On Thu, May 06, 2021 at 07:35:16AM +0800, kernel test robot wrote: > In file included from arch/ia64/include/asm/cacheflush.h:31, > from arch/ia64/include/asm/pgtable.h:153, > from include/linux/pgtable.h:6, > from arch/ia64/include/asm/uaccess.h:40, > from include/linux/uaccess.h:11, > from include/linux/sched/task.h:11, > from include/linux/sched/signal.h:9, > from arch/ia64/kernel/asm-offsets.c:10: > include/asm-generic/cacheflush.h: In function 'flush_dcache_folio': > >> include/asm-generic/cacheflush.h:61:19: error: implicit declaration of function 'folio_nr_pages'; did you mean 'folio_page'? [-Werror=implicit-function-declaration] Ugh, I can't be bothered to untangle the ia64 header file mess. I'll just move the function out of line.