[PATCH rfc v2 3/4] nvme-core: reduce io failover time

[Sagi Grimberg]

> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 2ae8caa4e25f..e3fae68f7de6 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -4548,8 +4548,13 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl)
>   
>   	down_read(&ctrl->namespaces_rwsem);
>   	list_for_each_entry(ns, &ctrl->namespaces, list)
> -		blk_mq_quiesce_queue(ns->queue);
> +		blk_mq_quiesce_queue_nowait(ns->queue);
>   	up_read(&ctrl->namespaces_rwsem);
> +	/*
> +	 * BLK_MQ_F_BLOCKING drivers should never call us
> +	 */
> +	WARN_ON_ONCE(ctrl->tagset.flags & BLK_MQ_F_BLOCKING);

Woops^2 tagset is a pointer... will resend v3 after I get some
feedback...