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Date: Wed, 18 Apr 2007 11:35:06 +0200
From: Cornelia Huck <cornelia.huck@de.ibm.com>
To: Tejun Heo <htejun@gmail.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
       Alan Stern <stern@rowland.harvard.edu>, Greg K-H <greg@kroah.com>,
       Rusty Russell <rusty@rustcorp.com.au>, dmitry.torokhov@gmail.com
Subject: Re: [PATCH RFD] alternative kobject release wait mechanism
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On Wed, 18 Apr 2007 17:46:09 +0900,
Tejun Heo <htejun@gmail.com> wrote:

> It's debatable but I think things will be safer this way.  If we wait by
> default, we are forced to check that all references are dropped and will
> have a stack dump indicating which object is causing problem when
> something goes wrong, which is better than silent object leaking and/or
> jumping to non-existent address way later.

I agree that oopsing is bad. However, lingering references are not
always coding errors. What if it will just take long for a reference to
be given up? You'd have a hanging device_unregister(), with no
particular gain.

> 
> I personally think all driver interface should be made this way such
> that completion of unregister function guarantees no further access to
> the object or module.  IMHO, it's more intuitive and easier to force
> correctness.

If we really did this, we should also provide a non-waiting alternative.