Merge 6.10-rc6 into char-misc-next

We need the char/misc/iio fixes in here as well to build on top of.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 12 insertions, 1 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index dd04f578c19c..20cb9f5f7446 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1654,7 +1654,16 @@ static int migrate_pages_batch(struct list_head *from,
 
 			/*
 			 * The rare folio on the deferred split list should
-			 * be split now. It should not count as a failure.
+			 * be split now. It should not count as a failure:
+			 * but increment nr_failed because, without doing so,
+			 * migrate_pages() may report success with (split but
+			 * unmigrated) pages still on its fromlist; whereas it
+			 * always reports success when its fromlist is empty.
+			 * stats->nr_thp_failed should be increased too,
+			 * otherwise stats inconsistency will happen when
+			 * migrate_pages_batch is called via migrate_pages()
+			 * with MIGRATE_SYNC and MIGRATE_ASYNC.
+			 *
 			 * Only check it without removing it from the list.
 			 * Since the folio can be on deferred_split_scan()
 			 * local list and removing it can cause the local list
@@ -1669,6 +1678,8 @@ static int migrate_pages_batch(struct list_head *from,
 			if (nr_pages > 2 &&
 			   !list_empty(&folio->_deferred_list)) {
 				if (try_split_folio(folio, split_folios) == 0) {
+					nr_failed++;
+					stats->nr_thp_failed += is_thp;
 					stats->nr_thp_split += is_thp;
 					stats->nr_split++;
 					continue;