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>
Cc: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxx>
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
---
* v3
- Add ABI documentation
- Add more detail to Kconfig help text
.../ABI/testing/sysfs-class-led-trigger-blk | 37 ++++
block/genhd.c | 2 +
drivers/leds/trigger/Kconfig | 9 +
drivers/leds/trigger/Makefile | 1 +
drivers/leds/trigger/ledtrig-blk.c | 225 +++++++++++++++++++++
include/linux/genhd.h | 3 +
include/linux/leds.h | 27 +++
7 files changed, 304 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-blk
create mode 100644 drivers/leds/trigger/ledtrig-blk.c
diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-blk b/Documentation/ABI/testing/sysfs-class-led-trigger-blk
new file mode 100644
index 0000000..73472c3
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-blk
@@ -0,0 +1,37 @@
+What: /sys/class/leds/<led>/interval
+Date: Aug 2019
+KernelVersion: 5.4
+Contact: linux-leds@xxxxxxxxxxxxxxx
+Description:
+ Specifies the duration of the LED blink in milliseconds.
+ Defaults to 50 ms.
+
+What: /sys/class/leds/<led>/read
+Date: Aug 2019
+KernelVersion: 5.4
+Contact: linux-leds@xxxxxxxxxxxxxxx
+Description:
+ Signal data read on the block device.
+ If set to 0, the LED will not blink on data read.
+ If set to 1 (default), the LED will blink for the milliseconds
+ specified in interval to signal data read.
+
+What: /sys/class/leds/<led>/write
+Date: Aug 2019
+KernelVersion: 5.4
+Contact: linux-leds@xxxxxxxxxxxxxxx
+Description:
+ Signal data written on the block device.
+ If set to 0, the LED will not blink on data written.
+ If set to 1 (default), the LED will blink for the milliseconds
+ specified in interval to signal data written.
+
+What: /sys/class/leds/<led>/discard
+Date: Aug 2019
+KernelVersion: 5.4
+Contact: linux-leds@xxxxxxxxxxxxxxx
+Description:
+ Signal data discarded on the block device.
+ If set to 0, the LED will not blink on data discarded.
+ If set to 1 (default), the LED will blink for the milliseconds
+ specified in interval to signal data discarded.
diff --git a/block/genhd.c b/block/genhd.c
index 54f1f0d3..1c68861 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);
+ ledtrig_blk_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;
+ ledtrig_blk_unregister(disk);
blk_integrity_del(disk);
disk_del_events(disk);
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index ce9429c..e399a11 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -144,4 +144,13 @@ config LEDS_TRIGGER_AUDIO
the audio mute and mic-mute changes.
If unsure, say N
+config LEDS_TRIGGER_BLOCK
+ bool "LED Block device Trigger"
+ depends on BLOCK
+ help
+ This allows LEDs to be controlled by block device activity.
+ This trigger doesn't require the lower level drivers to have any
+ instrumentation. The activity is collected by polling the disk stats.
+ If unsure, say Y.
+
endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 733a83e..60200eb 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_LEDS_TRIGGER_PANIC) += ledtrig-panic.o
obj-$(CONFIG_LEDS_TRIGGER_NETDEV) += ledtrig-netdev.o
obj-$(CONFIG_LEDS_TRIGGER_PATTERN) += ledtrig-pattern.o
obj-$(CONFIG_LEDS_TRIGGER_AUDIO) += ledtrig-audio.o
+obj-$(CONFIG_LEDS_TRIGGER_BLOCK) += ledtrig-blk.o
diff --git a/drivers/leds/trigger/ledtrig-blk.c b/drivers/leds/trigger/ledtrig-blk.c
new file mode 100644
index 0000000..d5808c9
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-blk.c
@@ -0,0 +1,225 @@
+// 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>
+#include "../leds.h"
+
+enum ledtrig_blk_attr {
+ LEDTRIG_BLK_READ,
+ LEDTRIG_BLK_WRITE,
+ LEDTRIG_BLK_DISCARD
+};
+
+struct ledtrig_blk_data {
+ struct delayed_work work;
+ struct led_classdev *led_cdev;
+
+ atomic_t interval;
+ u64 last_activity;
+
+ unsigned long mode;
+};
+
+static ssize_t ledtrig_blk_attr_show(struct device *dev, char *buf,
+ enum ledtrig_blk_attr attr)
+{
+ struct ledtrig_blk_data *trig_data = led_trigger_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", test_bit(attr, &trig_data->mode));
+}
+
+static ssize_t ledtrig_blk_attr_store(struct device *dev, const char *buf,
+ size_t size, enum ledtrig_blk_attr attr)
+{
+ struct ledtrig_blk_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(attr, &trig_data->mode);
+ else
+ clear_bit(attr, &trig_data->mode);
+
+ return size;
+}
+
+static ssize_t read_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return ledtrig_blk_attr_show(dev, buf, LEDTRIG_BLK_READ);
+}
+static ssize_t read_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ return ledtrig_blk_attr_store(dev, buf, size, LEDTRIG_BLK_READ);
+}
+static DEVICE_ATTR_RW(read);
+
+static ssize_t write_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return ledtrig_blk_attr_show(dev, buf, LEDTRIG_BLK_WRITE);
+}
+static ssize_t write_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ return ledtrig_blk_attr_store(dev, buf, size, LEDTRIG_BLK_WRITE);
+}
+static DEVICE_ATTR_RW(write);
+
+static ssize_t discard_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return ledtrig_blk_attr_show(dev, buf, LEDTRIG_BLK_DISCARD);
+}
+static ssize_t discard_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ return ledtrig_blk_attr_store(dev, buf, size, LEDTRIG_BLK_DISCARD);
+}
+static DEVICE_ATTR_RW(discard);
+
+static ssize_t interval_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct ledtrig_blk_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 ledtrig_blk_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 *ledtrig_blk_attrs[] = {
+ &dev_attr_read.attr,
+ &dev_attr_write.attr,
+ &dev_attr_discard.attr,
+ &dev_attr_interval.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(ledtrig_blk);
+
+static void ledtrig_blk_work(struct work_struct *work)
+{
+ struct ledtrig_blk_data *trig_data =
+ container_of(work, struct ledtrig_blk_data, work.work);
+ struct gendisk *disk = container_of(trig_data->led_cdev->trigger,
+ struct gendisk, led.trig);
+ u64 activity = 0;
+
+ if (test_bit(LEDTRIG_BLK_READ, &trig_data->mode))
+ activity += part_stat_read(&disk->part0, ios[STAT_READ]);
+ if (test_bit(LEDTRIG_BLK_WRITE, &trig_data->mode))
+ activity += part_stat_read(&disk->part0, ios[STAT_WRITE]);
+ if (test_bit(LEDTRIG_BLK_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 ledtrig_blk_activate(struct led_classdev *led_cdev)
+{
+ struct ledtrig_blk_data *trig_data;
+
+ trig_data = kzalloc(sizeof(*trig_data), GFP_KERNEL);
+ if (!trig_data)
+ return -ENOMEM;
+
+ trig_data->mode = BIT(LEDTRIG_BLK_READ) | BIT(LEDTRIG_BLK_WRITE) |
+ BIT(LEDTRIG_BLK_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, ledtrig_blk_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 ledtrig_blk_deactivate(struct led_classdev *led_cdev)
+{
+ struct ledtrig_blk_data *trig_data = led_get_trigger_data(led_cdev);
+
+ cancel_delayed_work_sync(&trig_data->work);
+ kfree(trig_data);
+}
+
+int ledtrig_blk_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 = ledtrig_blk_activate;
+ disk->led.trig.deactivate = ledtrig_blk_deactivate;
+ disk->led.trig.groups = ledtrig_blk_groups;
+
+ ret = led_trigger_register(&disk->led.trig);
+ if (ret) {
+ kfree(disk->led.trig.name);
+ disk->led.trig.name = NULL;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ledtrig_blk_register);
+
+void ledtrig_blk_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;
+}
+EXPORT_SYMBOL_GPL(ledtrig_blk_unregister);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 8b5330d..b2c934e 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 +220,8 @@ struct gendisk {
int node_id;
struct badblocks *bb;
struct lockdep_map lockdep_map;
+
+ struct ledtrig_blk led;
};
static inline struct gendisk *part_to_disk(struct hd_struct *part)
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 9b2bf57..395fa61 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -517,4 +517,31 @@ static inline void ledtrig_audio_set(enum led_audio type,
}
#endif
+struct gendisk;
+
+#ifdef CONFIG_LEDS_TRIGGER_BLOCK
+
+struct ledtrig_blk {
+ struct led_trigger trig;
+};
+
+int ledtrig_blk_register(struct gendisk *disk);
+void ledtrig_blk_unregister(struct gendisk *disk);
+
+#else
+
+struct ledtrig_blk {
+};
+
+static inline int ledtrig_blk_register(struct gendisk *disk)
+{
+ return 0;
+}
+
+static inline void ledtrig_blk_unregister(struct gendisk *disk)
+{
+}
+
+#endif /* CONFIG_LEDS_TRIGGER_BLOCK */
+
#endif /* __LINUX_LEDS_H_INCLUDED */
--
2.7.4
