linux-kernel - [PATCH v4 1/5] gpio: sysfs: use cleanup guards for gpiod

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Message-Id: <20241031-gpio-notify-sysfs-v4-1-142021c2195c@linaro.org>
Date: Thu, 31 Oct 2024 21:01:51 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Linus Walleij <linus.walleij@...aro.org>, 
 Bartosz Golaszewski <brgl@...ev.pl>, Kent Gibson <warthog618@...il.com>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v4 1/5] gpio: sysfs: use cleanup guards for
 gpiod_data::mutex

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

Shrink the code and drop some goto labels by using lock guards around
gpiod_data::mutex.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/gpio/gpiolib-sysfs.c | 82 ++++++++++++++++----------------------------
 1 file changed, 30 insertions(+), 52 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 0c713baa7784..a0926a1061ae 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -77,12 +77,10 @@ static ssize_t direction_show(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	int value;
 
-	mutex_lock(&data->mutex);
-
-	gpiod_get_direction(desc);
-	value = !!test_bit(FLAG_IS_OUT, &desc->flags);
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex) {
+		gpiod_get_direction(desc);
+		value = !!test_bit(FLAG_IS_OUT, &desc->flags);
+	}
 
 	return sysfs_emit(buf, "%s\n", value ? "out" : "in");
 }
@@ -94,7 +92,7 @@ static ssize_t direction_store(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	ssize_t			status;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
 	if (sysfs_streq(buf, "high"))
 		status = gpiod_direction_output_raw(desc, 1);
@@ -105,8 +103,6 @@ static ssize_t direction_store(struct device *dev,
 	else
 		status = -EINVAL;
 
-	mutex_unlock(&data->mutex);
-
 	return status ? : size;
 }
 static DEVICE_ATTR_RW(direction);
@@ -118,11 +114,8 @@ static ssize_t value_show(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	ssize_t			status;
 
-	mutex_lock(&data->mutex);
-
-	status = gpiod_get_value_cansleep(desc);
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex)
+		status = gpiod_get_value_cansleep(desc);
 
 	if (status < 0)
 		return status;
@@ -140,18 +133,17 @@ static ssize_t value_store(struct device *dev,
 
 	status = kstrtol(buf, 0, &value);
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
-	if (!test_bit(FLAG_IS_OUT, &desc->flags)) {
-		status = -EPERM;
-	} else if (status == 0) {
-		gpiod_set_value_cansleep(desc, value);
-		status = size;
-	}
+	if (!test_bit(FLAG_IS_OUT, &desc->flags))
+		return -EPERM;
 
-	mutex_unlock(&data->mutex);
+	if (status)
+		return status;
 
-	return status;
+	gpiod_set_value_cansleep(desc, value);
+
+	return size;
 }
 static DEVICE_ATTR_PREALLOC(value, S_IWUSR | S_IRUGO, value_show, value_store);
 
@@ -253,11 +245,8 @@ static ssize_t edge_show(struct device *dev,
 	struct gpiod_data *data = dev_get_drvdata(dev);
 	int flags;
 
-	mutex_lock(&data->mutex);
-
-	flags = data->irq_flags;
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex)
+		flags = data->irq_flags;
 
 	if (flags >= ARRAY_SIZE(trigger_names))
 		return 0;
@@ -276,26 +265,22 @@ static ssize_t edge_store(struct device *dev,
 	if (flags < 0)
 		return flags;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
-	if (flags == data->irq_flags) {
-		status = size;
-		goto out_unlock;
-	}
+	if (flags == data->irq_flags)
+		return size;
 
 	if (data->irq_flags)
 		gpio_sysfs_free_irq(dev);
 
-	if (flags) {
-		status = gpio_sysfs_request_irq(dev, flags);
-		if (!status)
-			status = size;
-	}
+	if (!flags)
+		return size;
 
-out_unlock:
-	mutex_unlock(&data->mutex);
+	status = gpio_sysfs_request_irq(dev, flags);
+	if (status)
+		return status;
 
-	return status;
+	return size;
 }
 static DEVICE_ATTR_RW(edge);
 
@@ -330,11 +315,8 @@ static ssize_t active_low_show(struct device *dev,
 	struct gpio_desc *desc = data->desc;
 	int value;
 
-	mutex_lock(&data->mutex);
-
-	value = !!test_bit(FLAG_ACTIVE_LOW, &desc->flags);
-
-	mutex_unlock(&data->mutex);
+	scoped_guard(mutex, &data->mutex)
+		value = !!test_bit(FLAG_ACTIVE_LOW, &desc->flags);
 
 	return sysfs_emit(buf, "%d\n", value);
 }
@@ -350,13 +332,9 @@ static ssize_t active_low_store(struct device *dev,
 	if (status)
 		return status;
 
-	mutex_lock(&data->mutex);
+	guard(mutex)(&data->mutex);
 
-	status = gpio_sysfs_set_active_low(dev, value);
-
-	mutex_unlock(&data->mutex);
-
-	return status ? : size;
+	return gpio_sysfs_set_active_low(dev, value) ?: size;
 }
 static DEVICE_ATTR_RW(active_low);
 

-- 
2.45.2