Hi Yukuai, On Thu, May 19, 2022 at 5:25 AM yukuai (C) <yukuai3@xxxxxxxxxx> wrote: > 在 2022/05/19 10:11, yukuai (C) 写道: > > 在 2022/05/18 23:52, kernel test robot 写道: > >> Thank you for the patch! Yet something to improve: > >> > >> [auto build test ERROR on next-20220517] > >> > >> url: > >> https://github.com/intel-lab-lkp/linux/commits/Yu-Kuai/bugfix-for-blk-throttle/20220518-151713 > >> > >> base: 47c1c54d1bcd0a69a56b49473bc20f17b70e5242 > >> config: m68k-allyesconfig > >> (https://download.01.org/0day-ci/archive/20220518/202205182347.tMOOqyfL-lkp@xxxxxxxxx/config) > >> > >> compiler: m68k-linux-gcc (GCC) 11.3.0 > >> 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/intel-lab-lkp/linux/commit/f8345dbaf4ed491742aab29834aff66b4930c087 > >> > >> git remote add linux-review > >> https://github.com/intel-lab-lkp/linux > >> git fetch --no-tags linux-review > >> Yu-Kuai/bugfix-for-blk-throttle/20220518-151713 > >> git checkout f8345dbaf4ed491742aab29834aff66b4930c087 > >> # save the config file > >> mkdir build_dir && cp config build_dir/.config > >> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 > >> make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash > >> > >> If you fix the issue, kindly add following tag as appropriate > >> Reported-by: kernel test robot <lkp@xxxxxxxxx> > >> > >> All errors (new ones prefixed by >>): > >> > >> m68k-linux-ld: block/blk-throttle.o: in function `tg_conf_updated': > >>>> blk-throttle.c:(.text+0x25bc): undefined reference to `__udivdi3' > >>>> m68k-linux-ld: blk-throttle.c:(.text+0x2626): undefined reference to > >>>> `__udivdi3' > > Hi, > > > > I'm confused here, the only place that I can relate to this: > > > > return dispatched * new_limit / old_limit; > > > > However, I don't understand yet why this is problematic... > >> `.exit.text' referenced in section `.data' of > >> sound/soc/codecs/tlv320adc3xxx.o: defined in discarded section > >> `.exit.text' of sound/soc/codecs/tlv320adc3xxx.o > > + static u64 throtl_update_bytes_disp(u64 dispatched, u64 new_limit, > + u64 old_limit) > + { > + if (new_limit == old_limit) > + return dispatched; > + > + if (new_limit == U64_MAX) > + return 0; > + > + return dispatched * new_limit / old_limit; > > I understand it now. I'm doing (u64 / u64), I should use div64_u64 Better, use mul_u64_u64_div_u64(), as "dispatched * new_limit" may overflow? > + } > + > + static u32 throtl_update_io_disp(u32 dispatched, u32 new_limit, u32 old_limit) > + { > + if (new_limit == old_limit) > + return dispatched; > + > + if (new_limit == UINT_MAX) > + return 0; > + > + return dispatched * new_limit / old_limit; This is the same as above, but now operating on u32s instead of u64s. Likewise, can the multiplication overflow? > + } Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
