[PATCH v5 2/2] nvme: use blk_mq_[un]quiesce_tagset

[Sagi Grimberg]

On 7/27/20 4:10 PM, Sagi Grimberg wrote:
> All controller namespaces share the same tagset, so we
> can use this interface which does the optimal operation
> for parallel quiesce based on the tagset type (e.g.
> blocking tagsets and non-blocking tagsets).
> 
> Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
> ---
>   drivers/nvme/host/core.c | 14 ++------------
>   1 file changed, 2 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 05aa568a60af..c41df20996d7 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -4557,23 +4557,13 @@ EXPORT_SYMBOL_GPL(nvme_start_freeze);
>   
>   void nvme_stop_queues(struct nvme_ctrl *ctrl)
>   {
> -	struct nvme_ns *ns;
> -
> -	down_read(&ctrl->namespaces_rwsem);
> -	list_for_each_entry(ns, &ctrl->namespaces, list)
> -		blk_mq_quiesce_queue(ns->queue);
> -	up_read(&ctrl->namespaces_rwsem);
> +	blk_mq_quiesce_tagset(ctrl->tagset);

Rrr.. this one is slightly annoying. We have the connect_q in
fabrics that we use to issue the connect command which is now
quiesced too...

If we will use this interface, we can unquiesce it right away,
but that seems kinda backwards...

--
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 05aa568a60af..70af0ff63e7f 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4557,23 +4557,15 @@ EXPORT_SYMBOL_GPL(nvme_start_freeze);

  void nvme_stop_queues(struct nvme_ctrl *ctrl)
  {
-       struct nvme_ns *ns;
-
-       down_read(&ctrl->namespaces_rwsem);
-       list_for_each_entry(ns, &ctrl->namespaces, list)
-               blk_mq_quiesce_queue(ns->queue);
-       up_read(&ctrl->namespaces_rwsem);
+       blk_mq_quiesce_tagset(ctrl->tagset);
+       if (ctrl->connect_q)
+               blk_mq_unquiesce_queue(ctrl->connect_q);
  }
  EXPORT_SYMBOL_GPL(nvme_stop_queues);
--

Thoughts?