genirq/cpuhotplug: Do not migrated shutdown irqs

Interrupts, which are shut down are tried to be migrated as well. That's
pointless because the interrupt cannot fire and the next startup will move
it to the proper place anyway.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20170619235445.447550992@linutronix.de

kernel/irq/cpuhotplug.c

@@ -33,10 +33,15 @@ static bool migrate_one_irq(struct irq_desc *desc)
 	}
 
 	/*
-	 * If this is a per-CPU interrupt, or the affinity does not
-	 * include this CPU, then we have nothing to do.
+	 * No move required, if:
+	 * - Interrupt is per cpu
+	 * - Interrupt is not started
+	 * - Affinity mask does not include this CPU.
+	 *
+	 * Note: Do not check desc->action as this might be a chained
+	 * interrupt.
 	 */
-	if (irqd_is_per_cpu(d) ||
+	if (irqd_is_per_cpu(d) || !irqd_is_started(d) ||
 	    !cpumask_test_cpu(smp_processor_id(), affinity))
 		return false;