mm/khugepaged: fix the address passed to notifier on testing young

Commit 8ee5382 ("thp: mmu_notifier_test_young") introduced
mmu_notifier_test_young(), but we are passing the wrong address.
In xxx_scan_pmd(), the actual iteration address is "_address" not
"address".  We seem to misuse the variable on the very beginning.

Change it to the right one.

[[email protected] fix whitespace, per everyone]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 8ee5382 ("thp: mmu_notifier_test_young")
Signed-off-by: Wei Yang <[email protected]>
Reviewed-by: Dev Jain <[email protected]>
Reviewed-by: Zi Yan <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Nico Pache <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Barry Song <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: RichardWeiYang

mm/khugepaged.c

@@ -1417,8 +1417,8 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
 		 */
 		if (cc->is_khugepaged &&
 		    (pte_young(pteval) || folio_test_young(folio) ||
-		     folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
-								     address)))
+		     folio_test_referenced(folio) ||
+		     mmu_notifier_test_young(vma->vm_mm, _address)))
 			referenced++;
 	}
 	if (!writable) {