This allows LEDs to be controlled by block device activity.
We already have ledtrig-disk (LED disk activity trigger), but the lower
level disk drivers need to utilize ledtrig_disk_activity() to make the
LED blink.
The LED block device trigger doesn't require the lower level drivers to
have any instrumentation. The activity is collected by polling the disk
stats.
Example:
echo block-nvme0n1 > /sys/class/leds/diy/trigger
Cc: Frank Steiner <fsteiner-mail1@xxxxxxxxxxxxxx>
Cc: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>
Cc: Pavel Machek <pavel@xxxxxx>
Cc: Dan Murphy <dmurphy@xxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
---
block/Makefile | 1 +
block/blk-ledtrig.c | 219 ++++++++++++++++++++++++++++++++++++++++++++++++++
block/blk.h | 13 +++
block/genhd.c | 2 +
include/linux/genhd.h | 4 +
5 files changed, 239 insertions(+)
create mode 100644 block/blk-ledtrig.c
diff --git a/block/Makefile b/block/Makefile
index eee1b4c..c74d84e6 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -35,3 +35,4 @@ obj-$(CONFIG_BLK_DEBUG_FS) += blk-mq-debugfs.o
obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
obj-$(CONFIG_BLK_SED_OPAL) += sed-opal.o
obj-$(CONFIG_BLK_PM) += blk-pm.o
+obj-$(CONFIG_LEDS_TRIGGERS) += blk-ledtrig.o
diff --git a/block/blk-ledtrig.c b/block/blk-ledtrig.c
new file mode 100644
index 0000000..da93b06
--- /dev/null
+++ b/block/blk-ledtrig.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0
+// LED Kernel Blockdev Trigger
+// Derived from ledtrig-netdev.c
+
+#include <linux/atomic.h>
+#include <linux/genhd.h>
+#include <linux/leds.h>
+#include <linux/workqueue.h>
+
+struct blk_ledtrig_data {
+ struct delayed_work work;
+ struct led_classdev *led_cdev;
+
+ atomic_t interval;
+ u64 last_activity;
+
+ unsigned long mode;
+#define BLK_LEDTRIG_READ BIT(0)
+#define BLK_LEDTRIG_WRITE BIT(1)
+#define BLK_LEDTRIG_DISCARD BIT(2)
+};
+
+static ssize_t blk_ledtrig_attr_show(struct device *dev, char *buf,
+ unsigned long blk_ledtrig)
+{
+ struct blk_ledtrig_data *trig_data = led_trigger_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", test_bit(blk_ledtrig, &trig_data->mode));
+}
+
+static ssize_t blk_ledtrig_attr_store(struct device *dev, const char *buf,
+ size_t size, unsigned long blk_ledtrig)
+{
+ struct blk_ledtrig_data *trig_data = led_trigger_get_drvdata(dev);
+ unsigned long state;
+ int ret;
+
+ ret = kstrtoul(buf, 0, &state);
+ if (ret)
+ return ret;
+
+ if (state)
+ set_bit(blk_ledtrig, &trig_data->mode);
+ else
+ clear_bit(blk_ledtrig, &trig_data->mode);
+
+ return size;
+}
+
+static ssize_t read_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return blk_ledtrig_attr_show(dev, buf, BLK_LEDTRIG_READ);
+}
+static ssize_t read_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ return blk_ledtrig_attr_store(dev, buf, size, BLK_LEDTRIG_READ);
+}
+static DEVICE_ATTR_RW(read);
+
+static ssize_t write_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return blk_ledtrig_attr_show(dev, buf, BLK_LEDTRIG_WRITE);
+}
+static ssize_t write_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ return blk_ledtrig_attr_store(dev, buf, size, BLK_LEDTRIG_WRITE);
+}
+static DEVICE_ATTR_RW(write);
+
+static ssize_t discard_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return blk_ledtrig_attr_show(dev, buf, BLK_LEDTRIG_DISCARD);
+}
+static ssize_t discard_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ return blk_ledtrig_attr_store(dev, buf, size, BLK_LEDTRIG_DISCARD);
+}
+static DEVICE_ATTR_RW(discard);
+
+static ssize_t interval_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct blk_ledtrig_data *trig_data = led_trigger_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n",
+ jiffies_to_msecs(atomic_read(&trig_data->interval)));
+}
+static ssize_t interval_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct blk_ledtrig_data *trig_data = led_trigger_get_drvdata(dev);
+ unsigned long value;
+ int ret;
+
+ ret = kstrtoul(buf, 0, &value);
+ if (ret)
+ return ret;
+
+ /* impose some basic bounds on the timer interval */
+ if (value >= 5 && value <= 10000) {
+ cancel_delayed_work_sync(&trig_data->work);
+ atomic_set(&trig_data->interval, msecs_to_jiffies(value));
+ schedule_delayed_work(&trig_data->work,
+ atomic_read(&trig_data->interval) * 2);
+ }
+
+ return size;
+}
+static DEVICE_ATTR_RW(interval);
+
+static struct attribute *blk_ledtrig_attrs[] = {
+ &dev_attr_read.attr,
+ &dev_attr_write.attr,
+ &dev_attr_discard.attr,
+ &dev_attr_interval.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(blk_ledtrig);
+
+static void blk_ledtrig_work(struct work_struct *work)
+{
+ struct blk_ledtrig_data *trig_data =
+ container_of(work, struct blk_ledtrig_data, work.work);
+ struct gendisk *disk = container_of(trig_data->led_cdev->trigger,
+ struct gendisk, led_trig);
+ u64 activity = 0;
+
+ if (test_bit(BLK_LEDTRIG_READ, &trig_data->mode))
+ activity += part_stat_read(&disk->part0, ios[STAT_READ]);
+ if (test_bit(BLK_LEDTRIG_WRITE, &trig_data->mode))
+ activity += part_stat_read(&disk->part0, ios[STAT_WRITE]);
+ if (test_bit(BLK_LEDTRIG_DISCARD, &trig_data->mode))
+ activity += part_stat_read(&disk->part0, ios[STAT_DISCARD]);
+
+ if (trig_data->last_activity != activity) {
+ unsigned long interval;
+
+ led_stop_software_blink(trig_data->led_cdev);
+ interval = jiffies_to_msecs(atomic_read(&trig_data->interval));
+ led_blink_set_oneshot(trig_data->led_cdev, &interval, &interval,
+ 0);
+
+ trig_data->last_activity = activity;
+ }
+
+ schedule_delayed_work(&trig_data->work,
+ atomic_read(&trig_data->interval) * 2);
+}
+
+static int blk_ledtrig_activate(struct led_classdev *led_cdev)
+{
+ struct blk_ledtrig_data *trig_data;
+
+ trig_data = kzalloc(sizeof(*trig_data), GFP_KERNEL);
+ if (!trig_data)
+ return -ENOMEM;
+
+ trig_data->mode = BLK_LEDTRIG_READ | BLK_LEDTRIG_WRITE |
+ BLK_LEDTRIG_DISCARD;
+
+ atomic_set(&trig_data->interval, msecs_to_jiffies(50));
+ trig_data->last_activity = 0;
+ trig_data->led_cdev = led_cdev;
+
+ INIT_DELAYED_WORK(&trig_data->work, blk_ledtrig_work);
+
+ led_set_trigger_data(led_cdev, trig_data);
+
+ schedule_delayed_work(&trig_data->work,
+ atomic_read(&trig_data->interval) * 2);
+
+ return 0;
+}
+
+static void blk_ledtrig_deactivate(struct led_classdev *led_cdev)
+{
+ struct blk_ledtrig_data *trig_data = led_get_trigger_data(led_cdev);
+
+ cancel_delayed_work_sync(&trig_data->work);
+ kfree(trig_data);
+}
+
+int blk_ledtrig_register(struct gendisk *disk)
+{
+ int ret;
+
+ disk->led_trig.name = kasprintf(GFP_KERNEL, "block-%s",
+ disk->disk_name);
+ if (!disk->led_trig.name)
+ return -ENOMEM;
+
+ disk->led_trig.activate = blk_ledtrig_activate;
+ disk->led_trig.deactivate = blk_ledtrig_deactivate;
+ disk->led_trig.groups = blk_ledtrig_groups;
+
+ ret = led_trigger_register(&disk->led_trig);
+ if (ret) {
+ kfree(disk->led_trig.name);
+ disk->led_trig.name = NULL;
+ }
+
+ return ret;
+}
+
+void blk_ledtrig_unregister(struct gendisk *disk)
+{
+ if (!disk->led_trig.name)
+ return;
+
+ led_trigger_unregister(&disk->led_trig);
+ kfree(disk->led_trig.name);
+ disk->led_trig.name = NULL;
+}
diff --git a/block/blk.h b/block/blk.h
index 7814aa2..dd4c230a 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -331,4 +331,17 @@ void blk_queue_free_zone_bitmaps(struct request_queue *q);
static inline void blk_queue_free_zone_bitmaps(struct request_queue *q) {}
#endif
+#ifdef CONFIG_LEDS_TRIGGERS
+int blk_ledtrig_register(struct gendisk *disk);
+void blk_ledtrig_unregister(struct gendisk *disk);
+#else
+static inline int blk_ledtrig_register(struct gendisk *disk)
+{
+ return 0;
+}
+static inline void blk_ledtrig_unregister(struct gendisk *disk)
+{
+}
+#endif /* CONFIG_LEDS_TRIGGERS */
+
#endif /* BLK_INTERNAL_H */
diff --git a/block/genhd.c b/block/genhd.c
index 24654e1..dfd210c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -745,6 +745,7 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
disk_add_events(disk);
blk_integrity_add(disk);
+ blk_ledtrig_register(disk);
}
void device_add_disk(struct device *parent, struct gendisk *disk,
@@ -766,6 +767,7 @@ void del_gendisk(struct gendisk *disk)
struct disk_part_iter piter;
struct hd_struct *part;
+ blk_ledtrig_unregister(disk);
blk_integrity_del(disk);
disk_del_events(disk);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 8b5330d..9250e9c 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -17,6 +17,7 @@
#include <linux/percpu-refcount.h>
#include <linux/uuid.h>
#include <linux/blk_types.h>
+#include <linux/leds.h>
#include <asm/local.h>
#ifdef CONFIG_BLOCK
@@ -219,6 +220,9 @@ struct gendisk {
int node_id;
struct badblocks *bb;
struct lockdep_map lockdep_map;
+#ifdef CONFIG_LEDS_TRIGGERS
+ struct led_trigger led_trig;
+#endif
};
static inline struct gendisk *part_to_disk(struct hd_struct *part)
--
2.7.4
