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Subject: Re: [PATCH] mm/huge_memory.c: use helper range_in_vma() in
 __split_huge_p[u|m]d_locked()
To:     Miaohe Lin <linmiaohe@huawei.com>, akpm@linux-foundation.org
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20210201093259.52798-1-linmiaohe@huawei.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <b3b4aabb-f98b-6514-61ac-03f0c62f4b0a@redhat.com>
Date:   Mon, 1 Feb 2021 11:54:50 +0100
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On 01.02.21 10:32, Miaohe Lin wrote:
> The helper range_in_vma() is introduced via commit 017b1660df89 ("mm:
> migration: fix migration of huge PMD shared pages"). But we forgot to
> use it in __split_huge_pud_locked() and __split_huge_pmd_locked().
> 
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> ---
>   mm/huge_memory.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 987cf5e4cf90..33353a4f95fb 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1959,8 +1959,7 @@ static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud,
>   		unsigned long haddr)
>   {
>   	VM_BUG_ON(haddr & ~HPAGE_PUD_MASK);
> -	VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
> -	VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma);
> +	VM_BUG_ON_VMA(!range_in_vma(vma, haddr, haddr + HPAGE_PUD_SIZE), vma);
>   	VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud));
>   
>   	count_vm_event(THP_SPLIT_PUD);
> @@ -2039,8 +2038,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
>   	int i;
>   
>   	VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);
> -	VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
> -	VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);
> +	VM_BUG_ON_VMA(!range_in_vma(vma, haddr, haddr + HPAGE_PMD_SIZE), vma);
>   	VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd)
>   				&& !pmd_devmap(*pmd));
>   
> 

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb