Re: [PATCH 1/2] arm64: hugetlb: remove the wrong pmd check in find_num_contig()

From	Catalin Marinas <catalin.marinas@arm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] arm64: hugetlb: remove the wrong pmd check in find_num_contig()
Date	2016-11-04 01:20 +0100
Message-ID	<szAoG-2F9-9@gated-at.bofh.it> (permalink)
References	<szAoG-2F9-11@gated-at.bofh.it> <szAoG-2F9-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Nov 03, 2016 at 10:27:38AM +0800, Huang Shijie wrote:
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index 2e49bd2..4811ef1 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -61,10 +61,6 @@ static int find_num_contig(struct mm_struct *mm, unsigned long addr,
>  		return 1;
>  	}
>  	pmd = pmd_offset(pud, addr);
> -	if (!pmd_present(*pmd)) {
> -		VM_BUG_ON(!pmd_present(*pmd));
> -		return 1;
> -	}
>  	if ((pte_t *)pmd == ptep) {
>  		*pgsize = PMD_SIZE;
>  		return CONT_PMDS;

BTW, for the !pud_present() and !pgd_present() cases, shouldn't
find_num_contig() actually return 0? These are more likely real bugs, so
no point in setting the huge pte.

-- 
Catalin

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Re: [PATCH 1/2] arm64: hugetlb: remove the wrong pmd check in  find_num_contig() Catalin Marinas <catalin.marinas@arm.com> - 2016-11-04 01:20 +0100
  Re: [PATCH 1/2] arm64: hugetlb: remove the wrong pmd check in  find_num_contig() Catalin Marinas <catalin.marinas@arm.com> - 2016-11-04 16:50 +0100

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