linux-kernel - [PATCH 09/17] Input: lm8323 - use guard notation when acquiring mutexes

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Message-ID: <20240825051627.2848495-10-dmitry.torokhov@gmail.com>
Date: Sat, 24 Aug 2024 22:16:13 -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 09/17] Input: lm8323 - use guard notation when acquiring mutexes

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/lm8323.c | 49 +++++++++++++++------------------
 1 file changed, 22 insertions(+), 27 deletions(-)

diff --git a/drivers/input/keyboard/lm8323.c b/drivers/input/keyboard/lm8323.c
index cf67ba13477a..e26bf2956344 100644
--- a/drivers/input/keyboard/lm8323.c
+++ b/drivers/input/keyboard/lm8323.c
@@ -350,11 +350,11 @@ static int lm8323_configure(struct lm8323_chip *lm)
 
 static void pwm_done(struct lm8323_pwm *pwm)
 {
-	mutex_lock(&pwm->lock);
+	guard(mutex)(&pwm->lock);
+
 	pwm->running = false;
 	if (pwm->desired_brightness != pwm->brightness)
 		schedule_work(&pwm->work);
-	mutex_unlock(&pwm->lock);
 }
 
 /*
@@ -367,7 +367,7 @@ static irqreturn_t lm8323_irq(int irq, void *_lm)
 	u8 ints;
 	int i;
 
-	mutex_lock(&lm->lock);
+	guard(mutex)(&lm->lock);
 
 	while ((lm8323_read(lm, LM8323_CMD_READ_INT, &ints, 1) == 1) && ints) {
 		if (likely(ints & INT_KEYPAD))
@@ -394,8 +394,6 @@ static irqreturn_t lm8323_irq(int irq, void *_lm)
 		}
 	}
 
-	mutex_unlock(&lm->lock);
-
 	return IRQ_HANDLED;
 }
 
@@ -445,7 +443,7 @@ static void lm8323_pwm_work(struct work_struct *work)
 	u16 pwm_cmds[3];
 	int num_cmds = 0;
 
-	mutex_lock(&pwm->lock);
+	guard(mutex)(&pwm->lock);
 
 	/*
 	 * Do nothing if we're already at the requested level,
@@ -454,7 +452,7 @@ static void lm8323_pwm_work(struct work_struct *work)
 	 * finishes.
 	 */
 	if (pwm->running || pwm->desired_brightness == pwm->brightness)
-		goto out;
+		return;
 
 	kill = (pwm->desired_brightness == 0);
 	up = (pwm->desired_brightness > pwm->brightness);
@@ -489,9 +487,6 @@ static void lm8323_pwm_work(struct work_struct *work)
 
 	lm8323_write_pwm(pwm, kill, num_cmds, pwm_cmds);
 	pwm->brightness = pwm->desired_brightness;
-
- out:
-	mutex_unlock(&pwm->lock);
 }
 
 static void lm8323_pwm_set_brightness(struct led_classdev *led_cdev,
@@ -500,9 +495,9 @@ static void lm8323_pwm_set_brightness(struct led_classdev *led_cdev,
 	struct lm8323_pwm *pwm = cdev_to_pwm(led_cdev);
 	struct lm8323_chip *lm = pwm->chip;
 
-	mutex_lock(&pwm->lock);
-	pwm->desired_brightness = brightness;
-	mutex_unlock(&pwm->lock);
+	scoped_guard(mutex, &pwm->lock) {
+		pwm->desired_brightness = brightness;
+	}
 
 	if (in_interrupt()) {
 		schedule_work(&pwm->work);
@@ -510,12 +505,12 @@ static void lm8323_pwm_set_brightness(struct led_classdev *led_cdev,
 		/*
 		 * Schedule PWM work as usual unless we are going into suspend
 		 */
-		mutex_lock(&lm->lock);
-		if (likely(!lm->pm_suspend))
-			schedule_work(&pwm->work);
-		else
-			lm8323_pwm_work(&pwm->work);
-		mutex_unlock(&lm->lock);
+		scoped_guard(mutex, &lm->lock) {
+			if (likely(!lm->pm_suspend))
+				schedule_work(&pwm->work);
+			else
+				lm8323_pwm_work(&pwm->work);
+		}
 	}
 }
 
@@ -608,9 +603,9 @@ static ssize_t lm8323_set_disable(struct device *dev,
 	if (ret)
 		return ret;
 
-	mutex_lock(&lm->lock);
+	guard(mutex)(&lm->lock);
+
 	lm->kp_enabled = !i;
-	mutex_unlock(&lm->lock);
 
 	return count;
 }
@@ -758,9 +753,9 @@ static int lm8323_suspend(struct device *dev)
 	irq_set_irq_wake(client->irq, 0);
 	disable_irq(client->irq);
 
-	mutex_lock(&lm->lock);
-	lm->pm_suspend = true;
-	mutex_unlock(&lm->lock);
+	scoped_guard(mutex, &lm->lock) {
+		lm->pm_suspend = true;
+	}
 
 	for (i = 0; i < 3; i++)
 		if (lm->pwm[i].enabled)
@@ -775,9 +770,9 @@ static int lm8323_resume(struct device *dev)
 	struct lm8323_chip *lm = i2c_get_clientdata(client);
 	int i;
 
-	mutex_lock(&lm->lock);
-	lm->pm_suspend = false;
-	mutex_unlock(&lm->lock);
+	scoped_guard(mutex, &lm->lock) {
+		lm->pm_suspend = false;
+	}
 
 	for (i = 0; i < 3; i++)
 		if (lm->pwm[i].enabled)
-- 
2.46.0.295.g3b9ea8a38a-goog