[PATCH v3 21/21] nvme-fc: Extend FENCING state per TP4129 on CCR failure

[Mohamed Khalfella]

If CCR operations fail and CQT is supported, we must defer the retry of
inflight requests per TP4129. Update ctrl->fencing_work to schedule
ctrl->fenced_work, effectively extending the FENCING state. This delay
ensures that inflight requests are held until it is safe for them to be
retired.

Signed-off-by: Mohamed Khalfella <mkhalfella at purestorage.com>
---
 drivers/nvme/host/fc.c | 39 +++++++++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index eac3a7ccaa5c..81088a4ce298 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -167,6 +167,7 @@ struct nvme_fc_ctrl {
 	struct blk_mq_tag_set	tag_set;
 
 	struct work_struct	fencing_work;
+	struct delayed_work	fenced_work;
 	struct work_struct	ioerr_work;
 	struct delayed_work	connect_work;
 
@@ -1878,6 +1879,18 @@ __nvme_fc_fcpop_chk_teardowns(struct nvme_fc_ctrl *ctrl,
 	return ret;
 }
 
+static void nvme_fc_fenced_work(struct work_struct *work)
+{
+	struct nvme_fc_ctrl *fc_ctrl = container_of(to_delayed_work(work),
+					struct nvme_fc_ctrl, fenced_work);
+	struct nvme_ctrl *ctrl = &fc_ctrl->ctrl;
+
+	dev_info(ctrl->device, "Time-based recovery finished\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_fencing_work(struct work_struct *work)
 {
 	struct nvme_fc_ctrl *fc_ctrl =
@@ -1886,16 +1899,33 @@ static void nvme_fc_fencing_work(struct work_struct *work)
 	unsigned long rem;
 
 	rem = nvme_fence_ctrl(ctrl);
-	if (rem) {
+	if (!rem)
+		goto done;
+
+	if (!ctrl->cqt) {
 		dev_info(ctrl->device,
-			 "CCR failed, skipping time-based recovery\n");
+			 "CCR failed, CQT not supported, skip time-based recovery\n");
+		goto done;
 	}
 
+	dev_info(ctrl->device,
+		 "CCR failed, switch to time-based recovery, timeout = %ums\n",
+		 jiffies_to_msecs(rem));
+	queue_delayed_work(nvme_wq, &fc_ctrl->fenced_work, rem);
+	return;
+
+done:
 	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_flush_fencing_works(struct nvme_fc_ctrl *ctrl)
+{
+	flush_work(&ctrl->fencing_work);
+	flush_delayed_work(&ctrl->fenced_work);
+}
+
 static void
 nvme_fc_ctrl_ioerr_work(struct work_struct *work)
 {
@@ -1917,7 +1947,7 @@ nvme_fc_ctrl_ioerr_work(struct work_struct *work)
 		return;
 	}
 
-	flush_work(&ctrl->fencing_work);
+	nvme_fc_flush_fencing_works(ctrl);
 	nvme_fc_error_recovery(ctrl);
 }
 
@@ -3396,7 +3426,7 @@ nvme_fc_reset_ctrl_work(struct work_struct *work)
 	struct nvme_fc_ctrl *ctrl =
 		container_of(work, struct nvme_fc_ctrl, ctrl.reset_work);
 
-	flush_work(&ctrl->fencing_work);
+	nvme_fc_flush_fencing_works(ctrl);
 	nvme_stop_ctrl(&ctrl->ctrl);
 
 	/* will block will waiting for io to terminate */
@@ -3573,6 +3603,7 @@ 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_DELAYED_WORK(&ctrl->fenced_work, nvme_fc_fenced_work);
 	INIT_WORK(&ctrl->ioerr_work, nvme_fc_ctrl_ioerr_work);
 	spin_lock_init(&ctrl->lock);
 
-- 
2.52.0