mm: use linear_page_index() in do_fault()

do_fault() assumes that PAGE_SIZE is the same as PAGE_CACHE_SIZE.  Use
linear_page_index() to calculate pgoff in the correct units.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 8adb5b756264..032f05cd6a2f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3124,8 +3124,7 @@ static int do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                 unsigned long address, pte_t *page_table, pmd_t *pmd,
                 unsigned int flags, pte_t orig_pte)
 {
-        pgoff_t pgoff = (((address & PAGE_MASK)
-                        - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+        pgoff_t pgoff = linear_page_index(vma, address);
 
         pte_unmap(page_table);
         /* The VMA was not fully populated on mmap() or missing VM_DONTEXPAND */