The patch titled
Subject: mm: teach pfn_to_online_page() to consider subsection validity
has been removed from the -mm tree. Its filename was
mm-teach-pfn_to_online_page-to-consider-subsection-validity.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm: teach pfn_to_online_page() to consider subsection validity
pfn_to_online_page is primarily used to filter out offline or fully
uninitialized pages. pfn_valid resp. online_section_nr have a coarse
per memory section granularity. If a section shared with a partially
offline memory (e.g. part of ZONE_DEVICE) then pfn_to_online_page
would lead to a false positive on some pfns. Fix this by adding
pfn_section_valid check which is subsection aware.
[mhocko@xxxxxxxxxx: changelog rewrite]
Link: https://lkml.kernel.org/r/161058500148.1840162.4365921007820501696.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: b13bc35193d9 ("mm/hotplug: invalid PFNs from pfn_to_online_page()")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
--- a/mm/memory_hotplug.c~mm-teach-pfn_to_online_page-to-consider-subsection-validity
+++ a/mm/memory_hotplug.c
@@ -308,11 +308,26 @@ static int check_hotplug_memory_addressa
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 && online_section_nr(nr) &&
- pfn_valid_within(pfn))
- return pfn_to_page(pfn);
- return NULL;
+ 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;
+
+ return pfn_to_page(pfn);
}
EXPORT_SYMBOL_GPL(pfn_to_online_page);
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
