#define pfn_valid(pfn) ((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
#define virt_to_page(kaddr) (pfn_to_page(__pa(kaddr) >> PAGE_SHIFT))
#define pfn_valid(pfn) ((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
#define virt_to_page(kaddr) (pfn_to_page(__pa(kaddr) >> PAGE_SHIFT))