[S390] topology: fix cpu masks for topology=off case

Fix cpu masks for 'topology=off' case. Folding of the scheduling domains
happen in such a way that everything belongs to the MC domain instead
of the CPU doimain.
This should fix a performance regression introduced with
eafd2b6d "[S390] topology: use default MC domain initializer" and also
makes sure we have the same behavious as if CONFIG_SCHED_MC was not
selected at all.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index a9dee9048ee5..94b06c31fc8a 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -53,8 +53,10 @@ static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
         cpumask_t mask;
 
         cpus_clear(mask);
-        if (!topology_enabled || !MACHINE_HAS_TOPOLOGY)
-                return cpu_possible_map;
+        if (!topology_enabled || !MACHINE_HAS_TOPOLOGY) {
+                cpumask_copy(&mask, cpumask_of(cpu));
+                return mask;
+        }
         while (info) {
                 if (cpu_isset(cpu, info->mask)) {
                         mask = info->mask;