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From: Oliver Neukum <oliver@neukum.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Tejun Heo <tj@kernel.org>,
	Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: Warn people about flush_scheduled_work()
Date: Mon, 14 Dec 2009 23:12:20 +0100	[thread overview]
Message-ID: <200912142312.20163.oliver@neukum.org> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0912141701040.2690-100000@iolanthe.rowland.org>

Am Montag, 14. Dezember 2009 23:02:51 schrieb Alan Stern:
> On Mon, 14 Dec 2009, Oliver Neukum wrote:
> 
> > Am Montag, 14. Dezember 2009 22:33:38 schrieb Alan Stern:
> > >         Consider using cancel_work_sync() or cancel_delayed_work_sync()
> > >         instead.  In most situations they will accomplish what you 
> > >         need.
> > 
> > In which respect is cancel_work_sync() fundamentally safer?
> > If the work is already running and takes a lock you are holding,
> > then what?
> 
> With cancel_work_sync() you know what locks the work item is going to
> take, since it's your work item.  With flush_scheduled_work() you have
> no idea what locks will be needed by the items on the queue.  They 
> could come from anywhere.

True, but what use is that if you don't know your call chain and the locks
it takes.

	Regards
		Oliver

  reply	other threads:[~2009-12-14 22:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-14 21:33 Alan Stern
2009-12-14 21:42 ` Oliver Neukum
2009-12-14 22:02   ` Alan Stern
2009-12-14 22:12     ` Oliver Neukum [this message]
2009-12-14 23:04       ` Alan Stern
2009-12-14 22:38 ` Tejun Heo
2009-12-14 23:14   ` Alan Stern
2009-12-14 23:25     ` Tejun Heo
2009-12-16 15:52   ` [PATCH] Warn " Alan Stern
2009-12-21  8:26     ` Tejun Heo
2010-02-12  8:47       ` Tejun Heo

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