From 14b5d6dd40b3091cb5f566568baa4a74dc619286 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Wed, 10 Mar 2010 18:32:18 +0100 Subject: [PATCH] leds: Fix race between LED device uevent and actual attributes creation If we were to dynamically register/unregister leds and have udev or other daemons handle the leds class uevents, we would be notified of the adding of a new LED and if the daemon immediately tries to open one of the attributes of the led device, it would fail with a "no such file or directory" error since this the attributes are not yet created. Fix this by switching attributes to be class-wide, such that the driver core will register these attributes with device_add_attrs and then emit the kobject_uevent ADD signal. Signed-off-by: Fainelli Signed-off-by: Richard Purdie --- drivers/leds/led-class.c | 40 ++++++++-------------------------------- 1 file changed, 8 insertions(+), 32 deletions(-) diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c index 349e073..69e7d86 100644 --- a/drivers/leds/led-class.c +++ b/drivers/leds/led-class.c @@ -72,11 +72,14 @@ static ssize_t led_max_brightness_show(struct device *dev, return sprintf(buf, "%u\n", led_cdev->max_brightness); } -static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store); -static DEVICE_ATTR(max_brightness, 0444, led_max_brightness_show, NULL); +static struct device_attribute led_class_attrs[] = { + __ATTR(brightness, 0644, led_brightness_show, led_brightness_store), + __ATTR(max_brightness, 0644, led_max_brightness_show, NULL), #ifdef CONFIG_LEDS_TRIGGERS -static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); + __ATTR(trigger, 0644, led_trigger_show, led_trigger_store), #endif + __ATTR_NULL, +}; /** * led_classdev_suspend - suspend an led_classdev. @@ -127,18 +130,11 @@ static int led_resume(struct device *dev) */ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) { - int rc; - led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, "%s", led_cdev->name); if (IS_ERR(led_cdev->dev)) return PTR_ERR(led_cdev->dev); - /* register the attributes */ - rc = device_create_file(led_cdev->dev, &dev_attr_brightness); - if (rc) - goto err_out; - #ifdef CONFIG_LEDS_TRIGGERS init_rwsem(&led_cdev->trigger_lock); #endif @@ -150,17 +146,9 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) if (!led_cdev->max_brightness) led_cdev->max_brightness = LED_FULL; - rc = device_create_file(led_cdev->dev, &dev_attr_max_brightness); - if (rc) - goto err_out_attr_max; - led_update_brightness(led_cdev); #ifdef CONFIG_LEDS_TRIGGERS - rc = device_create_file(led_cdev->dev, &dev_attr_trigger); - if (rc) - goto err_out_led_list; - led_trigger_set_default(led_cdev); #endif @@ -168,18 +156,8 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) led_cdev->name); return 0; - -#ifdef CONFIG_LEDS_TRIGGERS -err_out_led_list: - device_remove_file(led_cdev->dev, &dev_attr_max_brightness); -#endif -err_out_attr_max: - device_remove_file(led_cdev->dev, &dev_attr_brightness); - list_del(&led_cdev->node); -err_out: - device_unregister(led_cdev->dev); - return rc; } + EXPORT_SYMBOL_GPL(led_classdev_register); /** @@ -190,10 +168,7 @@ EXPORT_SYMBOL_GPL(led_classdev_register); */ void led_classdev_unregister(struct led_classdev *led_cdev) { - device_remove_file(led_cdev->dev, &dev_attr_max_brightness); - device_remove_file(led_cdev->dev, &dev_attr_brightness); #ifdef CONFIG_LEDS_TRIGGERS - device_remove_file(led_cdev->dev, &dev_attr_trigger); down_write(&led_cdev->trigger_lock); if (led_cdev->trigger) led_trigger_set(led_cdev, NULL); @@ -215,6 +190,7 @@ static int __init leds_init(void) return PTR_ERR(leds_class); leds_class->suspend = led_suspend; leds_class->resume = led_resume; + leds_class->dev_attrs = led_class_attrs; return 0; } -- 2.7.4