NVMe: Need to lock queue during interrupt handling

If we're sharing a queue between multiple CPUs and we cancel a sync I/O,
we must have the queue locked to avoid corrupting the stack of the thread
that submitted the I/O.  It turns out this is the same locking that's needed
for the threaded irq handler, so share that code.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

drivers/block/nvme.c

@@ -476,11 +476,6 @@ static irqreturn_t nvme_process_cq(struct nvme_queue *nvmeq)
 }
 
 static irqreturn_t nvme_irq(int irq, void *data)
-{
-	return nvme_process_cq(data);
-}
-
-static irqreturn_t nvme_irq_thread(int irq, void *data)
 {
 	irqreturn_t result;
 	struct nvme_queue *nvmeq = data;
@@ -676,7 +671,7 @@ static int queue_request_irq(struct nvme_dev *dev, struct nvme_queue *nvmeq,
 {
 	if (use_threaded_interrupts)
 		return request_threaded_irq(dev->entry[nvmeq->cq_vector].vector,
-					nvme_irq_check, nvme_irq_thread,
+					nvme_irq_check, nvme_irq,
 					IRQF_DISABLED | IRQF_SHARED,
 					name, nvmeq);
 	return request_irq(dev->entry[nvmeq->cq_vector].vector, nvme_irq,