Input: pegasus_notetaker - 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.

Reviewed-by: Javier Carrasco <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/tablet/pegasus_notetaker.c

···
 			error);
 }
 
+static int __pegasus_open(struct pegasus *pegasus)
+{
+	int error;
+
+	guard(mutex)(&pegasus->pm_mutex);
+
+	pegasus->irq->dev = pegasus->usbdev;
+	if (usb_submit_urb(pegasus->irq, GFP_KERNEL))
+		return -EIO;
+
+	error = pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
+	if (error) {
+		usb_kill_urb(pegasus->irq);
+		cancel_work_sync(&pegasus->init);
+		return error;
+	}
+
+	pegasus->is_open = true;
+
+	return 0;
+}
+
 static int pegasus_open(struct input_dev *dev)
 {
 	struct pegasus *pegasus = input_get_drvdata(dev);
···
 	if (error)
 		return error;
 
-	mutex_lock(&pegasus->pm_mutex);
-	pegasus->irq->dev = pegasus->usbdev;
-	if (usb_submit_urb(pegasus->irq, GFP_KERNEL)) {
-		error = -EIO;
-		goto err_autopm_put;
+	error = __pegasus_open(pegasus);
+	if (error) {
+		usb_autopm_put_interface(pegasus->intf);
+		return error;
 	}
 
-	error = pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
-	if (error)
-		goto err_kill_urb;
-
-	pegasus->is_open = true;
-	mutex_unlock(&pegasus->pm_mutex);
 	return 0;
-
-err_kill_urb:
-	usb_kill_urb(pegasus->irq);
-	cancel_work_sync(&pegasus->init);
-err_autopm_put:
-	mutex_unlock(&pegasus->pm_mutex);
-	usb_autopm_put_interface(pegasus->intf);
-	return error;
 }
 
 static void pegasus_close(struct input_dev *dev)
 {
 	struct pegasus *pegasus = input_get_drvdata(dev);
 
-	mutex_lock(&pegasus->pm_mutex);
-	usb_kill_urb(pegasus->irq);
-	cancel_work_sync(&pegasus->init);
-	pegasus->is_open = false;
-	mutex_unlock(&pegasus->pm_mutex);
+	scoped_guard(mutex, &pegasus->pm_mutex) {
+		usb_kill_urb(pegasus->irq);
+		cancel_work_sync(&pegasus->init);
+
+		pegasus->is_open = false;
+	}
 
 	usb_autopm_put_interface(pegasus->intf);
 }
···
 {
 	struct pegasus *pegasus = usb_get_intfdata(intf);
 
-	mutex_lock(&pegasus->pm_mutex);
+	guard(mutex)(&pegasus->pm_mutex);
+
 	usb_kill_urb(pegasus->irq);
 	cancel_work_sync(&pegasus->init);
-	mutex_unlock(&pegasus->pm_mutex);
 
 	return 0;
 }
···
 static int pegasus_resume(struct usb_interface *intf)
 {
 	struct pegasus *pegasus = usb_get_intfdata(intf);
-	int retval = 0;
 
-	mutex_lock(&pegasus->pm_mutex);
+	guard(mutex)(&pegasus->pm_mutex);
+
 	if (pegasus->is_open && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
-		retval = -EIO;
-	mutex_unlock(&pegasus->pm_mutex);
+		return -EIO;
 
-	return retval;
+	return 0;
 }
 
 static int pegasus_reset_resume(struct usb_interface *intf)
 {
 	struct pegasus *pegasus = usb_get_intfdata(intf);
-	int retval = 0;
+	int error;
 
-	mutex_lock(&pegasus->pm_mutex);
+	guard(mutex)(&pegasus->pm_mutex);
+
 	if (pegasus->is_open) {
-		retval = pegasus_set_mode(pegasus, PEN_MODE_XY,
+		error = pegasus_set_mode(pegasus, PEN_MODE_XY,
 					  NOTETAKER_LED_MOUSE);
-		if (!retval && usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
-			retval = -EIO;
-	}
-	mutex_unlock(&pegasus->pm_mutex);
+		if (error)
+			return error;
 
-	return retval;
+		if (usb_submit_urb(pegasus->irq, GFP_NOIO) < 0)
+			return -EIO;
+	}
+
+	return 0;
 }
 
 static const struct usb_device_id pegasus_ids[] = {