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From: Tejun Heo <tj@kernel.org>
To: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: linux1394-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] firewire: sbp2: parallelize login/inquiry, reconnect, and shutdown
Date: Tue, 12 Oct 2010 15:50:27 +0200	[thread overview]
Message-ID: <4CB467A3.4010200@kernel.org> (raw)
In-Reply-To: <tkrat.1386de42b88d7218@s5r6.in-berlin.de>

Hello,

On 10/11/2010 11:27 PM, Stefan Richter wrote:
>> Hmmm... from glancing the code, there doesn't seem to anything which
>> can guarantee sbp2_release_target/reconnect() are finished before
>> sbp2_cleanup() returns, so the code section might go away with code
>> still running.  It seems like the right thing to do here would be
>> using alloc_workqueue(KBUILD_MODNAME, WQ_NON_REENTRANT, 0).  Am I
>> missing something?
> 
> There are indeed situations where the last module reference was already
> put down before the work is run for the last time.  Thanks for the hint.
> 
> What is preferable, an own workqueue instance whose destroy_workqueue()
> lets sbp2_cleanup wait for unfinished work, or module ref-counting like
> below?

The best would be flushing the specific works but that isn't possible
when works are used to do the final put.  I would go for using a
separate workqueue.  With cmwq, each workqueue is much cheaper than
before anyway.

Thanks.

-- 
tejun

  parent reply	other threads:[~2010-10-12 13:50 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-10 14:55 [PATCH] firewire: core: use non-reentrant workqueue where necessary Stefan Richter
2010-10-10 14:57 ` [PATCH] firewire: sbp2: parallelize login/inquiry, reconnect, and shutdown Stefan Richter
2010-10-11 13:43   ` Tejun Heo
2010-10-11 21:27     ` Stefan Richter
2010-10-11 21:39       ` Stefan Richter
2010-10-12 13:55         ` Tejun Heo
2010-10-12 16:15           ` Stefan Richter
2010-10-12 16:46             ` Tejun Heo
2010-10-12 13:50       ` Tejun Heo [this message]
2010-10-12 21:39   ` [PATCH unfinished update] " Stefan Richter
2010-10-12 22:25     ` Stefan Richter
2010-10-12 23:09       ` Stefan Richter
2010-10-13  9:45         ` Tejun Heo
2010-10-11 13:29 ` [PATCH] firewire: core: use non-reentrant workqueue where necessary Tejun Heo
2010-10-11 19:05   ` Stefan Richter
2010-10-12 21:29 ` [PATCH update] firewire: core: use non-reentrant workqueue with rescuer Stefan Richter
2010-10-13  9:47   ` Tejun Heo

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