From: Cornelia Huck <cornelia.huck@de.ibm.com>
To: Greg KH <gregkh@suse.de>
Cc: Alex Chiang <achiang@hp.com>,
Vegard Nossum <vegard.nossum@gmail.com>,
Pekka Enberg <penberg@cs.helsinki.fi>,
Ingo Molnar <mingo@elte.hu>,
jbarnes@virtuousgeek.org, tj@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH, RFC] sysfs: only allow one scheduled removal callback per kobj
Date: Wed, 11 Mar 2009 18:47:29 +0100 [thread overview]
Message-ID: <20090311184729.110761e4@gondolin> (raw)
In-Reply-To: <20090311153228.GA21217@suse.de>
On Wed, 11 Mar 2009 08:32:28 -0700,
Greg KH <gregkh@suse.de> wrote:
> Why can't you use device_unregister()? Or, you could use device_del(),
> which lets you rely on the fact that the device structure is still
> around for a bit, but it will disappear from sysfs. Just don't forget
> to do the final put_device() on it to free the memory and "really"
> release it.
>
> Or am I missing something else here?
You can't unregister a device from one of its attribute callbacks, it
locks up in sysfs (removing the sysfs dir waits for all active
references to be dropped, but the reference obtained before calling
->store won't be dropped until after ->store returned...)
device_schedule_callback() was introduced to solve exactly that problem.
(For the original oops, I'd rather solve the problem by making sure the
caller doesn't trigger removal several times - should probably be less
code than the proposed patch?)
next prev parent reply other threads:[~2009-03-11 17:47 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-10 23:20 [PATCH, RFC] sysfs: only allow one scheduled removal callback per kobj Alex Chiang
2009-03-11 4:41 ` Greg KH
2009-03-11 7:03 ` Alex Chiang
2009-03-11 7:20 ` Tejun Heo
2009-03-12 0:27 ` Alex Chiang
2009-03-12 3:22 ` Greg KH
2009-03-12 22:02 ` Alex Chiang
2009-03-13 12:03 ` Cornelia Huck
2009-03-13 18:08 ` Alex Chiang
2009-03-11 15:32 ` Greg KH
2009-03-11 17:47 ` Cornelia Huck [this message]
2009-03-11 18:14 ` Alex Chiang
2009-03-11 18:19 ` Greg KH
2009-03-11 18:42 ` Alex Chiang
2009-03-12 10:25 ` Cornelia Huck
2009-03-12 21:33 ` Alex Chiang
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