Hi Matthew, Thank you for the patch! Yet something to improve: [auto build test ERROR on ia64/next] [also build test ERROR on m68k/for-next s390/features linus/master v5.7-rc1 next-20200416] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Matthew-Wilcox/Make-PageWritebac... base: https://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux.git next config: mips-allyesconfig (attached as .config) compiler: mips-linux-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from include/linux/bitops.h:29, from include/linux/kernel.h:12, from include/asm-generic/bug.h:19, from arch/mips/include/asm/bug.h:42, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: arch/mips/include/asm/bitops.h: In function 'clear_bit_unlock_is_negative_byte': 154 | return test_bit(7, p); | ^~~~~~~~ | set_bit In file included from arch/mips/include/asm/bitops.h:294, from include/linux/bitops.h:29, from include/linux/kernel.h:12, from include/asm-generic/bug.h:19, from arch/mips/include/asm/bug.h:42, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: include/asm-generic/bitops/non-atomic.h: At top level: include/asm-generic/bitops/non-atomic.h:104:19: error: static declaration of 'test_bit' follows non-static declaration 104 | static inline int test_bit(int nr, const volatile unsigned long *addr) | ^~~~~~~~ In file included from include/linux/bitops.h:29, from include/linux/kernel.h:12, from include/asm-generic/bug.h:19, from arch/mips/include/asm/bug.h:42, from include/linux/bug.h:5, from include/linux/page-flags.h:10, from kernel/bounds.c:10: arch/mips/include/asm/bitops.h:154:9: note: previous implicit declaration of 'test_bit' was here 154 | return test_bit(7, p); | ^~~~~~~~ cc1: some warnings being treated as errors make[2]: *** [scripts/Makefile.build:101: kernel/bounds.s] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1113: prepare0] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:180: sub-make] Error 2 23 real 7 user 10 sys 75.85% cpu make prepare vim +154 arch/mips/include/asm/bitops.h 149 150 static inline bool clear_bit_unlock_is_negative_byte(unsigned int nr, 151 volatile unsigned long *p) 152 { 153 clear_bit_unlock(nr, p); 155 } 156 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org