[PATCH v2 10/15] leds: trigger: blkdev: Add LED trigger activate function

[Ian Pilcher]

Allocate per-LED data structure and initialize with default values

Create /sys/class/leds/<led>/block_devices directory

Increment module reference count.  Module can only be removed when no LEDs
are associated with the trigger.

Signed-off-by: Ian Pilcher <arequipeno@xxxxxxxxx>
---
 drivers/leds/trigger/ledtrig-blkdev.c | 57 +++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/drivers/leds/trigger/ledtrig-blkdev.c b/drivers/leds/trigger/ledtrig-blkdev.c
index 40dc55e5d4f3..6f78a9515976 100644
--- a/drivers/leds/trigger/ledtrig-blkdev.c
+++ b/drivers/leds/trigger/ledtrig-blkdev.c
@@ -164,6 +164,62 @@ static void blkdev_process(struct work_struct *const work)
 }
 
 
+/*
+ *
+ *	Associate an LED with the blkdev trigger
+ *
+ */
+
+static int blkdev_activate(struct led_classdev *const led_dev)
+{
+	struct ledtrig_blkdev_led *led;
+	int ret;
+
+	/* Don't allow module to be removed while any LEDs are linked */
+	if (WARN_ON(!try_module_get(THIS_MODULE))) {
+		ret = -ENODEV;		/* Shouldn't ever happen */
+		goto exit_return;
+	}
+
+	led = kmalloc(sizeof(*led), GFP_KERNEL);
+	if (led == NULL) {
+		ret = -ENOMEM;
+		goto exit_put_module;
+	}
+
+	led->led_dev = led_dev;
+	led->blink_msec = LEDTRIG_BLKDEV_BLINK_MSEC;
+	led->mode = LEDTRIG_BLKDEV_MODE_RW;
+	INIT_HLIST_HEAD(&led->disks);
+
+	ret = mutex_lock_interruptible(&ledtrig_blkdev_mutex);
+	if (ret != 0)
+		goto exit_free;
+
+	led->dir = kobject_create_and_add("linked_devices",
+					  &led_dev->dev->kobj);
+	if (led->dir == NULL) {
+		ret = -ENOMEM;
+		goto exit_unlock;
+	}
+
+	hlist_add_head(&led->leds_node, &ledtrig_blkdev_leds);
+	led_set_trigger_data(led_dev, led);
+	ret = 0;
+
+exit_unlock:
+	mutex_unlock(&ledtrig_blkdev_mutex);
+exit_free:
+	if (ret != 0)
+		kfree(led);
+exit_put_module:
+	if (ret != 0)
+		module_put(THIS_MODULE);
+exit_return:
+	return ret;
+}
+
+
 /*
  *
  *	Initialization - register the trigger
@@ -185,5 +241,6 @@ static const struct attribute_group *ledtrig_blkdev_attr_groups[] = {
 
 struct led_trigger ledtrig_blkdev_trigger = {
 	.name		= "blkdev",
+	.activate	= blkdev_activate,
 	.groups		= ledtrig_blkdev_attr_groups,
 };
-- 
2.31.1