Fix VM_FAULT flags conversion for hugetlb

It seems a simple mistake was made when converting follow_hugetlb_page()
over to the VM_FAULT flags bitmasks (in "mm: fault feedback #2", commit
83c54070ee1a2d05c89793884bea1a03f2851ed4).

By using the wrong bitmask, hugetlb_fault() failures are not being
recognized.  This results in an infinite loop whenever follow_hugetlb_page
is involved in a failed fault.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -643,7 +643,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 			spin_unlock(&mm->page_table_lock);
 			ret = hugetlb_fault(mm, vma, vaddr, 0);
 			spin_lock(&mm->page_table_lock);
-			if (!(ret & VM_FAULT_MAJOR))
+			if (!(ret & VM_FAULT_ERROR))
 				continue;
 
 			remainder = 0;