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Subject: Re: [PATCH 1/2] hugetlb: really allocate vma lock for all sharable
 vmas
To:     Mike Kravetz <mike.kravetz@oracle.com>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>
CC:     Muchun Song <songmuchun@bytedance.com>,
        David Hildenbrand <david@redhat.com>,
        Peter Xu <peterx@redhat.com>,
        Naoya Horiguchi <naoya.horiguchi@linux.dev>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
        James Houghton <jthoughton@google.com>,
        Mina Almasry <almasrymina@google.com>,
        Andrew Morton <akpm@linux-foundation.org>
References: <20221212235042.178355-1-mike.kravetz@oracle.com>
From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <fece3f24-5915-b3c4-e1fb-4e7b1ad76df5@huawei.com>
Date:   Sat, 17 Dec 2022 09:59:40 +0800
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On 2022/12/13 7:50, Mike Kravetz wrote:
> Commit bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas")
> removed the pmd sharable checks in the vma lock helper routines.
> However, it left the functional version of helper routines behind #ifdef
> CONFIG_ARCH_WANT_HUGE_PMD_SHARE.  Therefore, the vma lock is not being

Oh, we missed !CONFIG_ARCH_WANT_HUGE_PMD_SHARE case in the previous review. :(

> used for sharable vmas on architectures that do not support pmd sharing.
> On these architectures, a potential fault/truncation race is exposed
> that could leave pages in a hugetlb file past i_size until the file is
> removed.
> 
> Move the functional vma lock helpers outside the ifdef, and remove the
> non-functional stubs.  Since the vma lock is not just for pmd sharing,
> rename the routine __vma_shareable_flags_pmd.
> 
> Fixes: bbff39cc6cbc ("hugetlb: allocate vma lock for all sharable vmas")
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>

Thanks for fixing. This patch looks good to me. Thanks.

Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>

Thanks,
Miaohe Lin