Merge branch 'master'

1 files changed, 12 insertions, 2 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 2a8206009422..b21869a39f0b 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -330,9 +330,19 @@ check_range(struct mm_struct *mm, unsigned long start, unsigned long end,
         int err;
         struct vm_area_struct *first, *vma, *prev;
 
-        /* Clear the LRU lists so pages can be isolated */
-        if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+        if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
+                /* Must have swap device for migration */
+                if (nr_swap_pages <= 0)
+                        return ERR_PTR(-ENODEV);
+
+                /*
+                 * Clear the LRU lists so pages can be isolated.
+                 * Note that pages may be moved off the LRU after we have
+                 * drained them. Those pages will fail to migrate like other
+                 * pages that may be busy.
+                 */
                 lru_add_drain_all();
+        }
 
         first = find_vma(mm, start);
         if (!first)