[PATCH RFC -next v2 10/41] md/md-bitmap: introduce struct bitmap_operations

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

The structure is empty for now, and will be used in later patches to
merge in bitmap operations, so that bitmap implementation won't be
exposed.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 drivers/md/md-bitmap.c | 8 ++++++++
 drivers/md/md-bitmap.h | 4 ++++
 drivers/md/md.c        | 1 +
 drivers/md/md.h        | 1 +
 4 files changed, 14 insertions(+)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index ee3ed1e3daf9..eed3b930ade4 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2711,3 +2711,11 @@ const struct attribute_group md_bitmap_group = {
 	.name = "bitmap",
 	.attrs = md_bitmap_attrs,
 };
+
+static struct bitmap_operations bitmap_ops = {
+};
+
+void mddev_set_bitmap_ops(struct mddev *mddev)
+{
+	mddev->bitmap_ops = &bitmap_ops;
+}
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index cad1de79775f..a8a5d4804174 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -245,7 +245,11 @@ struct md_bitmap_stats {
 	bool behind_wait;
 };
 
+struct bitmap_operations {
+};
+
 /* the bitmap API */
+void mddev_set_bitmap_ops(struct mddev *mddev);
 
 /* these are used only by md/bitmap */
 struct bitmap *md_bitmap_create(struct mddev *mddev, int slot);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 628fa49170e1..f67f2540fd6c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -772,6 +772,7 @@ int mddev_init(struct mddev *mddev)
 	mddev->resync_min = 0;
 	mddev->resync_max = MaxSector;
 	mddev->level = LEVEL_NONE;
+	mddev_set_bitmap_ops(mddev);
 
 	INIT_WORK(&mddev->sync_work, md_start_sync);
 	INIT_WORK(&mddev->del_work, mddev_delayed_delete);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index a0d6827dced9..e56193f71ab4 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -536,6 +536,7 @@ struct mddev {
 	int				sync_checkers;	/* # of threads checking writes_pending */
 
 	struct bitmap			*bitmap; /* the bitmap for the device */
+	struct bitmap_operations	*bitmap_ops;
 	struct {
 		struct file		*file; /* the bitmap file */
 		loff_t			offset; /* offset from superblock of
-- 
2.39.2