RDS/IB: Disallow connections less than RDS 3.1

RDS 3.0 connections (in OFED 1.3 and earlier) put the
header at the end. 3.1 connections put it at the head.
The code has significant added complexity in order to
handle both configurations. In OFED 1.6 we can
drop this and simplify the code by only supporting
"header-first" configuration.

This patch checks the protocol version, and if prior
to 3.1, does not complete the connection.

Signed-off-by: Andy Grover <andy.grover@oracle.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
index 3134336ca17d..8b0c743c0900 100644
--- a/net/rds/ib_cm.c
+++ b/net/rds/ib_cm.c
@@ -111,11 +111,21 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even
                 }
         }
 
-        printk(KERN_NOTICE "RDS/IB: connected to %pI4 version %u.%u%s\n",
-                        &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(3,1)) {
+                printk(KERN_NOTICE "RDS/IB: Connection to %pI4 version %u.%u failed,"
+                       " no longer supported\n",
+                       &conn->c_faddr,
+                       RDS_PROTOCOL_MAJOR(conn->c_version),
+                       RDS_PROTOCOL_MINOR(conn->c_version));
+                rds_conn_destroy(conn);
+                return;
+        } else {
+                printk(KERN_NOTICE "RDS/IB: connected to %pI4 version %u.%u%s\n",
+                       &conn->c_faddr,
+                       RDS_PROTOCOL_MAJOR(conn->c_version),
+                       RDS_PROTOCOL_MINOR(conn->c_version),
+                       ic->i_flowctl ? ", flow control" : "");
+        }
 
         /*
          * Init rings and fill recv. this needs to wait until protocol negotiation