ARM CCN driver fixes

Hello Arnd, Kevin, Olof,

Here are two tiny CCN driver fixes. The first bug was known for a while now, but never caused any issue, so the patch wasn't critical.

The second one removes a spurious warning that has been observed last week, thus is cc-ed to stable.

Both can wait till the next merge window, unless you're willing to push them out as late fixes in this cycle.

Cheers!

Pawel

Pawel Moll (2):
bus: arm-ccn: Handle correctly no-more-cpus case
bus: arm-ccn: Fix irq affinity setting on CPU migration

 drivers/bus/arm-ccn.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

2.1.4

When migrating events the driver picks another cpu using cpumask_any_but() function, which returns value >= nr_cpu_ids when there is none available, not a negative value as the code assumed. Fixed now.

---
 drivers/bus/arm-ccn.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 7d9879e..cc322fb 100644
@@ -1184,7 +1184,7 @@ static int arm_ccn_pmu_cpu_notifier(struct notifier_block *nb,
 		if (!cpumask_test_and_clear_cpu(cpu, &dt->cpu))
 			break;
 		target = cpumask_any_but(cpu_online_mask, cpu);
-		if (target < 0)
+		if (target >= nr_cpu_ids)
 			break;
 		perf_pmu_migrate_context(&dt->pmu, cpu, target);
 		cpumask_set_cpu(target, &dt->cpu);

2.1.4

When PMU context is migrating between CPUs, interrupt affinity is set as well. Only this should not happen when the CCN interrupt is not being used at all (the driver is using a hrtimer tick instead).

Fixed now.

---
 drivers/bus/arm-ccn.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index cc322fb..7082c72 100644
@@ -1188,7 +1188,8 @@ static int arm_ccn_pmu_cpu_notifier(struct notifier_block *nb,
 			break;
 		perf_pmu_migrate_context(&dt->pmu, cpu, target);
 		cpumask_set_cpu(target, &dt->cpu);
-		WARN_ON(irq_set_affinity(ccn->irq, &dt->cpu) != 0);
+		if (ccn->irq)
+			WARN_ON(irq_set_affinity(ccn->irq, &dt->cpu) != 0);
 	default:
 		break;
 	}

2.1.4

Applied both to fixes, thanks!

ARnd