Re: [PATCH v3 07/15] mm/pte_ref: add support for user PTE page table page allocation

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

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Hi Qi,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on hnaz-mm/master]
[also build test ERROR on linus/master next-20211111]
[cannot apply to tip/perf/core tip/x86/core v5.15]
[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]

url:    https://github.com/0day-ci/linux/commits/Qi-Zheng/Free-user-PTE-page-table-pages/20211110-185837
base:   https://github.com/hnaz/linux-mm master
config: ia64-defconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 11.2.0
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/0day-ci/linux/commit/6e3cc5bb722cbd2fc4170d2f5371e52792d17d2e
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Qi-Zheng/Free-user-PTE-page-table-pages/20211110-185837
        git checkout 6e3cc5bb722cbd2fc4170d2f5371e52792d17d2e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=ia64 

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

All errors (new ones prefixed by >>):

   In file included from arch/ia64/include/uapi/asm/gcc_intrin.h:11,
                    from arch/ia64/include/asm/gcc_intrin.h:10,
                    from arch/ia64/include/uapi/asm/intrinsics.h:20,
                    from arch/ia64/include/asm/intrinsics.h:11,
                    from arch/ia64/include/asm/page.h:11,
                    from arch/ia64/include/asm/pgtable.h:18,
                    from include/linux/pgtable.h:6,
                    from include/linux/pte_ref.h:10,
                    from mm/pte_ref.c:8:
   mm/pte_ref.c: In function 'pte_try_get':
>> mm/pte_ref.c:37:22: error: implicit declaration of function 'is_huge_pmd'; did you mean 'zap_huge_pmd'? [-Werror=implicit-function-declaration]
      37 |         if (unlikely(is_huge_pmd(*pmd)))
         |                      ^~~~~~~~~~~
   include/linux/compiler.h:78:45: note: in definition of macro 'unlikely'
      78 | # define unlikely(x)    __builtin_expect(!!(x), 0)
         |                                             ^
   cc1: some warnings being treated as errors


vim +37 mm/pte_ref.c

e03404013f81d7 Qi Zheng 2021-11-10  20  
e03404013f81d7 Qi Zheng 2021-11-10  21  /*
e03404013f81d7 Qi Zheng 2021-11-10  22   * pte_try_get - Try to increment refcount for the PTE page table.
e03404013f81d7 Qi Zheng 2021-11-10  23   * @pmd: a pointer to the pmd entry corresponding to the PTE page table.
e03404013f81d7 Qi Zheng 2021-11-10  24   *
e03404013f81d7 Qi Zheng 2021-11-10  25   * Return true if the increment succeeded. Otherwise return false.
e03404013f81d7 Qi Zheng 2021-11-10  26   *
e03404013f81d7 Qi Zheng 2021-11-10  27   * Before Operating the PTE page table, we need to hold a refcount
e03404013f81d7 Qi Zheng 2021-11-10  28   * to protect against the concurrent release of the PTE page table.
e03404013f81d7 Qi Zheng 2021-11-10  29   * But we will fail in the following case:
e03404013f81d7 Qi Zheng 2021-11-10  30   * 	- The content mapped in @pmd is not a PTE page
e03404013f81d7 Qi Zheng 2021-11-10  31   * 	- The refcount of the PTE page table is zero, it will be freed
e03404013f81d7 Qi Zheng 2021-11-10  32   */
e03404013f81d7 Qi Zheng 2021-11-10  33  enum pte_tryget_type pte_try_get(pmd_t *pmd)
e03404013f81d7 Qi Zheng 2021-11-10  34  {
e03404013f81d7 Qi Zheng 2021-11-10  35  	if (unlikely(pmd_none(*pmd)))
e03404013f81d7 Qi Zheng 2021-11-10  36  		return TRYGET_FAILED_NONE;
e03404013f81d7 Qi Zheng 2021-11-10 @37  	if (unlikely(is_huge_pmd(*pmd)))
e03404013f81d7 Qi Zheng 2021-11-10  38  		return TRYGET_FAILED_HUGE_PMD;
e03404013f81d7 Qi Zheng 2021-11-10  39  
e03404013f81d7 Qi Zheng 2021-11-10  40  	return TRYGET_SUCCESSED;
e03404013f81d7 Qi Zheng 2021-11-10  41  }
e03404013f81d7 Qi Zheng 2021-11-10  42  

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

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