From: Tejun Heo <tj@kernel.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Peter Zijlstra <peterz@infradead.org>,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: Lockdep false positive in sysfs
Date: Fri, 4 May 2012 09:52:32 -0700 [thread overview]
Message-ID: <20120504165232.GB24639@google.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1205031720480.1232-100000@iolanthe.rowland.org>
On Thu, May 03, 2012 at 05:30:30PM -0400, Alan Stern wrote:
> On Fri, 27 Apr 2012, Tejun Heo wrote:
>
> > > Would it be better to release just the lockdep annotation while
> > > continuing to hold the actual lock, or to really drop the lock?
> >
> > Just the lockdep annotation, I think.
>
> This is turning out to be harder than it looked.
>
> In order to release the lockdep annotation, I need the lockdep_map
> which is stored in the sysfs_dirent structure. But when the attribute
> method is called, all it is given is a pointer to the attribute itself
> (which contains the lockdep_class_key but not the lockdep_map) and a
> pointer to the corresponding kobject.
>
> Is there any reasonable way to get from the kobject and the attribute
> to the appropriate sysfs_dirent? Search through all the groups
> attached to the kobject? Restrict the new interface so that it can be
> used only by attributes at the kobject's top level (i.e., not in a
> named group)?
>
> Any suggestions?
Urgh... I can't think of anything pretty. How about just marking the
attr as "I'm special" and let sysfs code override lockdep annotation?
Thanks.
--
tejun
next prev parent reply other threads:[~2012-05-04 16:52 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-25 18:58 Lockdep false positive in sysfs Alan Stern
2012-04-25 21:59 ` Tejun Heo
2012-04-26 8:16 ` Eric W. Biederman
2012-04-26 18:14 ` Alan Stern
2012-04-26 22:17 ` Tejun Heo
2012-04-27 15:57 ` Alan Stern
2012-04-27 16:09 ` Tejun Heo
2012-05-03 21:30 ` Alan Stern
2012-05-04 16:52 ` Tejun Heo [this message]
2012-05-04 19:08 ` Alan Stern
2012-05-07 19:46 ` Tejun Heo
2012-05-07 21:51 ` Alan Stern
2012-05-07 21:55 ` Tejun Heo
2012-05-08 18:53 ` Alan Stern
2012-05-09 17:41 ` Tejun Heo
2012-05-09 17:47 ` Alan Stern
2012-05-09 17:48 ` Tejun Heo
2012-04-27 16:27 ` Eric W. Biederman
2012-04-27 18:27 ` Alan Stern
2012-04-27 20:17 ` Tejun Heo
2012-04-27 21:09 ` Eric W. Biederman
2012-04-27 21:16 ` Tejun Heo
2012-04-29 2:00 ` Alan Stern
2012-04-29 2:35 ` Eric W. Biederman
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