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Subject[PATCH 3.4 108/176] gpio: sysfs: fix gpio device-attribute leak
Date
From: Johan Hovold <johan@kernel.org>

3.4.107-rc1 review patch. If anyone has any objections, please let me know.

------------------


commit 0915e6feb38de8d3601819992a5bd050201a56fa upstream.

The gpio device attributes were never destroyed when the gpio was
unexported (or on export failures).

Use device_create_with_groups() to create the default device attributes
of the gpio class device. Note that this also fixes the
attribute-creation race with userspace for these attributes.

Remove contingent attributes in export error path and on unexport.

Fixes: d8f388d8dc8d ("gpio: sysfs interface")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[lizf: Backported to 3.4:
- adjust filename
- adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/gpio/gpiolib.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index c579f3d..4db6c55 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -319,7 +319,7 @@ static ssize_t gpio_value_store(struct device *dev,
return status;
}

-static const DEVICE_ATTR(value, 0644,
+static DEVICE_ATTR(value, 0644,
gpio_value_show, gpio_value_store);

static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
@@ -542,18 +542,15 @@ static ssize_t gpio_active_low_store(struct device *dev,
return status ? : size;
}

-static const DEVICE_ATTR(active_low, 0644,
+static DEVICE_ATTR(active_low, 0644,
gpio_active_low_show, gpio_active_low_store);

-static const struct attribute *gpio_attrs[] = {
+static struct attribute *gpio_attrs[] = {
&dev_attr_value.attr,
&dev_attr_active_low.attr,
NULL,
};
-
-static const struct attribute_group gpio_attr_group = {
- .attrs = (struct attribute **) gpio_attrs,
-};
+ATTRIBUTE_GROUPS(gpio);

/*
* /sys/class/gpio/gpiochipN/
@@ -737,17 +734,14 @@ int gpio_export(unsigned gpio, bool direction_may_change)
if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
ioname = desc->chip->names[gpio - desc->chip->base];

- dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
- desc, ioname ? ioname : "gpio%u", gpio);
+ dev = device_create_with_groups(&gpio_class, desc->chip->dev,
+ MKDEV(0, 0), desc, gpio_groups,
+ ioname ? ioname : "gpio%u", gpio);
if (IS_ERR(dev)) {
status = PTR_ERR(dev);
goto fail_unlock;
}

- status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
- if (status)
- goto fail_unregister_device;
-
if (direction_may_change) {
status = device_create_file(dev, &dev_attr_direction);
if (status)
@@ -758,13 +752,15 @@ int gpio_export(unsigned gpio, bool direction_may_change)
!test_bit(FLAG_IS_OUT, &desc->flags))) {
status = device_create_file(dev, &dev_attr_edge);
if (status)
- goto fail_unregister_device;
+ goto fail_remove_attr_direction;
}

set_bit(FLAG_EXPORT, &desc->flags);
mutex_unlock(&sysfs_lock);
return 0;

+fail_remove_attr_direction:
+ device_remove_file(dev, &dev_attr_direction);
fail_unregister_device:
device_unregister(dev);
fail_unlock:
@@ -904,6 +900,8 @@ void gpio_unexport(unsigned gpio)

mutex_unlock(&sysfs_lock);
if (dev) {
+ device_remove_file(dev, &dev_attr_edge);
+ device_remove_file(dev, &dev_attr_direction);
device_unregister(dev);
put_device(dev);
}
--
1.9.1


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