rds_ib_ring_alloc
u32 rds_ib_ring_alloc(struct rds_ib_work_ring *ring, u32 val, u32 *pos);
rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos);
work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);