From: Alan Stern <stern@rowland.harvard.edu>
To: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hugh@veritas.com>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Oliver Neukum <oneukum@suse.de>,
Maneesh Soni <maneesh@in.ibm.com>, <gregkh@suse.de>,
Richard Purdie <rpurdie@rpsys.net>,
James Bottomley <James.Bottomley@SteelEye.com>,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: 2.6.21-rc suspend regression: sysfs deadlock
Date: Thu, 15 Mar 2007 10:27:19 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.0703150953420.13086-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <20070315112725.7eadb7b7@gondolin.boeblingen.de.ibm.com>
On Thu, 15 Mar 2007, Cornelia Huck wrote:
> > > The naming seems a bit unintuitive, but I don't have a good
> > > alternative idea. Perhaps sysfs_work_struct, sysfs_delayed_work()?
> >
> > sysfs_work_struct is too generic; other parts of sysfs might also want to
> > use workqueues for different purposes.
>
> > I don't like calling it "delayed"-anything, because the operations aren't
> > necessarily delayed! On an SMP system they might even execute before the
> > sysfs_access_in_other_task() call returns. (Although the two examples we
> > have so far can't do that because of lock contention.)
>
> Sure. But then you shouldn't refer to "delay" in the comments for the
> functions as well :)
Fair enough. One use of "delay" is in a comment you wrote; I'll change it
as well.
> > The major feature added here is that the work takes place in a different
> > task's context, not that it is delayed. Hence the choice of names.
>
> Hm. Perhaps device_schedule_access()?
On Thu, 15 Mar 2007, Hugh Dickins wrote:
> It's really none of my business, I'm merely the reporter the
> deadlock being fixed, and I don't know my way around sysfs at all ...
>
> ... but I have to say I share your discomfort with Alan's
> "sysfs_access_in_other_task" naming, it sounded very weird to me.
>
> Quite apart from this mysterious "other task", I don't understand
> "access" either.
>
> Perhaps "defer" would best capture the idea of another-task and
> maybe-delay? sysfs_defer_work(), struct sysfs_deferred_work?
On Thu, 15 Mar 2007, Oliver Neukum wrote:
> But we do not wish to defer or delay anything.
> How about: sysfs_action_from_neutral_context
On Thu, 15 Mar 2007, Dmitry Torokhov wrote:
> How about sysfs_schedule_work? That is what it does - schedules a work
> on a sysfs object and everyone here knows what schedule_work() does.
On Thu, 15 Mar 2007, Hugh Dickins wrote:
> I'm ashamed to have suggested anything else: certainly gets my vote.
Personally I don't understand what was wrong with my name. What's weird
or unintuitive about doing something in a different task's context?
Dmitry's suggestion is slightly inappropriate because the function doesn't
take a workstruct as an argument and it isn't itself a workqueue callback.
Would people be happier with sysfs_schedule_callback() and
device_schedule_callback()? At least the functions do take a callback
pointer as an argument, even though they aren't callbacks themselves.
Alan Stern
next prev parent reply other threads:[~2007-03-15 14:27 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-08 13:05 refcounting drivers' data structures used in sysfs buffers Oliver Neukum
2007-03-08 16:02 ` Alan Stern
2007-03-09 0:45 ` Oliver Neukum
2007-03-09 16:32 ` Alan Stern
2007-03-09 16:44 ` Oliver Neukum
2007-03-09 17:02 ` Dmitry Torokhov
2007-03-09 17:18 ` Oliver Neukum
2007-03-09 17:34 ` Dmitry Torokhov
2007-03-09 19:32 ` Alan Stern
2007-03-09 20:05 ` Oliver Neukum
2007-03-09 20:27 ` Alan Stern
2007-03-09 20:39 ` Oliver Neukum
2007-03-09 20:08 ` Alan Stern
2007-03-09 20:48 ` Oliver Neukum
2007-03-10 19:19 ` Alan Stern
2007-03-12 8:54 ` Oliver Neukum
2007-03-12 14:57 ` Alan Stern
2007-03-12 15:23 ` Oliver Neukum
2007-03-12 15:42 ` Dmitry Torokhov
2007-03-12 15:59 ` Oliver Neukum
2007-03-12 16:21 ` Alan Stern
2007-03-12 18:25 ` Oliver Neukum
2007-03-12 19:31 ` Alan Stern
2007-03-12 19:49 ` Oliver Neukum
2007-03-12 20:03 ` Alan Stern
2007-03-12 20:15 ` Oliver Neukum
2007-03-12 20:31 ` Dmitry Torokhov
2007-03-12 20:45 ` Alan Stern
2007-03-12 21:31 ` Richard Purdie
2007-03-13 15:00 ` 2.6.21-rc suspend regression: sysfs deadlock Alan Stern
2007-03-13 18:42 ` Cornelia Huck
2007-03-13 21:20 ` Linus Torvalds
2007-03-14 16:12 ` Alan Stern
2007-03-14 18:43 ` Cornelia Huck
2007-03-14 19:23 ` Alan Stern
2007-03-15 10:27 ` Cornelia Huck
2007-03-15 12:31 ` Hugh Dickins
2007-03-15 13:02 ` Oliver Neukum
2007-03-15 13:22 ` Dmitry Torokhov
2007-03-15 13:59 ` Hugh Dickins
2007-03-15 14:27 ` Alan Stern [this message]
2007-03-15 15:32 ` Cornelia Huck
2007-03-15 16:29 ` Hugh Dickins
2007-03-15 16:51 ` Linus Torvalds
2007-03-15 19:50 ` [PATCH] sysfs and driver core: add callback helper, used by SCSI and S390 Alan Stern
2007-03-15 19:51 ` [PATCH] sysfs: reinstate exclusion between method calls and attribute unregistration Alan Stern
2007-03-13 19:00 ` 2.6.21-rc suspend regression: sysfs deadlock Hugh Dickins
2007-03-13 20:09 ` Alan Stern
2007-03-13 20:55 ` Hugh Dickins
2007-03-13 21:08 ` Dmitry Torokhov
2007-03-13 21:20 ` Alan Stern
-- strict thread matches above, loose matches on Subject: below --
2007-03-10 20:44 Alan Stern
2007-03-06 19:20 Hugh Dickins
2007-03-06 20:16 ` Oliver Neukum
2007-03-07 1:56 ` Linus Torvalds
2007-03-07 14:38 ` Oliver Neukum
2007-03-07 15:56 ` Dmitry Torokhov
2007-03-07 16:52 ` Linus Torvalds
2007-03-07 16:59 ` Oliver Neukum
2007-03-07 18:02 ` Linus Torvalds
2007-03-07 18:16 ` Oliver Neukum
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