fmd_topo_hold
ahp->ah_topo = fmd_topo_hold();
fmd_topo_t *ftp = fmd_topo_hold();
prev = fmd_topo_hold();
ftp = fmd_topo_hold();
ftp = fmd_topo_hold();
mp->mod_topo_current = fmd_topo_hold();
extern fmd_topo_t *fmd_topo_hold(void);