Re: [PATCH] mm/vmalloc: Replace the ternary conditional operator with min()

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

Hi Lu,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Lu-Hongfei/mm-vmalloc-Replace-the-ternary-conditional-operator-with-min/20230609-141417
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20230609061309.42453-1-luhongfei%40vivo.com
patch subject: [PATCH] mm/vmalloc: Replace the ternary conditional operator with min()
config: i386-randconfig-i011-20230608 (https://download.01.org/0day-ci/archive/20230609/202306091701.KHIG4Osf-lkp@intel.com/config)
compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
reproduce (this is a W=1 build):
        mkdir -p ~/bin
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git remote add akpm-mm https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git
        git fetch akpm-mm mm-everything
        git checkout akpm-mm/mm-everything
        b4 shazam https://lore.kernel.org/r/20230609061309.42453-1-luhongfei@vivo.com
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

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/202306091701.KHIG4Osf-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/vmalloc.c:3574:9: warning: comparison of distinct pointer types ('typeof (remains) *' (aka 'unsigned int *') and 'typeof (((1UL) << 12)) *' (aka 'unsigned long *')) [-Wcompare-distinct-pointer-types]
                   num = min(remains, PAGE_SIZE);
                         ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(x, y, <)
                           ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
           __builtin_choose_expr(__safe_cmp(x, y), \
                                 ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                   (__typecheck(x, y) && __no_side_effects(x, y))
                    ^~~~~~~~~~~~~~~~~
   include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
           (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~
   1 warning generated.


vim +3574 mm/vmalloc.c

  3561	
  3562	/*
  3563	 * Atomically zero bytes in the iterator.
  3564	 *
  3565	 * Returns the number of zeroed bytes.
  3566	 */
  3567	static size_t zero_iter(struct iov_iter *iter, size_t count)
  3568	{
  3569		size_t remains = count;
  3570	
  3571		while (remains > 0) {
  3572			size_t num, copied;
  3573	
> 3574			num = min(remains, PAGE_SIZE);
  3575			copied = copy_page_to_iter_nofault(ZERO_PAGE(0), 0, num, iter);
  3576			remains -= copied;
  3577	
  3578			if (copied < num)
  3579				break;
  3580		}
  3581	
  3582		return count - remains;
  3583	}
  3584	

-- 
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https://github.com/intel/lkp-tests/wiki