nvme: don't poll the CQ from the kthread

There is no reason to do unconditional polling of CQs per the NVMe
spec.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 21b0be480fa56611c36dab97c97ca03dd3b0dba5..10839f76179c9ae00c72424b6f968a9ce08a1d9e 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1156,9 +1156,6 @@ static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev, int qid,
        nvmeq->qid = qid;
        nvmeq->cq_vector = -1;
        dev->queues[qid] = nvmeq;
-
-       /* make sure queue descriptor is set before queue count, for kthread */
-       mb();
        dev->queue_count++;
 
        return nvmeq;
@@ -1345,7 +1342,6 @@ static int nvme_kthread(void *data)
                set_current_state(TASK_INTERRUPTIBLE);
                spin_lock(&dev_list_lock);
                list_for_each_entry_safe(dev, next, &dev_list, node) {
-                       int i;
                        u32 csts = readl(dev->bar + NVME_REG_CSTS);
 
                        /*
@@ -1363,14 +1359,6 @@ static int nvme_kthread(void *data)
                                }
                                continue;
                        }
-                       for (i = 0; i < dev->queue_count; i++) {
-                               struct nvme_queue *nvmeq = dev->queues[i];
-                               if (!nvmeq)
-                                       continue;
-                               spin_lock_irq(&nvmeq->q_lock);
-                               nvme_process_cq(nvmeq);
-                               spin_unlock_irq(&nvmeq->q_lock);
-                       }
                }
                spin_unlock(&dev_list_lock);
                schedule_timeout(round_jiffies_relative(HZ));