RDS: TCP: Enable multipath RDS for TCP

Use RDS probe-ping to compute how many paths may be used with
the peer, and to synchronously start the multiple paths. If mprds is
supported, hash outgoing traffic to one of multiple paths in rds_sendmsg()
when multipath RDS is supported by the transport.

CC: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 9 deletions

diff --git a/net/rds/connection.c b/net/rds/connection.c
index 19a4fee5f4dd..f5058559bb08 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -155,7 +155,7 @@ static struct rds_connection *__rds_conn_create(struct net *net,
         struct hlist_head *head = rds_conn_bucket(laddr, faddr);
         struct rds_transport *loop_trans;
         unsigned long flags;
-        int ret;
+        int ret, i;
 
         rcu_read_lock();
         conn = rds_conn_lookup(net, head, laddr, faddr, trans);
@@ -211,6 +211,12 @@ static struct rds_connection *__rds_conn_create(struct net *net,
 
         conn->c_trans = trans;
 
+        init_waitqueue_head(&conn->c_hs_waitq);
+        for (i = 0; i < RDS_MPATH_WORKERS; i++) {
+                __rds_conn_path_init(conn, &conn->c_path[i],
+                                     is_outgoing);
+                conn->c_path[i].cp_index = i;
+        }
         ret = trans->conn_alloc(conn, gfp);
         if (ret) {
                 kmem_cache_free(rds_conn_slab, conn);
@@ -263,14 +269,6 @@ static struct rds_connection *__rds_conn_create(struct net *net,
                         kmem_cache_free(rds_conn_slab, conn);
                         conn = found;
                 } else {
-                        int i;
-
-                        for (i = 0; i < RDS_MPATH_WORKERS; i++) {
-                                __rds_conn_path_init(conn, &conn->c_path[i],
-                                                     is_outgoing);
-                                conn->c_path[i].cp_index = i;
-                        }
-
                         hlist_add_head_rcu(&conn->c_hash_node, head);
                         rds_cong_add_conn(conn);
                         rds_conn_count++;
@@ -668,6 +666,7 @@ EXPORT_SYMBOL_GPL(rds_conn_path_drop);
 
 void rds_conn_drop(struct rds_connection *conn)
 {
+        WARN_ON(conn->c_trans->t_mp_capable);
         rds_conn_path_drop(&conn->c_path[0]);
 }
 EXPORT_SYMBOL_GPL(rds_conn_drop);