Hi Bean, Thank you for the patch! Yet something to improve: [auto build test ERROR on linus/master] [also build test ERROR on v5.7-rc6 next-20200518] [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/Bean-Huo/Micron-SLC-NAND-filling... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git b9bbe6ed63b2b9f2c9ee5cbd0f2c946a2723f4ce config: m68k-allmodconfig (attached as .config) compiler: m68k-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 COMPILER=gcc-9.3.0 make.cross ARCH=m68k 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 >>, old ones prefixed by <<): drivers/mtd/nand/raw/nand_base.c: In function 'nand_check_is_erased_page': 2611 | max_bitflips = 0; | ^~~~~~~~~~~~ drivers/mtd/nand/raw/nand_base.c:2611:2: note: each undeclared identifier is reported only once for each function it appears in vim +/max_bitflips +2611 drivers/mtd/nand/raw/nand_base.c 2586 2587 /** 2588 * nand_check_is_erased_page - check if this page is a empty page 2589 * @chip: nand chip info structure 2590 * @page_data: data buffer containing the data in the page being checked 2591 * @oob: indicate if chip->oob_poi points to oob date of the page 2592 * 2593 * Returns true if this is an un-programmed page, false otherwise. 2594 */ 2595 int nand_check_is_erased_page(struct nand_chip *chip, u8 *page_data, bool oob) 2596 { 2597 struct mtd_info *mtd = nand_to_mtd(chip); 2598 int ret, i; 2599 u8 *databuf, *eccbuf = NULL; 2600 struct mtd_oob_region oobregion; 2601 int datasize, eccbytes = 0; 2602 2603 databuf = page_data; 2604 datasize = chip->ecc.size; 2605 2606 if (oob) { 2607 mtd_ooblayout_ecc(mtd, 0, &oobregion); 2608 eccbuf = chip->oob_poi + oobregion.offset; 2609 eccbytes = chip->ecc.bytes; 2610 } 2612 2613 for (i = 0; i < chip->ecc.steps; i++) { 2614 ret = nand_check_erased_ecc_chunk(databuf, datasize, 2615 eccbuf, eccbytes, 2616 NULL, 0, chip->ecc.strength); 2617 if (ret < 0) 2618 return false; 2619 2620 databuf += chip->ecc.size; 2621 eccbuf += chip->ecc.bytes; 2622 } 2623 2624 return ret; 2625 } 2626 EXPORT_SYMBOL(nand_check_is_erased_page); 2627 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org