linux-kernel - Re: [PATCH 12/31] mm/vmalloc: vmalloc_to_page() use pte_offset

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Message-ID: <8c744725-5f58-4656-823b-997a302085f6@lucifer.local>
Date:   Mon, 22 May 2023 08:27:14 +0100
From:   Lorenzo Stoakes <lstoakes@...il.com>
To:     Hugh Dickins <hughd@...gle.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Mike Rapoport <rppt@...nel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Matthew Wilcox <willy@...radead.org>,
        David Hildenbrand <david@...hat.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Qi Zheng <zhengqi.arch@...edance.com>,
        Yang Shi <shy828301@...il.com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Peter Xu <peterx@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Will Deacon <will@...nel.org>, Yu Zhao <yuzhao@...gle.com>,
        Alistair Popple <apopple@...dia.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Steven Price <steven.price@....com>,
        SeongJae Park <sj@...nel.org>,
        Naoya Horiguchi <naoya.horiguchi@....com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Zack Rusin <zackr@...are.com>, Jason Gunthorpe <jgg@...pe.ca>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Pasha Tatashin <pasha.tatashin@...een.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Minchan Kim <minchan@...nel.org>,
        Christoph Hellwig <hch@...radead.org>,
        Song Liu <song@...nel.org>,
        Thomas Hellstrom <thomas.hellstrom@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 12/31] mm/vmalloc: vmalloc_to_page() use
 pte_offset_kernel()

On Sun, May 21, 2023 at 10:04:07PM -0700, Hugh Dickins wrote:
> vmalloc_to_page() was using pte_offset_map() (followed by pte_unmap()),
> but it's intended for userspace page tables: prefer pte_offset_kernel().
>
> Signed-off-by: Hugh Dickins <hughd@...gle.com>
> ---
>  mm/vmalloc.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 9683573f1225..741722d247d5 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -703,11 +703,10 @@ struct page *vmalloc_to_page(const void *vmalloc_addr)
>  	if (WARN_ON_ONCE(pmd_bad(*pmd)))
>  		return NULL;
>
> -	ptep = pte_offset_map(pmd, addr);
> +	ptep = pte_offset_kernel(pmd, addr);
>  	pte = *ptep;
>  	if (pte_present(pte))
>  		page = pte_page(pte);
> -	pte_unmap(ptep);
>
>  	return page;
>  }
> --
> 2.35.3
>

Looks good to me,

Reviewed-by: Lorenzo Stoakes <lstoakes@...il.com>