linux-kernel - Re: [PATCH 2/2] kthread: Do not use TIMER

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Date:   Wed, 13 Feb 2019 13:02:51 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
        tglx@...utronix.de
Subject: Re: [PATCH 2/2] kthread: Do not use TIMER_IRQSAFE

On Tue 2019-02-12 17:25:54, Sebastian Andrzej Siewior wrote:
> The TIMER_IRQSAFE was introduced in commit
> 
>   22597dc3d97b1 ("kthread: initial support for delayed kthread work")
> 
> which modelled the delayed kthread code after workqueue's code. The
> workqueue code requires the flag TIMER_IRQSAFE for synchronisation
> purpose. This is not true for kthread's delay timer since all
> operations occur under a lock.

Great catch! The original proposal used a lockless code. We missed
that the irq safe timer was not longer needed with the spin lock.

> Remove TIMER_IRQSAFE from the timer initialisation.
> Use timer_setup() for initialisation purpose which is the official
> function.
> 
> Cc: Petr Mladek <pmladek@...e.com>
> Cc: Ingo Molnar <mingo@...nel.org>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>

Reviewed-by: Petr Mladek <pmladek@...e.com>

Best Regards,
Petr