在 2022/05/19 15:01, Geert Uytterhoeven 写道:
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?
Hi,
It's right that it can overflow, I'll handle such case in next version.
+ }
+
+ 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?
same as above.
Thanks,
Kuai
+ }
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
.
