1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 96326594e55..a1e14363494 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -94,6 +94,12 @@
 /* PG_owner_priv_1 users should have descriptive aliases */
 #define PG_checked              PG_owner_priv_1 /* Used by some filesystems */
 
+/*
+ * Marks tail portion of a compound page. We currently do not reclaim
+ * compound pages so we can reuse a flag only used for reclaim here.
+ */
+#define PG_tail                 PG_reclaim
+
 #if (BITS_PER_LONG > 32)
 /*
  * 64-bit-only flags build down from bit 31
@@ -241,6 +247,14 @@ static inline void SetPageUptodate(struct page *page)
 #define __SetPageCompound(page) __set_bit(PG_compound, &(page)->flags)
 #define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags)
 
+/*
+ * Note: PG_tail is an alias of another page flag. The result of PageTail()
+ * is only valid if PageCompound(page) is true.
+ */
+#define PageTail(page)  test_bit(PG_tail, &(page)->flags)
+#define __SetPageTail(page)     __set_bit(PG_tail, &(page)->flags)
+#define __ClearPageTail(page)   __clear_bit(PG_tail, &(page)->flags)
+
 #ifdef CONFIG_SWAP
 #define PageSwapCache(page)     test_bit(PG_swapcache, &(page)->flags)
 #define SetPageSwapCache(page)  set_bit(PG_swapcache, &(page)->flags)