get_entry_count
return PAGE_MAP_MAGIC_LENGTH + sizeof(u64) + sizeof(u16) * get_entry_count(geometry);
for (i = 0; i < get_entry_count(map->geometry); i++)
for (i = 0; i < get_entry_count(map->geometry); i++)
result = vdo_allocate(get_entry_count(geometry), "Index Page Map Entries",