Re: [PATCH] hugetlb: Remove PageHeadHuge()

[Sidhartha Kumar <sidhartha.kumar@oracle.com>]

On 3/27/23 8:10 AM, Matthew Wilcox (Oracle) wrote:
> Sidhartha Kumar removed the last caller of PageHeadHuge(), so we can
> now remove it and make folio_test_hugetlb() the real implementation.
> Add kernel-doc for folio_test_hugetlb().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>   include/linux/page-flags.h |  7 +------
>   mm/hugetlb.c               | 18 +++++++++++-------
>   2 files changed, 12 insertions(+), 13 deletions(-)
> 
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 6b3e138613e1..88600a94fa91 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -811,14 +811,9 @@ static inline void ClearPageCompound(struct page *page)
>   
>   #ifdef CONFIG_HUGETLB_PAGE
>   int PageHuge(struct page *page);
> -int PageHeadHuge(struct page *page);
> -static inline bool folio_test_hugetlb(struct folio *folio)
> -{
> -	return PageHeadHuge(&folio->page);
> -}
> +bool folio_test_hugetlb(struct folio *folio);
>   #else
>   TESTPAGEFLAG_FALSE(Huge, hugetlb)
> -TESTPAGEFLAG_FALSE(HeadHuge, headhuge)
>   #endif
>   
>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 4dd722c35a7f..ff686074c481 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2050,19 +2050,23 @@ int PageHuge(struct page *page)
>   }
>   EXPORT_SYMBOL_GPL(PageHuge);
>   
> -/*
> - * PageHeadHuge() only returns true for hugetlbfs head page, but not for
> - * normal or transparent huge pages.
> +/**
> + * folio_test_hugetlb - Determine if the folio belongs to hugetlbfs
> + * @folio: The folio to test.
> + *
> + * Context: Any context.  Caller should have a reference on the folio to
> + * prevent it from being turned into a tail page.
> + * Return: True for hugetlbfs folios, false for anon folios or folios
> + * belonging to other filesystems.
>    */
> -int PageHeadHuge(struct page *page_head)
> +bool folio_test_hugetlb(struct folio *folio)
>   {
> -	struct folio *folio = (struct folio *)page_head;
>   	if (!folio_test_large(folio))
> -		return 0;
> +		return false;
>   
>   	return folio->_folio_dtor == HUGETLB_PAGE_DTOR;
>   }
> -EXPORT_SYMBOL_GPL(PageHeadHuge);
> +EXPORT_SYMBOL_GPL(folio_test_hugetlb);
>   
>   /*
>    * Find and lock address space (mapping) in write mode.
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>