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

[Andrew Morton]

On Wed, 2 Nov 2022 14:55:32 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:

> Hi all,
> 
> After merging the mm tree, today's linux-next build (arm
> multi_v7_defconfig) failed like this:
> 
> mm/migrate.c: In function 'unmap_and_move_huge_page':
> mm/migrate.c:1315:13: error: implicit declaration of function 'hugetlb_folio_subpool'; did you mean 'hugetlb_page_subpool'? [-Werror=implicit-function-declaration]
>  1315 |         if (hugetlb_folio_subpool(src) && !folio_mapping(src)) {
>       |             ^~~~~~~~~~~~~~~~~~~~~
>       |             hugetlb_page_subpool
> cc1: some warnings being treated as errors
> 
> Caused by commit
> 
>   fa7dc4d80445 ("mm/hugetlb: convert move_hugetlb_state() to folios")
> 
> This build does *not* have CONFIG_HUGETLB_PAGE set.
> 

Thanks, let's try this:

--- a/include/linux/hugetlb.h~mm-hugetlb-convert-move_hugetlb_state-to-folios-fix
+++ a/include/linux/hugetlb.h
@@ -991,6 +991,11 @@ void hugetlb_unregister_node(struct node
 #else	/* CONFIG_HUGETLB_PAGE */
 struct hstate {};
 
+static inline struct hugepage_subpool *hugetlb_folio_subpool(struct folio *folio)
+{
+	return NULL;
+}
+
 static inline struct hugepage_subpool *hugetlb_page_subpool(struct page *hpage)
 {
 	return NULL;
_