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

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

[Dmitry Torokhov]

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@gmail.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

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

[rydberg]

On Sat, Aug 24, 2024 at 10:29:56PM -0700, Dmitry Torokhov wrote:
> 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@gmail.com>
> ---
>  drivers/input/mouse/bcm5974.c | 35 +++++++++++++----------------------
>  1 file changed, 13 insertions(+), 22 deletions(-)
> 

Thanks Dmitry,

Acked-by: Henrik Rydberg <rydberg@bitmath.org>

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

[Markus Elfring]

> This makes the code …

Is there a need to improve such a change description with imperative wordings?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.11-rc5#n94

Regards,
Markus