1 files changed, 10 insertions, 12 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 914d04b98bee..2e034a0b89ab 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -225,7 +225,9 @@ vma_address(struct page *page, struct vm_area_struct *vma)
 
 /*
  * At what user virtual address is page expected in vma? checking that the
- * page matches the vma: currently only used by unuse_process, on anon pages.
+ * page matches the vma: currently only used on anon pages, by unuse_vma;
+ * and by extraordinary checks on anon pages in VM_UNPAGED vmas, taking
+ * care that an mmap of /dev/mem might window free and foreign pages.
  */
 unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 {
@@ -234,7 +236,8 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
                     (void *)page->mapping - PAGE_MAPPING_ANON)
                         return -EFAULT;
         } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
-                if (vma->vm_file->f_mapping != page->mapping)
+                if (!vma->vm_file ||
+                    vma->vm_file->f_mapping != page->mapping)
                         return -EFAULT;
         } else
                 return -EFAULT;
@@ -529,10 +532,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
          * If the page is mlock()d, we cannot swap it out.
          * If it's recently referenced (perhaps page_referenced
          * skipped over this mm) then we should reactivate it.
-         *
-         * Pages belonging to VM_RESERVED regions should not happen here.
          */
-        if ((vma->vm_flags & (VM_LOCKED|VM_RESERVED)) ||
+        if ((vma->vm_flags & VM_LOCKED) ||
                         ptep_clear_flush_young(vma, address, pte)) {
                 ret = SWAP_FAIL;
                 goto out_unmap;
@@ -727,7 +728,7 @@ static int try_to_unmap_file(struct page *page)
 
         list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
                                                 shared.vm_set.list) {
-                if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+                if (vma->vm_flags & VM_LOCKED)
                         continue;
                 cursor = (unsigned long) vma->vm_private_data;
                 if (cursor > max_nl_cursor)
@@ -761,7 +762,7 @@ static int try_to_unmap_file(struct page *page)
         do {
                 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
                                                 shared.vm_set.list) {
-                        if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+                        if (vma->vm_flags & VM_LOCKED)
                                 continue;
                         cursor = (unsigned long) vma->vm_private_data;
                         while ( cursor < max_nl_cursor &&
@@ -783,11 +784,8 @@ static int try_to_unmap_file(struct page *page)
          * in locked vmas).  Reset cursor on all unreserved nonlinear
          * vmas, now forgetting on which ones it had fallen behind.
          */
-        list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
-                                                shared.vm_set.list) {
-                if (!(vma->vm_flags & VM_RESERVED))
-                        vma->vm_private_data = NULL;
-        }
+        list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+                vma->vm_private_data = NULL;
 out:
         spin_unlock(&mapping->i_mmap_lock);
         return ret;