ARM: fix a migrating irq bug when hotplug cpu

From: Yang Yingliang <[email protected]>

When cpu is disabled, all irqs will be migratged to another cpu. In some cases, a new affinity is different, it needed to be coppied to irq's affinity. But if the type of irq is LPI, it's affinity will not be coppied because of irq_set_affinity's return value. So copy the affinity, when the return value is IRQ_SET_MASK_OK_DONE.

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

index 350f188..32f2140 100644
@@ -157,10 +157,13 @@ static bool migrate_one_irq(struct irq_desc *desc)
  	}
 
  	c = irq_data_get_irq_chip(d);
-	if (!c->irq_set_affinity)
+	if (!c->irq_set_affinity) {
  		pr_debug("IRQ%u: unable to set affinity\n", d->irq);
-	else if (c->irq_set_affinity(d, affinity, false) == IRQ_SET_MASK_OK && 

ret)
- cpumask_copy(d->affinity, affinity);
+ } else {
+ int r = c->irq_set_affinity(d, affinity, false);
+ if ((r == IRQ_SET_MASK_OK || r == IRQ_SET_MASK_OK_DONE) && ret)
+ cpumask_copy(d->affinity, affinity);
+ }

return ret;
}

2.5.0