From: Tatsuya Sasaki <tatsuya6.sasaki@kioxia.com>
Date: Wed, 1 Sep 2021 08:23:42 +0000
Subject: nvme: update keep alive interval when kato is modified
Patch-mainline: v5.15-rc1
Git-commit: b58da2d270dbcc67db73f15028774d27c85e16d7
References: bsc#1190569

Currently the connection between host and NVMe-oF target gets
disconnected by keep-alive timeout when a user connects to a target
with a relatively large kato value and then sets the smaller kato
with a set features command (e.g. connects with 60 seconds kato value
and then sets 10 seconds kato value).

The cause is that keep alive command interval on the host, which is
defined as unsigned int kato in nvme_ctrl structure, does not follow
the kato value changes.

This patch updates the keep alive interval in the following steps when
the kato is modified by a set features command: stops the keep alive
work queue, then sets the kato as new timer value and re-start the queue.

Signed-off-by: Tatsuya Sasaki <tatsuya6.sasaki@kioxia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/core.c |   42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -116,6 +116,8 @@ static struct class *nvme_ns_chr_class;
 static void nvme_put_subsystem(struct nvme_subsystem *subsys);
 static void nvme_remove_invalid_namespaces(struct nvme_ctrl *ctrl,
 					   unsigned nsid);
+static void nvme_update_keep_alive(struct nvme_ctrl *ctrl,
+				   struct nvme_command *cmd);
 
 /*
  * Prepare a queue for teardown.
@@ -1153,7 +1155,8 @@ static u32 nvme_passthru_start(struct nv
 	return effects;
 }
 
-static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects)
+static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects,
+			      struct nvme_command *cmd, int status)
 {
 	if (effects & NVME_CMD_EFFECTS_CSE_MASK) {
 		nvme_unfreeze(ctrl);
@@ -1168,6 +1171,26 @@ static void nvme_passthru_end(struct nvm
 		nvme_queue_scan(ctrl);
 		flush_work(&ctrl->scan_work);
 	}
+
+	switch (cmd->common.opcode) {
+	case nvme_admin_set_features:
+		switch (le32_to_cpu(cmd->common.cdw10) & 0xFF) {
+		case NVME_FEAT_KATO:
+			/*
+			 * Keep alive commands interval on the host should be
+			 * updated when KATO is modified by Set Features
+			 * commands.
+			 */
+			if (!status)
+				nvme_update_keep_alive(ctrl, cmd);
+			break;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
 }
 
 int nvme_execute_passthru_rq(struct request *rq)
@@ -1182,7 +1205,7 @@ int nvme_execute_passthru_rq(struct requ
 	effects = nvme_passthru_start(ctrl, ns, cmd->common.opcode);
 	ret = nvme_execute_rq(disk, rq, false);
 	if (effects) /* nothing to be done for zero cmd effects */
-		nvme_passthru_end(ctrl, effects);
+		nvme_passthru_end(ctrl, effects, cmd, ret);
 
 	return ret;
 }
@@ -1270,6 +1293,21 @@ void nvme_stop_keep_alive(struct nvme_ct
 }
 EXPORT_SYMBOL_GPL(nvme_stop_keep_alive);
 
+static void nvme_update_keep_alive(struct nvme_ctrl *ctrl,
+				   struct nvme_command *cmd)
+{
+	unsigned int new_kato =
+		DIV_ROUND_UP(le32_to_cpu(cmd->common.cdw11), 1000);
+
+	dev_info(ctrl->device,
+		 "keep alive interval updated from %u ms to %u ms\n",
+		 ctrl->kato * 1000 / 2, new_kato * 1000 / 2);
+
+	nvme_stop_keep_alive(ctrl);
+	ctrl->kato = new_kato;
+	nvme_start_keep_alive(ctrl);
+}
+
 /*
  * In NVMe 1.0 the CNS field was just a binary controller or namespace
  * flag, thus sending any new CNS opcodes has a big chance of not working.