Re: [PATCH 2/2] lib/string.c: Optimize memchr()
From: kernel test robot
Date: Sun Jul 10 2022 - 13:00:58 EST
Hi Yu-Jen,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linus/master]
[also build test ERROR on v5.19-rc5 next-20220708]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Yu-Jen-Chang/Optimize-memchr/20220710-223118
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git b1c428b6c3684ee8ddf4137d68b3e8d51d2a700f
config: hexagon-randconfig-r041-20220710 (https://download.01.org/0day-ci/archive/20220711/202207110028.KNZ3Yupd-lkp@xxxxxxxxx/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 6ce63e267aab79ca87bf63453d34dd3909ab978d)
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/307ee542c2bd8378b2225910f3f9b982df7a7669
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Yu-Jen-Chang/Optimize-memchr/20220710-223118
git checkout 307ee542c2bd8378b2225910f3f9b982df7a7669
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>
All errors (new ones prefixed by >>):
>> lib/string.c:902:7: error: conflicting types for 'memchr'
void *memchr(const void *p, int c, unsigned long length)
^
include/linux/string.h:162:15: note: previous declaration is here
extern void * memchr(const void *,int,__kernel_size_t);
^
1 error generated.
vim +/memchr +902 lib/string.c
891
892 #ifndef __HAVE_ARCH_MEMCHR
893 /**
894 * memchr - Find a character in an area of memory.
895 * @p: The memory area
896 * @c: The byte to search for
897 * @length: The size of the area.
898 *
899 * returns the address of the first occurrence of @c, or %NULL
900 * if @c is not found
901 */
> 902 void *memchr(const void *p, int c, unsigned long length)
903 {
904 u64 mask, val;
905 const void *end = p + length;
906
907 c &= 0xff;
908 if (p <= end - 8) {
909 mask = c;
910 MEMCHR_MASK_GEN(mask);
911
912 for (; p <= end - 8; p += 8) {
913 val = *(u64 *)p ^ mask;
914 if ((val + 0xfefefefefefefeffu) &
915 (~val & 0x8080808080808080u))
916 break;
917 }
918 }
919
920 for (; p < end; p++)
921 if (*(unsigned char *)p == c)
922 return (void *)p;
923
924 return NULL;
925 }
926 EXPORT_SYMBOL(memchr);
927 #endif
928
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