linux-kernel - [PATCH 3/5] hwmon: (gpio-fan) Ensure lock is held during set_fan

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Message-Id: <20250210145934.761280-4-alexander.stein@ew.tq-group.com>
Date: Mon, 10 Feb 2025 15:59:31 +0100
From: Alexander Stein <alexander.stein@...tq-group.com>
To: Jean Delvare <jdelvare@...e.com>,
	Guenter Roeck <linux@...ck-us.net>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>
Cc: Alexander Stein <alexander.stein@...tq-group.com>,
	linux-hwmon@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/5] hwmon: (gpio-fan) Ensure lock is held during set_fan_speed()

Instead of just documenting by comment, ensure locking per code.

Signed-off-by: Alexander Stein <alexander.stein@...tq-group.com>
---
 drivers/hwmon/gpio-fan.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c
index b779240328d59..322b161d5ca1f 100644
--- a/drivers/hwmon/gpio-fan.c
+++ b/drivers/hwmon/gpio-fan.c
@@ -124,9 +124,10 @@ static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 	return ctrl_val;
 }
 
-/* Must be called with fan_data->lock held, except during initialization. */
 static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 {
+	WARN_ON_ONCE(!mutex_is_locked(&fan_data->lock));
+
 	if (fan_data->speed_index == speed_index)
 		return;
 
-- 
2.34.1