s390: gup_huge_pmd() return 0 if pte changes

s390 didn't return 0 in that case, if it's rolling back the *nr pointer it
should also return zero to avoid adding pages to the array at the wrong
offset.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 10 deletions

diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 668dda964f20..da33a0281d9d 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -93,16 +93,17 @@ static inline int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
                 *nr -= refs;
                 while (refs--)
                         put_page(head);
-        } else {
-                /*
-                 * Any tail page need their mapcount reference taken
-                 * before we return.
-                 */
-                while (refs--) {
-                        if (PageTail(tail))
-                                get_huge_page_tail(tail);
-                        tail++;
-                }
+                return 0;
+        }
+
+        /*
+         * Any tail page need their mapcount reference taken before we
+         * return.
+         */
+        while (refs--) {
+                if (PageTail(tail))
+                        get_huge_page_tail(tail);
+                tail++;
         }
 
         return 1;