pgdat->node_mem_map + (__pfn - pgdat->node_start_pfn); \
})
#define page_to_pfn(_page) ({ \
- struct page *__p = (_page); \
+ const struct page *__p = (_page); \
struct pglist_data *pgdat; \
pgdat = &pg_data_map[page_to_nid(__p)]; \
((__p) - pgdat->node_mem_map) + pgdat->node_start_pfn; \