linux-kernel - [PATCH 16/17] Input: st-keyscan - use guard notation when acquiring mutex

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Message-ID: <20240825051627.2848495-17-dmitry.torokhov@gmail.com>
Date: Sat, 24 Aug 2024 22:16:20 -0700
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: linux-input@...r.kernel.org
Cc: Michael Hennerich <michael.hennerich@...log.com>,
	Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Laxman Dewangan <ldewangan@...dia.com>,
	Thierry Reding <thierry.reding@...il.com>,
	Hans de Goede <hdegoede@...hat.com>,
	Tony Lindgren <tony@...mide.com>,
	Jeff LaBundy <jeff@...undy.com>,
	linux-kernel@...r.kernel.org,
	imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-tegra@...r.kernel.org
Subject: [PATCH 16/17] Input: st-keyscan - 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/keyboard/st-keyscan.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/input/keyboard/st-keyscan.c b/drivers/input/keyboard/st-keyscan.c
index 0d27324af809..e53ef4c670e4 100644
--- a/drivers/input/keyboard/st-keyscan.c
+++ b/drivers/input/keyboard/st-keyscan.c
@@ -216,14 +216,13 @@ static int keyscan_suspend(struct device *dev)
 	struct st_keyscan *keypad = platform_get_drvdata(pdev);
 	struct input_dev *input = keypad->input_dev;
 
-	mutex_lock(&input->mutex);
+	guard(mutex)(&input->mutex);
 
 	if (device_may_wakeup(dev))
 		enable_irq_wake(keypad->irq);
 	else if (input_device_enabled(input))
 		keyscan_stop(keypad);
 
-	mutex_unlock(&input->mutex);
 	return 0;
 }
 
@@ -232,17 +231,19 @@ static int keyscan_resume(struct device *dev)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct st_keyscan *keypad = platform_get_drvdata(pdev);
 	struct input_dev *input = keypad->input_dev;
-	int retval = 0;
+	int error;
 
-	mutex_lock(&input->mutex);
+	guard(mutex)(&input->mutex);
 
-	if (device_may_wakeup(dev))
+	if (device_may_wakeup(dev)) {
 		disable_irq_wake(keypad->irq);
-	else if (input_device_enabled(input))
-		retval = keyscan_start(keypad);
+	} else if (input_device_enabled(input)) {
+		error = keyscan_start(keypad);
+		if (error)
+			return error;
+	}
 
-	mutex_unlock(&input->mutex);
-	return retval;
+	return 0;
 }
 
 static DEFINE_SIMPLE_DEV_PM_OPS(keyscan_dev_pm_ops,
-- 
2.46.0.295.g3b9ea8a38a-goog