linux-kernel - [ammarfaizi2-block:dhowells/linux-fs/netfs-linked-list 30/57] lib/iov_iter.c:1464:9: warning: comparison of distinct pointer types ('typeof (nr * ((1UL) << 12) - offset) *' (aka 'unsigned long *') and 'typeof (maxsize) *' (aka 'unsigned int *'))

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Message-ID: <202206111500.VcHCpPMw-lkp@intel.com>
Date:   Sat, 11 Jun 2022 15:45:10 +0800
From:   kernel test robot <lkp@...el.com>
To:     David Howells <dhowells@...hat.com>
Cc:     llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
        GNU/Weeb Mailing List <gwml@...r.gnuweeb.org>,
        linux-kernel@...r.kernel.org
Subject: [ammarfaizi2-block:dhowells/linux-fs/netfs-linked-list 30/57]
 lib/iov_iter.c:1464:9: warning: comparison of distinct pointer types
 ('typeof (nr * ((1UL) << 12) - offset) *' (aka 'unsigned long *') and
 'typeof (maxsize) *' (aka 'unsigned int *'))

tree:   https://github.com/ammarfaizi2/linux-block dhowells/linux-fs/netfs-linked-list
head:   c19d336b7f0c53bd31e73f6d7d6c1524f0df55b8
commit: cce0a847405ef7d076fde956ba5dd1a4d7d901c2 [30/57] iov_iter: Fix iter_xarray_get_pages{,_alloc}()
config: arm-randconfig-r034-20220610 (https://download.01.org/0day-ci/archive/20220611/202206111500.VcHCpPMw-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project ff4abe755279a3a47cc416ef80dbc900d9a98a19)
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
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/ammarfaizi2/linux-block/commit/cce0a847405ef7d076fde956ba5dd1a4d7d901c2
        git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
        git fetch --no-tags ammarfaizi2-block dhowells/linux-fs/netfs-linked-list
        git checkout cce0a847405ef7d076fde956ba5dd1a4d7d901c2
        # 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=arm SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@...el.com>

All warnings (new ones prefixed by >>):

>> lib/iov_iter.c:1464:9: warning: comparison of distinct pointer types ('typeof (nr * ((1UL) << 12) - offset) *' (aka 'unsigned long *') and 'typeof (maxsize) *' (aka 'unsigned int *')) [-Wcompare-distinct-pointer-types]
           return min(nr * PAGE_SIZE - offset, maxsize);
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:45:19: 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)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~
   lib/iov_iter.c:1628:9: warning: comparison of distinct pointer types ('typeof (nr * ((1UL) << 12) - offset) *' (aka 'unsigned long *') and 'typeof (maxsize) *' (aka 'unsigned int *')) [-Wcompare-distinct-pointer-types]
           return min(nr * PAGE_SIZE - offset, maxsize);
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:45:19: 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)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~
   2 warnings generated.


vim +1464 lib/iov_iter.c

  1430	
  1431	static ssize_t iter_xarray_get_pages(struct iov_iter *i,
  1432					     struct page **pages, size_t maxsize,
  1433					     unsigned maxpages, size_t *_start_offset)
  1434	{
  1435		unsigned nr, offset;
  1436		pgoff_t index, count;
  1437		size_t size = maxsize;
  1438		loff_t pos;
  1439	
  1440		if (!size || !maxpages)
  1441			return 0;
  1442	
  1443		pos = i->xarray_start + i->iov_offset;
  1444		index = pos >> PAGE_SHIFT;
  1445		offset = pos & ~PAGE_MASK;
  1446		*_start_offset = offset;
  1447	
  1448		count = 1;
  1449		if (size > PAGE_SIZE - offset) {
  1450			size -= PAGE_SIZE - offset;
  1451			count += size >> PAGE_SHIFT;
  1452			size &= ~PAGE_MASK;
  1453			if (size)
  1454				count++;
  1455		}
  1456	
  1457		if (count > maxpages)
  1458			count = maxpages;
  1459	
  1460		nr = iter_xarray_populate_pages(pages, i->xarray, index, count);
  1461		if (nr == 0)
  1462			return 0;
  1463	
> 1464		return min(nr * PAGE_SIZE - offset, maxsize);
  1465	}
  1466	

-- 
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https://01.org/lkp