/* Subtle, we encode the real pfn into the mem_map such that the identity pfn - section_mem_map will return the actual physical page frame number.  */
static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
/* Subtle, we encode the real pfn into the mem_map such that the identity pfn - section_mem_map will return the actual physical page frame number.  */
static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum)
{
	return (unsigned long)(mem_map - (section_nr_to_pfn(pnum)));
}