nvme-rdma: fix possible hang when failing to set io queues

We only setup io queues for nvme controllers, and it makes absolutely no
sense to allow a controller (re)connect without any I/O queues.  If we
happen to fail setting the queue count for any reason, we should not allow
this to be a successful reconnect as I/O has no chance in going through.
Instead just fail and schedule another reconnect.
Reported-by: NChao Leng <lengchao@huawei.com>
Fixes: 71102307 ("nvme-rdma: add a NVMe over Fabrics RDMA host driver")
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChao Leng <lengchao@huawei.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

drivers/nvme/host/rdma.c

@@ -736,8 +736,11 @@ static int nvme_rdma_alloc_io_queues(struct nvme_rdma_ctrl *ctrl)
 		return ret;
 
 	ctrl->ctrl.queue_count = nr_io_queues + 1;
-	if (ctrl->ctrl.queue_count < 2)
-		return 0;
+	if (ctrl->ctrl.queue_count < 2) {
+		dev_err(ctrl->ctrl.device,
+			"unable to set any I/O queues\n");
+		return -ENOMEM;
+	}
 
 	dev_info(ctrl->ctrl.device,
 		"creating %d I/O queues.\n", nr_io_queues);