mei_cl_read_cb
cb = mei_cl_read_cb(cl, NULL);
mei_cl_read_cb(cl, NULL) ||
mei_cl_read_cb(cl, NULL) ||
cb = mei_cl_read_cb(cl, NULL);
struct mei_cl_cb *mei_cl_read_cb(struct mei_cl *cl, const struct file *fp);
cb = mei_cl_read_cb(cl, file);
mei_cl_read_cb(cl, file) ||
cb = mei_cl_read_cb(cl, file);
if (mei_cl_read_cb(cl, file))