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authorFlorian Fainelli <ffainelli@freebox.fr>2010-03-10 12:32:18 -0500
committerRichard Purdie <rpurdie@linux.intel.com>2010-03-16 16:27:25 -0400
commit14b5d6dd40b3091cb5f566568baa4a74dc619286 (patch)
treea7373270c8a0c90e03addbd1df7f3d849f8a7e52 /drivers/leds/led-class.c
parent0493a4ff10959ff4c8e0d65efee25b7ffd4fa5db (diff)
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 <ffainelli@freebox.fr> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
Diffstat (limited to 'drivers/leds/led-class.c')
-rw-r--r--drivers/leds/led-class.c40
1 files changed, 8 insertions, 32 deletions
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 349e07350144..69e7d86a5143 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,
72 return sprintf(buf, "%u\n", led_cdev->max_brightness); 72 return sprintf(buf, "%u\n", led_cdev->max_brightness);
73} 73}
74 74
75static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store); 75static struct device_attribute led_class_attrs[] = {
76static DEVICE_ATTR(max_brightness, 0444, led_max_brightness_show, NULL); 76 __ATTR(brightness, 0644, led_brightness_show, led_brightness_store),
77 __ATTR(max_brightness, 0644, led_max_brightness_show, NULL),
77#ifdef CONFIG_LEDS_TRIGGERS 78#ifdef CONFIG_LEDS_TRIGGERS
78static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store); 79 __ATTR(trigger, 0644, led_trigger_show, led_trigger_store),
79#endif 80#endif
81 __ATTR_NULL,
82};
80 83
81/** 84/**
82 * led_classdev_suspend - suspend an led_classdev. 85 * led_classdev_suspend - suspend an led_classdev.
@@ -127,18 +130,11 @@ static int led_resume(struct device *dev)
127 */ 130 */
128int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) 131int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
129{ 132{
130 int rc;
131
132 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev, 133 led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,
133 "%s", led_cdev->name); 134 "%s", led_cdev->name);
134 if (IS_ERR(led_cdev->dev)) 135 if (IS_ERR(led_cdev->dev))
135 return PTR_ERR(led_cdev->dev); 136 return PTR_ERR(led_cdev->dev);
136 137
137 /* register the attributes */
138 rc = device_create_file(led_cdev->dev, &dev_attr_brightness);
139 if (rc)
140 goto err_out;
141
142#ifdef CONFIG_LEDS_TRIGGERS 138#ifdef CONFIG_LEDS_TRIGGERS
143 init_rwsem(&led_cdev->trigger_lock); 139 init_rwsem(&led_cdev->trigger_lock);
144#endif 140#endif
@@ -150,17 +146,9 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
150 if (!led_cdev->max_brightness) 146 if (!led_cdev->max_brightness)
151 led_cdev->max_brightness = LED_FULL; 147 led_cdev->max_brightness = LED_FULL;
152 148
153 rc = device_create_file(led_cdev->dev, &dev_attr_max_brightness);
154 if (rc)
155 goto err_out_attr_max;
156
157 led_update_brightness(led_cdev); 149 led_update_brightness(led_cdev);
158 150
159#ifdef CONFIG_LEDS_TRIGGERS 151#ifdef CONFIG_LEDS_TRIGGERS
160 rc = device_create_file(led_cdev->dev, &dev_attr_trigger);
161 if (rc)
162 goto err_out_led_list;
163
164 led_trigger_set_default(led_cdev); 152 led_trigger_set_default(led_cdev);
165#endif 153#endif
166 154
@@ -168,18 +156,8 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
168 led_cdev->name); 156 led_cdev->name);
169 157
170 return 0; 158 return 0;
171
172#ifdef CONFIG_LEDS_TRIGGERS
173err_out_led_list:
174 device_remove_file(led_cdev->dev, &dev_attr_max_brightness);
175#endif
176err_out_attr_max:
177 device_remove_file(led_cdev->dev, &dev_attr_brightness);
178 list_del(&led_cdev->node);
179err_out:
180 device_unregister(led_cdev->dev);
181 return rc;
182} 159}
160
183EXPORT_SYMBOL_GPL(led_classdev_register); 161EXPORT_SYMBOL_GPL(led_classdev_register);
184 162
185/** 163/**
@@ -190,10 +168,7 @@ EXPORT_SYMBOL_GPL(led_classdev_register);
190 */ 168 */
191void led_classdev_unregister(struct led_classdev *led_cdev) 169void led_classdev_unregister(struct led_classdev *led_cdev)
192{ 170{
193 device_remove_file(led_cdev->dev, &dev_attr_max_brightness);
194 device_remove_file(led_cdev->dev, &dev_attr_brightness);
195#ifdef CONFIG_LEDS_TRIGGERS 171#ifdef CONFIG_LEDS_TRIGGERS
196 device_remove_file(led_cdev->dev, &dev_attr_trigger);
197 down_write(&led_cdev->trigger_lock); 172 down_write(&led_cdev->trigger_lock);
198 if (led_cdev->trigger) 173 if (led_cdev->trigger)
199 led_trigger_set(led_cdev, NULL); 174 led_trigger_set(led_cdev, NULL);
@@ -215,6 +190,7 @@ static int __init leds_init(void)
215 return PTR_ERR(leds_class); 190 return PTR_ERR(leds_class);
216 leds_class->suspend = led_suspend; 191 leds_class->suspend = led_suspend;
217 leds_class->resume = led_resume; 192 leds_class->resume = led_resume;
193 leds_class->dev_attrs = led_class_attrs;
218 return 0; 194 return 0;
219} 195}
220 196