Re: Re: fs/proc/task_mmu: Implement IOCTL for efficient page table scanning

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

Hi Michał,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master v6.5-rc2 next-20230720]
[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/Micha-Miros-aw/Re-fs-proc-task_mmu-Implement-IOCTL-for-efficient-page-table-scanning/20230721-033050
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/a0b5c6776b2ed91f78a7575649f8b100e58bd3a9.1689881078.git.mirq-linux%40rere.qmqm.pl
patch subject: Re: fs/proc/task_mmu: Implement IOCTL for efficient page table scanning
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20230721/202307210528.2qgK1vwi-lkp@intel.com/config)
compiler: mips-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230721/202307210528.2qgK1vwi-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/202307210528.2qgK1vwi-lkp@intel.com/

All warnings (new ones prefixed by >>):

   fs/proc/task_mmu.c: In function 'pagemap_scan_test_walk':
   fs/proc/task_mmu.c:1921:13: error: implicit declaration of function 'userfaultfd_wp_async'; did you mean 'userfaultfd_wp'? [-Werror=implicit-function-declaration]
    1921 |         if (userfaultfd_wp_async(vma) && userfaultfd_wp_use_markers(vma))
         |             ^~~~~~~~~~~~~~~~~~~~
         |             userfaultfd_wp
   fs/proc/task_mmu.c: In function 'pagemap_scan_init_bounce_buffer':
>> fs/proc/task_mmu.c:2290:22: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    2290 |         p->vec_out = (void __user *)p->arg.vec;
         |                      ^
   fs/proc/task_mmu.c: At top level:
   fs/proc/task_mmu.c:1967:13: warning: 'pagemap_scan_backout_range' defined but not used [-Wunused-function]
    1967 | static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +2290 fs/proc/task_mmu.c

  2264	
  2265	static int pagemap_scan_init_bounce_buffer(struct pagemap_scan_private *p)
  2266	{
  2267		if (!p->arg.vec_len) {
  2268			/*
  2269			 * An arbitrary non-page-aligned sentinel value for
  2270			 * pagemap_scan_push_range().
  2271			 */
  2272			p->cur_buf.start = p->cur_buf.end = ULLONG_MAX;
  2273			return 0;
  2274		}
  2275	
  2276		/*
  2277		 * Allocate a smaller buffer to get output from inside the page
  2278		 * walk functions and walk the range in PAGEMAP_WALK_SIZE chunks.
  2279		 * The last range is always stored in p.cur_buf to allow coalescing
  2280		 * consecutive ranges that have the same categories returned across
  2281		 * walk_page_range() calls.
  2282		 */
  2283		p->vec_buf_len = min_t(size_t, PAGEMAP_WALK_SIZE >> PAGE_SHIFT,
  2284				       p->arg.vec_len - 1);
  2285		p->vec_buf = kmalloc_array(p->vec_buf_len, sizeof(*p->vec_buf),
  2286					   GFP_KERNEL);
  2287		if (!p->vec_buf)
  2288			return -ENOMEM;
  2289	
> 2290		p->vec_out = (void __user *)p->arg.vec;
  2291	
  2292		return 0;
  2293	}
  2294	

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