tree 587c8156338a9af7451985f7cb5c4c7ca466d8cb
parent 5edb56491d4812c42175980759da53388e5d86f5
author Christian Borntraeger <borntraeger@de.ibm.com> 1465816496 +0200
committer Martin Schwidefsky <schwidefsky@de.ibm.com> 1465826289 +0200

KVM: s390/mm: Fix CMMA reset during reboot

commit 1e133ab296f ("s390/mm: split arch/s390/mm/pgtable.c") factored
out the page table handling code from __gmap_zap and  __s390_reset_cmma
into ptep_zap_unused and added a simple flag that tells which one of the
function (reset or not) is to be made. This also changed the behaviour,
as it also zaps unused page table entries on reset.
Turns out that this is wrong as s390_reset_cmma uses the page walker,
which DOES NOT take the ptl lock.

The most simple fix is to not do the zapping part on reset (which uses
the walker)

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 1e133ab296f ("s390/mm: split arch/s390/mm/pgtable.c")
Cc: stable@vger.kernel.org # 4.6+
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>