impl-link: handle mixer failures better

It is possible that the mixer input can't be created because of hitting
the max limits of dsp mixer or client-node. Make sure we handle those
errors, destroy the link and clean up properly.

src/modules/module-client-node/client-node.c

@@ -219,6 +219,8 @@ static struct mix *find_mix(struct port *p, uint32_t mix_id)
 	if (mix_id >= len) {
 		size_t need = sizeof(struct mix) * (mix_id + 1 - len);
 		void *ptr = pw_array_add(&p->mix, need);
+		if (ptr == NULL)
+			return NULL;
 		memset(ptr, 0, need);
 	}
 	mix = pw_array_get_unchecked(&p->mix, mix_id, struct mix);

src/pipewire/impl-link.c

@@ -451,7 +451,7 @@ static int port_set_io(struct pw_impl_link *this, struct pw_impl_port *port, uin
 	return res;
 }
 
-static int select_io(struct pw_impl_link *this)
+static void select_io(struct pw_impl_link *this)
 {
 	struct impl *impl = SPA_CONTAINER_OF(this, struct impl, this);
 	struct spa_io_buffers *io;
@@ -461,13 +461,9 @@ static int select_io(struct pw_impl_link *this)
 		io = this->rt.out_mix.io;
 	if (io == NULL)
 		io = &impl->io;
-	if (io == NULL)
-		return -EIO;
 
 	this->io = io;
 	*this->io = SPA_IO_BUFFERS_INIT;
-
-	return 0;
 }
 
 static int do_allocation(struct pw_impl_link *this)
@@ -1229,6 +1225,16 @@ struct pw_impl_link *pw_context_create_link(struct pw_context *context,
 	spa_hook_list_init(&this->listener_list);
 
 	impl->format_filter = format_filter;
+	this->info.format = NULL;
+	this->info.props = &this->properties->dict;
+
+	this->rt.out_mix.peer_id = input->global->id;
+	this->rt.in_mix.peer_id = output->global->id;
+
+	if ((res = pw_impl_port_init_mix(output, &this->rt.out_mix)) < 0)
+		goto error_output_mix;
+	if ((res = pw_impl_port_init_mix(input, &this->rt.in_mix)) < 0)
+		goto error_input_mix;
 
 	pw_impl_port_add_listener(input, &impl->input_port_listener, &input_port_events, impl);
 	pw_impl_node_add_listener(input_node, &impl->input_node_listener, &input_node_events, impl);
@@ -1245,19 +1251,9 @@ struct pw_impl_link *pw_context_create_link(struct pw_context *context,
 	spa_list_append(&output->links, &this->output_link);
 	spa_list_append(&input->links, &this->input_link);
 
-	this->info.format = NULL;
-	this->info.props = &this->properties->dict;
-
 	impl->io = SPA_IO_BUFFERS_INIT;
 
-	this->rt.out_mix.peer_id = input->global->id;
+	select_io(this);
-	this->rt.in_mix.peer_id = output->global->id;
-
-	pw_impl_port_init_mix(output, &this->rt.out_mix);
-	pw_impl_port_init_mix(input, &this->rt.in_mix);
-
-	if ((res = select_io(this)) < 0)
-		goto error_no_io;
 
 	if (this->feedback) {
 		impl->inode = output_node;
@@ -1317,8 +1313,12 @@ error_work_queue:
 	res = -errno;
 	pw_log_debug("work queue failed: %m");
 	goto error_free;
-error_no_io:
+error_output_mix:
-	pw_log_debug("%p: can't set io %d (%s)", this, res, spa_strerror(res));
+	pw_log_error("%p: can't get output mix %d (%s)", this, res, spa_strerror(res));
+	goto error_free;
+error_input_mix:
+	pw_log_error("%p: can't get input mix %d (%s)", this, res, spa_strerror(res));
+	pw_impl_port_release_mix(output, &this->rt.out_mix);
 	goto error_free;
 error_free:
 	free(impl);

src/pipewire/impl-port.c

@@ -214,16 +214,16 @@ int pw_impl_port_init_mix(struct pw_impl_port *port, struct pw_impl_port_mix *mi
 	if (port_id == SPA_ID_INVALID)
 		return -errno;
 
+	if ((res = spa_node_add_port(port->mix, port->direction, port_id, NULL)) < 0 &&
+	    res != -ENOTSUP)
+		goto error_remove_map;
+
 	mix->port.direction = port->direction;
 	mix->port.port_id = port_id;
-
-	spa_list_append(&port->mix_list, &mix->link);
-	port->n_mix++;
 	mix->p = port;
 
-	spa_node_add_port(port->mix, port->direction, port_id, NULL);
+	if ((res = pw_impl_port_call_init_mix(port, mix)) < 0)
-
+		goto error_remove_port;
-	res = pw_impl_port_call_init_mix(port, mix);
 
 	/* set the same format on the mixer as on the port if any */
 	{
@@ -242,11 +242,20 @@ int pw_impl_port_init_mix(struct pw_impl_port *port, struct pw_impl_port_mix *mi
 		}
 	}
 
+	spa_list_append(&port->mix_list, &mix->link);
+	port->n_mix++;
+
 	pw_log_debug("%p: init mix n_mix:%d %d.%d io:%p: (%s)", port,
 			port->n_mix, port->port_id, mix->port.port_id,
 			mix->io, spa_strerror(res));
 
 	return res;
+
+error_remove_port:
+	spa_node_remove_port(port->mix, port->direction, port_id);
+error_remove_map:
+	pw_map_remove(&port->mix_port_map, port_id);
+	return res;
 }
 
 SPA_EXPORT
@@ -261,7 +270,9 @@ int pw_impl_port_release_mix(struct pw_impl_port *port, struct pw_impl_port_mix
 
 	res = pw_impl_port_call_release_mix(port, mix);
 
-	spa_node_remove_port(port->mix, port->direction, port_id);
+	if ((res = spa_node_remove_port(port->mix, port->direction, port_id)) < 0 &&
+	    res != -ENOTSUP)
+		pw_log_warn("can't remove mix port %d: %s", port_id, spa_strerror(res));
 
 	pw_log_debug("%p: release mix %d %d.%d", port,
 			port->n_mix, port->port_id, mix->port.port_id);