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Subject[PATCH v2 12/15] leds: trigger: blkdev: Enable unlinking block devices from LEDs
Date
Add /sys/class/leds/<led>/unlink_device sysfs attribute

Remove symlinks in /sys/class/leds/<led>/block_devices and
/sys/block/<disk>/blkdev_leds

Decrement reference count on /sys/block/<disk>/blkdev_leds
directory (removes directory when empty)

Cancel delayed work if no devices are associated with *any* LEDs

Signed-off-by: Ian Pilcher <arequipeno@gmail.com>
---
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 26509837f037..fff67ebd28f2 100644
--- a/drivers/leds/trigger/ledtrig-blkdev.c
+++ b/drivers/leds/trigger/ledtrig-blkdev.c
@@ -379,6 +379,62 @@ static ssize_t link_device_store(struct device *const dev,
static DEVICE_ATTR_WO(link_device);


+/*
+ *
+ * unlink_device sysfs attribute - disassociate a device from this LED
+ *
+ */
+
+static void blkdev_disk_unlink_locked(struct ledtrig_blkdev_led *const led,
+ struct ledtrig_blkdev_link *const link,
+ struct ledtrig_blkdev_disk *const disk)
+{
+ --ledtrig_blkdev_count;
+
+ if (ledtrig_blkdev_count == 0)
+ WARN_ON(!cancel_delayed_work_sync(&ledtrig_blkdev_work));
+
+ sysfs_remove_link(led->dir, disk->gd->disk_name);
+ sysfs_remove_link(disk->dir, led->led_dev->name);
+ kobject_put(disk->dir);
+
+ hlist_del(&link->led_disks_node);
+ hlist_del(&link->disk_leds_node);
+ kfree(link);
+
+ if (hlist_empty(&disk->leds)) {
+ disk->gd->ledtrig = NULL;
+ kfree(disk);
+ }
+
+ put_disk(disk->gd);
+}
+
+static ssize_t unlink_device_store(struct device *const dev,
+ struct device_attribute *const attr,
+ const char *const buf, const size_t count)
+{
+ struct ledtrig_blkdev_led *const led = led_trigger_get_drvdata(dev);
+ struct ledtrig_blkdev_link *link;
+
+ mutex_lock(&ledtrig_blkdev_mutex);
+
+ hlist_for_each_entry(link, &led->disks, led_disks_node) {
+
+ if (sysfs_streq(link->disk->gd->disk_name, buf)) {
+ blkdev_disk_unlink_locked(led, link, link->disk);
+ break;
+ }
+ }
+
+ mutex_unlock(&ledtrig_blkdev_mutex);
+
+ return count;
+}
+
+static DEVICE_ATTR_WO(unlink_device);
+
+
/*
*
* Initialization - register the trigger
@@ -387,6 +443,7 @@ static DEVICE_ATTR_WO(link_device);

static struct attribute *ledtrig_blkdev_attrs[] = {
&dev_attr_link_device.attr,
+ &dev_attr_unlink_device.attr,
NULL
};

--
2.31.1
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