leds: triggers: let struct led_trigger::activate() return an error code

Given that activating a trigger can fail, let the callback return an
indication. This prevents to have a trigger active according to the
"trigger" sysfs attribute but not functional.

All users are changed accordingly to return 0 for now. There is no intended
change in behaviour.

Signed-off-by: Uwe Kleine-König <[e-mail]>
Acked-by: Pavel Machek <[e-mail]>
Signed-off-by: Jacek Anaszewski <[e-mail]>

drivers/leds/led-triggers.c

···
 EXPORT_SYMBOL_GPL(led_trigger_show);
 
 /* Caller must ensure led_cdev->trigger_lock held */
-void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
+int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
 {
 	unsigned long flags;
 	char *event = NULL;
 	char *envp[2];
 	const char *name;
+	int ret;
 
 	if (!led_cdev->trigger && !trig)
-		return;
+		return 0;
 
 	name = trig ? trig->name : "none";
 	event = kasprintf(GFP_KERNEL, "TRIGGER=%s", name);
···
 		list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
 		write_unlock_irqrestore(&trig->leddev_list_lock, flags);
 		led_cdev->trigger = trig;
+
 		if (trig->activate)
-			trig->activate(led_cdev);
+			ret = trig->activate(led_cdev);
+		else
+			ret = 0;
+
+		if (ret)
+			goto err_activate;
 	}
 
 	if (event) {
···
 				"%s: Error sending uevent\n", __func__);
 		kfree(event);
 	}
+
+	return 0;
+
+err_activate:
+	led_cdev->trigger = NULL;
+	write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
+	list_del(&led_cdev->trig_list);
+	write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
+	led_set_brightness(led_cdev, LED_OFF);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(led_trigger_set);
 

drivers/leds/trigger/ledtrig-activity.c

···
 
 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
 
-static void activity_activate(struct led_classdev *led_cdev)
+static int activity_activate(struct led_classdev *led_cdev)
 {
 	struct activity_data *activity_data;
 	int rc;
 
 	activity_data = kzalloc(sizeof(*activity_data), GFP_KERNEL);
 	if (!activity_data)
-		return;
+		return 0;
 
 	led_cdev->trigger_data = activity_data;
 	rc = device_create_file(led_cdev->dev, &dev_attr_invert);
 	if (rc) {
 		kfree(led_cdev->trigger_data);
-		return;
+		return 0;
 	}
 
 	activity_data->led_cdev = led_cdev;
···
 	led_activity_function(&activity_data->timer);
 	set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 	led_cdev->activated = true;
+
+	return 0;
 }
 
 static void activity_deactivate(struct led_classdev *led_cdev)

drivers/leds/trigger/ledtrig-backlight.c

···
 }
 static DEVICE_ATTR(inverted, 0644, bl_trig_invert_show, bl_trig_invert_store);
 
-static void bl_trig_activate(struct led_classdev *led)
+static int bl_trig_activate(struct led_classdev *led)
 {
 	int ret;
 
···
 	led->trigger_data = n;
 	if (!n) {
 		dev_err(led->dev, "unable to allocate backlight trigger\n");
-		return;
+		return 0;
 	}
 
 	ret = device_create_file(led->dev, &dev_attr_inverted);
···
 		dev_err(led->dev, "unable to register backlight trigger\n");
 	led->activated = true;
 
-	return;
+	return 0;
 
 err_invert:
 	led->trigger_data = NULL;
 	kfree(n);
+
+	return 0;
 }
 
 static void bl_trig_deactivate(struct led_classdev *led)

drivers/leds/trigger/ledtrig-default-on.c

···
 #include <linux/leds.h>
 #include "../leds.h"
 
-static void defon_trig_activate(struct led_classdev *led_cdev)
+static int defon_trig_activate(struct led_classdev *led_cdev)
 {
 	led_set_brightness_nosleep(led_cdev, led_cdev->max_brightness);
+	return 0;
 }
 
 static struct led_trigger defon_led_trigger = {

drivers/leds/trigger/ledtrig-gpio.c

···
 }
 static DEVICE_ATTR(gpio, 0644, gpio_trig_gpio_show, gpio_trig_gpio_store);
 
-static void gpio_trig_activate(struct led_classdev *led)
+static int gpio_trig_activate(struct led_classdev *led)
 {
 	struct gpio_trig_data *gpio_data;
 	int ret;
 
 	gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL);
 	if (!gpio_data)
-		return;
+		return 0;
 
 	ret = device_create_file(led->dev, &dev_attr_gpio);
 	if (ret)
···
 	led->trigger_data = gpio_data;
 	led->activated = true;
 
-	return;
+	return 0;
 
 err_brightness:
 	device_remove_file(led->dev, &dev_attr_inverted);
···
 
 err_gpio:
 	kfree(gpio_data);
+
+	return 0;
 }
 
 static void gpio_trig_deactivate(struct led_classdev *led)

drivers/leds/trigger/ledtrig-heartbeat.c

···
 
 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
 
-static void heartbeat_trig_activate(struct led_classdev *led_cdev)
+static int heartbeat_trig_activate(struct led_classdev *led_cdev)
 {
 	struct heartbeat_trig_data *heartbeat_data;
 	int rc;
 
 	heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
 	if (!heartbeat_data)
-		return;
+		return 0;
 
 	led_cdev->trigger_data = heartbeat_data;
 	heartbeat_data->led_cdev = led_cdev;
 	rc = device_create_file(led_cdev->dev, &dev_attr_invert);
 	if (rc) {
 		kfree(led_cdev->trigger_data);
-		return;
+		return 0;
 	}
 
 	timer_setup(&heartbeat_data->timer, led_heartbeat_function, 0);
···
 	led_heartbeat_function(&heartbeat_data->timer);
 	set_bit(LED_BLINK_SW, &led_cdev->work_flags);
 	led_cdev->activated = true;
+
+	return 0;
 }
 
 static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)

drivers/leds/trigger/ledtrig-netdev.c

···
 			(atomic_read(&trigger_data->interval)*2));
 }
 
-static void netdev_trig_activate(struct led_classdev *led_cdev)
+static int netdev_trig_activate(struct led_classdev *led_cdev)
 {
 	struct led_netdev_data *trigger_data;
 	int rc;
 
 	trigger_data = kzalloc(sizeof(struct led_netdev_data), GFP_KERNEL);
 	if (!trigger_data)
-		return;
+		return 0;
 
 	spin_lock_init(&trigger_data->lock);
 
···
 	rc = register_netdevice_notifier(&trigger_data->notifier);
 	if (rc)
 		goto err_out_interval;
-	return;
+	return 0;
 
 err_out_interval:
 	device_remove_file(led_cdev->dev, &dev_attr_interval);
···
 err_out:
 	led_cdev->trigger_data = NULL;
 	kfree(trigger_data);
+
+	return 0;
 }
 
 static void netdev_trig_deactivate(struct led_classdev *led_cdev)

drivers/leds/trigger/ledtrig-oneshot.c

···
 static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
 static DEVICE_ATTR(shot, 0200, NULL, led_shot);
 
-static void oneshot_trig_activate(struct led_classdev *led_cdev)
+static int oneshot_trig_activate(struct led_classdev *led_cdev)
 {
 	struct oneshot_trig_data *oneshot_data;
 	int rc;
 
 	oneshot_data = kzalloc(sizeof(*oneshot_data), GFP_KERNEL);
 	if (!oneshot_data)
-		return;
+		return 0;
 
 	led_cdev->trigger_data = oneshot_data;
 
···
 
 	led_cdev->activated = true;
 
-	return;
+	return 0;
 
 err_out_invert:
 	device_remove_file(led_cdev->dev, &dev_attr_invert);
···
 	device_remove_file(led_cdev->dev, &dev_attr_delay_on);
 err_out_trig_data:
 	kfree(led_cdev->trigger_data);
+
+	return 0;
 }
 
 static void oneshot_trig_deactivate(struct led_classdev *led_cdev)

drivers/leds/trigger/ledtrig-timer.c

···
 static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
 static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
 
-static void timer_trig_activate(struct led_classdev *led_cdev)
+static int timer_trig_activate(struct led_classdev *led_cdev)
 {
 	int rc;
 
···
 
 	rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
 	if (rc)
-		return;
+		return 0;
 	rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
 	if (rc)
 		goto err_out_delayon;
···
 		      &led_cdev->blink_delay_off);
 	led_cdev->activated = true;
 
-	return;
+	return 0;
 
 err_out_delayon:
 	device_remove_file(led_cdev->dev, &dev_attr_delay_on);
+
+	return 0;
 }
 
 static void timer_trig_deactivate(struct led_classdev *led_cdev)

drivers/leds/trigger/ledtrig-transient.c

···
 		   transient_duration_store);
 static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store);
 
-static void transient_trig_activate(struct led_classdev *led_cdev)
+static int transient_trig_activate(struct led_classdev *led_cdev)
 {
 	int rc;
 	struct transient_trig_data *tdata;
···
 	if (!tdata) {
 		dev_err(led_cdev->dev,
 			"unable to allocate transient trigger\n");
-		return;
+		return 0;
 	}
 	led_cdev->trigger_data = tdata;
 	tdata->led_cdev = led_cdev;
···
 	timer_setup(&tdata->timer, transient_timer_function, 0);
 	led_cdev->activated = true;
 
-	return;
+	return 0;
 
 err_out_state:
 	device_remove_file(led_cdev->dev, &dev_attr_duration);
···
 	dev_err(led_cdev->dev, "unable to register transient trigger\n");
 	led_cdev->trigger_data = NULL;
 	kfree(tdata);
+
+	return 0;
 }
 
 static void transient_trig_deactivate(struct led_classdev *led_cdev)

drivers/tty/vt/keyboard.c

···
 	unsigned int mask;
 };
 
-static void kbd_led_trigger_activate(struct led_classdev *cdev)
+static int kbd_led_trigger_activate(struct led_classdev *cdev)
 {
 	struct kbd_led_trigger *trigger =
 		container_of(cdev->trigger, struct kbd_led_trigger, trigger);
···
 				  ledstate & trigger->mask ?
 					LED_FULL : LED_OFF);
 	tasklet_enable(&keyboard_tasklet);
+
+	return 0;
 }
 
 #define KBD_LED_TRIGGER(_led_bit, _name) {			\

drivers/usb/core/ledtrig-usbport.c

···
 	return NOTIFY_DONE;
 }
 
-static void usbport_trig_activate(struct led_classdev *led_cdev)
+static int usbport_trig_activate(struct led_classdev *led_cdev)
 {
 	struct usbport_trig_data *usbport_data;
 	int err;
 
 	usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL);
 	if (!usbport_data)
-		return;
+		return 0;
 	usbport_data->led_cdev = led_cdev;
 
 	/* List of ports */
···
 	usb_register_notify(&usbport_data->nb);
 
 	led_cdev->activated = true;
-	return;
+	return 0;
 
 err_free:
 	kfree(usbport_data);
+	return 0;
 }
 
 static void usbport_trig_deactivate(struct led_classdev *led_cdev)

include/linux/leds.h

···
 struct led_trigger {
 	/* Trigger Properties */
 	const char	 *name;
-	void		(*activate)(struct led_classdev *led_cdev);
+	int		(*activate)(struct led_classdev *led_cdev);
 	void		(*deactivate)(struct led_classdev *led_cdev);
 
 	/* LEDs under control by this trigger (for simple triggers) */
···
 				      unsigned long *delay_off,
 				      int invert);
 extern void led_trigger_set_default(struct led_classdev *led_cdev);
-extern void led_trigger_set(struct led_classdev *led_cdev,
-			struct led_trigger *trigger);
+extern int led_trigger_set(struct led_classdev *led_cdev,
+			   struct led_trigger *trigger);
 extern void led_trigger_remove(struct led_classdev *led_cdev);
 
 static inline void *led_get_trigger_data(struct led_classdev *led_cdev)
···
 				      unsigned long *delay_off,
 				      int invert) {}
 static inline void led_trigger_set_default(struct led_classdev *led_cdev) {}
-static inline void led_trigger_set(struct led_classdev *led_cdev,
-				struct led_trigger *trigger) {}
+static inline int led_trigger_set(struct led_classdev *led_cdev,
+				  struct led_trigger *trigger)
+{
+	return 0;
+}
+
 static inline void led_trigger_remove(struct led_classdev *led_cdev) {}
 static inline void *led_get_trigger_data(struct led_classdev *led_cdev)
 {

net/bluetooth/leds.c

···
 	led_trigger_event(bt_power_led_trigger, enabled ? LED_FULL : LED_OFF);
 }
 
-static void power_activate(struct led_classdev *led_cdev)
+static int power_activate(struct led_classdev *led_cdev)
 {
 	struct hci_basic_led_trigger *htrig;
 	bool powered;
···
 	powered = test_bit(HCI_UP, &htrig->hdev->flags);
 
 	led_trigger_event(led_cdev->trigger, powered ? LED_FULL : LED_OFF);
+
+	return 0;
 }
 
 static struct led_trigger *led_allocate_basic(struct hci_dev *hdev,
-			void (*activate)(struct led_classdev *led_cdev),
+			int (*activate)(struct led_classdev *led_cdev),
 			const char *name)
 {
 	struct hci_basic_led_trigger *htrig;

net/mac80211/led.c

···
 	kfree(local->radio_led.name);
 }
 
-static void ieee80211_tx_led_activate(struct led_classdev *led_cdev)
+static int ieee80211_tx_led_activate(struct led_classdev *led_cdev)
 {
 	struct ieee80211_local *local = container_of(led_cdev->trigger,
 						     struct ieee80211_local,
 						     tx_led);
 
 	atomic_inc(&local->tx_led_active);
+
+	return 0;
 }
 
 static void ieee80211_tx_led_deactivate(struct led_classdev *led_cdev)
···
 	atomic_dec(&local->tx_led_active);
 }
 
-static void ieee80211_rx_led_activate(struct led_classdev *led_cdev)
+static int ieee80211_rx_led_activate(struct led_classdev *led_cdev)
 {
 	struct ieee80211_local *local = container_of(led_cdev->trigger,
 						     struct ieee80211_local,
 						     rx_led);
 
 	atomic_inc(&local->rx_led_active);
+
+	return 0;
 }
 
 static void ieee80211_rx_led_deactivate(struct led_classdev *led_cdev)
···
 	atomic_dec(&local->rx_led_active);
 }
 
-static void ieee80211_assoc_led_activate(struct led_classdev *led_cdev)
+static int ieee80211_assoc_led_activate(struct led_classdev *led_cdev)
 {
 	struct ieee80211_local *local = container_of(led_cdev->trigger,
 						     struct ieee80211_local,
 						     assoc_led);
 
 	atomic_inc(&local->assoc_led_active);
+
+	return 0;
 }
 
 static void ieee80211_assoc_led_deactivate(struct led_classdev *led_cdev)
···
 	atomic_dec(&local->assoc_led_active);
 }
 
-static void ieee80211_radio_led_activate(struct led_classdev *led_cdev)
+static int ieee80211_radio_led_activate(struct led_classdev *led_cdev)
 {
 	struct ieee80211_local *local = container_of(led_cdev->trigger,
 						     struct ieee80211_local,
 						     radio_led);
 
 	atomic_inc(&local->radio_led_active);
+
+	return 0;
 }
 
 static void ieee80211_radio_led_deactivate(struct led_classdev *led_cdev)
···
 	atomic_dec(&local->radio_led_active);
 }
 
-static void ieee80211_tpt_led_activate(struct led_classdev *led_cdev)
+static int ieee80211_tpt_led_activate(struct led_classdev *led_cdev)
 {
 	struct ieee80211_local *local = container_of(led_cdev->trigger,
 						     struct ieee80211_local,
 						     tpt_led);
 
 	atomic_inc(&local->tpt_led_active);
+
+	return 0;
 }
 
 static void ieee80211_tpt_led_deactivate(struct led_classdev *led_cdev)

net/rfkill/core.c

···
 		led_trigger_event(trigger, LED_FULL);
 }
 
-static void rfkill_led_trigger_activate(struct led_classdev *led)
+static int rfkill_led_trigger_activate(struct led_classdev *led)
 {
 	struct rfkill *rfkill;
 
 	rfkill = container_of(led->trigger, struct rfkill, led_trigger);
 
 	rfkill_led_trigger_event(rfkill);
+
+	return 0;
 }
 
 const char *rfkill_get_led_trigger_name(struct rfkill *rfkill)