From 74af283102b358b0da545460d0d176f473e110f6 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Fri, 14 Nov 2008 18:18:07 +0100
Subject: [PATCH] [S390] cpu topology: fix locking

cpu_coregroup_map used to grab a mutex on s390 since it was only
called from process context.
Since c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 "block: add support
for IO CPU affinity" this is not true anymore.
It now also gets called from softirq context.

To prevent possible deadlocks change this in architecture code and
use a spinlock instead of a mutex.

Cc: stable@kernel.org
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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