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Date: Tue, 19 Nov 2013 13:23:22 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: NeilBrown <neilb@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>, Dean Nelson <dcn@sgi.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
        lkml <linux-kernel@vger.kernel.org>,
        "Dr. H. Nikolaus Schaller" <hns@goldelico.com>,
        Marek Belisko <marek@goldelico.com>, Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH/RFC] wait_for_completion_timeout() considered harmful.
Message-ID: <20131119122322.GM3866@twins.programming.kicks-ass.net>
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On Tue, Nov 19, 2013 at 07:58:51PM +1100, NeilBrown wrote:
> 	/*
> 	 * TODO: Make sure that we wait at least required delay but why we
> 	 * have to extend it one tick more?
> 	 */
> 	schedule_timeout_interruptible(msecs_to_jiffies(delay) + 2);

What makes me sad is that clearly people knew stuff was broken but
somehow it never got properly fixed.

Yes, changing something like this is risky, but I prefer to fix the
implementation to the sane and documented behaviour and fix up whatever
fallout that generates. The end result is saner code in general and less
new bugs.