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 <u.kleine-koenig@pengutronix.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

10 files changed, 63 insertions, 28 deletions

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 431123b048a2..a8786f4b3453 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -103,15 +103,16 @@ ssize_t led_trigger_show(struct device *dev, struct device_attribute *attr,
 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);
@@ -134,8 +135,14 @@ void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
                 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) {
@@ -146,6 +153,17 @@ void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
                                 "%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);
 
diff --git a/drivers/leds/trigger/ledtrig-activity.c b/drivers/leds/trigger/ledtrig-activity.c
index b39e1bb9a9ec..2fc065fb1754 100644
--- a/drivers/leds/trigger/ledtrig-activity.c
+++ b/drivers/leds/trigger/ledtrig-activity.c
@@ -178,20 +178,20 @@ static ssize_t led_invert_store(struct device *dev,
 
 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;
@@ -201,6 +201,8 @@ static void activity_activate(struct led_classdev *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)
diff --git a/drivers/leds/trigger/ledtrig-backlight.c b/drivers/leds/trigger/ledtrig-backlight.c
index 1ca1f1608f76..84512960d630 100644
--- a/drivers/leds/trigger/ledtrig-backlight.c
+++ b/drivers/leds/trigger/ledtrig-backlight.c
@@ -97,7 +97,7 @@ static ssize_t bl_trig_invert_store(struct device *dev,
 }
 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;
 
@@ -107,7 +107,7 @@ static void bl_trig_activate(struct led_classdev *led)
         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);
@@ -124,11 +124,13 @@ static void bl_trig_activate(struct led_classdev *led)
                 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)
diff --git a/drivers/leds/trigger/ledtrig-default-on.c b/drivers/leds/trigger/ledtrig-default-on.c
index 4ccea04b7a6b..2996fe672198 100644
--- a/drivers/leds/trigger/ledtrig-default-on.c
+++ b/drivers/leds/trigger/ledtrig-default-on.c
@@ -16,9 +16,10 @@
 #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 = {
diff --git a/drivers/leds/trigger/ledtrig-gpio.c b/drivers/leds/trigger/ledtrig-gpio.c
index 93906a17a4b6..f5358c40d03f 100644
--- a/drivers/leds/trigger/ledtrig-gpio.c
+++ b/drivers/leds/trigger/ledtrig-gpio.c
@@ -162,14 +162,14 @@ static ssize_t gpio_trig_gpio_store(struct device *dev,
 }
 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)
@@ -187,7 +187,7 @@ static void gpio_trig_activate(struct led_classdev *led)
         led->trigger_data = gpio_data;
         led->activated = true;
 
-        return;
+        return 0;
 
 err_brightness:
         device_remove_file(led->dev, &dev_attr_inverted);
@@ -197,6 +197,8 @@ err_inverted:
 
 err_gpio:
         kfree(gpio_data);
+
+        return 0;
 }
 
 static void gpio_trig_deactivate(struct led_classdev *led)
diff --git a/drivers/leds/trigger/ledtrig-heartbeat.c b/drivers/leds/trigger/ledtrig-heartbeat.c
index 304b929edb8e..03a8dfce8fb9 100644
--- a/drivers/leds/trigger/ledtrig-heartbeat.c
+++ b/drivers/leds/trigger/ledtrig-heartbeat.c
@@ -121,21 +121,21 @@ static ssize_t led_invert_store(struct device *dev,
 
 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);
@@ -145,6 +145,8 @@ static void heartbeat_trig_activate(struct led_classdev *led_cdev)
         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)
diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
index 6df4781a6308..bb05937255de 100644
--- a/drivers/leds/trigger/ledtrig-netdev.c
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -388,14 +388,14 @@ static void netdev_trig_work(struct work_struct *work)
                         (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);
 
@@ -432,7 +432,7 @@ static void netdev_trig_activate(struct led_classdev *led_cdev)
         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);
@@ -447,6 +447,8 @@ err_out_device_name:
 err_out:
         led_cdev->trigger_data = NULL;
         kfree(trigger_data);
+
+        return 0;
 }
 
 static void netdev_trig_deactivate(struct led_classdev *led_cdev)
diff --git a/drivers/leds/trigger/ledtrig-oneshot.c b/drivers/leds/trigger/ledtrig-oneshot.c
index b8ea9f0f1e19..7bbf92bd7f80 100644
--- a/drivers/leds/trigger/ledtrig-oneshot.c
+++ b/drivers/leds/trigger/ledtrig-oneshot.c
@@ -122,14 +122,14 @@ static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
 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;
 
@@ -151,7 +151,7 @@ static void oneshot_trig_activate(struct led_classdev *led_cdev)
 
         led_cdev->activated = true;
 
-        return;
+        return 0;
 
 err_out_invert:
         device_remove_file(led_cdev->dev, &dev_attr_invert);
@@ -161,6 +161,8 @@ err_out_delayon:
         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)
diff --git a/drivers/leds/trigger/ledtrig-timer.c b/drivers/leds/trigger/ledtrig-timer.c
index 10fc0966b0e3..527055d815ad 100644
--- a/drivers/leds/trigger/ledtrig-timer.c
+++ b/drivers/leds/trigger/ledtrig-timer.c
@@ -70,7 +70,7 @@ static ssize_t led_delay_off_store(struct device *dev,
 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;
 
@@ -78,7 +78,7 @@ static void timer_trig_activate(struct led_classdev *led_cdev)
 
         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;
@@ -87,10 +87,12 @@ static void timer_trig_activate(struct led_classdev *led_cdev)
                       &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)
diff --git a/drivers/leds/trigger/ledtrig-transient.c b/drivers/leds/trigger/ledtrig-transient.c
index 9d1769073562..a55fc58179a9 100644
--- a/drivers/leds/trigger/ledtrig-transient.c
+++ b/drivers/leds/trigger/ledtrig-transient.c
@@ -152,7 +152,7 @@ static DEVICE_ATTR(duration, 0644, transient_duration_show,
                    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;
@@ -161,7 +161,7 @@ static void transient_trig_activate(struct led_classdev *led_cdev)
         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;
@@ -181,7 +181,7 @@ static void transient_trig_activate(struct led_classdev *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);
@@ -191,6 +191,8 @@ err_out:
         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)