nvmet: Disable keep-alive timer when kato is cleared to 0h

Based on nvme spec, when keep alive timeout is set to zero
the keep-alive timer should be disabled.

Signed-off-by: Amit Engel <amit.engel@dell.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/target/core.c

@@ -397,6 +397,9 @@ static void nvmet_keep_alive_timer(struct work_struct *work)
 
 static void nvmet_start_keep_alive_timer(struct nvmet_ctrl *ctrl)
 {
+	if (unlikely(ctrl->kato == 0))
+		return;
+
 	pr_debug("ctrl %d start keep-alive timer for %d secs\n",
 		ctrl->cntlid, ctrl->kato);
 
@@ -406,6 +409,9 @@ static void nvmet_start_keep_alive_timer(struct nvmet_ctrl *ctrl)
 
 static void nvmet_stop_keep_alive_timer(struct nvmet_ctrl *ctrl)
 {
+	if (unlikely(ctrl->kato == 0))
+		return;
+
 	pr_debug("ctrl %d stop keep-alive\n", ctrl->cntlid);
 
 	cancel_delayed_work_sync(&ctrl->ka_work);