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From:   Thomas Gleixner <tglx@linutronix.de>
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To:     Duoming Zhou <duoming@zju.edu.cn>, linux-kernel@vger.kernel.org
Cc:     jstultz@google.com, sboyd@kernel.org, edumazet@google.com,
        Duoming Zhou <duoming@zju.edu.cn>
Subject: Re: [PATCH] timers: fix synchronization rules in comments of
 del_timer_sync
In-Reply-To: <20220701085535.17018-1-duoming@zju.edu.cn>
References: <20220701085535.17018-1-duoming@zju.edu.cn>
Date:   Mon, 08 Aug 2022 16:01:57 +0200
Message-ID: <877d3irfze.ffs@tglx>
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On Fri, Jul 01 2022 at 16:55, Duoming Zhou wrote:
> - * Synchronization rules: Callers must prevent restarting of the timer,
> - * otherwise this function is meaningless. It must not be called from
> - * interrupt contexts unless the timer is an irqsafe one. The caller must
> - * not hold locks which would prevent completion of the timer's
> - * handler. The timer's handler must not call add_timer_on(). Upon exit the
> - * timer is not queued and the handler is not running on any CPU.
> + * Synchronization rules: Callers must prevent restarting of the timer in
> + * other places except for the timer's handler, otherwise this function is
> + * meaningless. It must not be called from interrupt contexts unless the
> + * timer is an irqsafe one. The caller must not hold locks which would
> + * prevent completion of the timer's handler. The timer's handler must
> + * not call add_timer_on().

If we are making this correct: What's so special about add_timer_on()?

Thanks,

        tglx