linux-kernel - [PATCH v2 20/22] Input: regulator-haptic - use guard notation when acquiring mutex

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Message-ID: <ZtjJKxQRRzJE0aWZ@google.com>
Date: Wed, 4 Sep 2024 13:55:07 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Javier Carrasco <javier.carrasco.cruz@...il.com>
Cc: linux-input@...r.kernel.org,
	Michael Hennerich <michael.hennerich@...log.com>,
	Ville Syrjala <syrjala@....fi>,
	Support Opensource <support.opensource@...semi.com>,
	Eddie James <eajames@...ux.ibm.com>,
	Andrey Moiseev <o2g.org.ru@...il.com>,
	Hans de Goede <hdegoede@...hat.com>,
	Jeff LaBundy <jeff@...undy.com>, linux-kernel@...r.kernel.org
Subject: [PATCH v2 20/22] Input: regulator-haptic - use guard notation when
 acquiring mutex

Using guard notation makes the code more compact and error handling
more robust by ensuring that mutexes are released in all code paths
when control leaves critical section.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---

v2: drop no linger used "error" variable in regulator_haptic_suspend()

 drivers/input/misc/regulator-haptic.c |   24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/drivers/input/misc/regulator-haptic.c b/drivers/input/misc/regulator-haptic.c
index 02f73b7c0462..3666ba6d1f30 100644
--- a/drivers/input/misc/regulator-haptic.c
+++ b/drivers/input/misc/regulator-haptic.c
@@ -83,12 +83,10 @@ static void regulator_haptic_work(struct work_struct *work)
 	struct regulator_haptic *haptic = container_of(work,
 					struct regulator_haptic, work);
 
-	mutex_lock(&haptic->mutex);
+	guard(mutex)(&haptic->mutex);
 
 	if (!haptic->suspended)
 		regulator_haptic_set_voltage(haptic, haptic->magnitude);
-
-	mutex_unlock(&haptic->mutex);
 }
 
 static int regulator_haptic_play_effect(struct input_dev *input, void *data,
@@ -205,19 +203,15 @@ static int regulator_haptic_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct regulator_haptic *haptic = platform_get_drvdata(pdev);
-	int error;
 
-	error = mutex_lock_interruptible(&haptic->mutex);
-	if (error)
-		return error;
-
-	regulator_haptic_set_voltage(haptic, 0);
+	scoped_guard(mutex_intr, &haptic->mutex) {
+		regulator_haptic_set_voltage(haptic, 0);
+		haptic->suspended = true;
 
-	haptic->suspended = true;
-
-	mutex_unlock(&haptic->mutex);
+		return 0;
+	}
 
-	return 0;
+	return -EINTR;
 }
 
 static int regulator_haptic_resume(struct device *dev)
@@ -226,7 +220,7 @@ static int regulator_haptic_resume(struct device *dev)
 	struct regulator_haptic *haptic = platform_get_drvdata(pdev);
 	unsigned int magnitude;
 
-	mutex_lock(&haptic->mutex);
+	guard(mutex)(&haptic->mutex);
 
 	haptic->suspended = false;
 
@@ -234,8 +228,6 @@ static int regulator_haptic_resume(struct device *dev)
 	if (magnitude)
 		regulator_haptic_set_voltage(haptic, magnitude);
 
-	mutex_unlock(&haptic->mutex);
-
 	return 0;
 }