From 1fc4a182bdfaeeaec6f8d609676d6938b1241c2a Mon Sep 17 00:00:00 2001
From: Ben Walker <benjamin.walker@intel.com>
Date: Thu, 7 Jul 2016 16:32:26 -0700
Subject: [PATCH] nvmf: Subsystem now has a pointer to the session

There is only one controller per subsystem, so therefore
there can be 0 or 1 sessions. Change the list of sessions
to a pointer that can be NULL if no session exists.

Change-Id: I2c0d042d9cecacae93da3e806093faf0155ddd6e
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
---
 lib/nvmf/session.c   | 15 ++++++---------
 lib/nvmf/subsystem.c | 10 +++-------
 lib/nvmf/subsystem.h |  3 +--
 3 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/lib/nvmf/session.c b/lib/nvmf/session.c
index 7c61462ee..f89eb0f3c 100644
--- a/lib/nvmf/session.c
+++ b/lib/nvmf/session.c
@@ -183,9 +183,6 @@ nvmf_create_session(const char *subnqn)
 		return NULL;
 	}
 
-	subsystem->num_sessions++;
-	TAILQ_INSERT_HEAD(&subsystem->sessions, session, entries);
-
 	TAILQ_INIT(&session->connections);
 	session->num_connections = 0;
 	session->subsys = subsystem;
@@ -193,20 +190,20 @@ nvmf_create_session(const char *subnqn)
 
 	nvmf_init_session_properties(session);
 
+	subsystem->session = session;
+
 	return session;
 }
 
 static void
 nvmf_delete_session(struct nvmf_session	*session)
 {
-	session->subsys->num_sessions--;
-	TAILQ_REMOVE(&session->subsys->sessions, session, entries);
-
+	session->subsys->session = NULL;
 	free(session);
 }
 
 static struct nvmf_session *
-nvmf_find_session_by_id(const char *subnqn, uint16_t cntl_id)
+nvmf_find_session(const char *subnqn)
 {
 	struct spdk_nvmf_subsystem *subsystem;
 
@@ -215,7 +212,7 @@ nvmf_find_session_by_id(const char *subnqn, uint16_t cntl_id)
 		return NULL;
 	}
 
-	return TAILQ_FIRST(&subsystem->sessions);
+	return subsystem->session;
 }
 
 struct nvmf_session *
@@ -243,7 +240,7 @@ nvmf_connect(struct spdk_nvmf_conn *conn,
 		}
 	} else {
 		SPDK_TRACELOG(SPDK_TRACE_NVMF, "CONNECT I/O Queue for controller id %d\n", connect_data->cntlid);
-		session = nvmf_find_session_by_id(connect_data->subnqn, connect_data->cntlid);
+		session = nvmf_find_session(connect_data->subnqn);
 		if (session == NULL) {
 			SPDK_ERRLOG("Unknown controller id %d\n", connect_data->cntlid);
 			response->status.sc = SPDK_NVMF_FABRIC_SC_RESTART_DISCOVERY;
diff --git a/lib/nvmf/subsystem.c b/lib/nvmf/subsystem.c
index a0adeb1ed..fe5f6353f 100644
--- a/lib/nvmf/subsystem.c
+++ b/lib/nvmf/subsystem.c
@@ -85,7 +85,6 @@ nvmf_create_subsystem(int num, char *name, enum spdk_nvmf_subsystem_types sub_ty
 	subsystem->num = num;
 	subsystem->subtype = sub_type;
 	snprintf(subsystem->subnqn, sizeof(subsystem->subnqn), "%s", name);
-	TAILQ_INIT(&subsystem->sessions);
 
 	TAILQ_INSERT_HEAD(&g_subsystems, subsystem, entries);
 
@@ -95,18 +94,15 @@ nvmf_create_subsystem(int num, char *name, enum spdk_nvmf_subsystem_types sub_ty
 int
 nvmf_delete_subsystem(struct spdk_nvmf_subsystem *subsystem)
 {
-	struct nvmf_session *sess, *tsess;
-
 	if (subsystem == NULL) {
 		SPDK_TRACELOG(SPDK_TRACE_NVMF,
 			      "nvmf_delete_subsystem: there is no subsystem\n");
 		return 0;
 	}
 
-	TAILQ_FOREACH_SAFE(sess, &subsystem->sessions, entries, tsess) {
-		subsystem->num_sessions--;
-		TAILQ_REMOVE(&subsystem->sessions, sess, entries);
-		free(sess);
+	if (subsystem->session) {
+		/* TODO: Call a session function that closes all connections */
+		free(subsystem->session);
 	}
 
 	TAILQ_REMOVE(&g_subsystems, subsystem, entries);
diff --git a/lib/nvmf/subsystem.h b/lib/nvmf/subsystem.h
index 7820b0738..95042c5ad 100644
--- a/lib/nvmf/subsystem.h
+++ b/lib/nvmf/subsystem.h
@@ -50,9 +50,8 @@ struct spdk_nvmf_conn;
 struct spdk_nvmf_subsystem {
 	uint16_t num;
 	char subnqn[MAX_NQN_SIZE];
-	int num_sessions;
 	enum spdk_nvmf_subsystem_types subtype;
-	TAILQ_HEAD(session_q, nvmf_session) sessions;
+	struct nvmf_session *session;
 	struct spdk_nvme_ctrlr *ctrlr;
 	struct spdk_nvme_qpair *io_qpair;