Hi all,

After merging the mm tree, today's linux-next build (arm
multi_v7_defconfig) failed like this:

fs/proc/task_mmu.c: In function 'pagemap_scan_pmd_entry':
fs/proc/task_mmu.c:2153:22: error: implicit declaration of function 'pagemap_scan_is_interesting_page'; did you mean 'pagemap_scan_is_interesting_vma'? [-Werror=implicit-function-declaration]
 2153 |                 if (!pagemap_scan_is_interesting_page(categories, p))
      |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                      pagemap_scan_is_interesting_vma

Caused by commit

  825ebc8e4bf9 ("fs/proc/task_mmu: hide unused pagemap_scan_backout_range() function")

I applied the following fix patch.

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Thu, 28 Sep 2023 09:09:26 +1000
Subject: [PATCH] fix for "fs/proc/task_mmu: hide unused pagemap_scan_backout_range() function"

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
 fs/proc/task_mmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index fdad3536d8ab..d4ef9a2bf95d 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1940,6 +1940,7 @@ static void make_uffd_wp_huge_pte(struct vm_area_struct *vma,
 		set_huge_pte_at(vma->vm_mm, addr, ptep,
 				make_pte_marker(PTE_MARKER_UFFD_WP), psize);
 }
+#endif /* CONFIG_HUGETLB_PAGE */
 
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLB_PAGE)
 static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
@@ -1954,7 +1955,7 @@ static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
 
 	p->found_pages -= (end - addr) / PAGE_SIZE;
 }
-#endif /* CONFIG_HUGETLB_PAGE */
+#endif
 
 static bool pagemap_scan_is_interesting_page(unsigned long categories,
 					     const struct pagemap_scan_private *p)
@@ -1967,7 +1968,6 @@ static bool pagemap_scan_is_interesting_page(unsigned long categories,
 
 	return true;
 }
-#endif
 
 static bool pagemap_scan_is_interesting_vma(unsigned long categories,
 					    const struct pagemap_scan_private *p)
-- 
2.40.1

-- 
Cheers,
Stephen Rothwell

On Thu, Sep 28, 2023, at 01:22, Stephen Rothwell wrote:
> Hi all,
>
> After merging the mm tree, today's linux-next build (arm
> multi_v7_defconfig) failed like this:
>
> fs/proc/task_mmu.c: In function 'pagemap_scan_pmd_entry':
> fs/proc/task_mmu.c:2153:22: error: implicit declaration of function 
> 'pagemap_scan_is_interesting_page'; did you mean 
> 'pagemap_scan_is_interesting_vma'? 
> [-Werror=implicit-function-declaration]
>  2153 |                 if 
> (!pagemap_scan_is_interesting_page(categories, p))
>       |                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>       |                      pagemap_scan_is_interesting_vma
>
> Caused by commit
>
>   825ebc8e4bf9 ("fs/proc/task_mmu: hide unused 
> pagemap_scan_backout_range() function")
>
> I applied the following fix patch.
>
> From: Stephen Rothwell <sfr@canb.auug.org.au>
> Date: Thu, 28 Sep 2023 09:09:26 +1000
> Subject: [PATCH] fix for "fs/proc/task_mmu: hide unused 
> pagemap_scan_backout_range() function"
>
> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Thanks for the fix. I don't see what happened exactly,
maybe we had two conflicting workarounds for the same problem
applied. The version in linux-next works for me on the randconfig
builds, so folding your patch on top should be fine.

    Arnd