Re: [PATCH 23/32] iov_iter: copy_folio_from_iter_atomic()

kernel test robot
2023-05-10T02:21:14Z

Hi Kent,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/locking/core]
[cannot apply to axboe-block/for-next akpm-mm/mm-everything kdave/for-next linus/master v6.4-rc1 next-20230509]
[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/Kent-Overstreet/Compiler-Attributes-add-__flatten/20230510-010302
base: tip/locking/core
patch link: https://lore.kernel.org/r/20230509165657.1735798-24-kent.overstreet%40linux.dev
patch subject: [PATCH 23/32] iov_iter: copy_folio_from_iter_atomic()
config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20230510/202305101003.uncpRKqA-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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/0e5d4229f5e7671dabba56ea36583b1ca20a9a18
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Kent-Overstreet/Compiler-Attributes-add-__flatten/20230510-010302
git checkout 0e5d4229f5e7671dabba56ea36583b1ca20a9a18
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202305101003.uncpRKqA-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> lib/iov_iter.c:839:16: warning: comparison of distinct pointer types ('typeof (bytes) *' (aka 'unsigned int *') and 'typeof (((1UL) << 12) - (offset & (~(((1UL) << 12) - 1)))) *' (aka 'unsigned long *')) [-Wcompare-distinct-pointer-types]
unsigned b = min(bytes, PAGE_SIZE - (offset & PAGE_MASK));
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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 +839 lib/iov_iter.c

825
826 size_t copy_folio_from_iter_atomic(struct folio *folio, size_t offset,
827 size_t bytes, struct iov_iter *i)
828 {
829 size_t ret = 0;
830
831 if (WARN_ON(offset + bytes > folio_size(folio)))
832 return 0;
833 if (WARN_ON_ONCE(!i->data_source))
834 return 0;
835
836 #ifdef CONFIG_HIGHMEM
837 while (bytes) {
838 struct page *page = folio_page(folio, offset >> PAGE_SHIFT);
> 839 unsigned b = min(bytes, PAGE_SIZE - (offset & PAGE_MASK));
840 unsigned r = __copy_page_from_iter_atomic(page, offset, b, i);
841
842 offset += r;
843 bytes -= r;
844 ret += r;
845
846 if (r != b)
847 break;
848 }
849 #else
850 ret = __copy_page_from_iter_atomic(&folio->page, offset, bytes, i);
851 #endif
852
853 return ret;
854 }
855 EXPORT_SYMBOL(copy_folio_from_iter_atomic);
856

--
0-DAY CI Kernel Test Service