#define page_to_bus(page) (page_to_phys(page))
#define phys_to_page(paddr) (pfn_to_page(phys_to_pfn(paddr)))
-#define pfn_valid(pfn) ((pfn) >= min_low_pfn && (pfn) < max_mapnr)
+#define pfn_valid(pfn) (((pfn) >= min_low_pfn) && ((pfn) < max_low_pfn))
#define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT)