Re: [RFC PATCH v4 12/27] nvme-tcp-offload: Add controller level error recovery implementation

On 5/1/21 7:29 PM, Hannes Reinecke wrote:

On 4/29/21 9:09 PM, Shai Malin wrote:

quoted

From: Arie Gershberg <redacted>

In this patch, we implement controller level error handling and recovery.
Upon an error discovered by the ULP or reset controller initiated by the
nvme-core (using reset_ctrl workqueue), the ULP will initiate a controller
recovery which includes teardown and re-connect of all queues.

Acked-by: Igor Russkikh <redacted>
Signed-off-by: Arie Gershberg <redacted>
Signed-off-by: Prabhakar Kushwaha <redacted>
Signed-off-by: Omkar Kulkarni <redacted>
Signed-off-by: Michal Kalderon <mkalderon@marvell.com>
Signed-off-by: Ariel Elior <redacted>
Signed-off-by: Shai Malin <redacted>
---
  drivers/nvme/host/tcp-offload.c | 138 +++++++++++++++++++++++++++++++-
  drivers/nvme/host/tcp-offload.h |   1 +
  2 files changed, 137 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/tcp-offload.c b/drivers/nvme/host/tcp-offload.c
index 59e1955e02ec..9082b11c133f 100644
--- a/drivers/nvme/host/tcp-offload.c
+++ b/drivers/nvme/host/tcp-offload.c

@@ -74,6 +74,23 @@ void nvme_tcp_ofld_unregister_dev(struct nvme_tcp_ofld_dev *dev)
  }
  EXPORT_SYMBOL_GPL(nvme_tcp_ofld_unregister_dev);

+/**
+ * nvme_tcp_ofld_error_recovery() - NVMeTCP Offload Library error recovery.
+ * function.
+ * @nctrl:   NVMe controller instance to change to resetting.
+ *
+ * API function that change the controller state to resseting.
+ * Part of the overall controller reset sequence.
+ */
+void nvme_tcp_ofld_error_recovery(struct nvme_ctrl *nctrl)
+{
+     if (!nvme_change_ctrl_state(nctrl, NVME_CTRL_RESETTING))
+             return;
+
+     queue_work(nvme_reset_wq, &to_tcp_ofld_ctrl(nctrl)->err_work);
+}
+EXPORT_SYMBOL_GPL(nvme_tcp_ofld_error_recovery);
+
  /**
   * nvme_tcp_ofld_report_queue_err() - NVMeTCP Offload report error event
   * callback function. Pointed to by nvme_tcp_ofld_queue->report_err.

@@ -84,7 +101,8 @@ EXPORT_SYMBOL_GPL(nvme_tcp_ofld_unregister_dev);
   */
  int nvme_tcp_ofld_report_queue_err(struct nvme_tcp_ofld_queue *queue)
  {
-     /* Placeholder - invoke error recovery flow */
+     pr_err("nvme-tcp-offload queue error\n");
+     nvme_tcp_ofld_error_recovery(&queue->ctrl->nctrl);

      return 0;
  }

@@ -296,6 +314,28 @@ nvme_tcp_ofld_configure_io_queues(struct nvme_ctrl *nctrl, bool new)
      return rc;
  }

+static void nvme_tcp_ofld_reconnect_or_remove(struct nvme_ctrl *nctrl)
+{
+     /* If we are resetting/deleting then do nothing */
+     if (nctrl->state != NVME_CTRL_CONNECTING) {
+             WARN_ON_ONCE(nctrl->state == NVME_CTRL_NEW ||
+                          nctrl->state == NVME_CTRL_LIVE);
+
+             return;
+     }
+
+     if (nvmf_should_reconnect(nctrl)) {
+             dev_info(nctrl->device, "Reconnecting in %d seconds...\n",
+                      nctrl->opts->reconnect_delay);
+             queue_delayed_work(nvme_wq,
+                                &to_tcp_ofld_ctrl(nctrl)->connect_work,
+                                nctrl->opts->reconnect_delay * HZ);
+     } else {
+             dev_info(nctrl->device, "Removing controller...\n");
+             nvme_delete_ctrl(nctrl);
+     }
+}
+
  static int nvme_tcp_ofld_setup_ctrl(struct nvme_ctrl *nctrl, bool new)
  {
      struct nvmf_ctrl_options *opts = nctrl->opts;

@@ -407,10 +447,68 @@ nvme_tcp_ofld_teardown_io_queues(struct nvme_ctrl *nctrl, bool remove)
      /* Placeholder - teardown_io_queues */
  }

+static void nvme_tcp_ofld_reconnect_ctrl_work(struct work_struct *work)
+{
+     struct nvme_tcp_ofld_ctrl *ctrl =
+                             container_of(to_delayed_work(work),
+                                          struct nvme_tcp_ofld_ctrl,
+                                          connect_work);
+     struct nvme_ctrl *nctrl = &ctrl->nctrl;
+
+     ++nctrl->nr_reconnects;
+
+     if (ctrl->dev->ops->setup_ctrl(ctrl, false))
+             goto requeue;
+
+     if (nvme_tcp_ofld_setup_ctrl(nctrl, false))
+             goto release_and_requeue;
+
+     dev_info(nctrl->device, "Successfully reconnected (%d attempt)\n",
+              nctrl->nr_reconnects);
+
+     nctrl->nr_reconnects = 0;
+
+     return;
+
+release_and_requeue:
+     ctrl->dev->ops->release_ctrl(ctrl);
+requeue:
+     dev_info(nctrl->device, "Failed reconnect attempt %d\n",
+              nctrl->nr_reconnects);
+     nvme_tcp_ofld_reconnect_or_remove(nctrl);
+}
+
+static void nvme_tcp_ofld_error_recovery_work(struct work_struct *work)
+{
+     struct nvme_tcp_ofld_ctrl *ctrl =
+             container_of(work, struct nvme_tcp_ofld_ctrl, err_work);
+     struct nvme_ctrl *nctrl = &ctrl->nctrl;
+
+     nvme_stop_keep_alive(nctrl);
+     nvme_tcp_ofld_teardown_io_queues(nctrl, false);
+     /* unquiesce to fail fast pending requests */
+     nvme_start_queues(nctrl);
+     nvme_tcp_ofld_teardown_admin_queue(nctrl, false);
+     blk_mq_unquiesce_queue(nctrl->admin_q);
+
+     if (!nvme_change_ctrl_state(nctrl, NVME_CTRL_CONNECTING)) {
+             /* state change failure is ok if we started nctrl delete */
+             WARN_ON_ONCE(nctrl->state != NVME_CTRL_DELETING &&
+                          nctrl->state != NVME_CTRL_DELETING_NOIO);
+
+             return;
+     }
+
+     nvme_tcp_ofld_reconnect_or_remove(nctrl);
+}
+
  static void
  nvme_tcp_ofld_teardown_ctrl(struct nvme_ctrl *nctrl, bool shutdown)
  {
-     /* Placeholder - err_work and connect_work */
+     struct nvme_tcp_ofld_ctrl *ctrl = to_tcp_ofld_ctrl(nctrl);
+
+     cancel_work_sync(&ctrl->err_work);
+     cancel_delayed_work_sync(&ctrl->connect_work);
      nvme_tcp_ofld_teardown_io_queues(nctrl, shutdown);
      blk_mq_quiesce_queue(nctrl->admin_q);
      if (shutdown)

@@ -425,6 +523,38 @@ static void nvme_tcp_ofld_delete_ctrl(struct nvme_ctrl *nctrl)
      nvme_tcp_ofld_teardown_ctrl(nctrl, true);
  }

+static void nvme_tcp_ofld_reset_ctrl_work(struct work_struct *work)
+{
+     struct nvme_ctrl *nctrl =
+             container_of(work, struct nvme_ctrl, reset_work);
+     struct nvme_tcp_ofld_ctrl *ctrl = to_tcp_ofld_ctrl(nctrl);
+
+     nvme_stop_ctrl(nctrl);
+     nvme_tcp_ofld_teardown_ctrl(nctrl, false);
+
+     if (!nvme_change_ctrl_state(nctrl, NVME_CTRL_CONNECTING)) {
+             /* state change failure is ok if we started ctrl delete */
+             WARN_ON_ONCE(nctrl->state != NVME_CTRL_DELETING &&
+                          nctrl->state != NVME_CTRL_DELETING_NOIO);
+
+             return;
+     }
+
+     if (ctrl->dev->ops->setup_ctrl(ctrl, false))
+             goto out_fail;
+
+     if (nvme_tcp_ofld_setup_ctrl(nctrl, false))
+             goto release_ctrl;
+
+     return;
+
+release_ctrl:
+     ctrl->dev->ops->release_ctrl(ctrl);
+out_fail:
+     ++nctrl->nr_reconnects;
+     nvme_tcp_ofld_reconnect_or_remove(nctrl);
+}
+
  static int
  nvme_tcp_ofld_init_request(struct blk_mq_tag_set *set,
                         struct request *rq,

@@ -521,6 +651,10 @@ nvme_tcp_ofld_create_ctrl(struct device *ndev, struct nvmf_ctrl_options *opts)
                           opts->nr_poll_queues + 1;
      nctrl->sqsize = opts->queue_size - 1;
      nctrl->kato = opts->kato;
+     INIT_DELAYED_WORK(&ctrl->connect_work,
+                       nvme_tcp_ofld_reconnect_ctrl_work);
+     INIT_WORK(&ctrl->err_work, nvme_tcp_ofld_error_recovery_work);
+     INIT_WORK(&nctrl->reset_work, nvme_tcp_ofld_reset_ctrl_work);
      if (!(opts->mask & NVMF_OPT_TRSVCID)) {
              opts->trsvcid =
                      kstrdup(__stringify(NVME_TCP_DISC_PORT), GFP_KERNEL);

diff --git a/drivers/nvme/host/tcp-offload.h b/drivers/nvme/host/tcp-offload.h
index 9fd270240eaa..b23b1d7ea6fa 100644
--- a/drivers/nvme/host/tcp-offload.h
+++ b/drivers/nvme/host/tcp-offload.h

@@ -204,3 +204,4 @@ struct nvme_tcp_ofld_ops {
  /* Exported functions for lower vendor specific offload drivers */
  int nvme_tcp_ofld_register_dev(struct nvme_tcp_ofld_dev *dev);
  void nvme_tcp_ofld_unregister_dev(struct nvme_tcp_ofld_dev *dev);
+void nvme_tcp_ofld_error_recovery(struct nvme_ctrl *nctrl);

Reviewed-by: Hannes Reinecke <hare@suse.de>

Thanks.

Cheers,

Hannes
--
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
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