Re: [PATCH 2/6] mm: Constify page_address_in_vma()

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

Hi Matthew,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master next-20240724]
[cannot apply to tip/x86/mm dennis-percpu/for-next v6.10]
[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/Matthew-Wilcox-Oracle/bootmem-Stop-using-page-index/20240723-233932
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240723153503.1669586-3-willy%40infradead.org
patch subject: [PATCH 2/6] mm: Constify page_address_in_vma()
config: sh-migor_defconfig (https://download.01.org/0day-ci/archive/20240724/202407241541.GgplaeTD-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240724/202407241541.GgplaeTD-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/202407241541.GgplaeTD-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from mm/rmap.c:56:
   mm/rmap.c: In function 'page_address_in_vma':
>> mm/rmap.c:796:47: warning: passing argument 1 of 'folio_pfn' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     796 |         pgoff = folio->index + folio_page_idx(folio, page);
         |                                               ^~~~~
   include/linux/mm.h:216:69: note: in definition of macro 'folio_page_idx'
     216 | #define folio_page_idx(folio, p)        (page_to_pfn(p) - folio_pfn(folio))
         |                                                                     ^~~~~
   include/linux/mm.h:1877:53: note: expected 'struct folio *' but argument is of type 'const struct folio *'
    1877 | static inline unsigned long folio_pfn(struct folio *folio)
         |                                       ~~~~~~~~~~~~~~^~~~~


vim +796 mm/rmap.c

72b252aed506b8 Mel Gorman              2015-09-04  769  
^1da177e4c3f41 Linus Torvalds          2005-04-16  770  /*
bf89c8c8673223 Huang Shijie            2009-10-01  771   * At what user virtual address is page expected in vma?
ab941e0fff3947 Naoya Horiguchi         2010-05-11  772   * Caller should check the page is actually part of the vma.
^1da177e4c3f41 Linus Torvalds          2005-04-16  773   */
eb7052fd71d991 Matthew Wilcox (Oracle  2024-07-23  774) unsigned long page_address_in_vma(const struct page *page,
eb7052fd71d991 Matthew Wilcox (Oracle  2024-07-23  775) 		struct vm_area_struct *vma)
^1da177e4c3f41 Linus Torvalds          2005-04-16  776  {
eb7052fd71d991 Matthew Wilcox (Oracle  2024-07-23  777) 	const struct folio *folio = page_folio(page);
412ad5fbe9285f Matthew Wilcox (Oracle  2024-03-28  778) 	pgoff_t pgoff;
412ad5fbe9285f Matthew Wilcox (Oracle  2024-03-28  779) 
e05b34539d008a Matthew Wilcox (Oracle  2022-01-29  780) 	if (folio_test_anon(folio)) {
e05b34539d008a Matthew Wilcox (Oracle  2022-01-29  781) 		struct anon_vma *page__anon_vma = folio_anon_vma(folio);
4829b906cc063c Hugh Dickins            2010-10-02  782  		/*
4829b906cc063c Hugh Dickins            2010-10-02  783  		 * Note: swapoff's unuse_vma() is more efficient with this
4829b906cc063c Hugh Dickins            2010-10-02  784  		 * check, and needs it to match anon_vma when KSM is active.
4829b906cc063c Hugh Dickins            2010-10-02  785  		 */
4829b906cc063c Hugh Dickins            2010-10-02  786  		if (!vma->anon_vma || !page__anon_vma ||
4829b906cc063c Hugh Dickins            2010-10-02  787  		    vma->anon_vma->root != page__anon_vma->root)
21d0d443cdc165 Andrea Arcangeli        2010-08-09  788  			return -EFAULT;
31657170deaf1d Jue Wang                2021-06-15  789  	} else if (!vma->vm_file) {
^1da177e4c3f41 Linus Torvalds          2005-04-16  790  		return -EFAULT;
e05b34539d008a Matthew Wilcox (Oracle  2022-01-29  791) 	} else if (vma->vm_file->f_mapping != folio->mapping) {
^1da177e4c3f41 Linus Torvalds          2005-04-16  792  		return -EFAULT;
31657170deaf1d Jue Wang                2021-06-15  793  	}
494334e43c16d6 Hugh Dickins            2021-06-15  794  
412ad5fbe9285f Matthew Wilcox (Oracle  2024-03-28  795) 	/* The !page__anon_vma above handles KSM folios */
412ad5fbe9285f Matthew Wilcox (Oracle  2024-03-28 @796) 	pgoff = folio->index + folio_page_idx(folio, page);
e0abfbb6714244 Matthew Wilcox (Oracle  2024-03-28  797) 	return vma_address(vma, pgoff, 1);
^1da177e4c3f41 Linus Torvalds          2005-04-16  798  }
^1da177e4c3f41 Linus Torvalds          2005-04-16  799  

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