Re: [PATCH 10/16] mm: replace pmd_to_swp_entry() with leafent_from_pmd()

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

On Mon, Nov 03, 2025 at 11:01:09PM +0800, kernel test robot wrote:
> Hi Lorenzo,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on akpm-mm/mm-everything]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-correctly-handle-UFFD-PTE-markers/20251103-204118
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/38c26e75ed00263e9ecbebb0c045dd6d8183ec67.1762171281.git.lorenzo.stoakes%40oracle.com
> patch subject: [PATCH 10/16] mm: replace pmd_to_swp_entry() with leafent_from_pmd()
> config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20251103/202511032203.LAN8NcTM-lkp@intel.com/config)
> compiler: or1k-linux-gcc (GCC) 15.1.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251103/202511032203.LAN8NcTM-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/202511032203.LAN8NcTM-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
>    In file included from include/linux/mm_inline.h:11,
>                     from kernel/fork.c:46:
>    include/linux/leafops.h: In function 'leafent_from_pmd':
> >> include/linux/leafops.h:111:22: error: implicit declaration of function '__pmd_to_swp_entry'; did you mean 'pte_to_swp_entry'? [-Wimplicit-function-declaration]
>      111 |         arch_entry = __pmd_to_swp_entry(pmd);
>          |                      ^~~~~~~~~~~~~~~~~~
>          |                      pte_to_swp_entry

Yeah this needs some #ifdeffery around CONFIG_ARCH_ENABLE_THP_MIGRATION.

Probably different arches do different things in terms of defining/not defining
this.

Will send fix-patch...

> >> include/linux/leafops.h:111:22: error: incompatible types when assigning to type 'leaf_entry_t' {aka 'swp_entry_t'} from type 'int'
> --
>    In file included from include/linux/leafops.h:6,
>                     from include/linux/migrate.h:9,
>                     from mm/folio-compat.c:7:
>    include/linux/swapops.h: In function 'swp_entry':
> >> include/linux/swapops.h:27:46: error: 'MAX_SWAPFILES_SHIFT' undeclared (first use in this function)
>       27 | #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
>          |                                              ^~~~~~~~~~~~~~~~~~~
>    include/linux/swapops.h:90:28: note: in expansion of macro 'SWP_TYPE_SHIFT'
>       90 |         ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
>          |                            ^~~~~~~~~~~~~~
>    include/linux/swapops.h:27:46: note: each undeclared identifier is reported only once for each function it appears in
>       27 | #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
>          |                                              ^~~~~~~~~~~~~~~~~~~
>    include/linux/swapops.h:90:28: note: in expansion of macro 'SWP_TYPE_SHIFT'
>       90 |         ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
>          |                            ^~~~~~~~~~~~~~
>    include/linux/swapops.h: In function 'swp_type':
> >> include/linux/swapops.h:27:46: error: 'MAX_SWAPFILES_SHIFT' undeclared (first use in this function)
>       27 | #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
>          |                                              ^~~~~~~~~~~~~~~~~~~
>    include/linux/swapops.h:100:30: note: in expansion of macro 'SWP_TYPE_SHIFT'
>      100 |         return (entry.val >> SWP_TYPE_SHIFT);
>          |                              ^~~~~~~~~~~~~~
>    include/linux/swapops.h: In function 'swp_offset':
> >> include/linux/swapops.h:27:46: error: 'MAX_SWAPFILES_SHIFT' undeclared (first use in this function)
>       27 | #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
>          |                                              ^~~~~~~~~~~~~~~~~~~
>    include/linux/swapops.h:28:34: note: in expansion of macro 'SWP_TYPE_SHIFT'
>       28 | #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
>          |                                  ^~~~~~~~~~~~~~
>    include/linux/swapops.h:109:28: note: in expansion of macro 'SWP_OFFSET_MASK'
>      109 |         return entry.val & SWP_OFFSET_MASK;
>          |                            ^~~~~~~~~~~~~~~
>    In file included from include/linux/bits.h:5,
>                     from include/linux/ratelimit_types.h:5,
>                     from include/linux/printk.h:9,
>                     from include/asm-generic/bug.h:22,
>                     from arch/openrisc/include/asm/bug.h:5,
>                     from include/linux/bug.h:5,
>                     from include/linux/mmdebug.h:5,
>                     from include/linux/mm.h:6,
>                     from include/linux/migrate.h:5:
>    include/linux/swapops.h: In function 'swp_offset_pfn':
> >> include/linux/swapops.h:27:46: error: 'MAX_SWAPFILES_SHIFT' undeclared (first use in this function)
>       27 | #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
>          |                                              ^~~~~~~~~~~~~~~~~~~
>    include/vdso/bits.h:7:44: note: in definition of macro 'BIT'
>        7 | #define BIT(nr)                 (UL(1) << (nr))
>          |                                            ^~
>    include/linux/minmax.h:89:9: note: in expansion of macro '__cmp_once_unique'
>       89 |         __cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
>          |         ^~~~~~~~~~~~~~~~~
>    include/linux/minmax.h:161:27: note: in expansion of macro '__cmp_once'
>      161 | #define min_t(type, x, y) __cmp_once(min, type, x, y)
>          |                           ^~~~~~~~~~
>    include/linux/swapops.h:38:33: note: in expansion of macro 'min_t'
>       38 | #define SWP_PFN_BITS            min_t(int, \
>          |                                 ^~~~~
>    include/linux/swapops.h:40:39: note: in expansion of macro 'SWP_TYPE_SHIFT'
>       40 |                                       SWP_TYPE_SHIFT)
>          |                                       ^~~~~~~~~~~~~~
>    include/linux/swapops.h:42:38: note: in expansion of macro 'SWP_PFN_BITS'
>       42 | #define SWP_PFN_MASK            (BIT(SWP_PFN_BITS) - 1)
>          |                                      ^~~~~~~~~~~~
>    include/linux/swapops.h:120:36: note: in expansion of macro 'SWP_PFN_MASK'
>      120 |         return swp_offset(entry) & SWP_PFN_MASK;
>          |                                    ^~~~~~~~~~~~
>    include/linux/swapops.h: In function 'make_pte_marker_entry':
> >> include/linux/swapops.h:395:26: error: 'SWP_PTE_MARKER' undeclared (first use in this function)
>      395 |         return swp_entry(SWP_PTE_MARKER, marker);
>          |                          ^~~~~~~~~~~~~~
>    In file included from <command-line>:
>    include/linux/swapops.h: In function 'is_pfn_swap_entry':
> >> include/linux/swapops.h:27:46: error: 'MAX_SWAPFILES_SHIFT' undeclared (first use in this function)
>       27 | #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
>          |                                              ^~~~~~~~~~~~~~~~~~~
>    include/linux/compiler_types.h:577:23: note: in definition of macro '__compiletime_assert'
>      577 |                 if (!(condition))                                       \
>          |                       ^~~~~~~~~
>    include/linux/compiler_types.h:597:9: note: in expansion of macro '_compiletime_assert'
>      597 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>          |         ^~~~~~~~~~~~~~~~~~~
>    include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
>       39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>          |                                     ^~~~~~~~~~~~~~~~~~
>    include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
>       50 |         BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
>          |         ^~~~~~~~~~~~~~~~
>    include/linux/swapops.h:448:9: note: in expansion of macro 'BUILD_BUG_ON'
>      448 |         BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS);
>          |         ^~~~~~~~~~~~
>    include/linux/swapops.h:448:22: note: in expansion of macro 'SWP_TYPE_SHIFT'
>      448 |         BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS);
>          |                      ^~~~~~~~~~~~~~
>    include/linux/swapops.h: In function 'non_swap_entry':
>    include/linux/swapops.h:491:35: error: 'MAX_SWAPFILES' undeclared (first use in this function); did you mean 'S_SWAPFILE'?
>      491 |         return swp_type(entry) >= MAX_SWAPFILES;
>          |                                   ^~~~~~~~~~~~~
>          |                                   S_SWAPFILE
>    include/linux/leafops.h: In function 'leafent_from_pmd':
> >> include/linux/leafops.h:111:22: error: implicit declaration of function '__pmd_to_swp_entry'; did you mean 'pte_to_swp_entry'? [-Wimplicit-function-declaration]
>      111 |         arch_entry = __pmd_to_swp_entry(pmd);
>          |                      ^~~~~~~~~~~~~~~~~~
>          |                      pte_to_swp_entry
> >> include/linux/leafops.h:111:22: error: incompatible types when assigning to type 'leaf_entry_t' {aka 'swp_entry_t'} from type 'int'
>
>
> vim +111 include/linux/leafops.h
>
>     90
>     91	/**
>     92	 * leafent_from_pmd() - Obtain a leaf entry from a PMD entry.
>     93	 * @pmd: PMD entry.
>     94	 *
>     95	 * If @pmd is present (therefore not a leaf entry) the function returns an empty
>     96	 * leaf entry. Otherwise, it returns a leaf entry.
>     97	 *
>     98	 * Returns: Leaf entry.
>     99	 */
>    100	static inline leaf_entry_t leafent_from_pmd(pmd_t pmd)
>    101	{
>    102		leaf_entry_t arch_entry;
>    103
>    104		if (pmd_present(pmd))
>    105			return leafent_mk_none();
>    106
>    107		if (pmd_swp_soft_dirty(pmd))
>    108			pmd = pmd_swp_clear_soft_dirty(pmd);
>    109		if (pmd_swp_uffd_wp(pmd))
>    110			pmd = pmd_swp_clear_uffd_wp(pmd);
>  > 111		arch_entry = __pmd_to_swp_entry(pmd);
>    112
>    113		/* Temporary until swp_entry_t eliminated. */
>    114		return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
>    115	}
>    116
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki