- /*
- * 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);