1 files changed, 10 insertions, 35 deletions

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index e9fd04ca1e51..830e65dc01ee 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -27,18 +27,15 @@
 struct anon_vma {
         struct anon_vma *root;  /* Root of this anon_vma tree */
         spinlock_t lock;        /* Serialize access to vma list */
-#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
-
         /*
-         * The external_refcount is taken by either KSM or page migration
-         * to take a reference to an anon_vma when there is no
+         * The refcount is taken on an anon_vma when there is no
          * guarantee that the vma of page tables will exist for
          * the duration of the operation. A caller that takes
          * the reference is responsible for clearing up the
          * anon_vma if they are the last user on release
          */
-        atomic_t external_refcount;
-#endif
+        atomic_t refcount;
+
         /*
          * NOTE: the LSB of the head.next is set by
          * mm_take_all_locks() _after_ taking the above lock. So the
@@ -71,42 +68,19 @@ struct anon_vma_chain {
 };
 
 #ifdef CONFIG_MMU
-#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
-static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
-{
-        atomic_set(&anon_vma->external_refcount, 0);
-}
-
-static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
-{
-        return atomic_read(&anon_vma->external_refcount);
-}
-
 static inline void get_anon_vma(struct anon_vma *anon_vma)
 {
-        atomic_inc(&anon_vma->external_refcount);
+        atomic_inc(&anon_vma->refcount);
 }
 
-void drop_anon_vma(struct anon_vma *);
-#else
-static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
-{
-}
+void __put_anon_vma(struct anon_vma *anon_vma);
 
-static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
-{
-        return 0;
-}
-
-static inline void get_anon_vma(struct anon_vma *anon_vma)
+static inline void put_anon_vma(struct anon_vma *anon_vma)
 {
+        if (atomic_dec_and_test(&anon_vma->refcount))
+                __put_anon_vma(anon_vma);
 }
 
-static inline void drop_anon_vma(struct anon_vma *anon_vma)
-{
-}
-#endif /* CONFIG_KSM */
-
 static inline struct anon_vma *page_anon_vma(struct page *page)
 {
         if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
@@ -148,7 +122,6 @@ void unlink_anon_vmas(struct vm_area_struct *);
 int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
 int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
 void __anon_vma_link(struct vm_area_struct *);
-void anon_vma_free(struct anon_vma *);
 
 static inline void anon_vma_merge(struct vm_area_struct *vma,
                                   struct vm_area_struct *next)
@@ -157,6 +130,8 @@ static inline void anon_vma_merge(struct vm_area_struct *vma,
         unlink_anon_vmas(next);
 }
 
+struct anon_vma *page_get_anon_vma(struct page *page);
+
 /*
  * rmap interfaces called when adding or removing pte of page
  */