padata: Use the online cpumask as the default

We use the active cpumask to determine the superset of cpus
to use for parallelization. However, the active cpumask is
for internal usage of the scheduler and therefore not the
appropriate cpumask for these purposes. So use the online
cpumask instead.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

kernel/padata.c

@@ -356,13 +356,13 @@ static int padata_setup_cpumasks(struct parallel_data *pd,
 	if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
 		return -ENOMEM;
 
-	cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_active_mask);
+	cpumask_and(pd->cpumask.pcpu, pcpumask, cpu_online_mask);
 	if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL)) {
 		free_cpumask_var(pd->cpumask.cbcpu);
 		return -ENOMEM;
 	}
 
-	cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_active_mask);
+	cpumask_and(pd->cpumask.cbcpu, cbcpumask, cpu_online_mask);
 	return 0;
 }
 
@@ -566,7 +566,7 @@ EXPORT_SYMBOL(padata_unregister_cpumask_notifier);
 static bool padata_validate_cpumask(struct padata_instance *pinst,
 				    const struct cpumask *cpumask)
 {
-	if (!cpumask_intersects(cpumask, cpu_active_mask)) {
+	if (!cpumask_intersects(cpumask, cpu_online_mask)) {
 		pinst->flags |= PADATA_INVALID;
 		return false;
 	}
@@ -680,7 +680,7 @@ static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
 {
 	struct parallel_data *pd;
 
-	if (cpumask_test_cpu(cpu, cpu_active_mask)) {
+	if (cpumask_test_cpu(cpu, cpu_online_mask)) {
 		pd = padata_alloc_pd(pinst, pinst->cpumask.pcpu,
 				     pinst->cpumask.cbcpu);
 		if (!pd)