[PATCH v6 14/18] nvme-fc: Use CCR to recover controller that hits an error

[Mohamed Khalfella]

An alive nvme controller that hits an error now will move to FENCING
state instead of RESETTING state. ctrl->fencing_work attempts CCR to
terminate inflight IOs. Regardless of the success or failure of CCR
operation the controller is transitioned to RESETTING state to continue
error recovery process.

Signed-off-by: Mohamed Khalfella <mkhalfella at purestorage.com>
---
 drivers/nvme/host/fc.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 5a530aa37641..42671cca439f 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -166,6 +166,7 @@ struct nvme_fc_ctrl {
 	struct blk_mq_tag_set	admin_tag_set;
 	struct blk_mq_tag_set	tag_set;
 
+	struct work_struct	fencing_work;
 	struct work_struct	ioerr_work;
 	struct delayed_work	connect_work;
 
@@ -990,6 +991,7 @@ 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);
+static void nvme_fc_delete_association(struct nvme_fc_ctrl *ctrl);
 
 static void
 __nvme_fc_finish_ls_req(struct nvmefc_ls_req_op *lsop)
@@ -1870,6 +1872,30 @@ __nvme_fc_fcpop_chk_teardowns(struct nvme_fc_ctrl *ctrl,
 	}
 }
 
+static void nvme_fc_fencing_work(struct work_struct *work)
+{
+	struct nvme_fc_ctrl *fc_ctrl =
+			container_of(work, struct nvme_fc_ctrl, fencing_work);
+	struct nvme_ctrl *ctrl = &fc_ctrl->ctrl;
+	unsigned long rem;
+
+	/*
+	 * Tear the association down now so the LLDD can finish unregistering
+	 * the remoteport/localport while the fencing this controller.
+	 */
+	nvme_stop_keep_alive(ctrl);
+	cancel_work_sync(&ctrl->async_event_work);
+	nvme_fc_delete_association(fc_ctrl);
+
+	rem = nvme_fence_ctrl(ctrl);
+	if (rem)
+		dev_info(ctrl->device, "CCR failed, starting error recovery\n");
+
+	nvme_change_ctrl_state(ctrl, NVME_CTRL_FENCED);
+	if (nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING))
+		queue_work(nvme_reset_wq, &fc_ctrl->ioerr_work);
+}
+
 static void
 nvme_fc_ctrl_ioerr_work(struct work_struct *work)
 {
@@ -1950,6 +1976,14 @@ nvme_fc_start_ioerr_recovery(struct nvme_fc_ctrl *ctrl, char *errmsg)
 		return;
 	}
 
+	if (nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_FENCING)) {
+		dev_warn(ctrl->ctrl.device,
+			 "NVME-FC{%d}: starting controller fencing %s\n",
+			 ctrl->cnum, errmsg);
+		queue_work(nvme_wq, &ctrl->fencing_work);
+		return;
+	}
+
 	if (nvme_change_ctrl_state(&ctrl->ctrl, NVME_CTRL_RESETTING)) {
 		dev_warn(ctrl->ctrl.device, "NVME-FC{%d}: starting error recovery %s\n",
 			 ctrl->cnum, errmsg);
@@ -2463,6 +2497,12 @@ nvme_fc_ctrl_get(struct nvme_fc_ctrl *ctrl)
 	return kref_get_unless_zero(&ctrl->ref);
 }
 
+static void
+nvme_fc_stop_ctrl(struct nvme_ctrl *nctrl)
+{
+	flush_work(&to_fc_ctrl(nctrl)->fencing_work);
+}
+
 /*
  * All accesses from nvme core layer done - can now free the
  * controller. Called after last nvme_put_ctrl() call
@@ -3428,6 +3468,7 @@ static const struct nvme_ctrl_ops nvme_fc_ctrl_ops = {
 	.submit_async_event	= nvme_fc_submit_async_event,
 	.delete_ctrl		= nvme_fc_delete_ctrl,
 	.get_address		= nvmf_get_address,
+	.stop_ctrl		= nvme_fc_stop_ctrl,
 	.get_virt_boundary	= nvmf_get_virt_boundary,
 };
 
@@ -3547,6 +3588,7 @@ nvme_fc_alloc_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_WORK(&ctrl->fencing_work, nvme_fc_fencing_work);
 	INIT_WORK(&ctrl->ioerr_work, nvme_fc_ctrl_ioerr_work);
 	spin_lock_init(&ctrl->lock);
 
-- 
2.55.0