linux-kernel - Re: [PATCH 2/3] mm/khugepaged: use enum scan

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b75674c4-2439-4515-9b4c-bc3d40f76fc9@kernel.org>
Date: Thu, 18 Dec 2025 10:17:36 +0100
From: "David Hildenbrand (Red Hat)" <david@...nel.org>
To: "Garg, Shivank" <shivankg@....com>, Zi Yan <ziy@...dia.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
 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>, Ryan Roberts <ryan.roberts@....com>,
 Dev Jain <dev.jain@....com>, Barry Song <baohua@...nel.org>,
 Lance Yang <lance.yang@...ux.dev>, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] mm/khugepaged: use enum scan_result for result
 variables

On 12/18/25 06:40, Garg, Shivank wrote:
> 
> 
> On 12/16/2025 9:08 PM, Zi Yan wrote:
>> On 16 Dec 2025, at 6:11, Shivank Garg wrote:
>>
> 
>>
>>>   int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
>>>   			    bool install_pmd)
>>>   {
>>
>> And here.
> Since this function is declared in khugepaged.h, I need to
> move the enum definition to that header. I see two options for handling
> the CONFIG_TRANSPARENT_HUGEPAGE check:
> 
> 1. Define enum OUTSIDE the ifdef: This allows the static inline stub
>     to also return enum scan_result, keeping the API consistent.
> 2. Define enum INSIDE the ifdef: The enum is hidden when THP is disabled,
>     forcing the stub to return int 0 instead.
> 
> The only external caller (uprobes.c) of collapse_pte_mapped_thp currently
> ignores the return value.

Probably best to not expose that enum (especially when nobody cares ...) 
and instead expose a new void function for uprobe purposes.

Maybe

void collapse_pte_mapped_thp(...)
{
	try_collapse_pte_mapped_thp();
}

Maybe something like that?

-- 
Cheers

David