[PATCH 5/6] nvem: tcp: move start freeze into nvme_tcp_configure_io_queues

[Sagi Grimberg]

Hey Ming, a few comments,

1. s/nvem/nvme/g
2. prefix is "nvme-tcp: "
3. Can you please phrase the patch title as a bug fix?

On 7/10/23 18:35, Ming Lei wrote:
> Move start_freeze into nvme_tcp_configure_io_queues(), and there is
> at least two benefits:
> 
> 1) freeze and unfreeze are done in pair
> 
> 2) IO during error recovery can be failfast quickly because nvme fabrics
> unquiesces queues after teardown.
> 
> One side-effect is that !mpath request may timeout during connecting
> because of queue topo change, but that looks not one big deal:
> 
> 1) same problem exists with current code base
> 
> 2) compared with !mpath, mpath use case is dominant

4. I think we need a "Fixes: " tag for the commit that added
the freeze functionality. IIRC it is:
2875b0aecabe ("nvme-tcp: fix controller reset hang during traffic")

Similar comments on patch 6/6.

> 
> Signed-off-by: Ming Lei <ming.lei at redhat.com>
> ---
>   drivers/nvme/host/tcp.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index e68bf21af348..798bfc29bc88 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -1868,6 +1868,7 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
>   		goto out_cleanup_connect_q;
>   
>   	if (!new) {
> +		nvme_start_freeze(ctrl);
>   		nvme_unquiesce_io_queues(ctrl);
>   		if (!nvme_wait_freeze_timeout(ctrl, NVME_IO_TIMEOUT)) {
>   			/*
> @@ -1876,6 +1877,7 @@ static int nvme_tcp_configure_io_queues(struct nvme_ctrl *ctrl, bool new)
>   			 * to be safe.
>   			 */
>   			ret = -ENODEV;
> +			nvme_unfreeze(ctrl);
>   			goto out_wait_freeze_timed_out;
>   		}
>   		blk_mq_update_nr_hw_queues(ctrl->tagset,
> @@ -1976,7 +1978,6 @@ static void nvme_tcp_teardown_io_queues(struct nvme_ctrl *ctrl)
>   	if (ctrl->queue_count <= 1)
>   		return;
>   	nvme_quiesce_admin_queue(ctrl);
> -	nvme_start_freeze(ctrl);
>   	nvme_quiesce_io_queues(ctrl);
>   	nvme_sync_io_queues(ctrl);
>   	nvme_tcp_stop_io_queues(ctrl);

Can you please separate patches 1,5,6 to a separate series as these are
bug fixes that should go to stable.