Re: [PATCH] mm/page_table_check: Drop all redundant EXPORT_SYMBOL()

[Pasha Tatashin <pasha.tatashin@soleen.com>]

On Wed, Apr 20, 2022 at 2:01 AM Anshuman Khandual
<anshuman.khandual@arm.com> wrote:
>
> Function definitions need not be exported via EXPORT_SYMBOL() mechanism. In
> this case these functions just get called only inside their wrappers. Even
> __page_table_check_zero() gets called without such an export. Just drop all
> these redundant EXPORT_SYMBOL().
>
> Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> This applies on v5.18-rc3
>
>  mm/page_table_check.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/mm/page_table_check.c b/mm/page_table_check.c
> index 2458281bff89..5c2a96159832 100644
> --- a/mm/page_table_check.c
> +++ b/mm/page_table_check.c
> @@ -167,7 +167,6 @@ void __page_table_check_pte_clear(struct mm_struct *mm, unsigned long addr,
>                                        PAGE_SIZE >> PAGE_SHIFT);
>         }
>  }
> -EXPORT_SYMBOL(__page_table_check_pte_clear);
>
>  void __page_table_check_pmd_clear(struct mm_struct *mm, unsigned long addr,
>                                   pmd_t pmd)
> @@ -180,7 +179,6 @@ void __page_table_check_pmd_clear(struct mm_struct *mm, unsigned long addr,
>                                        PMD_PAGE_SIZE >> PAGE_SHIFT);
>         }
>  }
> -EXPORT_SYMBOL(__page_table_check_pmd_clear);
>
>  void __page_table_check_pud_clear(struct mm_struct *mm, unsigned long addr,
>                                   pud_t pud)
> @@ -193,7 +191,6 @@ void __page_table_check_pud_clear(struct mm_struct *mm, unsigned long addr,
>                                        PUD_PAGE_SIZE >> PAGE_SHIFT);
>         }
>  }
> -EXPORT_SYMBOL(__page_table_check_pud_clear);
>
>  void __page_table_check_pte_set(struct mm_struct *mm, unsigned long addr,
>                                 pte_t *ptep, pte_t pte)
> @@ -208,7 +205,6 @@ void __page_table_check_pte_set(struct mm_struct *mm, unsigned long addr,
>                                      pte_write(pte));
>         }
>  }
> -EXPORT_SYMBOL(__page_table_check_pte_set);

Hi Anshuman,

See this:
https://lore.kernel.org/all/20211124234754.l5co34dUK%25akpm@linux-foundation.org/

The rest of EXPORTs were added to be symmetric, and allow other
drivers to use set_*p**()/clear_p** calls.

Pasha