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    SubjectRe: [PATCH v2] leds: heartbeat: stop on shutdown
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    On Tue, 2012-04-24 at 17:07 +0200, Alexander Holler wrote:
    > A halted kernel should not show a heartbeat.
    >
    > Signed-off-by: Alexander Holler <holler@ahsoftware.de>
    > ---
    > drivers/leds/ledtrig-heartbeat.c | 18 +++++++++++++++++-
    > 1 files changed, 17 insertions(+), 1 deletions(-)
    >
    > diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c
    > index 759c0bb..1c05bd9 100644
    > --- a/drivers/leds/ledtrig-heartbeat.c
    > +++ b/drivers/leds/ledtrig-heartbeat.c
    > @@ -18,6 +18,7 @@
    > #include <linux/timer.h>
    > #include <linux/sched.h>
    > #include <linux/leds.h>
    > +#include <linux/reboot.h>
    > #include "leds.h"
    >
    > struct heartbeat_trig_data {
    > @@ -101,13 +102,28 @@ static struct led_trigger heartbeat_led_trigger = {
    > .deactivate = heartbeat_trig_deactivate,
    > };
    >
    > +static int heartbeat_reboot_notifier(struct notifier_block *nb,
    > + unsigned long code, void *unused)
    > +{
    > + led_trigger_unregister(&heartbeat_led_trigger);
    > + return NOTIFY_DONE;
    > +}
    > +
    > +static struct notifier_block heartbeat_reboot_nb = {
    > + .notifier_call = heartbeat_reboot_notifier,
    > +};
    > +
    > static int __init heartbeat_trig_init(void)
    > {
    > - return led_trigger_register(&heartbeat_led_trigger);
    > + int rc = led_trigger_register(&heartbeat_led_trigger);
    > + if( ! rc )
    > + register_reboot_notifier(&heartbeat_reboot_nb);

    Do you need to check return value here? I see return value being checked
    in some places in the kernel and not in others. Not checking is fine for
    now since register_reboot_notifier() always returns 0.

    Maybe adding return handling might not be a bad idea to be consistent
    with other places that do check.

    FYI - Andrew Morton is handling led patches these days. You might want
    to send include him <akpm@linux-foundation.org>

    > + return rc;
    > }
    >
    > static void __exit heartbeat_trig_exit(void)
    > {
    > + unregister_reboot_notifier(&heartbeat_reboot_nb);
    > led_trigger_unregister(&heartbeat_led_trigger);
    > }
    >




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