The inode() function has always been a bit of an outcast in the FileDescriptor class, as it's not related to the core feature provided by FileDescriptor, a shared ownership wrapper around file descriptors. As it's only used in the FrameBuffer implementation, move it to frame_buffer.cpp as a static function. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>