greybus: Cleanup connection leftovers

This wouldn't happen normally, but in a buggy corner case it is possible
that all the connections aren't removed properly and they are still
present after the interfaces and endo are removed.

Warn in such a case and cleanup connections, so that /sys/bus/greybus/
can be removed while removing greybus modules.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/connection.c

@@ -313,3 +313,13 @@ void gb_connection_exit(struct gb_connection *connection)
 				 cport_id, ret);
 	}
 }
+
+void gb_hd_connections_exit(struct greybus_host_device *hd)
+{
+	struct gb_connection *connection;
+
+	list_for_each_entry(connection, &hd->connections, hd_links) {
+		gb_connection_exit(connection);
+		gb_connection_destroy(connection);
+	}
+}

drivers/staging/greybus/connection.h

@@ -50,6 +50,7 @@ void gb_connection_destroy(struct gb_connection *connection);
 
 int gb_connection_init(struct gb_connection *connection);
 void gb_connection_exit(struct gb_connection *connection);
+void gb_hd_connections_exit(struct greybus_host_device *hd);
 
 void greybus_data_rcvd(struct greybus_host_device *hd, u16 cport_id,
 			u8 *data, size_t length);

drivers/staging/greybus/core.c

@@ -235,6 +235,13 @@ void greybus_remove_hd(struct greybus_host_device *hd)
 	 */
 	gb_interfaces_remove(hd);
 	gb_endo_remove(hd->endo);
+
+	/*
+	 * Make sure there are no leftovers that can potentially corrupt sysfs.
+	 */
+	if (WARN_ON(!list_empty(&hd->connections)))
+		gb_hd_connections_exit(hd);
+
 	kref_put_mutex(&hd->kref, free_hd, &hd_mutex);
 }
 EXPORT_SYMBOL_GPL(greybus_remove_hd);