linux-kernel - [PATCH v2] Input: maple_keyb - use guard notation when acquiring mutex

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Message-ID: <Zx8mGiWOw1Av28TX@google.com>
Date: Sun, 27 Oct 2024 22:50:18 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: linux-input@...r.kernel.org
Cc: Erick Archer <erick.archer@...look.com>, linux-kernel@...r.kernel.org
Subject: [PATCH v2] Input: maple_keyb - 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: fix typo pointed out by the kernel test robot

 drivers/input/keyboard/maple_keyb.c |    9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/input/keyboard/maple_keyb.c b/drivers/input/keyboard/maple_keyb.c
index 91a1d2958109..1a8f1fa53fbb 100644
--- a/drivers/input/keyboard/maple_keyb.c
+++ b/drivers/input/keyboard/maple_keyb.c
@@ -132,14 +132,11 @@ static void dc_kbd_callback(struct mapleq *mq)
 	 * We should always get the lock because the only
 	 * time it may be locked is if the driver is in the cleanup phase.
 	 */
-	if (likely(mutex_trylock(&maple_keyb_mutex))) {
-
+	scoped_guard(mutex_try, &maple_keyb_mutex) {
 		if (buf[1] == mapledev->function) {
 			memcpy(kbd->new, buf + 2, 8);
 			dc_scan_kbd(kbd);
 		}
-
-		mutex_unlock(&maple_keyb_mutex);
 	}
 }
 
@@ -211,14 +208,12 @@ static int remove_maple_kbd(struct device *dev)
 	struct maple_device *mdev = to_maple_dev(dev);
 	struct dc_kbd *kbd = maple_get_drvdata(mdev);
 
-	mutex_lock(&maple_keyb_mutex);
+	guard(mutex)(&maple_keyb_mutex);
 
 	input_unregister_device(kbd->dev);
 	kfree(kbd);
 
 	maple_set_drvdata(mdev, NULL);
-
-	mutex_unlock(&maple_keyb_mutex);
 	return 0;
 }
 

-- 
Dmitry