rds: make v3.1 as compat version

Mark RDSv3.1 as compat version and add v4.1 version macro's.
Subsequent patches enable TOS(Type of Service) feature which is
tied with v4.1 for RDMA transport.
Reviewed-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
[yanjun.zhu@oracle.com: Adapted original patch with ipv6 changes]
Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com>

net/rds/connection.c

@@ -139,6 +139,7 @@ static void __rds_conn_path_init(struct rds_connection *conn,
 	atomic_set(&cp->cp_state, RDS_CONN_DOWN);
 	cp->cp_send_gen = 0;
 	cp->cp_reconnect_jiffies = 0;
+	cp->cp_conn->c_proposed_version = RDS_PROTOCOL_VERSION;
 	INIT_DELAYED_WORK(&cp->cp_send_w, rds_send_worker);
 	INIT_DELAYED_WORK(&cp->cp_recv_w, rds_recv_worker);
 	INIT_DELAYED_WORK(&cp->cp_conn_w, rds_connect_worker);

net/rds/ib_cm.c

@@ -133,23 +133,24 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even
 		rds_ib_set_flow_control(conn, be32_to_cpu(credit));
 	}
 
-	if (conn->c_version < RDS_PROTOCOL(3, 1)) {
-		pr_notice("RDS/IB: Connection <%pI6c,%pI6c> version %u.%u no longer supported\n",
-			  &conn->c_laddr, &conn->c_faddr,
-			  RDS_PROTOCOL_MAJOR(conn->c_version),
-			  RDS_PROTOCOL_MINOR(conn->c_version));
-		set_bit(RDS_DESTROY_PENDING, &conn->c_path[0].cp_flags);
-		rds_conn_destroy(conn);
-		return;
-	} else {
-		pr_notice("RDS/IB: %s conn connected <%pI6c,%pI6c> version %u.%u%s\n",
-			  ic->i_active_side ? "Active" : "Passive",
-			  &conn->c_laddr, &conn->c_faddr,
-			  RDS_PROTOCOL_MAJOR(conn->c_version),
-			  RDS_PROTOCOL_MINOR(conn->c_version),
-			  ic->i_flowctl ? ", flow control" : "");
+	if (conn->c_version < RDS_PROTOCOL_VERSION) {
+		if (conn->c_version != RDS_PROTOCOL_COMPAT_VERSION) {
+			pr_notice("RDS/IB: Connection <%pI6c,%pI6c> version %u.%u no longer supported\n",
+				  &conn->c_laddr, &conn->c_faddr,
+				  RDS_PROTOCOL_MAJOR(conn->c_version),
+				  RDS_PROTOCOL_MINOR(conn->c_version));
+			rds_conn_destroy(conn);
+			return;
+		}
 	}
 
+	pr_notice("RDS/IB: %s conn connected <%pI6c,%pI6c> version %u.%u%s\n",
+		  ic->i_active_side ? "Active" : "Passive",
+		  &conn->c_laddr, &conn->c_faddr,
+		  RDS_PROTOCOL_MAJOR(conn->c_version),
+		  RDS_PROTOCOL_MINOR(conn->c_version),
+		  ic->i_flowctl ? ", flow control" : "");
+
 	atomic_set(&ic->i_cq_quiesce, 0);
 
 	/* Init rings and fill recv. this needs to wait until protocol
@@ -184,6 +185,7 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even
 					    NULL);
 	}
 
+	conn->c_proposed_version = conn->c_version;
 	rds_connect_complete(conn);
 }
 
@@ -667,6 +669,9 @@ static u32 rds_ib_protocol_compatible(struct rdma_cm_event *event, bool isv6)
 		version = RDS_PROTOCOL_3_0;
 		while ((common >>= 1) != 0)
 			version++;
+	} else if (RDS_PROTOCOL_COMPAT_VERSION ==
+		   RDS_PROTOCOL(major, minor)) {
+		version = RDS_PROTOCOL_COMPAT_VERSION;
 	} else {
 		if (isv6)
 			printk_ratelimited(KERN_NOTICE "RDS: Connection from %pI6c using incompatible protocol version %u.%u\n",
@@ -861,7 +866,7 @@ int rds_ib_cm_initiate_connect(struct rdma_cm_id *cm_id, bool isv6)
 
 	/* If the peer doesn't do protocol negotiation, we must
 	 * default to RDSv3.0 */
-	rds_ib_set_protocol(conn, RDS_PROTOCOL_3_0);
+	rds_ib_set_protocol(conn, RDS_PROTOCOL_VERSION);
 	ic->i_flowctl = rds_ib_sysctl_flow_control;	/* advertise flow control */
 
 	ret = rds_ib_setup_qp(conn);
@@ -870,7 +875,8 @@ int rds_ib_cm_initiate_connect(struct rdma_cm_id *cm_id, bool isv6)
 		goto out;
 	}
 
-	rds_ib_cm_fill_conn_param(conn, &conn_param, &dp, RDS_PROTOCOL_VERSION,
+	rds_ib_cm_fill_conn_param(conn, &conn_param, &dp,
+				  conn->c_proposed_version,
 				  UINT_MAX, UINT_MAX, isv6);
 	ret = rdma_connect(cm_id, &conn_param);
 	if (ret)

net/rds/rds.h

@@ -19,10 +19,13 @@
  */
 #define RDS_PROTOCOL_3_0	0x0300
 #define RDS_PROTOCOL_3_1	0x0301
+#define RDS_PROTOCOL_4_0	0x0400
+#define RDS_PROTOCOL_4_1	0x0401
 #define RDS_PROTOCOL_VERSION	RDS_PROTOCOL_3_1
 #define RDS_PROTOCOL_MAJOR(v)	((v) >> 8)
 #define RDS_PROTOCOL_MINOR(v)	((v) & 255)
 #define RDS_PROTOCOL(maj, min)	(((maj) << 8) | min)
+#define RDS_PROTOCOL_COMPAT_VERSION	RDS_PROTOCOL_3_1
 
 /* The following ports, 16385, 18634, 18635, are registered with IANA as
  * the ports to be used for RDS over TCP and UDP.  Currently, only RDS over
@@ -151,6 +154,7 @@ struct rds_connection {
 	struct rds_cong_map	*c_fcong;
 
 	/* Protocol version */
+	unsigned int		c_proposed_version;
 	unsigned int		c_version;
 	possible_net_t		c_net;
 

net/rds/threads.c

@@ -93,6 +93,7 @@ void rds_connect_path_complete(struct rds_conn_path *cp, int curr)
 		queue_delayed_work(rds_wq, &cp->cp_recv_w, 0);
 	}
 	rcu_read_unlock();
+	cp->cp_conn->c_proposed_version = RDS_PROTOCOL_VERSION;
 }
 EXPORT_SYMBOL_GPL(rds_connect_path_complete);