From: Greg KH <gregkh@linuxfoundation.org>
To: Ian Pilcher <arequipeno@gmail.com>
Cc: axboe@kernel.dk, pavel@ucw.cz, linux-leds@vger.kernel.org,
linux-block@vger.kernel.org, linux@vger.kernel.org,
kabel@kernel.org
Subject: Re: [PATCH 09/18] ledtrig-blkdev: Periodically check devices for activity & blink LEDs
Date: Sat, 4 Sep 2021 08:01:41 +0200 [thread overview]
Message-ID: <YTMLxdQ3TFKPN+WH@kroah.com> (raw)
In-Reply-To: <20210903204548.2745354-10-arequipeno@gmail.com>
On Fri, Sep 03, 2021 at 03:45:39PM -0500, Ian Pilcher wrote:
> Use a delayed workqueue to periodically check configured block devices for
> activity since the last check. Blink LEDs associated with devices on which
> the configured type of activity (read/write) has occurred.
>
> Signed-off-by: Ian Pilcher <arequipeno@gmail.com>
> ---
> drivers/leds/trigger/ledtrig-blkdev.c | 88 +++++++++++++++++++++++++++
> 1 file changed, 88 insertions(+)
>
> diff --git a/drivers/leds/trigger/ledtrig-blkdev.c b/drivers/leds/trigger/ledtrig-blkdev.c
> index 1f319529c3be..37ba9bb3542e 100644
> --- a/drivers/leds/trigger/ledtrig-blkdev.c
> +++ b/drivers/leds/trigger/ledtrig-blkdev.c
> @@ -7,7 +7,9 @@
> */
>
> #include <linux/ctype.h>
> +#include <linux/leds.h>
> #include <linux/module.h>
> +#include <linux/part_stat.h>
>
> #include "ledtrig-blkdev.h"
>
> @@ -68,6 +70,10 @@ static unsigned int ledtrig_blkdev_count;
> /* How often to check for drive activity - in jiffies */
> static unsigned int ledtrig_blkdev_interval;
>
> +/* Delayed work used to periodically check for activity & blink LEDs */
> +static void blkdev_process(struct work_struct *const work);
> +static DECLARE_DELAYED_WORK(ledtrig_blkdev_work, blkdev_process);
> +
>
> /*
> *
> @@ -110,3 +116,85 @@ static bool blkdev_write_mode(const enum ledtrig_blkdev_mode mode)
> {
> return mode != LEDTRIG_BLKDEV_MODE_RO;
> }
> +
> +
> +/*
> + *
> + * Periodically check for device acitivity and blink LEDs
> + *
> + */
> +
> +static void blkdev_blink(const struct ledtrig_blkdev_led *const led)
> +{
> + unsigned long delay_on = READ_ONCE(led->blink_msec);
> + unsigned long delay_off = 1; /* 0 leaves LED turned on */
> +
> + led_blink_set_oneshot(led->led_dev, &delay_on, &delay_off, 0);
> +}
> +
> +static void blkdev_update_disk(struct ledtrig_blkdev_disk *const disk,
> + const unsigned int generation)
> +{
> + const struct block_device *const part0 = disk->gd->part0;
> + const unsigned long read_ios = part_stat_read(part0, ios[STAT_READ]);
> + const unsigned long write_ios = part_stat_read(part0, ios[STAT_WRITE])
> + + part_stat_read(part0, ios[STAT_DISCARD])
> + + part_stat_read(part0, ios[STAT_FLUSH]);
> +
> + if (disk->read_ios != read_ios) {
> + disk->read_act = true;
> + disk->read_ios = read_ios;
> + } else {
> + disk->read_act = false;
> + }
> +
> + if (disk->write_ios != write_ios) {
> + disk->write_act = true;
> + disk->write_ios = write_ios;
> + } else {
> + disk->write_act = false;
> + }
> +
> + disk->generation = generation;
> +}
> +
> +static void blkdev_process(struct work_struct *const work)
> +{
> + static unsigned int generation;
> +
> + struct ledtrig_blkdev_led *led;
> + struct ledtrig_blkdev_link *link;
> + unsigned long delay;
> +
> + if (!mutex_trylock(&ledtrig_blkdev_mutex))
> + goto exit_reschedule;
> +
> + hlist_for_each_entry(led, &ledtrig_blkdev_leds, leds_node) {
> +
> + hlist_for_each_entry(link, &led->disks, led_disks_node) {
> +
> + struct ledtrig_blkdev_disk *const disk = link->disk;
> +
> + if (disk->generation != generation)
> + blkdev_update_disk(disk, generation);
> +
> + if (disk->read_act && blkdev_read_mode(led->mode)) {
> + blkdev_blink(led);
> + break;
> + }
> +
> + if (disk->write_act && blkdev_write_mode(led->mode)) {
> + blkdev_blink(led);
> + break;
> + }
> + }
> + }
> +
> + ++generation;
> +
> + mutex_unlock(&ledtrig_blkdev_mutex);
> +
> +exit_reschedule:
> + delay = READ_ONCE(ledtrig_blkdev_interval);
> + WARN_ON_ONCE(!schedule_delayed_work(&ledtrig_blkdev_work, delay));
You just rebooted a machine if it hit this :(
Please never use WARN_ON() in new code unless the machine is really
broken and you can not do anything else here.
thanks,
greg k-h
next prev parent reply other threads:[~2021-09-04 6:01 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-03 20:45 [PATCH 00/18] Introduce block device LED trigger Ian Pilcher
2021-09-03 20:45 ` [PATCH 01/18] docs: Add block device (blkdev) LED trigger documentation Ian Pilcher
2021-09-04 6:29 ` Pavel Machek
2021-09-05 14:49 ` Ian Pilcher
2021-09-05 18:42 ` Pavel Machek
2021-09-05 23:13 ` Ian Pilcher
2021-09-03 20:45 ` [PATCH 02/18] ledtrig-blkdev: Add build infra for block device LED trigger Ian Pilcher
2021-09-03 20:45 ` [PATCH 03/18] ledtrig-blkdev: Add function placeholders needed by block changes Ian Pilcher
2021-09-04 16:57 ` kernel test robot
2021-09-03 20:45 ` [PATCH 04/18] block: Add block device LED trigger integrations Ian Pilcher
2021-09-03 20:45 ` [PATCH 05/18] ledtrig-blkdev: Implement functions called from block subsystem Ian Pilcher
2021-09-03 20:45 ` [PATCH 06/18] ledtrig-blkdev: Add function to get gendisk by name Ian Pilcher
2021-09-03 20:45 ` [PATCH 07/18] ledtrig-blkdev: Add constants, data types, and global variables Ian Pilcher
2021-09-03 20:45 ` [PATCH 08/18] ledtrig-blkdev: Add miscellaneous helper functions Ian Pilcher
2021-09-04 6:00 ` Greg KH
2021-09-04 22:43 ` Ian Pilcher
2021-09-03 20:45 ` [PATCH 09/18] ledtrig-blkdev: Periodically check devices for activity & blink LEDs Ian Pilcher
2021-09-04 6:01 ` Greg KH [this message]
2021-09-05 14:39 ` Ian Pilcher
2021-09-05 14:51 ` Greg KH
2021-09-05 14:56 ` Ian Pilcher
2021-09-05 15:12 ` Greg KH
2021-09-05 16:55 ` Eric Biggers
2021-09-03 20:45 ` [PATCH 10/18] ledtrig-blkdev: Add function to associate the trigger with an LED Ian Pilcher
2021-09-03 20:45 ` [PATCH 11/18] ledtrig-blkdev: Add function to associate a device " Ian Pilcher
2021-09-03 20:45 ` [PATCH 12/18] ledtrig-blkdev: Add function to remove LED/device association Ian Pilcher
2021-09-03 20:45 ` [PATCH 13/18] ledtrig-blkdev: Add function to disassociate a device from all LEDs Ian Pilcher
2021-09-03 20:45 ` [PATCH 14/18] ledtrig-blkdev: Add function to disassociate an LED from the trigger Ian Pilcher
2021-09-03 20:45 ` [PATCH 15/18] ledtrig-blkdev: Add sysfs attributes to [un]link LEDs & devices Ian Pilcher
2021-09-04 5:57 ` Greg KH
2021-09-04 21:28 ` Ian Pilcher
2021-09-04 5:59 ` Greg KH
2021-09-04 22:35 ` Ian Pilcher
2021-09-05 14:51 ` Greg KH
2021-09-05 15:33 ` Ian Pilcher
2021-09-05 16:43 ` Greg KH
2021-09-03 20:45 ` [PATCH 16/18] ledtrig-blkdev: Add blink_time & interval sysfs attributes Ian Pilcher
2021-09-03 20:45 ` [PATCH 17/18] ledtrig-blkdev: Add mode (read/write/rw) sysfs attributue Ian Pilcher
2021-09-04 5:57 ` Greg KH
2021-09-04 21:01 ` Ian Pilcher
2021-09-05 14:50 ` Greg KH
2021-09-03 20:45 ` [PATCH 18/18] ledtrig-blkdev: Add initialization & exit functions Ian Pilcher
2021-09-04 6:35 ` [PATCH 00/18] Introduce block device LED trigger Pavel Machek
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