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

From: Stephen Rothwell <[email-masked]>
Date: Fri, 13 May 2022 17:18:38 +1000

Hi Catalin,

On Thu, 12 May 2022 12:07:41 +0100 Catalin Marinas <[email-masked]> wrote:
>
> Note that after the arm64 commit, get_clear_contig() no longer flushes
> the TLB. So maybe something like:
> 
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index 30f5b76aabe9..9a999550df8e 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -485,12 +485,15 @@ pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
>  {
>  	size_t pgsize;
>  	int ncontig;
> +	pte_t orig_pte;
> 
>  	if (!pte_cont(READ_ONCE(*ptep)))
>  		return ptep_clear_flush(vma, addr, ptep);
> 
>  	ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize);
> -	return get_clear_contig(vma->vm_mm, addr, ptep, pgsize, ncontig);
> +	orig_pte = get_clear_contig(vma->vm_mm, addr, ptep, pgsize, ncontig);
> +	flush_tlb_range(vma, addr, addr + pgsize * ncontig);
> +	return orig_pte;
>  }
> 
>  static int __init hugetlbpage_init(void)

I have modified my merge resolution patch to as in the above so it
looks like this now:

From: Stephen Rothwell <[email-masked]>
Date: Fri, 13 May 2022 17:08:07 +1000
Subject: [PATCH] fixup for "mm: change huge_ptep_clear_flush() to return the original pte"

It interacts with commit

  fb396bb459c1 ("arm64/hugetlb: Drop TLB flush from get_clear_flush()")

from the arm64 tree

Signed-off-by: Stephen Rothwell <[email-masked]>
---
 arch/arm64/mm/hugetlbpage.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 5bdf913dedc7..10b4a19ed6a2 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -485,12 +485,15 @@ pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
 {
 	size_t pgsize;
 	int ncontig;
+	pte_t orig_pte;
 
 	if (!pte_cont(READ_ONCE(*ptep)))
 		return ptep_clear_flush(vma, addr, ptep);
 
 	ncontig = find_num_contig(vma->vm_mm, addr, ptep, &pgsize);
-	return get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
+	orig_pte = get_clear_contig(vma->vm_mm, addr, ptep, pgsize, ncontig);
+	flush_tlb_range(vma, addr, addr + pgsize * ncontig);
+	return orig_pte;
 }
 
 static int __init hugetlbpage_init(void)
-- 
2.35.1

-- 
Cheers,
Stephen Rothwell