From mboxrd@z Thu Jan  1 00:00:00 1970
From: Greg KH <gregkh@suse.de>
Subject: Re: WARN... Device 'cpu1' does not have a release() function, it is
 broken and must be fixed. when doing 'xl vcpu-set <guest_id> 1'
Date: Thu, 26 Jan 2012 16:53:45 -0800
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To: Kay Sievers <kay.sievers@vrfy.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Linus Torvalds <torvalds@linux-foundation.org>, linux-kernel@vger.kernel.org, bp@amd64.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, lenb@kernel.org, xen-devel@lists.xensource.com
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On Fri, Jan 27, 2012 at 01:22:46AM +0100, Kay Sievers wrote:
> On Fri, Jan 27, 2012 at 01:06, Greg KH <gregkh@suse.de> wrote:
> > On Mon, Jan 23, 2012 at 01:06:01PM -0500, Konrad Rzeszutek Wilk wro=
te:
>=20
> >> Is anybody else hitting this with ACPI CPU hot-unplug? Or do I hav=
e
> >> the privilige of being the first? Oh, I hadn't done a full bisecti=
on
> >> but v3.2 does not have this.
> >
> > Kay, this is a mess.
> >
> > This cpu system device is is interconnected with the different arch=
es
> > and their cpu-specific structures. =A0Some arches have a static arr=
ay,
> > some allocate a huge structure (struct arch_cpu * NUM_CPUS), and ot=
hers
> > try to do the right thing with DECLARE_PER_CPU() but don't quite ge=
t it
> > right, making that a static array per cpu.
> >
> > To unwind all of this, is much beyond 3.3 material, as I'm sure I'l=
l get
> > it wrong, and have a bunch of non-x86-64 build problems along the w=
ay.
> >
> > Any objection to me just doing the "hack" of the empty release func=
tion
> > at the moment to get rid of this warning, and then clean it all up
> > properly for 3.4?
>=20
> No problem at all.
>=20
> It would be nice if we get all that to the usual model some day, but =
I
> can totally see that CPU devices try to deal with statically allocate=
d
> per-cpu memory. It seems fine, as long as they know what they are
> doing.
>=20
> Just silencing the driver-core warning here sounds fine to me.

Ok, I'll do that tomorrow and send a patch out and then start working o=
n
making all of this dynamic, as it really should be.

thanks,

greg k-h