Commit 0915e6fe authored by Johan Hovold's avatar Johan Hovold Committed by Linus Walleij
Browse files

gpio: sysfs: fix gpio device-attribute leak 



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: d8f388d8 ("gpio: sysfs interface")
Cc: stable <stable@vger.kernel.org>	# v2.6.27+
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 121b6a79

drivers/gpio/gpiolib-sysfs.c

+13 −15
Original line number Diff line number Diff line
@@ -128,7 +128,7 @@ 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)
@@ -353,18 +353,15 @@ 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/
@@ -561,18 +558,15 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) 
	if (desc->chip->names && desc->chip->names[offset])

		ioname = desc->chip->names[offset];



	dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),

			    desc, ioname ? ioname : "gpio%u",

	dev = device_create_with_groups(&gpio_class, desc->chip->dev,

					MKDEV(0, 0), desc, gpio_groups,

					ioname ? ioname : "gpio%u",

					desc_to_gpio(desc));

	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)
@@ -583,13 +577,15 @@ int gpiod_export(struct gpio_desc *desc, 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:
@@ -723,6 +719,8 @@ void gpiod_unexport(struct gpio_desc *desc) 
	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);

	}

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