The ifdef conditions in include/linux/mm.h presents three cases: - !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) There is no actual definition of function but include/linux/mm.h has a static inline stub defined. - defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) linux/mm.h does not define a prototype, but mm/page_alloc.c defines the function. Hence, compiler reports the following warning: mm/page_alloc.c:4300:15: warning: no previous prototype for ‘__early_pfn_to_nid’ [-Wmissing-prototypes] - defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) The architecture defines the function, and linux/mm.h has a prototype. Thus, join the conditions of Case 2 and 3 i.e. eliminate the ifdef condition of CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID to eliminate the missing prototype warning from file mm/page_alloc.c. Signed-off-by: Rashika Kheria <rashika.kheria@xxxxxxxxx> Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx> --- include/linux/mm.h | 2 -- 1 file changed, 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 1cedd00..5f8348f 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1589,10 +1589,8 @@ static inline int __early_pfn_to_nid(unsigned long pfn) #else /* please see mm/page_alloc.c */ extern int __meminit early_pfn_to_nid(unsigned long pfn); -#ifdef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID /* there is a per-arch backend function. */ extern int __meminit __early_pfn_to_nid(unsigned long pfn); -#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */ #endif extern void set_dma_reserve(unsigned long new_dma_reserve); -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>