[jgunthorpe:iommufd 23/29] drivers/iommu/iommufd/io_pagetable.c:488:6: warning: comparison of distinct pointer types ('typeof (iova) *' (aka 'unsigned long *') and 'typeof (length - 1) *' (aka 'unsigned int *'))

[kernel test robot]

tree:   https://github.com/jgunthorpe/linux iommufd
head:   086f3f78da96ed1f11c2ac71115bb46e940e141e
commit: b944c7f08293cd7b049be615e67622f5d0d74cfb [23/29] iommufd: Data structure to provide IOVA to PFN mapping
config: hexagon-allmodconfig (https://download.01.org/0day-ci/archive/20220201/202202011657.SZg7SZfW-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6b1e844b69f15bb7dffaf9365cd2b355d2eb7579)
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/jgunthorpe/linux/commit/b944c7f08293cd7b049be615e67622f5d0d74cfb
        git remote add jgunthorpe https://github.com/jgunthorpe/linux
        git fetch --no-tags jgunthorpe iommufd
        git checkout b944c7f08293cd7b049be615e67622f5d0d74cfb
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/iommu/iommufd/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> drivers/iommu/iommufd/io_pagetable.c:488:6: warning: comparison of distinct pointer types ('typeof (iova) *' (aka 'unsigned long *') and 'typeof (length - 1) *' (aka 'unsigned int *')) [-Wcompare-distinct-pointer-types]
           if (check_add_overflow(iova, length - 1, &last_iova))
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:66:15: note: expanded from macro 'check_add_overflow'
           (void) (&__a == &__b);                  \
                   ~~~~ ^  ~~~~
   drivers/iommu/iommufd/io_pagetable.c:548:14: warning: comparison of distinct pointer types ('typeof (iova) *' (aka 'unsigned long *') and 'typeof (length - 1) *' (aka 'unsigned int *')) [-Wcompare-distinct-pointer-types]
               WARN_ON(check_add_overflow(iova, length - 1, &last_iova)))
                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/overflow.h:66:15: note: expanded from macro 'check_add_overflow'
           (void) (&__a == &__b);                  \
                   ~~~~ ^  ~~~~
   include/asm-generic/bug.h:121:25: note: expanded from macro 'WARN_ON'
           int __ret_warn_on = !!(condition);                              \
                                  ^~~~~~~~~
   2 warnings generated.


vim +488 drivers/iommu/iommufd/io_pagetable.c

   462	
   463	/**
   464	* iopt_access_pages - Return a list of pages under the iova
   465	*
   466	* Reads @npages starting at iova and returns the struct page * pointers. These
   467	* can be kmap'd by the caller for CPU access.
   468	*
   469	* The caller must perform iopt_unaccess_pages() when done to balance this.
   470	*
   471	* iova can be unaligned from PAGE_SIZE. The first returned byte starts at
   472	* page_to_phys(out_pages[0]) + (iova % PAGE_SIZE). The caller promises not
   473	* to touch memory outside the requested iova slice.
   474	*
   475	* FIXME: callers that need a DMA mapping via a sgl should create another
   476	* interface to build the SGL efficiently
   477	*/
   478	int iopt_access_pages(struct io_pagetable *iopt, unsigned long iova,
   479			      size_t length, struct page **out_pages, bool write)
   480	{
   481		unsigned long cur_iova = iova;
   482		unsigned long last_iova;
   483		struct iopt_area *area;
   484		int rc;
   485	
   486		if (!length)
   487			return -EINVAL;
 > 488		if (check_add_overflow(iova, length - 1, &last_iova))
   489			return -EOVERFLOW;
   490	
   491		down_read(&iopt->rwsem);
   492		for (area = iopt_area_iter_first(iopt, iova, last_iova); area;
   493		     area = iopt_area_iter_next(area, iova, last_iova)) {
   494			unsigned long last = min(last_iova, iopt_area_last_iova(area));
   495			unsigned long last_index;
   496			unsigned long index;
   497	
   498			/* Need contiguous areas in the access */
   499			if (iopt_area_iova(area) < cur_iova) {
   500				rc = -EINVAL;
   501				goto out_remove;
   502			}
   503	
   504			index = iopt_iova_to_index(area, cur_iova);
   505			last_index = iopt_iova_to_index(area, last);
   506			rc = iopt_pages_add_user(area->pages, index, last_index,
   507						 out_pages, write);
   508			if (rc)
   509				goto out_remove;
   510			if (last == last_iova)
   511				break;
   512			/*
   513			 * Can't cross areas that are not aligned to the system page
   514			 * size with this API.
   515			 */
   516			if (cur_iova % PAGE_SIZE) {
   517				rc = -EINVAL;
   518				goto out_remove;
   519			}
   520			cur_iova = last + 1;
   521			out_pages += last_index - index;
   522			atomic_inc(&area->num_users);
   523		}
   524	
   525		up_read(&iopt->rwsem);
   526		return 0;
   527	
   528	out_remove:
   529		if (cur_iova != iova)
   530			iopt_unaccess_pages(iopt, iova, cur_iova - iova);
   531		return rc;
   532	}
   533	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx