linux-kernel - [PATCH 02/22] Input: ati_remote2 - use guard notation when acquiring mutex

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Message-ID: <20240904044244.1042174-3-dmitry.torokhov@gmail.com>
Date: Tue,  3 Sep 2024 21:42:22 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: linux-input@...r.kernel.org
Cc: 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>,
	Javier Carrasco <javier.carrasco.cruz@...il.com>,
	Jeff LaBundy <jeff@...undy.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 02/22] Input: ati_remote2 - 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>
---
 drivers/input/misc/ati_remote2.c | 57 +++++++++++---------------------
 1 file changed, 19 insertions(+), 38 deletions(-)

diff --git a/drivers/input/misc/ati_remote2.c b/drivers/input/misc/ati_remote2.c
index 795f69edb4b2..e84649af801d 100644
--- a/drivers/input/misc/ati_remote2.c
+++ b/drivers/input/misc/ati_remote2.c
@@ -244,29 +244,21 @@ static int ati_remote2_open(struct input_dev *idev)
 	if (r) {
 		dev_err(&ar2->intf[0]->dev,
 			"%s(): usb_autopm_get_interface() = %d\n", __func__, r);
-		goto fail1;
+		return r;
 	}
 
-	mutex_lock(&ati_remote2_mutex);
+	scoped_guard(mutex, &ati_remote2_mutex) {
+		if (!(ar2->flags & ATI_REMOTE2_SUSPENDED)) {
+			r = ati_remote2_submit_urbs(ar2);
+			if (r)
+				break;
+		}
 
-	if (!(ar2->flags & ATI_REMOTE2_SUSPENDED)) {
-		r = ati_remote2_submit_urbs(ar2);
-		if (r)
-			goto fail2;
+		ar2->flags |= ATI_REMOTE2_OPENED;
 	}
 
-	ar2->flags |= ATI_REMOTE2_OPENED;
-
-	mutex_unlock(&ati_remote2_mutex);
-
 	usb_autopm_put_interface(ar2->intf[0]);
 
-	return 0;
-
- fail2:
-	mutex_unlock(&ati_remote2_mutex);
-	usb_autopm_put_interface(ar2->intf[0]);
- fail1:
 	return r;
 }
 
@@ -276,14 +268,12 @@ static void ati_remote2_close(struct input_dev *idev)
 
 	dev_dbg(&ar2->intf[0]->dev, "%s()\n", __func__);
 
-	mutex_lock(&ati_remote2_mutex);
+	guard(mutex)(&ati_remote2_mutex);
 
 	if (!(ar2->flags & ATI_REMOTE2_SUSPENDED))
 		ati_remote2_kill_urbs(ar2);
 
 	ar2->flags &= ~ATI_REMOTE2_OPENED;
-
-	mutex_unlock(&ati_remote2_mutex);
 }
 
 static void ati_remote2_input_mouse(struct ati_remote2 *ar2)
@@ -713,16 +703,14 @@ static ssize_t ati_remote2_store_channel_mask(struct device *dev,
 		return r;
 	}
 
-	mutex_lock(&ati_remote2_mutex);
-
-	if (mask != ar2->channel_mask) {
-		r = ati_remote2_setup(ar2, mask);
-		if (!r)
-			ar2->channel_mask = mask;
+	scoped_guard(mutex, &ati_remote2_mutex) {
+		if (mask != ar2->channel_mask) {
+			r = ati_remote2_setup(ar2, mask);
+			if (!r)
+				ar2->channel_mask = mask;
+		}
 	}
 
-	mutex_unlock(&ati_remote2_mutex);
-
 	usb_autopm_put_interface(ar2->intf[0]);
 
 	return r ? r : count;
@@ -892,15 +880,13 @@ static int ati_remote2_suspend(struct usb_interface *interface,
 
 	dev_dbg(&ar2->intf[0]->dev, "%s()\n", __func__);
 
-	mutex_lock(&ati_remote2_mutex);
+	guard(mutex)(&ati_remote2_mutex);
 
 	if (ar2->flags & ATI_REMOTE2_OPENED)
 		ati_remote2_kill_urbs(ar2);
 
 	ar2->flags |= ATI_REMOTE2_SUSPENDED;
 
-	mutex_unlock(&ati_remote2_mutex);
-
 	return 0;
 }
 
@@ -917,7 +903,7 @@ static int ati_remote2_resume(struct usb_interface *interface)
 
 	dev_dbg(&ar2->intf[0]->dev, "%s()\n", __func__);
 
-	mutex_lock(&ati_remote2_mutex);
+	guard(mutex)(&ati_remote2_mutex);
 
 	if (ar2->flags & ATI_REMOTE2_OPENED)
 		r = ati_remote2_submit_urbs(ar2);
@@ -925,8 +911,6 @@ static int ati_remote2_resume(struct usb_interface *interface)
 	if (!r)
 		ar2->flags &= ~ATI_REMOTE2_SUSPENDED;
 
-	mutex_unlock(&ati_remote2_mutex);
-
 	return r;
 }
 
@@ -943,11 +927,11 @@ static int ati_remote2_reset_resume(struct usb_interface *interface)
 
 	dev_dbg(&ar2->intf[0]->dev, "%s()\n", __func__);
 
-	mutex_lock(&ati_remote2_mutex);
+	guard(mutex)(&ati_remote2_mutex);
 
 	r = ati_remote2_setup(ar2, ar2->channel_mask);
 	if (r)
-		goto out;
+		return r;
 
 	if (ar2->flags & ATI_REMOTE2_OPENED)
 		r = ati_remote2_submit_urbs(ar2);
@@ -955,9 +939,6 @@ static int ati_remote2_reset_resume(struct usb_interface *interface)
 	if (!r)
 		ar2->flags &= ~ATI_REMOTE2_SUSPENDED;
 
- out:
-	mutex_unlock(&ati_remote2_mutex);
-
 	return r;
 }
 
-- 
2.46.0.469.g59c65b2a67-goog