Get rid of the potential problems with atomic operations.

According to upcoming atomic_ops.txt by David Miller and Anton Blanchard
some archs may reoder atomic operations with nonatomic, since
the former are always visible but the latter are not, this can lead
to unpredicted behaviour.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>