nvmet: allow Keep Alive for Discovery controller

Per change to specification allowing Discovery controllers to have
explicit persistent connections, remove restriction on Discovery
controllers allowing kato on connect.
Signed-off-by: Jay Sternberg <jay.e.sternberg@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/target/admin-cmd.c

@@ -726,7 +726,7 @@ static void nvmet_execute_async_event(struct nvmet_req *req)
 	schedule_work(&ctrl->async_event_work);
 }
 
-static void nvmet_execute_keep_alive(struct nvmet_req *req)
+void nvmet_execute_keep_alive(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 

drivers/nvme/target/core.c

@@ -1180,31 +1180,17 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 	ctrl->cntlid = ret;
 
 	ctrl->ops = req->ops;
-	if (ctrl->subsys->type == NVME_NQN_DISC) {
-		/* Don't accept keep-alive timeout for discovery controllers */
-		if (kato) {
-			status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
-			goto out_remove_ida;
-		}
 
-		/*
-		 * Discovery controllers use some arbitrary high value in order
-		 * to cleanup stale discovery sessions
-		 *
-		 * From the latest base diff RC:
-		 * "The Keep Alive command is not supported by
-		 * Discovery controllers. A transport may specify a
-		 * fixed Discovery controller activity timeout value
-		 * (e.g., 2 minutes).  If no commands are received
-		 * by a Discovery controller within that time
-		 * period, the controller may perform the
-		 * actions for Keep Alive Timer expiration".
-		 */
-		ctrl->kato = NVMET_DISC_KATO;
-	} else {
-		/* keep-alive timeout in seconds */
-		ctrl->kato = DIV_ROUND_UP(kato, 1000);
-	}
+	/*
+	 * Discovery controllers may use some arbitrary high value
+	 * in order to cleanup stale discovery sessions
+	 */
+	if ((ctrl->subsys->type == NVME_NQN_DISC) && !kato)
+		kato = NVMET_DISC_KATO_MS;
+
+	/* keep-alive timeout in seconds */
+	ctrl->kato = DIV_ROUND_UP(kato, 1000);
+
 	nvmet_start_keep_alive_timer(ctrl);
 
 	mutex_lock(&subsys->lock);
@@ -1215,8 +1201,6 @@ u16 nvmet_alloc_ctrl(const char *subsysnqn, const char *hostnqn,
 	*ctrlp = ctrl;
 	return 0;
 
-out_remove_ida:
-	ida_simple_remove(&cntlid_ida, ctrl->cntlid);
 out_free_sqs:
 	kfree(ctrl->sqs);
 out_free_cqs:

drivers/nvme/target/discovery.c

@@ -194,6 +194,10 @@ u16 nvmet_parse_discovery_cmd(struct nvmet_req *req)
 	}
 
 	switch (cmd->common.opcode) {
+	case nvme_admin_keep_alive:
+		req->execute = nvmet_execute_keep_alive;
+		req->data_len = 0;
+		return 0;
 	case nvme_admin_get_log_page:
 		req->data_len = nvmet_get_log_page_len(cmd);
 

drivers/nvme/target/nvmet.h

@@ -372,6 +372,8 @@ void nvmet_req_complete(struct nvmet_req *req, u16 status);
 int nvmet_req_alloc_sgl(struct nvmet_req *req);
 void nvmet_req_free_sgl(struct nvmet_req *req);
 
+void nvmet_execute_keep_alive(struct nvmet_req *req);
+
 void nvmet_cq_setup(struct nvmet_ctrl *ctrl, struct nvmet_cq *cq, u16 qid,
 		u16 size);
 void nvmet_sq_setup(struct nvmet_ctrl *ctrl, struct nvmet_sq *sq, u16 qid,
@@ -442,7 +444,7 @@ u32 nvmet_get_log_page_len(struct nvme_command *cmd);
 #define NVMET_DEFAULT_ANA_GRPID	1
 
 #define NVMET_KAS		10
-#define NVMET_DISC_KATO		120
+#define NVMET_DISC_KATO_MS		120000
 
 int __init nvmet_init_configfs(void);
 void __exit nvmet_exit_configfs(void);