s390/vdso: use correct memory barrier

By definition smp_wmb only orders writes against writes. (Finish all
previous writes, and do not start any future write). To protect the
vdso init code against early reads on other CPUs, let's use a full
smp_mb at the end of vdso init. As right now smp_wmb is implemented
as full serialization, this needs no stable backport, but this change
will be necessary if we reimplement smp_wmb.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Christian Borntraeger 2015-09-11 16:23:06 +02:00 committed by Martin Schwidefsky
parent e0af21c56d
commit 33b5881d11

View File

@ -299,7 +299,7 @@ static int __init vdso_init(void)
get_page(virt_to_page(vdso_data));
smp_wmb();
smp_mb();
return 0;
}