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Subject[PATCH v2] s390/cpum_sf: Remove superfluous SMP function call
Date
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 <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
Changes in v2:
- Adapt referenced commit in commit message

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

--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1510,7 +1510,6 @@ static void cpumf_measurement_alert(stru
static int cpumf_pmu_notifier(struct notifier_block *self,
unsigned long action, void *hcpu)
{
- unsigned int cpu = (long) hcpu;
int flags;

/* Ignore the notification if no events are scheduled on the PMU.
@@ -1523,11 +1522,15 @@ static int cpumf_pmu_notifier(struct not
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;
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