1 files changed, 13 insertions, 4 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 669acb22b572..22ed3f71a674 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -183,7 +183,7 @@ void __init anon_vma_init(void)
  */
 static struct anon_vma *page_lock_anon_vma(struct page *page)
 {
-        struct anon_vma *anon_vma = NULL;
+        struct anon_vma *anon_vma;
         unsigned long anon_mapping;
 
         rcu_read_lock();
@@ -195,9 +195,16 @@ static struct anon_vma *page_lock_anon_vma(struct page *page)
 
         anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
         spin_lock(&anon_vma->lock);
+        return anon_vma;
 out:
         rcu_read_unlock();
-        return anon_vma;
+        return NULL;
+}
+
+static void page_unlock_anon_vma(struct anon_vma *anon_vma)
+{
+        spin_unlock(&anon_vma->lock);
+        rcu_read_unlock();
 }
 
 /*
@@ -333,7 +340,8 @@ static int page_referenced_anon(struct page *page)
                 if (!mapcount)
                         break;
         }
-        spin_unlock(&anon_vma->lock);
+
+        page_unlock_anon_vma(anon_vma);
         return referenced;
 }
 
@@ -802,7 +810,8 @@ static int try_to_unmap_anon(struct page *page, int migration)
                 if (ret == SWAP_FAIL || !page_mapped(page))
                         break;
         }
-        spin_unlock(&anon_vma->lock);
+
+        page_unlock_anon_vma(anon_vma);
         return ret;
 }