linux-kernel - Re: [PATCH 1/2] PM / wakeup: Remove timer from wakeup_source

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Date:   Mon, 11 Mar 2019 13:05:04 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        sunzhaosheng@...ilicon.com, jean.xupeng@...ilicon.com,
        yuwei3@...ilicon.com, gengyanping@...ilicon.com,
        peter.panshilin@...ilicon.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] PM / wakeup: Remove timer from wakeup_source_remove()

On Friday, March 8, 2019 10:53:11 AM CET Viresh Kumar wrote:
> wakeup_source_remove() is the counterpart of wakeup_source_add() helper
> and must undo the initializations done by wakeup_source_add(). Currently
> the timer is initialized by wakeup_source_add() but removed from
> wakeup_source_drop(), which doesn't look logically correct. Also it
> should be okay to call wakeup_source_add() right after calling
> wakeup_source_remove(), and in that case we may end up calling
> timer_setup() for a potentially scheduled timer which is surely
> incorrect.
> 
> Move the timer removal part to wakeup_source_remove() instead.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/base/power/wakeup.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index f1fee72ed970..18333962e3da 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -118,7 +118,6 @@ void wakeup_source_drop(struct wakeup_source *ws)
>  	if (!ws)
>  		return;
>  
> -	del_timer_sync(&ws->timer);
>  	__pm_relax(ws);
>  }
>  EXPORT_SYMBOL_GPL(wakeup_source_drop);
> @@ -205,6 +204,8 @@ void wakeup_source_remove(struct wakeup_source *ws)
>  	list_del_rcu(&ws->entry);
>  	raw_spin_unlock_irqrestore(&events_lock, flags);
>  	synchronize_srcu(&wakeup_srcu);
> +
> +	del_timer_sync(&ws->timer);
>  }
>  EXPORT_SYMBOL_GPL(wakeup_source_remove);
>  
> 

I've merged it with the [2/2], rewritten the subject and changelog and
queued the result as commit d856f39ac1cc ("PM / wakeup: Rework wakeup
source timer cancellation").