mm: add SECTION_ALIGN_UP() and SECTION_ALIGN_DOWN() macro

Add SECTION_ALIGN_UP() and SECTION_ALIGN_DOWN() macro which aligns given
pfn to upper section and lower section boundary accordingly.

Required for the latest memory hotplug support for the Xen balloon driver.

Signed-off-by: Daniel Kiper <[email protected]>
Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
David Rientjes <[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 d7152002e18de4c599e99b3bc39746adbbfd2180..217bcf6bca775315e2ccce93dcb7ff6678a877a8 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -956,6 +956,9 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn)
 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
 #define section_nr_to_pfn(sec) ((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)
+
 struct page;
 struct page_cgroup;
 struct mem_section {