From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Fri, 14 Nov 2008 17:18:07 +0000 (+0100)
Subject: S390: cpu topology: fix locking
X-Git-Tag: v2.6.27.7~21
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=65347ce15fb47f3aa58107be55ec00fa6f1eda22;p=pandora-kernel.git

S390: cpu topology: fix locking

commit 74af283102b358b0da545460d0d176f473e110f6 upstream.

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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

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