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/[email protected]
Signed-off-by: Yasuaki Ishimatsu <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Xishi Qiu <[email protected]>
Cc: Reza Arbab <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 356a814e7c8eb8b56179dd72bdbcf76703fa56b1..c8f89417740bb5819bc9cb2b81549e31a4af4fc0 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1094,8 +1094,14 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn)
 #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 --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 23d5bd96895017c2a05b993eaa1cd8c07ff50752..efd1ad37bb574c75d03d9f0ce05c92a8a18978db 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -551,7 +551,7 @@ static int __remove_section(struct zone *zone, struct mem_section *ms,
                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);