Re: [PATCH] Clockevents: Always call clockevents_program_event

[Sodagudi Prasad]

On 2017-10-24 01:37, Thomas Gleixner wrote:
> On Tue, 24 Oct 2017, Prasad Sodagudi wrote:
>
> > Currently tick_program_event function is not calling
> > clockevents_program_event when  'expires == KTIME_MAX',
> > it is just updating clockevent state to 
> > CLOCK_EVT_STATE_ONESHOT_STOPPED.
> > clockevents_program_event function updates clockevent
> > device next_event by checking clockevent device state,
> > so always call clockevents_program_event() from tick_program_event.
>
> No. This is fundmentally wrong. If the clockevent is in oneshot stopped
> mode then you cannot call clockevents_program_event(). There is even a
> warning in that code which will trigger.

<Prasad> Yes. There is warning and I overlooked at that part of the code 
and thought
it would return from the clockevents_program_event function after 
next_event update.
  dev->next_event = expires;

        if (clockevent_state_shutdown(dev))
                return 0;

Thanks tglx for reviewing patch.

How to clean next next_event from clockevent device in the 
ONESHOT_STOPPED state from tick_program_event()?

Shall I update the next patch set with following condition?  Or Any 
other suggestions to fix this path?

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 4237e07..21104b6 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -317,7 +317,8 @@ int clockevents_program_event(struct 
clock_event_device *dev, ktime_t expires,

        dev->next_event = expires;

-       if (clockevent_state_shutdown(dev))
+       if (clockevent_state_shutdown(dev) ||
+               clockevent_state_oneshot_stopped(dev))
                return 0;

> Thanks,
>
> 	tglx

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