Schedule affinity_notify work while migrating IRQs during hot plug

From: Sodagudi Prasad
Date: Tue Feb 21 2017 - 15:59:25 EST

Hi Thomas,

Currently irq_set_affinity() is called to migrate irqs from migrate_one_irq()
during cpu hot plug and clients which are interested to know the irq affinity change
not getting notified

take_cpu_down () --> __cpu_disable() --> irq_migrate_all_off_this_cpu();

irq_set_affinity() is changing the IRQ affinity at chip level
but it is not notifying the affinity_notify work.

How about below change, so that clients drivers gets notified about irq affinity changes?
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -207,6 +207,7 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
cpumask_copy(desc->irq_common_data.affinity, mask);
+ schedule_work(&desc->affinity_notify->work);
ret = 0;

With this change, notifications of IRQ affinity gets executed and notified
to client drivers.

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