BIT_CHUNK
&bitmap[BIT_CHUNK(nr)]);
ice_clear_bit_internal(BIT_IN_CHUNK(nr), &bitmap[BIT_CHUNK(nr)]);
ice_set_bit_internal(BIT_IN_CHUNK(nr), &bitmap[BIT_CHUNK(nr)]);
&bitmap[BIT_CHUNK(nr)]);
&bitmap[BIT_CHUNK(nr)]);
i = BIT_CHUNK(offset);