From: Dan Williams <dan.j.williams@intel.com>
To: akpm@linux-foundation.org
Cc: Qian Cai <cai@lca.pw>, Michal Hocko <mhocko@suse.com>,
Oscar Salvador <osalvador@suse.de>,
David Hildenbrand <david@redhat.com>,
linux-mm@kvack.org, linux-nvdimm@lists.01.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v4 2/5] mm: Teach pfn_to_online_page() to consider subsection validity
Date: Wed, 13 Jan 2021 16:43:21 -0800 [thread overview]
Message-ID: <161058500148.1840162.4365921007820501696.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <161058499000.1840162.702316708443239771.stgit@dwillia2-desk3.amr.corp.intel.com>
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>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
mm/memory_hotplug.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 55a69d4396e7..d0c81f7a3347 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -308,11 +308,26 @@ 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) && !pfn_valid(pfn))
+ return NULL;
+
+ if (!pfn_section_valid(ms, pfn))
+ return NULL;
- if (nr < NR_MEM_SECTIONS && online_section_nr(nr) &&
- pfn_valid_within(pfn))
- return pfn_to_page(pfn);
- return NULL;
+ return pfn_to_page(pfn);
}
EXPORT_SYMBOL_GPL(pfn_to_online_page);
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next prev parent reply other threads:[~2021-01-14 0:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 0:43 [PATCH v4 0/5] mm: Fix pfn_to_online_page() with respect to ZONE_DEVICE Dan Williams
2021-01-14 0:43 ` [PATCH v4 1/5] mm: Move pfn_to_online_page() out of line Dan Williams
2021-01-20 10:11 ` Michal Hocko
2021-01-14 0:43 ` Dan Williams [this message]
2021-01-20 10:24 ` [PATCH v4 2/5] mm: Teach pfn_to_online_page() to consider subsection validity Michal Hocko
2021-01-14 0:43 ` [PATCH v4 3/5] mm: Teach pfn_to_online_page() about ZONE_DEVICE section collisions Dan Williams
2021-01-20 10:30 ` Michal Hocko
2021-01-14 0:43 ` [PATCH v4 4/5] mm: Fix page reference leak in soft_offline_page() Dan Williams
2021-01-14 1:49 ` HORIGUCHI NAOYA(堀口 直也)
2021-01-14 6:18 ` Dan Williams
2021-01-14 6:30 ` Oscar Salvador
2021-01-14 7:10 ` HORIGUCHI NAOYA(堀口 直也)
2021-01-17 22:01 ` Andrew Morton
2021-01-17 22:35 ` Dan Williams
2021-01-14 0:43 ` [PATCH v4 5/5] mm: Fix memory_failure() handling of dax-namespace metadata Dan Williams
2021-01-14 2:25 ` HORIGUCHI NAOYA(堀口 直也)
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