linux-kernel - [PATCH v2 5/9] thermal/core: Introduce locked version of thermal_zone_device

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Date:   Thu, 10 Nov 2022 07:24:56 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Amit Kucheria <amitk@...nel.org>, Zhang Rui <rui.zhang@...el.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH v2 5/9] thermal/core: Introduce locked version of thermal_zone_device_update

In thermal_zone_device_set_mode(), the thermal zone mutex is released only
to be reacquired in the subsequent call to thermal_zone_device_update().

Introduce __thermal_zone_device_update(), which is similar to
thermal_zone_device_update() but has to be called with the thermal device
mutex held. Call the new function from thermal_zone_device_set_mode()
to avoid the extra thermal device mutex release/acquire sequence in that
function.

With the new function in place, re-implement thermal_zone_device_update()
as wrapper around __thermal_zone_device_update() to acquire and release
the thermal device mutex.

Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
v2: Reword description to clarify that the new function must be called with
    thermal device mutex held.

 drivers/thermal/thermal_core.c | 57 ++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 26 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 562ece8d16aa..9facd9c5b70f 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -403,6 +403,34 @@ static void thermal_zone_device_init(struct thermal_zone_device *tz)
 		pos->initialized = false;
 }
 
+static void __thermal_zone_device_update(struct thermal_zone_device *tz,
+					 enum thermal_notify_event event)
+{
+	int count;
+
+	if (atomic_read(&in_suspend))
+		return;
+
+	if (WARN_ONCE(!tz->ops->get_temp,
+		      "'%s' must not be called without 'get_temp' ops set\n",
+		      __func__))
+		return;
+
+	if (!thermal_zone_device_is_enabled(tz))
+		return;
+
+	update_temperature(tz);
+
+	__thermal_zone_set_trips(tz);
+
+	tz->notify_event = event;
+
+	for (count = 0; count < tz->num_trips; count++)
+		handle_thermal_trip(tz, count);
+
+	monitor_thermal_zone(tz);
+}
+
 static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
 					enum thermal_device_mode mode)
 {
@@ -423,9 +451,9 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
 	if (!ret)
 		tz->mode = mode;
 
-	mutex_unlock(&tz->lock);
+	__thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 
-	thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
+	mutex_unlock(&tz->lock);
 
 	if (mode == THERMAL_DEVICE_ENABLED)
 		thermal_notify_tz_enable(tz->id);
@@ -457,31 +485,8 @@ int thermal_zone_device_is_enabled(struct thermal_zone_device *tz)
 void thermal_zone_device_update(struct thermal_zone_device *tz,
 				enum thermal_notify_event event)
 {
-	int count;
-
-	if (atomic_read(&in_suspend))
-		return;
-
-	if (WARN_ONCE(!tz->ops->get_temp, "'%s' must not be called without "
-		      "'get_temp' ops set\n", __func__))
-		return;
-
 	mutex_lock(&tz->lock);
-
-	if (!thermal_zone_device_is_enabled(tz))
-		goto out;
-
-	update_temperature(tz);
-
-	__thermal_zone_set_trips(tz);
-
-	tz->notify_event = event;
-
-	for (count = 0; count < tz->num_trips; count++)
-		handle_thermal_trip(tz, count);
-
-	monitor_thermal_zone(tz);
-out:
+	__thermal_zone_device_update(tz, event);
 	mutex_unlock(&tz->lock);
 }
 EXPORT_SYMBOL_GPL(thermal_zone_device_update);
-- 
2.36.2