Re: [PATCH RFC 2/2] wcslen() prototype in string.h

[kernel test robot <lkp@intel.com>]

Hi Nathan,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on 78ab93c78fb31c5dfe207318aa2b7bd4e41f8dba]

url:    https://github.com/intel-lab-lkp/linux/commits/Nathan-Chancellor/lib-string-c-Add-wcslen/20250325-234847
base:   78ab93c78fb31c5dfe207318aa2b7bd4e41f8dba
patch link:    https://lore.kernel.org/r/20250325-string-add-wcslen-for-llvm-opt-v1-2-b8f1e2c17888%40kernel.org
patch subject: [PATCH RFC 2/2] wcslen() prototype in string.h
config: s390-randconfig-001-20250326 (https://download.01.org/0day-ci/archive/20250326/202503260611.MDurOUhF-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250326/202503260611.MDurOUhF-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202503260611.MDurOUhF-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from arch/s390/boot/ipl_data.c:3:
   In file included from include/linux/compat.h:14:
   In file included from include/linux/sem.h:5:
   In file included from include/uapi/linux/sem.h:5:
   In file included from include/linux/ipc.h:7:
   In file included from include/linux/rhashtable-types.h:12:
   In file included from include/linux/alloc_tag.h:13:
   In file included from include/linux/cpumask.h:12:
   In file included from include/linux/bitmap.h:13:
   In file included from include/linux/string.h:10:
>> include/linux/nls.h:101:34: warning: passing 'char[6]' to parameter of type 'unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign]
           charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE);
                                           ^~~
   1 warning generated.
--
   In file included from arch/s390/boot/decompressor.c:11:
   In file included from include/linux/string.h:10:
>> include/linux/nls.h:101:34: warning: passing 'char[6]' to parameter of type 'unsigned char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign]
           charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE);
                                           ^~~
   In file included from arch/s390/boot/decompressor.c:48:
   arch/s390/include/uapi/../../../../lib/decompress_unlz4.c:160:29: warning: passing 'u8 *' (aka 'unsigned char *') to parameter of type 'const char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign]
                   ret = LZ4_decompress_fast(inp, outp, dest_len);
                                             ^~~
   arch/s390/include/uapi/../../../../lib/lz4/lz4_decompress.c:477:37: note: passing argument to parameter 'source' here
   int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
                                       ^
   In file included from arch/s390/boot/decompressor.c:48:
   arch/s390/include/uapi/../../../../lib/decompress_unlz4.c:160:34: warning: passing 'u8 *' (aka 'unsigned char *') to parameter of type 'char *' converts between pointers to integer types where one is of the unique plain 'char' type and the other is not [-Wpointer-sign]
                   ret = LZ4_decompress_fast(inp, outp, dest_len);
                                                  ^~~~
   arch/s390/include/uapi/../../../../lib/lz4/lz4_decompress.c:477:51: note: passing argument to parameter 'dest' here
   int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
                                                     ^
   3 warnings generated.


vim +101 include/linux/nls.h

^1da177e4c3f41 Linus Torvalds 2005-04-16   86  
d37dc42ab6f040 Jeff Layton    2009-04-30   87  /*
d37dc42ab6f040 Jeff Layton    2009-04-30   88   * nls_nullsize - return length of null character for codepage
d37dc42ab6f040 Jeff Layton    2009-04-30   89   * @codepage - codepage for which to return length of NULL terminator
d37dc42ab6f040 Jeff Layton    2009-04-30   90   *
d37dc42ab6f040 Jeff Layton    2009-04-30   91   * Since we can't guarantee that the null terminator will be a particular
d37dc42ab6f040 Jeff Layton    2009-04-30   92   * length, we have to check against the codepage. If there's a problem
d37dc42ab6f040 Jeff Layton    2009-04-30   93   * determining it, assume a single-byte NULL terminator.
d37dc42ab6f040 Jeff Layton    2009-04-30   94   */
d37dc42ab6f040 Jeff Layton    2009-04-30   95  static inline int
d37dc42ab6f040 Jeff Layton    2009-04-30   96  nls_nullsize(const struct nls_table *codepage)
d37dc42ab6f040 Jeff Layton    2009-04-30   97  {
d37dc42ab6f040 Jeff Layton    2009-04-30   98  	int charlen;
d37dc42ab6f040 Jeff Layton    2009-04-30   99  	char tmp[NLS_MAX_CHARSET_SIZE];
d37dc42ab6f040 Jeff Layton    2009-04-30  100  
d37dc42ab6f040 Jeff Layton    2009-04-30 @101  	charlen = codepage->uni2char(0, tmp, NLS_MAX_CHARSET_SIZE);
d37dc42ab6f040 Jeff Layton    2009-04-30  102  
d37dc42ab6f040 Jeff Layton    2009-04-30  103  	return charlen > 0 ? charlen : 1;
d37dc42ab6f040 Jeff Layton    2009-04-30  104  }
d37dc42ab6f040 Jeff Layton    2009-04-30  105  

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