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 <[email protected]> Cc: Jacek Anaszewski <[email protected]> Cc: Pavel Machek <[email protected]> Cc: Dan Murphy <[email protected]> Cc: Jens Axboe <[email protected]> Cc: "James E.J. Bottomley" <[email protected]> Cc: "Martin K. Petersen" <[email protected]> Cc: Hannes Reinecke <[email protected]> Signed-off-by: Akinobu Mita <[email protected]> --- * 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: [email protected] +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: [email protected] +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: [email protected] +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: [email protected] +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
