Subject: Re: linux-next: build failure after merge of the mm-hotfixes tree

From: Yang Shi <[email-masked]>
Date: Mon, 1 Jul 2024 11:15:17 -0700

On 6/30/24 6:01 PM, Stephen Rothwell wrote:
> Hi all,
>
> On Mon, 1 Jul 2024 10:16:41 +1000 Stephen Rothwell <[email-masked]> wrote:
>> After merging the mm-hotfixes tree, today's linux-next build (powerpc
>> ppc64_defconfig) failed like this:
>>
>> mm/gup.c: In function 'gup_hugepte':
>> mm/gup.c:474:25: error: implicit declaration of function 'try_grab_folio_fast'; did you mean 'try_grab_folio'? [-Werror=implicit-function-declaration]
>>    474 |                 folio = try_grab_folio_fast(page, refs, flags);
>>        |                         ^~~~~~~~~~~~~~~~~~~
>>        |                         try_grab_folio
>> mm/gup.c:474:23: warning: assignment to 'struct folio *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
>>    474 |                 folio = try_grab_folio_fast(page, refs, flags);
>>        |                       ^
>> mm/gup.c: At top level:
>> mm/gup.c:2747:22: error: conflicting types for 'try_grab_folio_fast'; have 'struct folio *(struct page *, int,  unsigned int)'
>>   2747 | static struct folio *try_grab_folio_fast(struct page *page, int refs,
>>        |                      ^~~~~~~~~~~~~~~~~~~
>> mm/gup.c:474:25: note: previous implicit declaration of 'try_grab_folio_fast' with type 'int()'
>>    474 |                 folio = try_grab_folio_fast(page, refs, flags);
>>        |                         ^~~~~~~~~~~~~~~~~~~
>> cc1: some warnings being treated as errors
>>
>> Caused by commit
>>
>>    5f408bfe0d13 ("mm: gup: stop abusing try_grab_folio")
>>
>> I have reverted that commit for today.
> And I also had to revert commit
>
>    52cca85b0ebf ("mm-gup-introduce-memfd_pin_folios-for-pinning-memfd-folios-fix")
>
> from the mm-unstable branch of the mm tree.

The patch attached in this mail should fix the compile error.

https://lore.kernel.org/linux-mm/[email-masked]/