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Message-ID: <ZegNDhbFjPHTC3Pp@kernel.org>
Date: Wed, 6 Mar 2024 08:28:30 +0200
From: Mike Rapoport <rppt@...nel.org>
To: peterx@...hat.com
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Christophe Leroy <christophe.leroy@...roup.eu>, x86@...nel.org,
"Kirill A . Shutemov" <kirill@...temov.name>,
Jason Gunthorpe <jgg@...dia.com>, Yang Shi <shy828301@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
linuxppc-dev@...ts.ozlabs.org, Muchun Song <muchun.song@...ux.dev>,
Andrey Ryabinin <ryabinin.a.a@...il.com>,
Alexander Potapenko <glider@...gle.com>,
Andrey Konovalov <andreyknvl@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
kasan-dev@...glegroups.com
Subject: Re: [PATCH v3 06/10] mm/kasan: Use pXd_leaf() in shadow_mapped()
On Tue, Mar 05, 2024 at 12:37:46PM +0800, peterx@...hat.com wrote:
> From: Peter Xu <peterx@...hat.com>
>
> There is an old trick in shadow_mapped() to use pXd_bad() to detect huge
> pages. After commit 93fab1b22ef7 ("mm: add generic p?d_leaf() macros") we
> have a global API for huge mappings. Use that to replace the trick.
>
> Cc: Andrey Ryabinin <ryabinin.a.a@...il.com>
> Cc: Alexander Potapenko <glider@...gle.com>
> Cc: Andrey Konovalov <andreyknvl@...il.com>
> Cc: Dmitry Vyukov <dvyukov@...gle.com>
> Cc: Vincenzo Frascino <vincenzo.frascino@....com>
> Cc: kasan-dev@...glegroups.com
> Signed-off-by: Peter Xu <peterx@...hat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@...nel.org>
> ---
> mm/kasan/shadow.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
> index 9ef84f31833f..d6210ca48dda 100644
> --- a/mm/kasan/shadow.c
> +++ b/mm/kasan/shadow.c
> @@ -199,19 +199,12 @@ static bool shadow_mapped(unsigned long addr)
> pud = pud_offset(p4d, addr);
> if (pud_none(*pud))
> return false;
> -
> - /*
> - * We can't use pud_large() or pud_huge(), the first one is
> - * arch-specific, the last one depends on HUGETLB_PAGE. So let's abuse
> - * pud_bad(), if pud is bad then it's bad because it's huge.
> - */
> - if (pud_bad(*pud))
> + if (pud_leaf(*pud))
> return true;
> pmd = pmd_offset(pud, addr);
> if (pmd_none(*pmd))
> return false;
> -
> - if (pmd_bad(*pmd))
> + if (pmd_leaf(*pmd))
> return true;
> pte = pte_offset_kernel(pmd, addr);
> return !pte_none(ptep_get(pte));
> --
> 2.44.0
>
>
--
Sincerely yours,
Mike.
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