Make bt_graph_connect_ports() return a status code

bt_graph_connect_ports() can fail for multiple reasons, some of which
are not errors per se, but conditions which make the connection
impossible, for example a component refuses the connection, or the graph
is canceled.

With this version, the connection is returned as an output parameter,
which can be NULL if the user is not interested in the connection object
(most common case), and the function returns a graph status code.

Two new status codes are added in order to satisfy this patch:

* BT_GRAPH_STATUS_COMPONENT_REFUSES_PORT_CONNECTION
* BT_GRAPH_STATUS_NOMEM

The first one is not considered an error, that is, the graph's user
could only _try_ to connect two components until the function returns
BT_GRAPH_STATUS_OK (and retry in case of
BT_GRAPH_STATUS_COMPONENT_REFUSES_PORT_CONNECTION).

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/cli/babeltrace.c b/cli/babeltrace.c
index 66c74df44b85ca8024f2ef99cc5e07bd3232bbd0..b68ddf1531c51fd8e965cc4bdca2a3f1c7593090 100644 (file)
--- a/cli/babeltrace.c
+++ b/cli/babeltrace.c
@@ -1178,7 +1178,7 @@ int cmd_run_ctx_connect_upstream_port_to_downstream_component(
        uint64_t i;
        int64_t (*port_count_fn)(struct bt_component *);
        struct bt_port *(*port_by_index_fn)(struct bt_component *, uint64_t);
-       void *conn = NULL;
+       enum bt_graph_status status = BT_GRAPH_STATUS_ERROR;
 
        BT_LOGI("Connecting upstream port to the next available downstream port: "
                "upstream-port-addr=%p, upstream-port-name=\"%s\", "
@@ -1243,10 +1243,35 @@ int cmd_run_ctx_connect_upstream_port_to_downstream_component(
                                cfg_conn->downstream_port_glob->str, -1ULL,
                                downstream_port_name, -1ULL)) {
                        /* We have a winner! */
-                       conn = bt_graph_connect_ports(ctx->graph,
-                               upstream_port, downstream_port);
+                       status = bt_graph_connect_ports(ctx->graph,
+                               upstream_port, downstream_port, NULL);
                        bt_put(downstream_port);
-                       if (!conn) {
+                       switch (status) {
+                       case BT_GRAPH_STATUS_OK:
+                               break;
+                       case BT_GRAPH_STATUS_CANCELED:
+                               BT_LOGI_STR("Graph was canceled by user.");
+                               status = BT_GRAPH_STATUS_OK;
+                               break;
+                       case BT_GRAPH_STATUS_COMPONENT_REFUSES_PORT_CONNECTION:
+                               BT_LOGE("A component refused a connection to one of its ports: "
+                                       "upstream-comp-addr=%p, upstream-comp-name=\"%s\", "
+                                       "upstream-port-addr=%p, upstream-port-name=\"%s\", "
+                                       "downstream-comp-addr=%p, downstream-comp-name=\"%s\", "
+                                       "downstream-port-addr=%p, downstream-port-name=\"%s\", "
+                                       "conn-arg=\"%s\"",
+                                       upstream_comp, bt_component_get_name(upstream_comp),
+                                       upstream_port, bt_port_get_name(upstream_port),
+                                       downstream_comp, cfg_conn->downstream_comp_name->str,
+                                       downstream_port, downstream_port_name,
+                                       cfg_conn->arg->str);
+                               fprintf(stderr,
+                                       "A component refused a connection to one of its ports (`%s` to `%s`): %s\n",
+                                       bt_port_get_name(upstream_port),
+                                       downstream_port_name,
+                                       cfg_conn->arg->str);
+                               break;
+                       default:
                                BT_LOGE("Cannot create connection: graph refuses to connect ports: "
                                        "upstream-comp-addr=%p, upstream-comp-name=\"%s\", "
                                        "upstream-port-addr=%p, upstream-port-name=\"%s\", "
@@ -1284,7 +1309,7 @@ int cmd_run_ctx_connect_upstream_port_to_downstream_component(
                bt_put(downstream_port);
        }
 
-       if (!conn) {
+       if (status != BT_GRAPH_STATUS_OK) {
                BT_LOGE("Cannot create connection: cannot find a matching downstream port for upstream port: "
                        "upstream-port-addr=%p, upstream-port-name=\"%s\", "
                        "downstream-comp-name=\"%s\", conn-arg=\"%s\"",
@@ -1303,7 +1328,6 @@ error:
        ret = -1;
 
 end:
-       bt_put(conn);
        return ret;
 }
 

diff --git a/include/babeltrace/graph/graph-internal.h b/include/babeltrace/graph/graph-internal.h
index 7e8ea45fc4226709c51bb438e9d5b52d87e5f558..f8f0d1a17475f27cb7a783567eaa43134d2e9981 100644 (file)
--- a/include/babeltrace/graph/graph-internal.h
+++ b/include/babeltrace/graph/graph-internal.h
@@ -28,8 +28,10 @@
  */
 
 #include <babeltrace/graph/graph.h>
+#include <babeltrace/graph/component-status.h>
 #include <babeltrace/babeltrace-internal.h>
 #include <babeltrace/object-internal.h>
+#include <stdlib.h>
 #include <glib.h>
 
 struct bt_component;
@@ -107,9 +109,44 @@ const char *bt_graph_status_string(enum bt_graph_status status)
                return "BT_GRAPH_STATUS_NO_SINK";
        case BT_GRAPH_STATUS_ERROR:
                return "BT_GRAPH_STATUS_ERROR";
+       case BT_GRAPH_STATUS_COMPONENT_REFUSES_PORT_CONNECTION:
+               return "BT_GRAPH_STATUS_COMPONENT_REFUSES_PORT_CONNECTION";
+       case BT_GRAPH_STATUS_NOMEM:
+               return "BT_GRAPH_STATUS_NOMEM";
        default:
                return "(unknown)";
        }
 }
 
+static inline
+enum bt_graph_status bt_graph_status_from_component_status(
+               enum bt_component_status comp_status)
+{
+       switch (comp_status) {
+       case BT_COMPONENT_STATUS_OK:
+               return BT_GRAPH_STATUS_OK;
+       case BT_COMPONENT_STATUS_END:
+               return BT_GRAPH_STATUS_END;
+       case BT_COMPONENT_STATUS_AGAIN:
+               return BT_GRAPH_STATUS_AGAIN;
+       case BT_COMPONENT_STATUS_REFUSE_PORT_CONNECTION:
+               return BT_GRAPH_STATUS_COMPONENT_REFUSES_PORT_CONNECTION;
+       case BT_COMPONENT_STATUS_ERROR:
+               return BT_GRAPH_STATUS_ERROR;
+       case BT_COMPONENT_STATUS_UNSUPPORTED:
+               return BT_GRAPH_STATUS_ERROR;
+       case BT_COMPONENT_STATUS_INVALID:
+               return BT_GRAPH_STATUS_INVALID;
+       case BT_COMPONENT_STATUS_NOMEM:
+               return BT_GRAPH_STATUS_NOMEM;
+       case BT_COMPONENT_STATUS_NOT_FOUND:
+               return BT_GRAPH_STATUS_ERROR;
+       default:
+#ifdef BT_LOGF
+               BT_LOGF("Unknown component status: status=%d", comp_status);
+#endif
+               abort();
+       }
+}
+
 #endif /* BABELTRACE_COMPONENT_COMPONENT_GRAPH_INTERNAL_H */

diff --git a/include/babeltrace/graph/graph.h b/include/babeltrace/graph/graph.h
index 06f2af1b122407a46b07e29465a1fec1969f0d15..a2dfbd8235f85e63d64e3a48fd6e2c6fd8fe7130 100644 (file)
--- a/include/babeltrace/graph/graph.h
+++ b/include/babeltrace/graph/graph.h
@@ -38,6 +38,7 @@ struct bt_port;
 struct bt_connection;
 
 enum bt_graph_status {
+       BT_GRAPH_STATUS_COMPONENT_REFUSES_PORT_CONNECTION = 111,
        /** Canceled. */
        BT_GRAPH_STATUS_CANCELED = 125,
        /** No sink can consume at the moment. */
@@ -53,6 +54,7 @@ enum bt_graph_status {
        BT_GRAPH_STATUS_NO_SINK = -6,
        /** General error. */
        BT_GRAPH_STATUS_ERROR = -1,
+       BT_GRAPH_STATUS_NOMEM = -12,
 };
 
 typedef void (*bt_graph_port_added_listener)(struct bt_port *port,
@@ -73,9 +75,9 @@ extern struct bt_graph *bt_graph_create(void);
  * Creates a connection between two components using the two ports specified
  * and adds the connection and components (if not already added) to the graph.
  */
-extern struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
-               struct bt_port *upstream,
-               struct bt_port *downstream);
+extern enum bt_graph_status bt_graph_connect_ports(struct bt_graph *graph,
+               struct bt_port *upstream, struct bt_port *downstream,
+               struct bt_connection **connection);
 
 /**
  * Run graph to completion or until a single sink is left and "AGAIN" is received.

diff --git a/lib/graph/graph.c b/lib/graph/graph.c
index e71eaeede02e3e7696224a8553971716b6b3bf08..c66b4f3cd8655b4fb6ebba932cf3e86f90f91620 100644 (file)
--- a/lib/graph/graph.c
+++ b/lib/graph/graph.c
@@ -191,10 +191,11 @@ error:
        goto end;
 }
 
-struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
-               struct bt_port *upstream_port,
-               struct bt_port *downstream_port)
+enum bt_graph_status bt_graph_connect_ports(struct bt_graph *graph,
+               struct bt_port *upstream_port, struct bt_port *downstream_port,
+               struct bt_connection **user_connection)
 {
+       enum bt_graph_status status = BT_GRAPH_STATUS_OK;
        struct bt_connection *connection = NULL;
        struct bt_graph *upstream_graph = NULL;
        struct bt_graph *downstream_graph = NULL;
@@ -206,16 +207,19 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
 
        if (!graph) {
                BT_LOGW_STR("Invalid parameter: graph is NULL.");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
        if (!upstream_port) {
                BT_LOGW_STR("Invalid parameter: upstream port is NULL.");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
        if (!downstream_port) {
                BT_LOGW_STR("Invalid parameter: downstream port is NULL.");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
@@ -228,27 +232,32 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
 
        if (graph->canceled) {
                BT_LOGW_STR("Invalid parameter: graph is canceled.");
+               status = BT_GRAPH_STATUS_CANCELED;
                goto end;
        }
 
        /* Ensure appropriate types for upstream and downstream ports. */
        if (bt_port_get_type(upstream_port) != BT_PORT_TYPE_OUTPUT) {
                BT_LOGW_STR("Invalid parameter: upstream port is not an output port.");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
        if (bt_port_get_type(downstream_port) != BT_PORT_TYPE_INPUT) {
                BT_LOGW_STR("Invalid parameter: downstream port is not an input port.");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
        /* Ensure that both ports are currently unconnected. */
        if (bt_port_is_connected(upstream_port)) {
                BT_LOGW_STR("Invalid parameter: upstream port is already connected.");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
        if (bt_port_is_connected(downstream_port)) {
                BT_LOGW_STR("Invalid parameter: downstream port is already connected.");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
@@ -259,12 +268,14 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
        upstream_component = bt_port_get_component(upstream_port);
        if (!upstream_component) {
                BT_LOGW_STR("Invalid parameter: upstream port is loose (does not belong to a component)");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
        downstream_component = bt_port_get_component(downstream_port);
        if (!downstream_component) {
                BT_LOGW_STR("Invalid parameter: downstream port is loose (does not belong to a component)");
+               status = BT_GRAPH_STATUS_INVALID;
                goto end;
        }
 
@@ -279,14 +290,16 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
        if (upstream_graph && (graph != upstream_graph)) {
                BT_LOGW("Invalid parameter: upstream port's component is already part of another graph: "
                        "other-graph-addr=%p", upstream_graph);
-               goto error;
+               status = BT_GRAPH_STATUS_ALREADY_IN_A_GRAPH;
+               goto end;
        }
        upstream_was_already_in_graph = (graph == upstream_graph);
        downstream_graph = bt_component_get_graph(downstream_component);
        if (downstream_graph && (graph != downstream_graph)) {
                BT_LOGW("Invalid parameter: downstream port's component is already part of another graph: "
                        "other-graph-addr=%p", downstream_graph);
-               goto error;
+               status = BT_GRAPH_STATUS_ALREADY_IN_A_GRAPH;
+               goto end;
        }
        downstream_was_already_in_graph = (graph == downstream_graph);
 
@@ -306,7 +319,9 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
                                "status=%s", bt_component_status_string(component_status));
                }
 
-               goto error;
+               status = bt_graph_status_from_component_status(
+                       component_status);
+               goto end;
        }
 
        BT_LOGD_STR("Asking downstream component to accept the connection.");
@@ -320,7 +335,9 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
                                "status=%s", bt_component_status_string(component_status));
                }
 
-               goto error;
+               status = bt_graph_status_from_component_status(
+                       component_status);
+               goto end;
        }
 
        BT_LOGD_STR("Creating connection.");
@@ -328,7 +345,8 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
                        downstream_port);
        if (!connection) {
                BT_LOGW("Cannot create connection object.");
-               goto error;
+               status = BT_GRAPH_STATUS_NOMEM;
+               goto end;
        }
 
        BT_LOGD("Connection object created: conn-addr=%p", connection);
@@ -386,17 +404,17 @@ struct bt_connection *bt_graph_connect_ports(struct bt_graph *graph,
                upstream_port, bt_port_get_name(upstream_port),
                downstream_port, bt_port_get_name(downstream_port));
 
+       if (user_connection) {
+               BT_MOVE(*user_connection, connection);
+       }
+
 end:
        bt_put(upstream_graph);
        bt_put(downstream_graph);
        bt_put(upstream_component);
        bt_put(downstream_component);
-       return connection;
-
-error:
-       BT_PUT(upstream_component);
-       BT_PUT(downstream_component);
-       goto end;
+       bt_put(connection);
+       return status;
 }
 
 enum bt_graph_status bt_graph_consume(struct bt_graph *graph)

diff --git a/tests/lib/test_bt_notification_iterator.c b/tests/lib/test_bt_notification_iterator.c
index 6ba999526c2071ed759d34b62dad75f121caf62b..cace4019c035d9e21bfd00847081bf3cedd3e910 100644 (file)
--- a/tests/lib/test_bt_notification_iterator.c
+++ b/tests/lib/test_bt_notification_iterator.c
@@ -917,7 +917,6 @@ void do_std_test(enum test test, const char *name,
        struct bt_port *upstream_port;
        struct bt_port *downstream_port;
        struct bt_graph *graph;
-       void *conn;
        enum bt_graph_status graph_status = BT_GRAPH_STATUS_OK;
 
        clear_test_events();
@@ -932,9 +931,8 @@ void do_std_test(enum test test, const char *name,
        assert(upstream_port);
        downstream_port = bt_component_sink_get_input_port_by_name(sink_comp, "in");
        assert(downstream_port);
-       conn = bt_graph_connect_ports(graph, upstream_port, downstream_port);
-       assert(conn);
-       bt_put(conn);
+       graph_status = bt_graph_connect_ports(graph, upstream_port,
+               downstream_port, NULL);
        bt_put(upstream_port);
        bt_put(downstream_port);
 

diff --git a/tests/lib/test_graph_topo.c b/tests/lib/test_graph_topo.c
index 92ebac80b5baab7a68fbafc8c0b3a131fd963374..6b1976d16e2e2ca6a33ec6469e71128e1b97e74d 100644 (file)
--- a/tests/lib/test_graph_topo.c
+++ b/tests/lib/test_graph_topo.c
@@ -650,6 +650,7 @@ void test_sink_removes_port_in_port_connected_then_src_removes_disconnected_port
        struct bt_port *sink_def_port;
        struct bt_connection *conn;
        struct event event;
+       enum bt_graph_status status;
        size_t src_accept_port_connection_pos;
        size_t sink_accept_port_connection_pos;
        size_t src_port_connected_pos;
@@ -670,7 +671,9 @@ void test_sink_removes_port_in_port_connected_then_src_removes_disconnected_port
        assert(src_def_port);
        sink_def_port = bt_component_sink_get_input_port_by_name(sink, "in");
        assert(sink_def_port);
-       conn = bt_graph_connect_ports(graph, src_def_port, sink_def_port);
+       status = bt_graph_connect_ports(graph, src_def_port, sink_def_port,
+               &conn);
+       assert(status == 0);
        assert(conn);
 
        /* We're supposed to have 5 events so far */
@@ -812,6 +815,7 @@ void test_sink_removes_port_in_port_connected(void)
        struct bt_port *sink_def_port;
        struct bt_connection *conn;
        struct event event;
+       enum bt_graph_status status;
        size_t src_accept_port_connection_pos;
        size_t sink_accept_port_connection_pos;
        size_t src_port_connected_pos;
@@ -831,8 +835,9 @@ void test_sink_removes_port_in_port_connected(void)
        assert(src_def_port);
        sink_def_port = bt_component_sink_get_input_port_by_name(sink, "in");
        assert(sink_def_port);
-       conn = bt_graph_connect_ports(graph, src_def_port, sink_def_port);
-       assert(conn);
+       status = bt_graph_connect_ports(graph, src_def_port, sink_def_port,
+               &conn);
+       assert(status == 0);
 
        /* We're supposed to have 5 events so far */
        ok(events->len == 5, "we have the expected number of events (before consume)");
@@ -958,6 +963,7 @@ void test_src_adds_port_in_port_connected(void)
        struct bt_port *src_hello_port;
        struct bt_connection *conn;
        struct event event;
+       enum bt_graph_status status;
        size_t src_accept_port_connection_pos;
        size_t sink_accept_port_connection_pos;
        size_t src_port_connected_pos;
@@ -974,8 +980,9 @@ void test_src_adds_port_in_port_connected(void)
        assert(src_def_port);
        sink_def_port = bt_component_sink_get_input_port_by_name(sink, "in");
        assert(sink_def_port);
-       conn = bt_graph_connect_ports(graph, src_def_port, sink_def_port);
-       assert(conn);
+       status = bt_graph_connect_ports(graph, src_def_port, sink_def_port,
+               &conn);
+       assert(status == 0);
        src_hello_port = bt_component_source_get_output_port_by_name(src,
                "hello");
        assert(src_hello_port);
@@ -1065,6 +1072,7 @@ void test_simple(void)
        struct bt_port *sink_def_port;
        struct bt_connection *conn;
        struct event event;
+       enum bt_graph_status status;
        size_t src_accept_port_connection_pos;
        size_t sink_accept_port_connection_pos;
        size_t src_port_connected_pos;
@@ -1079,8 +1087,9 @@ void test_simple(void)
        assert(src_def_port);
        sink_def_port = bt_component_sink_get_input_port_by_name(sink, "in");
        assert(sink_def_port);
-       conn = bt_graph_connect_ports(graph, src_def_port, sink_def_port);
-       assert(conn);
+       status = bt_graph_connect_ports(graph, src_def_port, sink_def_port,
+               &conn);
+       assert(status == 0);
 
        /* We're supposed to have 5 events */
        ok(events->len == 5, "we have the expected number of events");

diff --git a/tests/plugins/test-utils-muxer.c b/tests/plugins/test-utils-muxer.c
index a706b99b4b8577bca24ee426cd1fbf0f2c8cab31..e9d2dca0a27a1caeff627fb6994a06653665be5e 100644 (file)
--- a/tests/plugins/test-utils-muxer.c
+++ b/tests/plugins/test-utils-muxer.c
@@ -988,7 +988,6 @@ void do_std_test(enum test test, const char *name,
        struct bt_graph *graph;
        int64_t i;
        int64_t count;
-       void *conn;
        enum bt_graph_status graph_status = BT_GRAPH_STATUS_OK;
 
        clear_test_events();
@@ -1010,10 +1009,9 @@ void do_std_test(enum test test, const char *name,
                        downstream_port = bt_component_filter_get_input_port_by_index(
                                muxer_comp, i);
                        assert(downstream_port);
-                       conn = bt_graph_connect_ports(graph,
-                               upstream_port, downstream_port);
-                       assert(conn);
-                       bt_put(conn);
+                       graph_status = bt_graph_connect_ports(graph,
+                               upstream_port, downstream_port, NULL);
+                       assert(graph_status == 0);
                        bt_put(upstream_port);
                        bt_put(downstream_port);
                }
@@ -1025,9 +1023,9 @@ void do_std_test(enum test test, const char *name,
        assert(upstream_port);
        downstream_port = bt_component_sink_get_input_port_by_name(sink_comp, "in");
        assert(downstream_port);
-       conn = bt_graph_connect_ports(graph, upstream_port, downstream_port);
-       assert(conn);
-       bt_put(conn);
+       graph_status = bt_graph_connect_ports(graph, upstream_port,
+               downstream_port, NULL);
+       assert(graph_status == 0);
        bt_put(upstream_port);
        bt_put(downstream_port);
 
@@ -1345,9 +1343,9 @@ void connect_port_to_first_avail_muxer_port(struct bt_graph *graph,
                struct bt_component *muxer_comp)
 {
        struct bt_port *avail_muxer_port = NULL;
-       void *conn;
        int64_t i;
        int64_t count;
+       enum bt_graph_status graph_status;
 
        count = bt_component_filter_get_input_port_count(muxer_comp);
        assert(count >= 0);
@@ -1367,9 +1365,9 @@ void connect_port_to_first_avail_muxer_port(struct bt_graph *graph,
                }
        }
 
-       conn = bt_graph_connect_ports(graph, source_port, avail_muxer_port);
-       assert(conn);
-       bt_put(conn);
+       graph_status = bt_graph_connect_ports(graph, source_port,
+               avail_muxer_port, NULL);
+       assert(graph_status == 0);
        bt_put(avail_muxer_port);
 }
 
@@ -1405,7 +1403,6 @@ void test_single_end_then_multiple_full(void)
        struct bt_graph *graph;
        int64_t i;
        int64_t count;
-       void *conn;
        int ret;
        enum bt_graph_status graph_status = BT_GRAPH_STATUS_OK;
        struct graph_listener_data graph_listener_data;
@@ -1501,9 +1498,9 @@ void test_single_end_then_multiple_full(void)
        assert(upstream_port);
        downstream_port = bt_component_sink_get_input_port_by_name(sink_comp, "in");
        assert(downstream_port);
-       conn = bt_graph_connect_ports(graph, upstream_port, downstream_port);
-       assert(conn);
-       bt_put(conn);
+       graph_status = bt_graph_connect_ports(graph, upstream_port,
+               downstream_port, NULL);
+       assert(graph_status == 0);
        bt_put(upstream_port);
        bt_put(downstream_port);
 
@@ -1533,7 +1530,6 @@ void test_single_again_end_then_multiple_full(void)
        struct bt_graph *graph;
        int64_t i;
        int64_t count;
-       void *conn;
        int ret;
        enum bt_graph_status graph_status = BT_GRAPH_STATUS_OK;
        struct graph_listener_data graph_listener_data;
@@ -1630,9 +1626,9 @@ void test_single_again_end_then_multiple_full(void)
        assert(upstream_port);
        downstream_port = bt_component_sink_get_input_port_by_name(sink_comp, "in");
        assert(downstream_port);
-       conn = bt_graph_connect_ports(graph, upstream_port, downstream_port);
-       assert(conn);
-       bt_put(conn);
+       graph_status = bt_graph_connect_ports(graph, upstream_port,
+               downstream_port, NULL);
+       assert(graph_status == 0);
        bt_put(upstream_port);
        bt_put(downstream_port);