Hi "Matthew, Thank you for the patch! Yet something to improve: [auto build test ERROR on hnaz-linux-mm/master] url: https://github.com/0day-ci/linux/commits/Matthew-Wilcox-Oracle/mm-Move-pa... base: https://github.com/hnaz/linux-mm master config: nios2-defconfig (attached as .config) compiler: nios2-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/0day-ci/linux/commit/5f7b112de945843f38fbf9f602dd54701... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Matthew-Wilcox-Oracle/mm-Move-page_mapping_file-to-pagemap-h/20210316-221138 git checkout 5f7b112de945843f38fbf9f602dd547010e8b8d0 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nios2 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>): arch/nios2/mm/cacheflush.c:160:6: warning: no previous prototype for '__flush_dcache_page' [-Wmissing-prototypes] 160 | void __flush_dcache_page(struct address_space *mapping, struct page *page) | ^~~~~~~~~~~~~~~~~~~ arch/nios2/mm/cacheflush.c: In function 'flush_dcache_page': 183 | mapping = page_mapping_file(page); | ^~~~~~~~~~~~~~~~~ | page_mapping 183 | mapping = page_mapping_file(page); | ^ arch/nios2/mm/cacheflush.c: In function 'update_mmu_cache': arch/nios2/mm/cacheflush.c:221:10: warning: assignment to 'struct address_space *' from 'int' makes pointer from integer without a cast [-Wint-conversion] 221 | mapping = page_mapping_file(page); | ^ cc1: some warnings being treated as errors vim +183 arch/nios2/mm/cacheflush.c 93c91cb228e76b Ley Foon Tan 2014-11-06 159 1a70db49a73535 Ley Foon Tan 2015-04-24 @160 void __flush_dcache_page(struct address_space *mapping, struct page *page) 1a70db49a73535 Ley Foon Tan 2015-04-24 161 { 1a70db49a73535 Ley Foon Tan 2015-04-24 162 /* 1a70db49a73535 Ley Foon Tan 2015-04-24 163 * Writeback any data associated with the kernel mapping of this 1a70db49a73535 Ley Foon Tan 2015-04-24 164 * page. This ensures that data in the physical page is mutually 1a70db49a73535 Ley Foon Tan 2015-04-24 165 * coherent with the kernels mapping. 1a70db49a73535 Ley Foon Tan 2015-04-24 166 */ 1a70db49a73535 Ley Foon Tan 2015-04-24 167 unsigned long start = (unsigned long)page_address(page); 1a70db49a73535 Ley Foon Tan 2015-04-24 168 8e3d7c834ba0f7 Ley Foon Tan 2015-11-26 169 __flush_dcache(start, start + PAGE_SIZE); 1a70db49a73535 Ley Foon Tan 2015-04-24 170 } 1a70db49a73535 Ley Foon Tan 2015-04-24 171 93c91cb228e76b Ley Foon Tan 2014-11-06 172 void flush_dcache_page(struct page *page) 93c91cb228e76b Ley Foon Tan 2014-11-06 173 { 93c91cb228e76b Ley Foon Tan 2014-11-06 174 struct address_space *mapping; 93c91cb228e76b Ley Foon Tan 2014-11-06 175 93c91cb228e76b Ley Foon Tan 2014-11-06 176 /* 93c91cb228e76b Ley Foon Tan 2014-11-06 177 * The zero page is never written to, so never has any dirty 93c91cb228e76b Ley Foon Tan 2014-11-06 178 * cache lines, and therefore never needs to be flushed. 93c91cb228e76b Ley Foon Tan 2014-11-06 179 */ 93c91cb228e76b Ley Foon Tan 2014-11-06 180 if (page == ZERO_PAGE(0)) 93c91cb228e76b Ley Foon Tan 2014-11-06 181 return; 93c91cb228e76b Ley Foon Tan 2014-11-06 182 cb9f753a3731f7 Huang Ying 2018-04-05 @183 mapping = page_mapping_file(page); 93c91cb228e76b Ley Foon Tan 2014-11-06 184 93c91cb228e76b Ley Foon Tan 2014-11-06 185 /* Flush this page if there are aliases. */ 93c91cb228e76b Ley Foon Tan 2014-11-06 186 if (mapping && !mapping_mapped(mapping)) { 93c91cb228e76b Ley Foon Tan 2014-11-06 187 clear_bit(PG_dcache_clean, &page->flags); 93c91cb228e76b Ley Foon Tan 2014-11-06 188 } else { 1a70db49a73535 Ley Foon Tan 2015-04-24 189 __flush_dcache_page(mapping, page); 1a70db49a73535 Ley Foon Tan 2015-04-24 190 if (mapping) { 93c91cb228e76b Ley Foon Tan 2014-11-06 191 unsigned long start = (unsigned long)page_address(page); 93c91cb228e76b Ley Foon Tan 2014-11-06 192 flush_aliases(mapping, page); 1a70db49a73535 Ley Foon Tan 2015-04-24 193 flush_icache_range(start, start + PAGE_SIZE); 1a70db49a73535 Ley Foon Tan 2015-04-24 194 } 93c91cb228e76b Ley Foon Tan 2014-11-06 195 set_bit(PG_dcache_clean, &page->flags); 93c91cb228e76b Ley Foon Tan 2014-11-06 196 } 93c91cb228e76b Ley Foon Tan 2014-11-06 197 } 93c91cb228e76b Ley Foon Tan 2014-11-06 198 EXPORT_SYMBOL(flush_dcache_page); 93c91cb228e76b Ley Foon Tan 2014-11-06 199 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org