URTWN_HOST_CMD_RING_COUNT
KASSERTMSG((ring->cur >= 0 && ring->cur < URTWN_HOST_CMD_RING_COUNT),
KASSERTMSG((ring->next >= 0 && ring->next < URTWN_HOST_CMD_RING_COUNT),
ring->queued <= URTWN_HOST_CMD_RING_COUNT),
ring->next = (ring->next + 1) % URTWN_HOST_CMD_RING_COUNT;
if (ring->queued == URTWN_HOST_CMD_RING_COUNT)
ring->cur = (ring->cur + 1) % URTWN_HOST_CMD_RING_COUNT;
struct urtwn_host_cmd cmd[URTWN_HOST_CMD_RING_COUNT];