RDS: TCP: Make rds_tcp_connection track the rds_conn_path

The struct rds_tcp_connection is the transport-specific private
data structure that tracks TCP information per rds_conn_path.
Modify this structure to have a back-pointer to the rds_conn_path
for which it is the ->cp_transport_data.

Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index c56fff2..c6b47f6 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -221,7 +221,7 @@
 		sock->sk->sk_data_ready = sock->sk->sk_user_data;
 
 	tc->t_sock = sock;
-	tc->conn = conn;
+	tc->t_cpath = &conn->c_path[0];
 	tc->t_orig_data_ready = sock->sk->sk_data_ready;
 	tc->t_orig_write_space = sock->sk->sk_write_space;
 	tc->t_orig_state_change = sock->sk->sk_state_change;
@@ -284,24 +284,29 @@
 static int rds_tcp_conn_alloc(struct rds_connection *conn, gfp_t gfp)
 {
 	struct rds_tcp_connection *tc;
+	int i;
 
-	tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
-	if (!tc)
-		return -ENOMEM;
+	for (i = 0; i < RDS_MPATH_WORKERS; i++) {
+		tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
+		if (!tc)
+			return -ENOMEM;
 
-	mutex_init(&tc->t_conn_lock);
-	tc->t_sock = NULL;
-	tc->t_tinc = NULL;
-	tc->t_tinc_hdr_rem = sizeof(struct rds_header);
-	tc->t_tinc_data_rem = 0;
+		mutex_init(&tc->t_conn_path_lock);
+		tc->t_sock = NULL;
+		tc->t_tinc = NULL;
+		tc->t_tinc_hdr_rem = sizeof(struct rds_header);
+		tc->t_tinc_data_rem = 0;
 
-	conn->c_transport_data = tc;
+		conn->c_path[i].cp_transport_data = tc;
+		tc->t_cpath = &conn->c_path[i];
 
-	spin_lock_irq(&rds_tcp_conn_lock);
-	list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
-	spin_unlock_irq(&rds_tcp_conn_lock);
+		spin_lock_irq(&rds_tcp_conn_lock);
+		list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
+		spin_unlock_irq(&rds_tcp_conn_lock);
+		rdsdebug("rds_conn_path [%d] tc %p\n", i,
+			 conn->c_path[i].cp_transport_data);
+	}
 
-	rdsdebug("alloced tc %p\n", conn->c_transport_data);
 	return 0;
 }
 
@@ -330,7 +335,7 @@
 	spin_unlock_irq(&rds_tcp_conn_lock);
 
 	list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
-		rds_conn_destroy(tc->conn);
+		rds_conn_destroy(tc->t_cpath->cp_conn);
 }
 
 static void rds_tcp_exit(void);
@@ -498,7 +503,7 @@
 	flush_work(&rtn->rds_tcp_accept_w);
 	spin_lock_irq(&rds_tcp_conn_lock);
 	list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
-		struct net *c_net = read_pnet(&tc->conn->c_net);
+		struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
 
 		if (net != c_net || !tc->t_sock)
 			continue;
@@ -509,7 +514,7 @@
 		sk = tc->t_sock->sk;
 		sk->sk_prot->disconnect(sk, 0);
 		tcp_done(sk);
-		rds_conn_destroy(tc->conn);
+		rds_conn_destroy(tc->t_cpath->cp_conn);
 	}
 }
 
@@ -547,12 +552,13 @@
 
 	spin_lock_irq(&rds_tcp_conn_lock);
 	list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
-		struct net *c_net = read_pnet(&tc->conn->c_net);
+		struct net *c_net = read_pnet(&tc->t_cpath->cp_conn->c_net);
 
 		if (net != c_net || !tc->t_sock)
 			continue;
 
-		rds_conn_drop(tc->conn); /* reconnect with new parameters */
+		/* reconnect with new parameters */
+		rds_conn_path_drop(tc->t_cpath);
 	}
 	spin_unlock_irq(&rds_tcp_conn_lock);
 }