[net-next][PATCH 1/5] rds: make v3.1 as compat version

[Santosh Shilimkar <santosh.shilimkar@oracle.com>]

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 |  1 +
 net/rds/ib_cm.c      | 40 +++++++++++++++++++++++-----------------
 net/rds/rds.h        |  4 ++++
 net/rds/threads.c    |  1 +
 4 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/net/rds/connection.c b/net/rds/connection.c
index 3bd2f4a..1ab14b6 100644
--- a/net/rds/connection.c
+++ b/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);
diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index bfbb31f..0eeae09 100644
--- a/net/rds/ib_cm.c
+++ b/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)
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 4ffe100..660023f 100644
--- a/net/rds/rds.h
+++ b/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;
 
diff --git a/net/rds/threads.c b/net/rds/threads.c
index e64f9e4..32dc50f 100644
--- a/net/rds/threads.c
+++ b/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);
 
-- 
1.9.1