Re: [PATCH 6/9] rv: Ensure synchronous cleanup for HA monitors

[Gabriele Monaco <gmonaco@redhat.com>]

On Mon, 2026-05-18 at 13:54 +0200, Gabriele Monaco wrote:
> Something like:
> 
> void __ha_monitor_timer_callback() {
> 	guard(rcu)(); //this is only for waiters, let them wait more
> 
> 	if (unlikely(!da_monitor_handling_event(&ha_mon->da_mon)))
> 		return;
> 	smp_rmb();
> 	curr_state = READ_ONCE(ha_mon->da_mon.curr_state);
> 	...
> }
> 
> void da_monitor_reset() {
> 	da_monitor_reset_hook(da_mon);
> 	WRITE_ONCE(da_mon->monitoring, 0);
> 	smp_wmb();
> 	WRITE_ONCE(da_mon->curr_state, model_get_initial_state());
> }

That's obviously not going to work unless I read curr_state earlier (and use the
acquire/release helpers while at it):

void __ha_monitor_timer_callback() {
	guard(rcu)(); //this is only for waiters, let them wait more

	curr_state = smp_load_acquire(&ha_mon->da_mon.curr_state);
	if (unlikely(!da_monitor_handling_event(&ha_mon->da_mon)))
		return;
	...
}

void da_monitor_reset() {
	da_monitor_reset_hook(da_mon);
	WRITE_ONCE(da_mon->monitoring, 0);
	smp_store_release(&da_mon->curr_state, model_get_initial_state());
}