There is not need to use a separate field in struct mddev, there are no
functional changes.

Signed-off-by: Yu Kuai <yukuai@fnnas.com>
---
 drivers/md/md.c | 6 +++---
 drivers/md/md.h | 3 ++-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 7b5c5967568f..b49fdee11a03 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6462,7 +6462,7 @@ int md_run(struct mddev *mddev)
 	 * the only valid external interface is through the md
 	 * device.
 	 */
-	mddev->has_superblocks = false;
+	clear_bit(MD_HAS_SUPERBLOCK, &mddev->flags);
 	rdev_for_each(rdev, mddev) {
 		if (test_bit(Faulty, &rdev->flags))
 			continue;
@@ -6475,7 +6475,7 @@ int md_run(struct mddev *mddev)
 		}
 
 		if (rdev->sb_page)
-			mddev->has_superblocks = true;
+			set_bit(MD_HAS_SUPERBLOCK, &mddev->flags);
 
 		/* perform some consistency tests on the device.
 		 * We don't want the data to overlap the metadata,
@@ -9085,7 +9085,7 @@ void md_write_start(struct mddev *mddev, struct bio *bi)
 	rcu_read_unlock();
 	if (did_change)
 		sysfs_notify_dirent_safe(mddev->sysfs_state);
-	if (!mddev->has_superblocks)
+	if (!test_bit(MD_HAS_SUPERBLOCK, &mddev->flags))
 		return;
 	wait_event(mddev->sb_wait,
 		   !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 6985f2829bbd..b4c9aa600edd 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -340,6 +340,7 @@ struct md_cluster_operations;
  *		   array is ready yet.
  * @MD_BROKEN: This is used to stop writes and mark array as failed.
  * @MD_DELETED: This device is being deleted
+ * @MD_HAS_SUPERBLOCK: There is persistence sb in member disks.
  *
  * change UNSUPPORTED_MDDEV_FLAGS for each array type if new flag is added
  */
@@ -356,6 +357,7 @@ enum mddev_flags {
 	MD_BROKEN,
 	MD_DO_DELETE,
 	MD_DELETED,
+	MD_HAS_SUPERBLOCK,
 };
 
 enum mddev_sb_flags {
@@ -623,7 +625,6 @@ struct mddev {
 	/* The sequence number for sync thread */
 	atomic_t sync_seq;
 
-	bool	has_superblocks:1;
 	bool	fail_last_dev:1;
 	bool	serialize_policy:1;
 };
-- 
2.51.0