nvme-tcp: 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.

Fixes: 3f2304f8 ("nvme-tcp: add NVMe over TCP host driver")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/tcp.c

@@ -1752,8 +1752,11 @@ static int nvme_tcp_alloc_io_queues(struct nvme_ctrl *ctrl)
 		return ret;
 
 	ctrl->queue_count = nr_io_queues + 1;
-	if (ctrl->queue_count < 2)
-		return 0;
+	if (ctrl->queue_count < 2) {
+		dev_err(ctrl->device,
+			"unable to set any I/O queues\n");
+		return -ENOMEM;
+	}
 
 	dev_info(ctrl->device,
 		"creating %d I/O queues.\n", nr_io_queues);