nvmet: reset keep alive timer in controller enable

From: Max Gurtuvoy <[email protected]>

Controllers that are not yet enabled should not really enforce keep alive timeout, but we still want to track a timeout and cleanup in case a host died before it enabled us. Hence, simply reset the keep alive timer when the controller is enabled.

---
Changes from v1:
- Added some code documentation

 drivers/nvme/target/core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

index a03da764ecae..1ade6fe9b830 100644
@@ -686,6 +686,14 @@ static void nvmet_start_ctrl(struct nvmet_ctrl *ctrl)
 	}
 
 	ctrl->csts = NVME_CSTS_RDY;
+	/*
+	 * Controllers that are not yet enabled should not really
+	 * enforce keep alive timeout, but we still want to track
+	 * a timeout and cleanup in case a host died before it enabled
+	 * us. Hence, simply reset the keep alive timer when the controller
+	 * is enabled.
+	 */
+	mod_delayed_work(system_wq, &ctrl->ka_work, ctrl->kato * HZ);
 }
 
 static void nvmet_clear_ctrl(struct nvmet_ctrl *ctrl)

2.14.1

From: Max Gurtuvoy <[email protected]>

We start the keep alive timer after all the I/O queues were created, this might be too late as the controller might have start its keep alive timer when it was enabled. Hence, start it right after controller enable was completed.

We stop the keep alive in nvme_stop_ctrl as its before the disable/shutdown and its independent of the transport connectivity.

---
 drivers/nvme/host/core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

index 3ba4232d114e..8673b7816e9a 100644
@@ -1761,7 +1761,14 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
 	ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
 	if (ret)
 		return ret;
-	return nvme_wait_ready(ctrl, cap, true);
+
+	ret = nvme_wait_ready(ctrl, cap, true);
+	if (ret)
+		return ret;
+
+	nvme_start_keep_alive(ctrl);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(nvme_enable_ctrl);
 

@@ -3418,9 +3425,6 @@ EXPORT_SYMBOL_GPL(nvme_stop_ctrl);
 
 void nvme_start_ctrl(struct nvme_ctrl *ctrl)
 {
-	if (ctrl->kato)
-		nvme_start_keep_alive(ctrl);
-
 	if (ctrl->queue_count > 1) {
 		nvme_queue_scan(ctrl);
 		nvme_enable_aen(ctrl);

2.14.1

I've applied both patches to nvme-4.18.

the second one is not complete for error flows (I've mentioned it yesterday). We should re-think about my V1 suggestion to start/stop keep-alive during configure/destroy admin queue, or find another solution. I find it strange to have exported nvme_stop_keep_alive and non exported nvme_start_keep_alive.

Yea - lets hold off on patch 2

Ok. I've dropped patch 2 for now.