[PATCH v0 6/6] nvme-fc: wait for connect attempt to finish

[Daniel Wagner]

The FC transport offloads the connect attempt to a workqueue. Thus
userspace is not able to wait on the result.

Thus, allow userspace to wait on the connect result by honnering the
'connect_sync' connect option.

Signed-off-by: Daniel Wagner <dwagner at suse.de>
---
 drivers/nvme/host/fc.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 7f9edab57550..5f1d0165de40 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -169,6 +169,7 @@ struct nvme_fc_ctrl {
 
 	struct work_struct	ioerr_work;
 	struct delayed_work	connect_work;
+	struct completion	connect_completion;
 
 	struct kref		ref;
 	unsigned long		flags;
@@ -803,6 +804,7 @@ nvme_fc_ctrl_connectivity_loss(struct nvme_fc_ctrl *ctrl)
 			dev_warn(ctrl->ctrl.device,
 				"NVME-FC{%d}: Couldn't schedule reset.\n",
 				ctrl->cnum);
+			complete(&ctrl->connect_completion);
 			nvme_fc_ctrl_put(ctrl);
 		}
 		break;
@@ -871,6 +873,7 @@ nvme_fc_unregister_remoteport(struct nvme_fc_remote_port *portptr)
 			dev_warn(ctrl->ctrl.device,
 				"NVME-FC{%d}: controller connectivity lost.\n",
 				ctrl->cnum);
+			complete(&ctrl->connect_completion);
 			nvme_fc_ctrl_put(ctrl);
 		} else
 			nvme_fc_ctrl_connectivity_loss(ctrl);
@@ -3308,6 +3311,7 @@ nvme_fc_reconnect_or_delete(struct nvme_fc_ctrl *ctrl, int status)
 				ctrl->cnum, min_t(int, portptr->dev_loss_tmo,
 					(ctrl->ctrl.opts->max_reconnects *
 					 ctrl->ctrl.opts->reconnect_delay)));
+		complete(&ctrl->connect_completion);
 		nvme_fc_ctrl_put(ctrl);
 	}
 }
@@ -3367,10 +3371,12 @@ nvme_fc_connect_ctrl_work(struct work_struct *work)
 	ret = nvme_fc_create_association(ctrl);
 	if (ret)
 		nvme_fc_reconnect_or_delete(ctrl, ret);
-	else
+	else {
 		dev_info(ctrl->ctrl.device,
 			"NVME-FC{%d}: controller connect complete\n",
 			ctrl->cnum);
+		complete(&ctrl->connect_completion);
+	}
 }
 
 
@@ -3477,6 +3483,7 @@ nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
 
 	INIT_WORK(&ctrl->ctrl.reset_work, nvme_fc_reset_ctrl_work);
 	INIT_DELAYED_WORK(&ctrl->connect_work, nvme_fc_connect_ctrl_work);
+	init_completion(&ctrl->connect_completion);
 	INIT_WORK(&ctrl->ioerr_work, nvme_fc_ctrl_ioerr_work);
 	spin_lock_init(&ctrl->lock);
 
@@ -3524,6 +3531,9 @@ nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
 	list_add_tail(&ctrl->ctrl_list, &rport->ctrl_list);
 	spin_unlock_irqrestore(&rport->lock, flags);
 
+	if (opts->connect_sync)
+		nvme_fc_ctrl_get(ctrl);
+
 	if (!nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING) ||
 	    !nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_CONNECTING)) {
 		dev_err(ctrl->ctrl.device,
@@ -3540,6 +3550,19 @@ nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
 
 	flush_delayed_work(&ctrl->connect_work);
 
+	if (opts->connect_sync) {
+		enum nvme_ctrl_state state;
+
+		wait_for_completion(&ctrl->connect_completion);
+		state = nvme_ctrl_state(&ctrl->ctrl);
+		nvme_fc_ctrl_put(ctrl);
+
+		if (state != NVME_CTRL_LIVE) {
+			/* Cleanup is handled by the connect state machine */
+			return ERR_PTR(-EIO);
+		}
+	}
+
 	dev_info(ctrl->ctrl.device,
 		"NVME-FC{%d}: new ctrl: NQN \"%s\", hostnqn: %s\n",
 		ctrl->cnum, nvmf_ctrl_subsysnqn(&ctrl->ctrl), opts->host->nqn);
@@ -3896,6 +3919,7 @@ nvme_fc_delete_controllers(struct nvme_fc_rport *rport)
 		dev_warn(ctrl->ctrl.device,
 			"NVME-FC{%d}: transport unloading: deleting ctrl\n",
 			ctrl->cnum);
+		complete(&ctrl->connect_completion);
 		nvme_fc_ctrl_put(ctrl);
 	}
 	spin_unlock(&rport->lock);
-- 
2.43.0