[PATCH v1 1/3] gpiolib: sysfs: Move sysfs_emit() calls outside of the mutex lock

From: Andy Shevchenko
Date: Wed Feb 09 2022 - 07:05:23 EST


In a few places we perform sysfs_emit() operations under mutex that
do not require any locking. Move them outside of the mutex locks.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib-sysfs.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 78ca7dee8b64..57d8ecab53b7 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -61,17 +61,16 @@ static ssize_t direction_show(struct device *dev,
{
struct gpiod_data *data = dev_get_drvdata(dev);
struct gpio_desc *desc = data->desc;
- ssize_t status;
+ int value;

mutex_lock(&data->mutex);

gpiod_get_direction(desc);
- status = sysfs_emit(buf, "%s\n",
- test_bit(FLAG_IS_OUT, &desc->flags) ? "out" : "in");
+ value = !!test_bit(FLAG_IS_OUT, &desc->flags);

mutex_unlock(&data->mutex);

- return status;
+ return sysfs_emit(buf, "%s\n", value ? "out" : "in");
}

static ssize_t direction_store(struct device *dev,
@@ -108,12 +107,13 @@ static ssize_t value_show(struct device *dev,
mutex_lock(&data->mutex);

status = gpiod_get_value_cansleep(desc);
- if (status >= 0)
- status = sysfs_emit(buf, "%zd\n", status);

mutex_unlock(&data->mutex);

- return status;
+ if (status < 0)
+ return status;
+
+ return sysfs_emit(buf, "%zd\n", status);
}

static ssize_t value_store(struct device *dev,
@@ -238,7 +238,6 @@ static ssize_t edge_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gpiod_data *data = dev_get_drvdata(dev);
- ssize_t status = 0;
int i;

mutex_lock(&data->mutex);
@@ -247,12 +246,13 @@ static ssize_t edge_show(struct device *dev,
if (data->irq_flags == trigger_types[i].flags)
break;
}
- if (i < ARRAY_SIZE(trigger_types))
- status = sysfs_emit(buf, "%s\n", trigger_types[i].name);

mutex_unlock(&data->mutex);

- return status;
+ if (i >= ARRAY_SIZE(trigger_types))
+ return 0;
+
+ return sysfs_emit(buf, "%s\n", trigger_types[i].name);
}

static ssize_t edge_store(struct device *dev,
@@ -324,16 +324,15 @@ static ssize_t active_low_show(struct device *dev,
{
struct gpiod_data *data = dev_get_drvdata(dev);
struct gpio_desc *desc = data->desc;
- ssize_t status;
+ int value;

mutex_lock(&data->mutex);

- status = sysfs_emit(buf, "%d\n",
- !!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
+ value = !!test_bit(FLAG_ACTIVE_LOW, &desc->flags);

mutex_unlock(&data->mutex);

- return status;
+ return sysfs_emit(buf, "%d\n", value);
}

static ssize_t active_low_store(struct device *dev,
--
2.34.1