[S390] xpram off by one error.

[linux-2.6] / mm / mempolicy.c

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index e07e27e846a22981a05804aefcdbdb31d88f15be..a9963ceddd65c483f589efe4f5c5124bddd36e8c 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1176,7 +1176,15 @@ static inline unsigned interleave_nid(struct mempolicy *pol,
        if (vma) {
                unsigned long off;
 
-               off = vma->vm_pgoff;
+               /*
+                * for small pages, there is no difference between
+                * shift and PAGE_SHIFT, so the bit-shift is safe.
+                * for huge pages, since vm_pgoff is in units of small
+                * pages, we need to shift off the always 0 bits to get
+                * a useful offset.
+                */
+               BUG_ON(shift < PAGE_SHIFT);
+               off = vma->vm_pgoff >> (shift - PAGE_SHIFT);
                off += (addr - vma->vm_start) >> shift;
                return offset_il_node(pol, vma, off);
        } else