)(&thermal_governor_lock);
 
 	list_for_each_entry(pos, &thermal_governor_list, governor_list) {
 		count += sysfs_emit_at(buf, count, "%s ", pos->name);
 	}
 	count += sysfs_emit_at(buf, count, "\n");
 
-	mutex_unlock(&thermal_governor_lock);
-
 	return count;
 }
 
@@ -663,17 +653,18 @@ int for_each_thermal_governor(int (*cb)(
 			      void *data)
 {
 	struct thermal_governor *gov;
-	int ret = 0;
 
-	mutex_lock(&thermal_governor_lock);
+	guard(mutex)(&thermal_governor_lock);
+
 	list_for_each_entry(gov, &thermal_governor_list, governor_list) {
+		int ret;
+
 		ret = cb(gov, data);
 		if (ret)
-			break;
+			return ret;
 	}
-	mutex_unlock(&thermal_governor_lock);
 
-	return ret;
+	return 0;
 }
 
 int for_each_thermal_cooling_device(int (*cb)(struct thermal_cooling_device *,
@@ -1345,20 +1336,15 @@ EXPORT_SYMBOL_GPL(thermal_zone_get_crit_
 static int thermal_zone_init_governor(struct thermal_zone_device *tz)
 {
 	struct thermal_governor *governor;
-	int ret;
 
-	mutex_lock(&thermal_governor_lock);
+	guard(mutex)(&thermal_governor_lock);
 
 	if (tz->tzp)
 		governor = __find_governor(tz->tzp->governor_name);
 	else
 		governor = def_governor;
 
-	ret = thermal_set_governor(tz, governor);
-
-	mutex_unlock(&thermal_governor_lock);
-
-	return ret;
+	return thermal_set_governor(tz, governor);
 }
 
 static void thermal_zone_init_complete(struct thermal_zone_device *tz)