This patch series adds configurable (i.e. user-defined) block device LED
triggers.
* Triggers can be created, listed, and deleted via sysfs block class
attributes (led_trigger_{new,list,del}).
* Once created, block device LED triggers are associated with LEDs just
like any other LED trigger (via /sys/class/leds/${LED}/trigger).
* Each block device gains a new device attribute (led_trigger) that can
be used to associate the device with a trigger or clear its
association.
* My expectation is that most configuration will be done via sysfs
(driven by udev), but there also in-kernel APIs for creating,
deleting, and (dis)associating triggers.
* Multiple devices can be associated with one trigger, so this supports
a single LED driven by multiple devices, multiple device-specific
LEDs, or arbitrary combinations.
Along with support for more than just ATA devices, this is the main
difference between this function and the current disk activity
trigger. It makes it suitable for use on systems like the Thecus
N5550 NAS, which has a software-driven activity LEDs for each disk.
* In addition to physical block devices, many types of virtual block
devices can drive LEDs; device mapper, MD RAID, and loop devices
work (but zram swap devices do not).
* The led trigger is "blinked" (75 msec on, 25 msec off) when a request
is successfully sent to the low-level driver. The intent is to
provide a visual indication of device activity, not any sort of exact
measurement.
* Related to the previous bullet, if the blink function is unable to
immediately acquire a lock on the device's LED trigger information
it simply returns, so that I/O processing can continue.
It's probably obvious that I'm basically a complete newbie at kernel
development, so I welcome feedback.
Thanks!
Ian Pilcher (8):
docs: Add block device LED trigger documentation
block: Add block device LED trigger list
block: Add kernel APIs to create & delete block device LED triggers
block: Add block class attributes to manage LED trigger list
block: Add block device LED trigger info to struct genhd
block: Add kernel APIs to set & clear per-block device LED triggers
block: Add block device attributes to set & clear LED triggers
block: Blink device LED when request is sent to low-level driver
Documentation/block/index.rst | 1 +
Documentation/block/led-triggers.rst | 124 ++++++
block/Kconfig | 10 +
block/Makefile | 1 +
block/blk-ledtrig.c | 570 +++++++++++++++++++++++++++
block/blk-ledtrig.h | 51 +++
block/blk-mq.c | 2 +
block/genhd.c | 14 +
include/linux/blk-ledtrig.h | 24 ++
include/linux/genhd.h | 4 +
10 files changed, 801 insertions(+)
create mode 100644 Documentation/block/led-triggers.rst
create mode 100644 block/blk-ledtrig.c
create mode 100644 block/blk-ledtrig.h
create mode 100644 include/linux/blk-ledtrig.h
--
2.31.1
