The masked difference is what needs to be compared against 1, rather
than the difference of masked values (which can be negative).
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Acked-by: NNick Piggin <npiggin@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>