audio: module_adapter: cap connected buffers at MODULE_MAX_CONNECTIONS

src/audio/module_adapter/README.md

@@ -51,6 +51,8 @@ sequenceDiagram
 
 Connection establishes buffer relationships (`comp_buffer`) connecting the component sources and sinks to the rest of the generic pipeline graph.
 
+Each connected buffer takes a slot in `mod->sinks[]` or `mod->sources[]`, which hold `CONFIG_MODULE_MAX_CONNECTIONS` entries each. A bind (IPC4) or prepare (IPC3) that would need more slots fails with `-EINVAL`.
+
 ```mermaid
 sequenceDiagram
     participant Pipe as Pipeline

src/audio/module_adapter/module_adapter_ipc3.c

@@ -320,13 +320,23 @@ int module_adapter_sink_src_prepare(struct comp_dev *dev)
 	/* acquire all sink and source buffers, get handlers to sink/source API */
 	i = 0;
 	comp_dev_for_each_consumer(dev, sink_buffer) {
+		if (i == CONFIG_MODULE_MAX_CONNECTIONS) {
+			comp_err(dev, "more than %d sinks connected",
+				 CONFIG_MODULE_MAX_CONNECTIONS);
+			return -EINVAL;
+		}
 		mod->sinks[i] = audio_buffer_get_sink(&sink_buffer->audio_buffer);
 		i++;
 	}
 	mod->num_of_sinks = i;
 
 	i = 0;
 	comp_dev_for_each_producer(dev, source_buffer) {
+		if (i == CONFIG_MODULE_MAX_CONNECTIONS) {
+			comp_err(dev, "more than %d sources connected",
+				 CONFIG_MODULE_MAX_CONNECTIONS);
+			return -EINVAL;
+		}
 		mod->sources[i] = audio_buffer_get_source(&source_buffer->audio_buffer);
 		i++;
 	}

src/audio/module_adapter/module_adapter_ipc4.c

@@ -471,10 +471,29 @@ __cold static int module_update_source_buffer_params(struct processing_module *m
 __cold int module_adapter_bind(struct comp_dev *dev, const struct bind_info *bind_data)
 {
 	struct processing_module *mod = comp_mod(dev);
+	struct comp_buffer *buffer;
+	unsigned int count = 0;
 	int ret;
 
 	assert_can_be_cold();
 
+	/*
+	 * The buffer is already connected here and every connected buffer
+	 * takes a slot in mod->sinks[] or mod->sources[].
+	 */
+	if (bind_data->bind_type == COMP_BIND_TYPE_SINK) {
+		comp_dev_for_each_consumer(dev, buffer)
+			count++;
+	} else {
+		comp_dev_for_each_producer(dev, buffer)
+			count++;
+	}
+
+	if (count > CONFIG_MODULE_MAX_CONNECTIONS) {
+		comp_err(dev, "%u connections exceed max %d", count, CONFIG_MODULE_MAX_CONNECTIONS);
+		return -EINVAL;
+	}
+
 	ret = module_update_source_buffer_params(mod, bind_data);
 	if (ret < 0)
 		return ret;

src/ipc/ipc4/helper.c

@@ -1058,10 +1058,17 @@ __cold int ipc4_comp_connect(struct ipc *ipc, const struct ipc4_module_bind_unbi
 	return IPC4_SUCCESS;
 
 e_sink_bind:
-	/* sink bind was already called */
+	/*
+	 * The source is already bound. Disconnect first, as
+	 * ipc4_comp_disconnect() does, so its unbind does not keep the
+	 * buffer in the source's sinks[].
+	 */
+	pipeline_disconnect(sink, buffer, PPL_CONN_DIR_BUFFER_TO_COMP);
+	pipeline_disconnect(source, buffer, PPL_CONN_DIR_COMP_TO_BUFFER);
 	bind_data.bind_type = COMP_BIND_TYPE_SINK;
 	bind_data.sink = audio_buffer_get_sink(&buffer->audio_buffer);
 	comp_unbind(source, &bind_data);
+	goto free;
 e_src_bind:
 	pipeline_disconnect(sink, buffer, PPL_CONN_DIR_BUFFER_TO_COMP);
 e_sink_connect: