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From: Tejun Heo <tj@kernel.org>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH 11/25] pm: don't use [delayed_]work_pending()
Date: Tue, 25 Dec 2012 08:44:33 -0800	[thread overview]
Message-ID: <20121225164433.GG10220@mtj.dyndns.org> (raw)
In-Reply-To: <1652427.IL3F6yol0I@vostro.rjw.lan>

Hello, Rafael.

On Sat, Dec 22, 2012 at 12:53:29PM +0100, Rafael J. Wysocki wrote:
> On Friday, December 21, 2012 05:57:01 PM Tejun Heo wrote:
> > There's no need to test whether a (delayed) work item in pending
> > before queueing, flushing or cancelling it.  Most uses are unnecessary
> > and quite a few of them are buggy.
> 
> Can you please say why they are buggy?

Usually one of the following two reasons.

* The user gets confused and fails to handle !PENDING && currently
  executing properly.

* work_pending() doesn't have any memory barrier and the caller
  assumes work_pending() is somehow properly synchronized by itself.

Thanks.

-- 
tejun

  reply	other threads:[~2012-12-25 16:44 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1356141435-17340-1-git-send-email-tj@kernel.org>
2012-12-22  1:57 ` [PATCH 11/25] pm: don't use [delayed_]work_pending() Tejun Heo
2012-12-22 11:53   ` Rafael J. Wysocki
2012-12-25 16:44     ` Tejun Heo [this message]
2012-12-22  1:57 ` [PATCH 16/25] PM / Domains: " Tejun Heo
2012-12-22 11:57   ` Rafael J. Wysocki
2012-12-25 17:03     ` Tejun Heo
2012-12-25 20:33       ` Rafael J. Wysocki
2012-12-26  1:23         ` Tejun Heo

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