[PATCH v2] s390/cpum_cf: Remove superfluous SMP function call

[Anna-Maria Gleixner]

Since commit 3b9d6da67e11 ("cpu/hotplug: Fix rollback during error-out
in __cpu_disable()") it is ensured that callbacks of CPU_ONLINE and
CPU_DOWN_PREPARE are processed on the hotplugged CPU. Due to this SMP
function calls are no longer required.

Replace smp_call_function_single() with a direct call of
setup_pmc_cpu(). To keep the calling convention, interrupts are
explicitly disabled around the call.

Cc: Martin Schwidefsky <schwidef...@de.ibm.com>
Cc: Heiko Carstens <heiko.carst...@de.ibm.com>
Cc: linux-s...@vger.kernel.org
Signed-off-by: Anna-Maria Gleixner <anna-ma...@linutronix.de>
---
Changes in v2:
        - Adapt referenced commit in commit message

 arch/s390/kernel/perf_cpum_cf.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/arch/s390/kernel/perf_cpum_cf.c
+++ b/arch/s390/kernel/perf_cpum_cf.c
@@ -665,18 +665,21 @@ static struct pmu cpumf_pmu = {
 static int cpumf_pmu_notifier(struct notifier_block *self, unsigned long 
action,
                              void *hcpu)
 {
-       unsigned int cpu = (long) hcpu;
        int flags;
 
        switch (action & ~CPU_TASKS_FROZEN) {
        case CPU_ONLINE:
        case CPU_DOWN_FAILED:
                flags = PMC_INIT;
-               smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
+               local_irq_disable();
+               setup_pmc_cpu(&flags);
+               local_irq_enable();
                break;
        case CPU_DOWN_PREPARE:
                flags = PMC_RELEASE;
-               smp_call_function_single(cpu, setup_pmc_cpu, &flags, 1);
+               local_irq_disable();
+               setup_pmc_cpu(&flags);
+               local_irq_enable();
                break;
        default:
                break;