Re: [GIT PULL] libata fixes for v3.13-rc5

From: Rafael J. Wysocki
Date: Wed Dec 25 2013 - 16:59:40 EST


On Wednesday, December 25, 2013 09:57:09 AM Alan Stern wrote:
> On Wed, 25 Dec 2013, Rafael J. Wysocki wrote:
>
> > On Tuesday, December 24, 2013 04:55:46 PM Alan Stern wrote:
> > > On Tue, 24 Dec 2013, Tejun Heo wrote:
> > >
> > > > Hello, Linus.
> > > >
> > > > libata fixes for v3.13-rc5. There's one interseting commit - "libata,
> > > > freezer: avoid block device removal while system is frozen". It's an
> > > > ugly hack working around a deadlock condition between driver core
> > > > resume and block layer device removal paths through freezer which was
> > > > made more reproducible by writeback being converted to workqueue some
> > > > releases ago. The bug has nothing to do with libata but it's just an
> > > > workaround which is easy to backport. After discussion, Rafael and I
> > > > seem to agree that we don't really need kernel freezables - both
> > > > kthread and workqueue. There are few specific workqueues which
> > > > constitute PM operations and require freezing, which will be converted
> > > > to use workqueue_set_max_active() instead. All other kernel freezer
> > > > uses are planned to be removed, followed by the removal of kthread and
> > > > workqueue freezer support, hopefully.
> > >
> > > Wait a minute. I don't recall anybody mentioning this earlier. What
> > > about khubd? There isn't any plan to remove _it_.
> >
> > No, but we are going to replace the freezing of kernel stuff with something
> > more direct, like "suspend" routines called from the system suspend code path
> > and causing things to stop (and corresponding "resume" starting them again).
>
> Is this discussed in more detail somewhere (an email thread, for
> example)?

This one, more or less: https://lkml.org/lkml/2013/12/13/402

Thanks,
Rafael

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