mm/hugetlb: fix potential missing huge page size info

The huge page size is encoded for VM_FAULT_HWPOISON errors only.  So if
we return VM_FAULT_HWPOISON, huge page size would just be ignored.

Link: https://lkml.kernel.org/r/20210107123449.38481-1-linmiaohe@huawei.com
Fixes: aa50d3a7 ("Encode huge page size for VM_FAULT_HWPOISON errors")
Signed-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -4371,7 +4371,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
 		 * So we need to block hugepage fault by PG_hwpoison bit check.
 		 */
 		if (unlikely(PageHWPoison(page))) {
-			ret = VM_FAULT_HWPOISON |
+			ret = VM_FAULT_HWPOISON_LARGE |
 				VM_FAULT_SET_HINDEX(hstate_index(h));
 			goto backout_unlocked;
 		}