[PATCH v3 19/21] nvme-tcp: 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/tcp.c | 39 +++++++++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 229cfdffd848..054e8a350d75 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -194,6 +194,7 @@ struct nvme_tcp_ctrl {
 	struct nvme_ctrl	ctrl;
 
 	struct work_struct	fencing_work;
+	struct delayed_work	fenced_work;
 	struct work_struct	err_work;
 	struct delayed_work	connect_work;
 	struct nvme_tcp_request async_req;
@@ -2477,6 +2478,18 @@ static void nvme_tcp_reconnect_ctrl_work(struct work_struct *work)
 	nvme_tcp_reconnect_or_remove(ctrl, ret);
 }
 
+static void nvme_tcp_fenced_work(struct work_struct *work)
+{
+	struct nvme_tcp_ctrl *tcp_ctrl = container_of(to_delayed_work(work),
+					 struct nvme_tcp_ctrl, fenced_work);
+	struct nvme_ctrl *ctrl = &tcp_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, &tcp_ctrl->err_work);
+}
+
 static void nvme_tcp_fencing_work(struct work_struct *work)
 {
 	struct nvme_tcp_ctrl *tcp_ctrl = container_of(work,
@@ -2485,23 +2498,40 @@ static void nvme_tcp_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, &tcp_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, &tcp_ctrl->err_work);
 }
 
+static void nvme_tcp_flush_fencing_works(struct nvme_ctrl *ctrl)
+{
+	flush_work(&to_tcp_ctrl(ctrl)->fencing_work);
+	flush_delayed_work(&to_tcp_ctrl(ctrl)->fenced_work);
+}
+
 static void nvme_tcp_error_recovery_work(struct work_struct *work)
 {
 	struct nvme_tcp_ctrl *tcp_ctrl = container_of(work,
 				struct nvme_tcp_ctrl, err_work);
 	struct nvme_ctrl *ctrl = &tcp_ctrl->ctrl;
 
-	flush_work(&to_tcp_ctrl(ctrl)->fencing_work);
+	nvme_tcp_flush_fencing_works(ctrl);
 	if (nvme_tcp_key_revoke_needed(ctrl))
 		nvme_auth_revoke_tls_key(ctrl);
 	nvme_stop_keep_alive(ctrl);
@@ -2544,7 +2574,7 @@ static void nvme_reset_ctrl_work(struct work_struct *work)
 		container_of(work, struct nvme_ctrl, reset_work);
 	int ret;
 
-	flush_work(&to_tcp_ctrl(ctrl)->fencing_work);
+	nvme_tcp_flush_fencing_works(ctrl);
 	if (nvme_tcp_key_revoke_needed(ctrl))
 		nvme_auth_revoke_tls_key(ctrl);
 	nvme_stop_ctrl(ctrl);
@@ -2934,6 +2964,7 @@ static struct nvme_tcp_ctrl *nvme_tcp_alloc_ctrl(struct device *dev,
 	INIT_DELAYED_WORK(&ctrl->connect_work,
 			nvme_tcp_reconnect_ctrl_work);
 	INIT_WORK(&ctrl->fencing_work, nvme_tcp_fencing_work);
+	INIT_DELAYED_WORK(&ctrl->fenced_work, nvme_tcp_fenced_work);
 	INIT_WORK(&ctrl->err_work, nvme_tcp_error_recovery_work);
 	INIT_WORK(&ctrl->ctrl.reset_work, nvme_reset_ctrl_work);
 
-- 
2.52.0