ring_buf_init
return ring_buf_init(r, nbytes);
if (ring_buf_init(&b->rbuf, b->req_buf_len) == 0) {
if (ring_buf_init(&b1->rbuf, b1->req_buf_len) == 0) {
if (ring_buf_init(&b2->rbuf, b2->req_buf_len) == 0) {
ring_buf_init(&ret->rbuf);
ring_buf_init(&qss->ring_buf);