kernull NULL pointer observed on initiator side after 'nvmetcli clear' on target side

[Sagi Grimberg]

> Hi Sagi
> With this patch, the NULL pointer fixed now.
> But from below log, we can see it will continue reconnecting in 10
> seconds and cannot be stopped.
>
> [36288.963890] Broke affinity for irq 16
> [36288.983090] Broke affinity for irq 28
> [36289.003104] Broke affinity for irq 90
> [36289.020488] Broke affinity for irq 93
> [36289.036911] Broke affinity for irq 97
> [36289.053344] Broke affinity for irq 100
> [36289.070166] Broke affinity for irq 104
> [36289.088076] smpboot: CPU 1 is now offline
> [36302.371160] nvme nvme0: reconnecting in 10 seconds
> [36312.953684] blk_mq_reinit_tagset: tag is null, continue
> [36312.983267] nvme nvme0: Connect rejected: status 8 (invalid service ID).
> [36313.017290] nvme nvme0: rdma_resolve_addr wait failed (-104).
> [36313.044937] nvme nvme0: Failed reconnect attempt, requeueing...
> [36323.171983] blk_mq_reinit_tagset: tag is null, continue
> [36323.200733] nvme nvme0: Connect rejected: status 8 (invalid service ID).
> [36323.233820] nvme nvme0: rdma_resolve_addr wait failed (-104).
> [36323.261027] nvme nvme0: Failed reconnect attempt, requeueing...
> [36333.412341] blk_mq_reinit_tagset: tag is null, continue
> [36333.441346] nvme nvme0: Connect rejected: status 8 (invalid service ID).
> [36333.476139] nvme nvme0: rdma_resolve_addr wait failed (-104).
> [36333.502794] nvme nvme0: Failed reconnect attempt, requeueing...
> [36343.652755] blk_mq_reinit_tagset: tag is null, continue
> [36343.682103] nvme nvme0: Connect rejected: status 8 (invalid service ID).
> [36343.716645] nvme nvme0: rdma_resolve_addr wait failed (-104).
> [36343.743581] nvme nvme0: Failed reconnect attempt, requeueing...
> [36353.893103] blk_mq_reinit_tagset: tag is null, continue
> [36353.921041] nvme nvme0: Connect rejected: status 8 (invalid service ID).
> [36353.953541] nvme nvme0: rdma_resolve_addr wait failed (-104).
> [36353.983528] nvme nvme0: Failed reconnect attempt, requeueing...
> [36364.133544] blk_mq_reinit_tagset: tag is null, continue
> [36364.162012] nvme nvme0: Connect rejected: status 8 (invalid service ID).
> [36364.195002] nvme nvme0: rdma_resolve_addr wait failed (-104).
> [36364.221671] nvme nvme0: Failed reconnect attempt, requeueing...
>

Yep... looks like we don't take into account that we can't use all the
queues now...

Does this patch help:
--
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index 29ac8fcb8d2c..25af3f75f6f1 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -337,8 +337,6 @@ static int __nvme_rdma_init_request(struct 
nvme_rdma_ctrl *ctrl,
         struct ib_device *ibdev = dev->dev;
         int ret;

-       BUG_ON(queue_idx >= ctrl->queue_count);
-
         ret = nvme_rdma_alloc_qe(ibdev, &req->sqe, sizeof(struct 
nvme_command),
                         DMA_TO_DEVICE);
         if (ret)
@@ -647,8 +645,22 @@ static int nvme_rdma_connect_io_queues(struct 
nvme_rdma_ctrl *ctrl)

  static int nvme_rdma_init_io_queues(struct nvme_rdma_ctrl *ctrl)
  {
+       struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
+       unsigned int nr_io_queues;
         int i, ret;

+       nr_io_queues = min(opts->nr_io_queues, num_online_cpus());
+       ret = nvme_set_queue_count(&ctrl->ctrl, &nr_io_queues);
+       if (ret)
+               return ret;
+
+       ctrl->queue_count = nr_io_queues + 1;
+       if (ctrl->queue_count < 2)
+               return 0;
+
+       dev_info(ctrl->ctrl.device,
+               "creating %d I/O queues.\n", nr_io_queues);
+
         for (i = 1; i < ctrl->queue_count; i++) {
                 ret = nvme_rdma_init_queue(ctrl, i,
                                            ctrl->ctrl.opts->queue_size);
@@ -1793,20 +1805,8 @@ static const struct nvme_ctrl_ops 
nvme_rdma_ctrl_ops = {

  static int nvme_rdma_create_io_queues(struct nvme_rdma_ctrl *ctrl)
  {
-       struct nvmf_ctrl_options *opts = ctrl->ctrl.opts;
         int ret;

-       ret = nvme_set_queue_count(&ctrl->ctrl, &opts->nr_io_queues);
-       if (ret)
-               return ret;
-
-       ctrl->queue_count = opts->nr_io_queues + 1;
-       if (ctrl->queue_count < 2)
-               return 0;
-
-       dev_info(ctrl->ctrl.device,
-               "creating %d I/O queues.\n", opts->nr_io_queues);
-
--