Message-ID: <17dea8a6-b473-44da-82d2-d84223b7cdf1@linux.dev>
Date: Thu, 30 Oct 2025 10:31:12 +0800
From: Lance Yang <lance.yang@...ux.dev>
To: Zi Yan <ziy@...dia.com>
Cc: kernel@...kajraghav.com, jane.chu@...cle.com, akpm@...ux-foundation.org,
 mcgrof@...nel.org, nao.horiguchi@...il.com, david@...hat.com,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
 Baolin Wang <baolin.wang@...ux.alibaba.com>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, Nico Pache <npache@...hat.com>,
 linmiaohe@...wei.com, Ryan Roberts <ryan.roberts@....com>,
 Dev Jain <dev.jain@....com>, Barry Song <baohua@...nel.org>,
 "Matthew Wilcox (Oracle)" <willy@...radead.org>,
 Wei Yang <richard.weiyang@...il.com>, Yang Shi <shy828301@...il.com>,
 linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org
Subject: Re: [PATCH v4 3/3] mm/huge_memory: fix kernel-doc comments for
 folio_split() and related.



On 2025/10/30 09:40, Zi Yan wrote:
> try_folio_split_to_order(), folio_split, __folio_split(), and
> __split_unmapped_folio() do not have correct kernel-doc comment format.
> Fix them.
> 
> Signed-off-by: Zi Yan <ziy@...dia.com>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
> Acked-by: David Hildenbrand <david@...hat.com>
> ---

LGTM.

Reviewed-by: Lance Yang <lance.yang@...ux.dev>

>   include/linux/huge_mm.h | 10 ++++++----
>   mm/huge_memory.c        | 27 +++++++++++++++------------
>   2 files changed, 21 insertions(+), 16 deletions(-)
> 
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 34f8d8453bf3..cbb2243f8e56 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -386,9 +386,9 @@ static inline int split_huge_page_to_order(struct page *page, unsigned int new_o
>   	return split_huge_page_to_list_to_order(page, NULL, new_order);
>   }
>   
> -/*
> - * try_folio_split_to_order - try to split a @folio at @page to @new_order using
> - * non uniform split.
> +/**
> + * try_folio_split_to_order() - try to split a @folio at @page to @new_order
> + * using non uniform split.
>    * @folio: folio to be split
>    * @page: split to @new_order at the given page
>    * @new_order: the target split order
> @@ -398,7 +398,7 @@ static inline int split_huge_page_to_order(struct page *page, unsigned int new_o
>    * folios are put back to LRU list. Use min_order_for_split() to get the lower
>    * bound of @new_order.
>    *
> - * Return: 0: split is successful, otherwise split failed.
> + * Return: 0 - split is successful, otherwise split failed.
>    */
>   static inline int try_folio_split_to_order(struct folio *folio,
>   		struct page *page, unsigned int new_order)
> @@ -486,6 +486,8 @@ static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
>   /**
>    * folio_test_pmd_mappable - Can we map this folio with a PMD?
>    * @folio: The folio to test
> + *
> + * Return: true - @folio can be mapped, false - @folio cannot be mapped.
>    */
>   static inline bool folio_test_pmd_mappable(struct folio *folio)
>   {
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 0e24bb7e90d0..381a49c5ac3f 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -3567,8 +3567,9 @@ static void __split_folio_to_order(struct folio *folio, int old_order,
>   		ClearPageCompound(&folio->page);
>   }
>   
> -/*
> - * It splits an unmapped @folio to lower order smaller folios in two ways.
> +/**
> + * __split_unmapped_folio() - splits an unmapped @folio to lower order folios in
> + * two ways: uniform split or non-uniform split.
>    * @folio: the to-be-split folio
>    * @new_order: the smallest order of the after split folios (since buddy
>    *             allocator like split generates folios with orders from @folio's
> @@ -3603,8 +3604,8 @@ static void __split_folio_to_order(struct folio *folio, int old_order,
>    * folio containing @page. The caller needs to unlock and/or free after-split
>    * folios if necessary.
>    *
> - * For !uniform_split, when -ENOMEM is returned, the original folio might be
> - * split. The caller needs to check the input folio.
> + * Return: 0 - successful, <0 - failed (if -ENOMEM is returned, @folio might be
> + * split but not to @new_order, the caller needs to check)
>    */
>   static int __split_unmapped_folio(struct folio *folio, int new_order,
>   		struct page *split_at, struct xa_state *xas,
> @@ -3722,8 +3723,8 @@ bool uniform_split_supported(struct folio *folio, unsigned int new_order,
>   	return true;
>   }
>   
> -/*
> - * __folio_split: split a folio at @split_at to a @new_order folio
> +/**
> + * __folio_split() - split a folio at @split_at to a @new_order folio
>    * @folio: folio to split
>    * @new_order: the order of the new folio
>    * @split_at: a page within the new folio
> @@ -3741,7 +3742,7 @@ bool uniform_split_supported(struct folio *folio, unsigned int new_order,
>    * 1. for uniform split, @lock_at points to one of @folio's subpages;
>    * 2. for buddy allocator like (non-uniform) split, @lock_at points to @folio.
>    *
> - * return: 0: successful, <0 failed (if -ENOMEM is returned, @folio might be
> + * Return: 0 - successful, <0 - failed (if -ENOMEM is returned, @folio might be
>    * split but not to @new_order, the caller needs to check)
>    */
>   static int __folio_split(struct folio *folio, unsigned int new_order,
> @@ -4130,14 +4131,13 @@ int __split_huge_page_to_list_to_order(struct page *page, struct list_head *list
>   				unmapped);
>   }
>   
> -/*
> - * folio_split: split a folio at @split_at to a @new_order folio
> +/**
> + * folio_split() - split a folio at @split_at to a @new_order folio
>    * @folio: folio to split
>    * @new_order: the order of the new folio
>    * @split_at: a page within the new folio
> - *
> - * return: 0: successful, <0 failed (if -ENOMEM is returned, @folio might be
> - * split but not to @new_order, the caller needs to check)
> + * @list: after-split folios are added to @list if not null, otherwise to LRU
> + *        list
>    *
>    * It has the same prerequisites and returns as
>    * split_huge_page_to_list_to_order().
> @@ -4151,6 +4151,9 @@ int __split_huge_page_to_list_to_order(struct page *page, struct list_head *list
>    * [order-4, {order-3}, order-3, order-5, order-6, order-7, order-8].
>    *
>    * After split, folio is left locked for caller.
> + *
> + * Return: 0 - successful, <0 - failed (if -ENOMEM is returned, @folio might be
> + * split but not to @new_order, the caller needs to check)
>    */
>   int folio_split(struct folio *folio, unsigned int new_order,
>   		struct page *split_at, struct list_head *list)

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