Despite the fact that subtraction of unsigned integers is a defined behaviour however such operations can lead to unexpected results. Thus it is better to check both left and right boundaries to avoid potential bugs as it done in the generic page.h. Signed-off-by: Yuriy Kolerov <yuriy.kolerov at synopsys.com> --- arch/arc/include/asm/page.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h index 296c342..81cfc6c7 100644 --- a/arch/arc/include/asm/page.h +++ b/arch/arc/include/asm/page.h @@ -88,7 +88,7 @@ typedef pte_t * pgtable_t; #define ARCH_PFN_OFFSET virt_to_pfn(CONFIG_LINUX_LINK_BASE) #ifdef CONFIG_FLATMEM -#define pfn_valid(pfn) (((pfn) - ARCH_PFN_OFFSET) < max_mapnr) +#define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr) #endif /* -- 2.7.4
