Re: [PATCH v2 12/14] nvme-fc: Decouple error recovery from controller reset

Hannes Reinecke
2026-02-03T05:40:38Z

On 1/30/26 23:34, Mohamed Khalfella wrote:
> nvme_fc_error_recovery() called from nvme_fc_timeout() while controller
> in CONNECTING state results in deadlock reported in link below. Update
> nvme_fc_timeout() to schedule error recovery to avoid the deadlock.
>
> Previous to this change if controller was LIVE error recovery resets
> the controller and this does not match nvme-tcp and nvme-rdma. Decouple
> error recovery from controller reset to match other fabric transports.
>
> Link: https://lore.kernel.org/all/20250529214928.2112990-1-mkhalfella@purestorage.com/
> Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
> ---
> drivers/nvme/host/fc.c | 94 ++++++++++++++++++------------------------
> 1 file changed, 41 insertions(+), 53 deletions(-)
>
> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
> index 6948de3f438a..f8f6071b78ed 100644
> --- a/drivers/nvme/host/fc.c
> +++ b/drivers/nvme/host/fc.c
> @@ -227,6 +227,8 @@ static DEFINE_IDA(nvme_fc_ctrl_cnt);
> static struct device *fc_udev_device;
>
> static void nvme_fc_complete_rq(struct request *rq);
> +static void nvme_fc_start_ioerr_recovery(struct nvme_fc_ctrl *ctrl,
> + char *errmsg);
>
> /* *********************** FC-NVME Port Management ************************ */
>
> @@ -788,7 +790,7 @@ nvme_fc_ctrl_connectivity_loss(struct nvme_fc_ctrl *ctrl)
> "Reconnect", ctrl->cnum);
>
> set_bit(ASSOC_FAILED, &ctrl->flags);
> - nvme_reset_ctrl(&ctrl->ctrl);
> + nvme_fc_start_ioerr_recovery(ctrl, "Connectivity Loss");
> }
>
> /**
> @@ -985,7 +987,7 @@ fc_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
> static void nvme_fc_ctrl_put(struct nvme_fc_ctrl *);
> static int nvme_fc_ctrl_get(struct nvme_fc_ctrl *);
>
> -static void nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl, char *errmsg);
> +static void nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl);
>
> static void
> __nvme_fc_finish_ls_req(struct nvmefc_ls_req_op *lsop)
> @@ -1567,9 +1569,8 @@ nvme_fc_ls_disconnect_assoc(struct nvmefc_ls_rcv_op *lsop)
> * for the association have been ABTS'd by
> * nvme_fc_delete_association().
> */
> -
> - /* fail the association */
> - nvme_fc_error_recovery(ctrl, "Disconnect Association LS received");
> + nvme_fc_start_ioerr_recovery(ctrl,
> + "Disconnect Association LS received");
>
> /* release the reference taken by nvme_fc_match_disconn_ls() */
> nvme_fc_ctrl_put(ctrl);
> @@ -1871,7 +1872,7 @@ nvme_fc_ctrl_ioerr_work(struct work_struct *work)
> struct nvme_fc_ctrl *ctrl =
> container_of(work, struct nvme_fc_ctrl, ioerr_work);
>
> - nvme_fc_error_recovery(ctrl, "transport detected io error");
> + nvme_fc_error_recovery(ctrl);
> }
>
> /*
> @@ -1892,6 +1893,17 @@ char *nvme_fc_io_getuuid(struct nvmefc_fcp_req *req)
> }
> EXPORT_SYMBOL_GPL(nvme_fc_io_getuuid);
>
> +static void nvme_fc_start_ioerr_recovery(struct nvme_fc_ctrl *ctrl,
> + char *errmsg)
> +{
> + if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING))
> + return;
> +
> + dev_warn(ctrl->ctrl.device, "NVME-FC{%d}: starting error recovery %s\n",
> + ctrl->cnum, errmsg);
> + queue_work(nvme_reset_wq, &ctrl->ioerr_work);
> +}
> +
> static void
> nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
> {
> @@ -2049,9 +2061,8 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
> nvme_fc_complete_rq(rq);
>
> check_error:
> - if (terminate_assoc &&
> - nvme_ctrl_state(&ctrl->ctrl) != NVME_CTRL_RESETTING)
> - queue_work(nvme_reset_wq, &ctrl->ioerr_work);
> + if (terminate_assoc)
> + nvme_fc_start_ioerr_recovery(ctrl, "io error");
> }
>
> static int
> @@ -2495,39 +2506,6 @@ __nvme_fc_abort_outstanding_ios(struct nvme_fc_ctrl *ctrl, bool start_queues)
> nvme_unquiesce_admin_queue(&ctrl->ctrl);
> }
>
> -static void
> -nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl, char *errmsg)
> -{
> - enum nvme_ctrl_state state = nvme_ctrl_state(&ctrl->ctrl);
> -
> - /*
> - * if an error (io timeout, etc) while (re)connecting, the remote
> - * port requested terminating of the association (disconnect_ls)
> - * or an error (timeout or abort) occurred on an io while creating
> - * the controller. Abort any ios on the association and let the
> - * create_association error path resolve things.
> - */
> - if (state == NVME_CTRL_CONNECTING) {
> - __nvme_fc_abort_outstanding_ios(ctrl, true);
> - dev_warn(ctrl->ctrl.device,
> - "NVME-FC{%d}: transport error during (re)connect\n",
> - ctrl->cnum);
> - return;
> - }
> -
> - /* Otherwise, only proceed if in LIVE state - e.g. on first error */
> - if (state != NVME_CTRL_LIVE)
> - return;
> -
> - dev_warn(ctrl->ctrl.device,
> - "NVME-FC{%d}: transport association event: %s\n",
> - ctrl->cnum, errmsg);
> - dev_warn(ctrl->ctrl.device,
> - "NVME-FC{%d}: resetting controller\n", ctrl->cnum);
> -
> - nvme_reset_ctrl(&ctrl->ctrl);
> -}
> -
> static enum blk_eh_timer_return nvme_fc_timeout(struct request *rq)
> {
> struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);
> @@ -2536,24 +2514,14 @@ static enum blk_eh_timer_return nvme_fc_timeout(struct request *rq)
> struct nvme_fc_cmd_iu *cmdiu = &op->cmd_iu;
> struct nvme_command *sqe = &cmdiu->sqe;
>
> - /*
> - * Attempt to abort the offending command. Command completion
> - * will detect the aborted io and will fail the connection.
> - */
> dev_info(ctrl->ctrl.device,
> "NVME-FC{%d.%d}: io timeout: opcode %d fctype %d (%s) w10/11: "
> "x%08x/x%08x\n",
> ctrl->cnum, qnum, sqe->common.opcode, sqe->fabrics.fctype,
> nvme_fabrics_opcode_str(qnum, sqe),
> sqe->common.cdw10, sqe->common.cdw11);
> - if (__nvme_fc_abort_op(ctrl, op))
> - nvme_fc_error_recovery(ctrl, "io timeout abort failed");
>
> - /*
> - * the io abort has been initiated. Have the reset timer
> - * restarted and the abort completion will complete the io
> - * shortly. Avoids a synchronous wait while the abort finishes.
> - */
> + nvme_fc_start_ioerr_recovery(ctrl, "io timeout");
> return BLK_EH_RESET_TIMER;
> }
>
> @@ -3352,6 +3320,26 @@ nvme_fc_reset_ctrl_work(struct work_struct *work)
> }
> }
>
> +static void
> +nvme_fc_error_recovery(struct nvme_fc_ctrl *ctrl)
> +{
> + nvme_stop_keep_alive(&ctrl->ctrl);
> + nvme_stop_ctrl(&ctrl->ctrl);
> +
> + /* will block while waiting for io to terminate */
> + nvme_fc_delete_association(ctrl);
> +
> + /* Do not reconnect if controller is being deleted */
> + if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_CONNECTING))
> + return;
> +
> + if (ctrl->rport->remoteport.port_state == FC_OBJSTATE_ONLINE) {
> + queue_delayed_work(nvme_wq, &ctrl->connect_work, 0);
> + return;
> + }
> +
> + nvme_fc_reconnect_or_delete(ctrl, -ENOTCONN);
> +}
>
> static const struct nvme_ctrl_ops nvme_fc_ctrl_ops = {
> .name = "fc",

I really don't get it. Why do you need to do additional steps here, when
all you do is split an existing function in half?

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich