NVMe: reap completion entries when deleting queue

Make sure that there are no unprocesssed entries on a completion
queue before deleting it, and check for validity of the CQ
door bell before writing completions to it.

This fixes problems with doing a sysfs reset of the device while
it's handling IO.

Tested-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 394fd1631cd0147c0ddd18da7814830f44a7fdd9..930042fa2d694d34b76217729edd4e09e8d22344 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -968,7 +968,8 @@ static void __nvme_process_cq(struct nvme_queue *nvmeq, unsigned int *tag)
        if (head == nvmeq->cq_head && phase == nvmeq->cq_phase)
                return;
 
-       writel(head, nvmeq->q_db + nvmeq->dev->db_stride);
+       if (likely(nvmeq->cq_vector >= 0))
+               writel(head, nvmeq->q_db + nvmeq->dev->db_stride);
        nvmeq->cq_head = head;
        nvmeq->cq_phase = phase;
 
@@ -2787,6 +2788,10 @@ static void nvme_del_queue_end(struct nvme_queue *nvmeq)
 {
        struct nvme_delq_ctx *dq = nvmeq->cmdinfo.ctx;
        nvme_put_dq(dq);
+
+       spin_lock_irq(&nvmeq->q_lock);
+       nvme_process_cq(nvmeq);
+       spin_unlock_irq(&nvmeq->q_lock);
 }
 
 static int adapter_async_del_queue(struct nvme_queue *nvmeq, u8 opcode,