On Tue, Jan 27, 2015 at 05:26:40PM -0800, Greg Kroah-Hartman wrote:
> 3.14-stable review patch. If anyone has any objections, please let me know.
>
> ------------------
>
> From: Johan Hovold <jo...@kernel.org>
>
> 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 <jo...@kernel.org>
> Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
>
>
> ---
> drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
> 1 file changed, 13 insertions(+), 14 deletions(-)
>
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -408,7 +408,7 @@ static ssize_t gpio_value_store(struct d
> 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)
> @@ -633,18 +633,16 @@ static ssize_t gpio_active_low_store(str
> 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/
> @@ -841,18 +839,15 @@ int gpiod_export(struct gpio_desc *desc,
> 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",
> - desc_to_gpio(desc));
> + 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)
> @@ -863,13 +858,15 @@ int gpiod_export(struct gpio_desc *desc,
> !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:
> @@ -994,6 +991,8 @@ void gpiod_unexport(struct gpio_desc *de
>
> dev = class_find_device(&gpio_class, NULL, desc, match_export);
> if (dev) {
> + device_remove_file(dev, &dev_attr_edge);
> + device_remove_file(dev, &dev_attr_direction);
> gpio_setup_irq(desc, dev, 0);
> clear_bit(FLAG_EXPORT, &desc->flags);
> } else
>
I believe there's a mistake in this backport: the changes to the
gpiod_unexport() function are being applied to the wrong code block;
they should be in:
if (dev) {
device_unregister(dev);
put_device(dev);
}
The backport to the 3.10 kernel have the same problem.
Cheers,
--
Luís
>
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