/* figure out power of two mapping: grow until larger than
comm size, then go back one, to get the largest power of
two less than comm size */
while (tmp_size <= size) tmp_size <<= 1;
tmp_size >>= 1;
remain = size - tmp_size;
/* figure out power of two mapping: grow until larger than
comm size, then go back one, to get the largest power of
two less than comm size */
while (tmp_size <= size) tmp_size <<= 1;
tmp_size >>= 1;
remain = size - tmp_size;