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From: Dan Williams <dan.j.williams@intel.com>
To: David Hildenbrand <david@redhat.com>
Cc: Linux MM <linux-mm@kvack.org>, Qian Cai <cai@lca.pw>,
	Michal Hocko <mhocko@suse.com>,
	Oscar Salvador <osalvador@suse.de>,
	Vishal L Verma <vishal.l.verma@intel.com>,
	linux-nvdimm <linux-nvdimm@lists.01.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/6] mm: Teach pfn_to_online_page() to consider subsection validity
Date: Wed, 13 Jan 2021 13:52:14 -0800	[thread overview]
Message-ID: <CAPcyv4i4yGjsMf2SyixLicDjzRGes97vaSa+mF4=Y9Uagk_0jg@mail.gmail.com> (raw)
In-Reply-To: <230efa36-9192-fe52-b8b6-16b2feafb70b@redhat.com>

On Wed, Jan 13, 2021 at 12:29 AM David Hildenbrand <david@redhat.com> wrote:
>
> On 13.01.21 08:35, Dan Williams wrote:
> > pfn_section_valid() determines pfn validity on subsection granularity
> > where pfn_valid() may be limited to coarse section granularity.
> > Explicitly validate subsections after pfn_valid() succeeds.
> >
> > Fixes: b13bc35193d9 ("mm/hotplug: invalid PFNs from pfn_to_online_page()")
> > Cc: Qian Cai <cai@lca.pw>
> > Cc: Michal Hocko <mhocko@suse.com>
> > Cc: Oscar Salvador <osalvador@suse.de>
> > Reported-by: David Hildenbrand <david@redhat.com>
> > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> > ---
> >  mm/memory_hotplug.c |   24 ++++++++++++++++++++----
> >  1 file changed, 20 insertions(+), 4 deletions(-)
> >
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index 55a69d4396e7..9f37f8a68da4 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -308,11 +308,27 @@ static int check_hotplug_memory_addressable(unsigned long pfn,
> >  struct page *pfn_to_online_page(unsigned long pfn)
> >  {
> >       unsigned long nr = pfn_to_section_nr(pfn);
> > +     struct mem_section *ms;
> > +
> > +     if (nr >= NR_MEM_SECTIONS)
> > +             return NULL;
> > +
> > +     ms = __nr_to_section(nr);
> > +     if (!online_section(ms))
> > +             return NULL;
> > +
> > +     /*
> > +      * Save some code text when online_section() +
> > +      * pfn_section_valid() are sufficient.
> > +      */
> > +     if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID))
> > +             if (!pfn_valid(pfn))
> > +                     return NULL;
>
> Nit:
>
> if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) &&
>     !pfn_valid(pfn))
>

Ok... I'll do a final resend "To: akpm" after the kbuild robot
finishes chewing on this series.

  reply	other threads:[~2021-01-13 22:05 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-13  7:35 [PATCH v3 0/6] mm: Fix pfn_to_online_page() with respect to ZONE_DEVICE Dan Williams
2021-01-13  7:35 ` [PATCH v3 1/6] mm: Move pfn_to_online_page() out of line Dan Williams
2021-01-13  7:35 ` [PATCH v3 2/6] mm: Teach pfn_to_online_page() to consider subsection validity Dan Williams
2021-01-13  8:29   ` David Hildenbrand
2021-01-13 21:52     ` Dan Williams [this message]
2021-01-13  8:30   ` Oscar Salvador
2021-01-13  7:35 ` [PATCH v3 3/6] mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions Dan Williams
2021-01-13  7:35 ` [PATCH v3 4/6] mm: Fix page reference leak in soft_offline_page() Dan Williams
2021-01-13  7:35 ` [PATCH v3 5/6] mm: Fix memory_failure() handling of dax-namespace metadata Dan Williams
2021-01-13  8:31   ` David Hildenbrand
2021-01-13  7:35 ` [PATCH v3 6/6] libnvdimm/namespace: Fix visibility of namespace resource attribute Dan Williams
2021-01-13  8:35   ` Greg KH

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