i_ldc_set_rx_head
if (rv = i_ldc_set_rx_head(ldcp, rx_head))
(void) i_ldc_set_rx_head(ldcp, rx_tail);
if (rv = i_ldc_set_rx_head(ldcp, rx_head)) {
ldcp->readq_set_head = i_ldc_set_rx_head;
rv = i_ldc_set_rx_head(ldcp, rx_head);
rv = i_ldc_set_rx_head(ldcp, rx_tail);
rv = i_ldc_set_rx_head(ldcp, rx_tail);
static int i_ldc_set_rx_head(ldc_chan_t *ldcp, uint64_t head);