[PATCH 2/2] s390/cpum_sf: Fix cpu hotplug notifier transitions

[Anna-Maria Gleixner]

The cpumf_pmu_notfier() hotplug callback lacks handling of the
CPU_DOWN_FAILED case. That means, if CPU_DOWN_PREPARE failes, the PMC
of the CPU is not setup again. Furthermore the CPU_ONLINE_FROZEN case
will never be processed because of masking the switch expression with
CPU_TASKS_FROZEN.

Add handling for CPU_DOWN_FAILED transition to setup the PMC of the
CPU. Remove CPU_ONLINE_FROZEN case.

Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: linux-s390@xxxxxxxxxxxxxxx
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
---
 arch/s390/kernel/perf_cpum_sf.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1518,7 +1518,7 @@ static int cpumf_pmu_notifier(struct not
 
 	switch (action & ~CPU_TASKS_FROZEN) {
 	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
+	case CPU_DOWN_FAILED:
 		flags = PMC_INIT;
 		smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
 		break;