nvme: fix regression when disconnect a recovering ctrl

We encountered a problem that the disconnect command hangs.
After analyzing the log and stack, we found that the triggering
process is as follows:
CPU0                          CPU1
                                nvme_rdma_error_recovery_work
                                  nvme_rdma_teardown_io_queues
nvme_do_delete_ctrl                 nvme_stop_queues
  nvme_remove_namespaces
  --clear ctrl->namespaces
                                    nvme_start_queues
                                    --no ns in ctrl->namespaces
    nvme_ns_remove                  return(because ctrl is deleting)
      blk_freeze_queue
        blk_mq_freeze_queue_wait
        --wait for ns to unquiesce to clean infligt IO, hang forever

This problem was not found in older kernels because we will flush
err work in nvme_stop_ctrl before nvme_remove_namespaces.It does not
seem to be modified for functional reasons, the patch can be revert
to solve the problem.

Revert commit 794a4cb3d2f7 ("nvme: remove the .stop_ctrl callout")

Signed-off-by: Ruozhu Li <liruozhu@huawei.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 009c2cf3..7a9e6ff 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -2193,9 +2193,6 @@ static void nvme_tcp_error_recovery_work(struct work_struct *work)
 
 static void nvme_tcp_teardown_ctrl(struct nvme_ctrl *ctrl, bool shutdown)
 {
-	cancel_work_sync(&to_tcp_ctrl(ctrl)->err_work);
-	cancel_delayed_work_sync(&to_tcp_ctrl(ctrl)->connect_work);
-
 	nvme_tcp_teardown_io_queues(ctrl, shutdown);
 	nvme_stop_admin_queue(ctrl);
 	if (shutdown)
@@ -2235,6 +2232,12 @@ static void nvme_reset_ctrl_work(struct work_struct *work)
 	nvme_tcp_reconnect_or_remove(ctrl);
 }
 
+static void nvme_tcp_stop_ctrl(struct nvme_ctrl *ctrl)
+{
+	cancel_work_sync(&to_tcp_ctrl(ctrl)->err_work);
+	cancel_delayed_work_sync(&to_tcp_ctrl(ctrl)->connect_work);
+}
+
 static void nvme_tcp_free_ctrl(struct nvme_ctrl *nctrl)
 {
 	struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl);
@@ -2556,6 +2559,7 @@ static const struct nvme_ctrl_ops nvme_tcp_ctrl_ops = {
 	.submit_async_event	= nvme_tcp_submit_async_event,
 	.delete_ctrl		= nvme_tcp_delete_ctrl,
 	.get_address		= nvmf_get_address,
+	.stop_ctrl		= nvme_tcp_stop_ctrl,
 };
 
 static bool