[RFC PATCH 07/14] nvme: Add RECOVERING nvme controller state

[Sagi Grimberg]

On 26/11/2025 4:11, Mohamed Khalfella wrote:
> Add NVME_CTRL_RECOVERING as a new controller state to be used when
> impacted controller is being recovered. A LIVE controller enters
> RECOVERING state when an IO error is encountered. While recovering
> inflight IOs will not be canceled if they timeout. These IOs will be
> canceled after recovery finishes. Also, while recovering a controller
> can not be reset or deleted. This is intentional because reset or delete
> will result in canceling inflight IOs. When recovery finishes, the
> impacted controller transitions from RECOVERING state to RESETTING state.
> Reset codepath takes care of queues teardown and inflight requests
> cancellation.

Is RECOVERING really capturing the nature of this state? Maybe RESETTLING?
or QUIESCING?

>
> Note, there is no transition from RECOVERING to RESETTING added to
> nvme_change_ctrl_state(). The reason is that user should not be allowed
> to reset or delete a controller that is being recovered.
>
> Add NVME_CTRL_RECOVERED controller flag. This flag is set on a controller
> about to schedule delayed work for time based recovery.
>
> Signed-off-by: Mohamed Khalfella <mkhalfella at purestorage.com>
> ---
>   drivers/nvme/host/core.c  | 10 ++++++++++
>   drivers/nvme/host/nvme.h  |  2 ++
>   drivers/nvme/host/sysfs.c |  1 +
>   3 files changed, 13 insertions(+)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index aa007a7b9606..f5b84bc327d3 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -574,6 +574,15 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
>   			break;
>   		}
>   		break;
> +	case NVME_CTRL_RECOVERING:
> +		switch (old_state) {
> +		case NVME_CTRL_LIVE:
> +			changed = true;
> +			fallthrough;
> +		default:
> +			break;
> +		}
> +		break;

That is a strange transition...