[PATCHv1, RFC 20/33] thp: introduce hpage_size() and hpage_mask()

[Kirill A. Shutemov]

Introduce new helpers which return size/mask of the page:
HPAGE_PMD_SIZE/HPAGE_PMD_MASK if the page is PageTransHuge() and
PAGE_SIZE/PAGE_MASK otherwise.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 include/linux/huge_mm.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 6f14de45b5ce..de2789b4402c 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -138,6 +138,20 @@ static inline int hpage_nr_pages(struct page *page)
 	return 1;
 }
 
+static inline int hpage_size(struct page *page)
+{
+	if (unlikely(PageTransHuge(page)))
+		return HPAGE_PMD_SIZE;
+	return PAGE_SIZE;
+}
+
+static inline unsigned long hpage_mask(struct page *page)
+{
+	if (unlikely(PageTransHuge(page)))
+		return HPAGE_PMD_MASK;
+	return PAGE_MASK;
+}
+
 extern int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t orig_pmd);
 
 extern struct page *huge_zero_page;
@@ -163,6 +177,8 @@ void put_huge_zero_page(void);
 #define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })
 
 #define hpage_nr_pages(x) 1
+#define hpage_size(x) PAGE_SIZE
+#define hpage_mask(x) PAGE_MASK
 
 #define transparent_hugepage_enabled(__vma) 0
 
-- 
2.8.1