A controller that supports traffic based keep-alive can restart the keep
alive timer even when no keep-alive was not received in the kato period
as long as other admin or I/O commands were received.  For each command
set ctrl->cmd_seen to true, and when keep-alive timer expires, if any
commands were seen, resched ka_work instead of escalating to a fatal
error.
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 
        /* XXX: figure out what to do about RTD3R/RTD3 */
        id->oaes = cpu_to_le32(NVMET_AEN_CFG_OPTIONAL);
-       id->ctratt = cpu_to_le32(NVME_CTRL_ATTR_HID_128_BIT);
+       id->ctratt = cpu_to_le32(NVME_CTRL_ATTR_HID_128_BIT |
+               NVME_CTRL_ATTR_TBKAS);
 
        id->oacs = 0;
 
 
 {
        struct nvmet_ctrl *ctrl = container_of(to_delayed_work(work),
                        struct nvmet_ctrl, ka_work);
+       bool cmd_seen = ctrl->cmd_seen;
+
+       ctrl->cmd_seen = false;
+       if (cmd_seen) {
+               pr_debug("ctrl %d reschedule traffic based keep-alive timer\n",
+                       ctrl->cntlid);
+               schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
+               return;
+       }
 
        pr_err("ctrl %d keep-alive timer (%d seconds) expired!\n",
                ctrl->cntlid, ctrl->kato);
                goto fail;
        }
 
+       if (sq->ctrl)
+               sq->ctrl->cmd_seen = true;
+
        return true;
 
 fail:
 
        struct nvmet_cq         **cqs;
        struct nvmet_sq         **sqs;
 
+       bool                    cmd_seen;
+
        struct mutex            lock;
        u64                     cap;
        u32                     cc;