3 files changed, 16 insertions, 11 deletions

diff --git a/mm/fremap.c b/mm/fremap.c
index 3235fb77c133..ab23a0673c35 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -89,6 +89,9 @@ int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
         size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
         if (!page->mapping || page->index >= size)
                 goto err_unlock;
+        err = -ENOMEM;
+        if (page_mapcount(page) > INT_MAX/2)
+                goto err_unlock;
 
         zap_pte(mm, vma, addr, pte);
 
diff --git a/mm/madvise.c b/mm/madvise.c
index 4454936f87d1..20e075d1c64c 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -83,6 +83,9 @@ static long madvise_willneed(struct vm_area_struct * vma,
 {
         struct file *file = vma->vm_file;
 
+        if (!file)
+                return -EBADF;
+
         if (file->f_mapping->a_ops->get_xip_page) {
                 /* no bad return value, but ignore advice */
                 return 0;
@@ -141,11 +144,7 @@ static long
 madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
                 unsigned long start, unsigned long end, int behavior)
 {
-        struct file *filp = vma->vm_file;
-        long error = -EBADF;
-
-        if (!filp)
-                goto  out;
+        long error;
 
         switch (behavior) {
         case MADV_NORMAL:
@@ -166,8 +165,6 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
                 error = -EINVAL;
                 break;
         }
-                
-out:
         return error;
 }
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0ea71e887bb6..64f9570cff56 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -511,10 +511,11 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
                  * PageDirty _after_ making sure that the page is freeable and
                  * not in use by anybody.       (pagecache + us == 2)
                  */
-                if (page_count(page) != 2 || PageDirty(page)) {
-                        write_unlock_irq(&mapping->tree_lock);
-                        goto keep_locked;
-                }
+                if (unlikely(page_count(page) != 2))
+                        goto cannot_free;
+                smp_rmb();
+                if (unlikely(PageDirty(page)))
+                        goto cannot_free;
 
 #ifdef CONFIG_SWAP
                 if (PageSwapCache(page)) {
@@ -538,6 +539,10 @@ free_it:
                         __pagevec_release_nonlru(&freed_pvec);
                 continue;
 
+cannot_free:
+                write_unlock_irq(&mapping->tree_lock);
+                goto keep_locked;
+
 activate_locked:
                 SetPageActive(page);
                 pgactivate++;