genirq: Adjust irq thread affinity on IRQ_SET_MASK_OK_NOCOPY return value

irq_move_masked_irq() checks the return code of
chip->irq_set_affinity() only for 0, but IRQ_SET_MASK_OK_NOCOPY is
also a valid return code, which is there to avoid a redundant copy of
the cpumask. But in case of IRQ_SET_MASK_OK_NOCOPY we not only avoid
the redundant copy, we also fail to adjust the thread affinity of an
eventually threaded interrupt handler.

Handle IRQ_SET_MASK_OK (==0) and IRQ_SET_MASK_OK_NOCOPY(==1) return
values correctly by checking the valid return values seperately.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Keping Chen <chenkeping@huawei.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1333120296-13563-2-git-send-email-jiang.liu@huawei.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/migration.c

@@ -43,12 +43,16 @@ void irq_move_masked_irq(struct irq_data *idata)
 	 * masking the irqs.
 	 */
 	if (likely(cpumask_any_and(desc->pending_mask, cpu_online_mask)
-		   < nr_cpu_ids))
-		if (!chip->irq_set_affinity(&desc->irq_data,
-					    desc->pending_mask, false)) {
+		   < nr_cpu_ids)) {
+		int ret = chip->irq_set_affinity(&desc->irq_data,
+						 desc->pending_mask, false);
+		switch (ret) {
+		case IRQ_SET_MASK_OK:
 			cpumask_copy(desc->irq_data.affinity, desc->pending_mask);
+		case IRQ_SET_MASK_OK_NOCOPY:
 			irq_set_thread_affinity(desc);
 		}
+	}
 
 	cpumask_clear(desc->pending_mask);
 }