linux-kernel - [PATCH] Input: bcm5974 - use guard notation when acquiring mutex

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Message-ID: <ZsrBVO2w9WwX73iU@google.com>
Date: Sat, 24 Aug 2024 22:29:56 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: linux-input@...r.kernel.org
Cc: Henrik Rydberg <rydberg@...math.org>,
	Javier Carrasco <javier.carrasco.cruz@...il.com>,
	Erick Archer <erick.archer@...look.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] Input: bcm5974 - use guard notation when acquiring mutex

This 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>
---
 drivers/input/mouse/bcm5974.c | 35 +++++++++++++----------------------
 1 file changed, 13 insertions(+), 22 deletions(-)

diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c
index 10a03a566905..dfdfb59cc8b5 100644
--- a/drivers/input/mouse/bcm5974.c
+++ b/drivers/input/mouse/bcm5974.c
@@ -834,13 +834,11 @@ static int bcm5974_open(struct input_dev *input)
 	if (error)
 		return error;
 
-	mutex_lock(&dev->pm_mutex);
-
-	error = bcm5974_start_traffic(dev);
-	if (!error)
-		dev->opened = 1;
-
-	mutex_unlock(&dev->pm_mutex);
+	scoped_guard(mutex, &dev->pm_mutex) {
+		error = bcm5974_start_traffic(dev);
+		if (!error)
+			dev->opened = 1;
+	}
 
 	if (error)
 		usb_autopm_put_interface(dev->intf);
@@ -852,12 +850,10 @@ static void bcm5974_close(struct input_dev *input)
 {
 	struct bcm5974 *dev = input_get_drvdata(input);
 
-	mutex_lock(&dev->pm_mutex);
-
-	bcm5974_pause_traffic(dev);
-	dev->opened = 0;
-
-	mutex_unlock(&dev->pm_mutex);
+	scoped_guard(mutex, &dev->pm_mutex) {
+		bcm5974_pause_traffic(dev);
+		dev->opened = 0;
+	}
 
 	usb_autopm_put_interface(dev->intf);
 }
@@ -866,29 +862,24 @@ static int bcm5974_suspend(struct usb_interface *iface, pm_message_t message)
 {
 	struct bcm5974 *dev = usb_get_intfdata(iface);
 
-	mutex_lock(&dev->pm_mutex);
+	guard(mutex)(&dev->pm_mutex);
 
 	if (dev->opened)
 		bcm5974_pause_traffic(dev);
 
-	mutex_unlock(&dev->pm_mutex);
-
 	return 0;
 }
 
 static int bcm5974_resume(struct usb_interface *iface)
 {
 	struct bcm5974 *dev = usb_get_intfdata(iface);
-	int error = 0;
 
-	mutex_lock(&dev->pm_mutex);
+	guard(mutex)(&dev->pm_mutex);
 
 	if (dev->opened)
-		error = bcm5974_start_traffic(dev);
+		return bcm5974_start_traffic(dev);
 
-	mutex_unlock(&dev->pm_mutex);
-
-	return error;
+	return 0;
 }
 
 static int bcm5974_probe(struct usb_interface *iface,
-- 
2.46.0.295.g3b9ea8a38a-goog


-- 
Dmitry