The patch titled
Subject: mm/memory_hotplug: change pfn_to_section_nr/section_nr_to_pfn macro to inline function
has been added to the -mm tree. Its filename is
mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function.patch
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From: YASUAKI ISHIMATSU <yasu.isimatu@xxxxxxxxx>
Subject: mm/memory_hotplug: change pfn_to_section_nr/section_nr_to_pfn macro to inline function
pfn_to_section_nr() and section_nr_to_pfn() are defined as macro.
pfn_to_section_nr() has no issue even if it is defined as macro. But
section_nr_to_pfn() has overflow issue if sec is defined as int.
section_nr_to_pfn() just shifts sec by PFN_SECTION_SHIFT. If sec is
defined as unsigned long, section_nr_to_pfn() returns pfn as 64 bit value.
But if sec is defined as int, section_nr_to_pfn() returns pfn as 32 bit
value.
__remove_section() calculates start_pfn using section_nr_to_pfn() and
scn_nr defined as int. So if hot-removed memory address is over 16TB,
overflow issue occurs and section_nr_to_pfn() does not calculate correct
pfn.
To make callers use proper arg, the patch changes the macros to inline
functions.
Fixes: 815121d2b5cd ("memory_hotplug: clear zone when removing the memory")
Link: http://lkml.kernel.org/r/e643a387-e573-6bbf-d418-c60c8ee3d15e@xxxxxxxxx
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Cc: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 10 ++++++++--
mm/memory_hotplug.c | 2 +-
2 files changed, 9 insertions(+), 3 deletions(-)
diff -puN include/linux/mmzone.h~mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function
+++ a/include/linux/mmzone.h
@@ -1094,8 +1094,14 @@ static inline unsigned long early_pfn_to
#error Allocator MAX_ORDER exceeds SECTION_SIZE
#endif
-#define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
-#define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
+static inline unsigned long pfn_to_section_nr(unsigned long pfn)
+{
+ return pfn >> PFN_SECTION_SHIFT;
+}
+static inline unsigned long section_nr_to_pfn(unsigned long sec)
+{
+ return sec << PFN_SECTION_SHIFT;
+}
#define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
#define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK)
diff -puN mm/memory_hotplug.c~mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function
+++ a/mm/memory_hotplug.c
@@ -551,7 +551,7 @@ static int __remove_section(struct zone
return ret;
scn_nr = __section_nr(ms);
- start_pfn = section_nr_to_pfn(scn_nr);
+ start_pfn = section_nr_to_pfn((unsigned long)scn_nr);
__remove_zone(zone, start_pfn);
sparse_remove_one_section(zone, ms, map_offset);
_
Patches currently in -mm which might be from yasu.isimatu@xxxxxxxxx are
mm-memory_hotplug-change-pfn_to_section_nr-section_nr_to_pfn-macro-to-inline-function.patch
mm-memory_hotplug-define-find_smallestbiggest_section_pfn-as-unsigned-long.patch
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