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From: Lance Yang Date: Tue, 30 Sep 2025 22:30:28 +0800 X-Gmail-Original-Message-ID: X-Gm-Features: AS18NWDSRA9_SfA-4xAgCAAwq9ckBLFuJLAQkfHgnyzZ7OPW9t0Fkeu1DptjuSI Message-ID: Subject: Re: [PATCH] mm/ptdump: Replace READ_ONCE() with standard page table accessors To: Anshuman Khandual Cc: linux-mm@kvack.org, Andrew Morton , David Hildenbrand , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 362B240005 X-Stat-Signature: bmjaf5iktwucck85kpmxosr6smizazhd X-HE-Tag: 1759242674-502530 X-HE-Meta: U2FsdGVkX19Ih5suB2pm4Ws/daGYdou1nVnUEEM+Doy1Wf9MXFdPDsS5IQIBSTs9Pfjs548LKp1Dt+oJVFKQ7zUm4YU8FjoSDaJGutGu99ba0UvwUF69cD6LCvPBcp4OBAHwAU0lC/KBtoc6xnVTShSYQGnY4UJUVgkJTYmiGVvU7hgmy0o7CpM3CSdvldQHNHnLOeA+nOAkUBTl3JhED/gtyMTOIKVddQmhDcitCjd6iaXlrvVS6pjdcYb8TbKahWlI/N3NCUz+ExEGpgkbayznzOWYWsdaPc9yjyC1VjT0rjGfgfWbJng+QEUGtiQ0hI6hWbuCQmgRYDGQ1d2v+OraqRqQMFDXRwpKAgTtL5dSZ9lE0EO0e5Q3Ky6PZiREt4hWgCI1xlh4KNcLeraD+nyJ6RxFtVEXOGBowaK+iTv8n0VWclD9QQgxCSinVLGk8hDUd+c6c0F9uRWR5/0uMe+99PnN9OJtUwxZJ+mm/jT+o03o5xOfztIkaB2W2g/knmu5tKKJRgF2sj99GQsILsyU+pXliA1AOdIEvXhDhRMhFASscnV9aoXpm4pFtIdve34LcRk15F34JFja4m/kaJg1ljkdpiDmHS39pNmxHvCMVVLWNwiT/B1YlLWAP6HbmMs2UZcDEJWjVJM5nkD3VXAaLzOYSSguXfuPNP6rLGYIbDjuOLjq0cmLbYSM/UO7sUnpBr/tdgIpYBL9WCP52HqabQT6ItHDwm/hn57ki7rswkAwZ+y80nBwiv4YtJ1dd/pVoByLEYpZHjFlGh48DBJBNpmm1Qio30AEJP4eaiCqQERIvz0YJn+GlkU7rnJCtl0/SDDO1f96ByURJxYo6BT34+w/Rvi5F1HW2AL06OMYFPerzzxiCvR1/bwz23Dx73cB0CW5NbMeWwJMD620Sg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 30, 2025 at 10:56=E2=80=AFAM Anshuman Khandual wrote: > > Replace READ_ONCE() with standard page table accessors i.e pxdp_get() whi= ch > anyways default into READ_ONCE() in cases where platform does not overrid= e. > > Cc: Andrew Morton > Cc: David Hildenbrand > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- Nice cleanup! I assume it's a no-op change on all architectures for now ;) Acked-by: Lance Yang > mm/ptdump.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/mm/ptdump.c b/mm/ptdump.c > index b600c7f864b8..18861501b533 100644 > --- a/mm/ptdump.c > +++ b/mm/ptdump.c > @@ -31,7 +31,7 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long a= ddr, > unsigned long next, struct mm_walk *walk) > { > struct ptdump_state *st =3D walk->private; > - pgd_t val =3D READ_ONCE(*pgd); > + pgd_t val =3D pgdp_get(pgd); > > #if CONFIG_PGTABLE_LEVELS > 4 && \ > (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW= _TAGS)) > @@ -54,7 +54,7 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long a= ddr, > unsigned long next, struct mm_walk *walk) > { > struct ptdump_state *st =3D walk->private; > - p4d_t val =3D READ_ONCE(*p4d); > + p4d_t val =3D p4dp_get(p4d); > > #if CONFIG_PGTABLE_LEVELS > 3 && \ > (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW= _TAGS)) > @@ -77,7 +77,7 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long a= ddr, > unsigned long next, struct mm_walk *walk) > { > struct ptdump_state *st =3D walk->private; > - pud_t val =3D READ_ONCE(*pud); > + pud_t val =3D pudp_get(pud); > > #if CONFIG_PGTABLE_LEVELS > 2 && \ > (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW= _TAGS)) > @@ -100,7 +100,7 @@ static int ptdump_pmd_entry(pmd_t *pmd, unsigned long= addr, > unsigned long next, struct mm_walk *walk) > { > struct ptdump_state *st =3D walk->private; > - pmd_t val =3D READ_ONCE(*pmd); > + pmd_t val =3D pmdp_get(pmd); > > #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) > if (pmd_page(val) =3D=3D virt_to_page(lm_alias(kasan_early_shadow= _pte))) > -- > 2.30.2 > >