From 121b6a79955a3a3fd7bbb9b8cb88d5b9dad6283d Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 13 Jan 2015 13:00:04 +0100 Subject: gpio: sysfs: fix gpio-chip device-attribute leak The gpio-chip device attributes were never destroyed when the device was removed. Fix by using device_create_with_groups() to create the device attributes of the chip class device. Note that this also fixes the attribute-creation race with userspace. Fixes: d8f388d8dc8d ("gpio: sysfs interface") Cc: stable # v2.6.27+ Signed-off-by: Johan Hovold Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib-sysfs.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'drivers/gpio/gpiolib-sysfs.c') diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index 2ac1800b58bb..33cf4bd0ed2d 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -400,16 +400,13 @@ static ssize_t chip_ngpio_show(struct device *dev, } static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL); -static const struct attribute *gpiochip_attrs[] = { +static struct attribute *gpiochip_attrs[] = { &dev_attr_base.attr, &dev_attr_label.attr, &dev_attr_ngpio.attr, NULL, }; - -static const struct attribute_group gpiochip_attr_group = { - .attrs = (struct attribute **) gpiochip_attrs, -}; +ATTRIBUTE_GROUPS(gpiochip); /* * /sys/class/gpio/export ... write-only @@ -750,13 +747,13 @@ int gpiochip_export(struct gpio_chip *chip) /* use chip->base for the ID; it's already known to be unique */ mutex_lock(&sysfs_lock); - dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip, - "gpiochip%d", chip->base); - if (!IS_ERR(dev)) { - status = sysfs_create_group(&dev->kobj, - &gpiochip_attr_group); - } else + dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0), + chip, gpiochip_groups, + "gpiochip%d", chip->base); + if (IS_ERR(dev)) status = PTR_ERR(dev); + else + status = 0; chip->exported = (status == 0); mutex_unlock(&sysfs_lock); -- cgit v1.2.1 From 0915e6feb38de8d3601819992a5bd050201a56fa Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 13 Jan 2015 13:00:05 +0100 Subject: 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: d8f388d8dc8d ("gpio: sysfs interface") Cc: stable # v2.6.27+ Signed-off-by: Johan Hovold Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib-sysfs.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) (limited to 'drivers/gpio/gpiolib-sysfs.c') diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index 33cf4bd0ed2d..fd4d9423f6e6 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -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", - 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) @@ -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); } -- cgit v1.2.1 From ebbeba120ab2ec6ac5f3afc1425ec6ff0b77ad6f Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 13 Jan 2015 13:00:06 +0100 Subject: gpio: sysfs: fix gpio attribute-creation race Fix attribute-creation race with userspace by using the default group to create also the contingent gpio device attributes. Fixes: d8f388d8dc8d ("gpio: sysfs interface") Signed-off-by: Johan Hovold Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib-sysfs.c | 61 ++++++++++++++++++++++++++++---------------- 1 file changed, 39 insertions(+), 22 deletions(-) (limited to 'drivers/gpio/gpiolib-sysfs.c') diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index fd4d9423f6e6..f62aa115d79a 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -356,12 +356,44 @@ static ssize_t gpio_active_low_store(struct device *dev, static DEVICE_ATTR(active_low, 0644, gpio_active_low_show, gpio_active_low_store); +static umode_t gpio_is_visible(struct kobject *kobj, struct attribute *attr, + int n) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct gpio_desc *desc = dev_get_drvdata(dev); + umode_t mode = attr->mode; + bool show_direction = test_bit(FLAG_SYSFS_DIR, &desc->flags); + + if (attr == &dev_attr_direction.attr) { + if (!show_direction) + mode = 0; + } else if (attr == &dev_attr_edge.attr) { + if (gpiod_to_irq(desc) < 0) + mode = 0; + if (!show_direction && test_bit(FLAG_IS_OUT, &desc->flags)) + mode = 0; + } + + return mode; +} + static struct attribute *gpio_attrs[] = { + &dev_attr_direction.attr, + &dev_attr_edge.attr, &dev_attr_value.attr, &dev_attr_active_low.attr, NULL, }; -ATTRIBUTE_GROUPS(gpio); + +static const struct attribute_group gpio_group = { + .attrs = gpio_attrs, + .is_visible = gpio_is_visible, +}; + +static const struct attribute_group *gpio_groups[] = { + &gpio_group, + NULL +}; /* * /sys/class/gpio/gpiochipN/ @@ -550,8 +582,11 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) goto fail_unlock; } - if (!desc->chip->direction_input || !desc->chip->direction_output) - direction_may_change = false; + if (desc->chip->direction_input && desc->chip->direction_output && + direction_may_change) { + set_bit(FLAG_SYSFS_DIR, &desc->flags); + } + spin_unlock_irqrestore(&gpio_lock, flags); offset = gpio_chip_hwgpio(desc); @@ -567,27 +602,10 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) goto fail_unlock; } - if (direction_may_change) { - status = device_create_file(dev, &dev_attr_direction); - if (status) - goto fail_unregister_device; - } - - if (gpiod_to_irq(desc) >= 0 && (direction_may_change || - !test_bit(FLAG_IS_OUT, &desc->flags))) { - status = device_create_file(dev, &dev_attr_edge); - if (status) - 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: mutex_unlock(&sysfs_lock); gpiod_dbg(desc, "%s: status %d\n", __func__, status); @@ -711,6 +729,7 @@ void gpiod_unexport(struct gpio_desc *desc) dev = class_find_device(&gpio_class, NULL, desc, match_export); if (dev) { gpio_setup_irq(desc, dev, 0); + clear_bit(FLAG_SYSFS_DIR, &desc->flags); clear_bit(FLAG_EXPORT, &desc->flags); } else status = -ENODEV; @@ -719,8 +738,6 @@ 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); } -- cgit v1.2.1