[PATCH md-6.14 03/13] md/md-bitmap: add md_bitmap_registered/enabled() helper

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

There are no functional changes, prepare to handle the case that
mddev->bitmap_ops can be NULL, which is possible after support to
build md-bitmap as kernel module.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 drivers/md/md-bitmap.c | 16 ++++------------
 drivers/md/md-bitmap.h | 19 ++++++++++++++++++-
 drivers/md/raid1-10.c  |  2 +-
 3 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index bf6de7ad3b6a..4450edd9774f 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -220,22 +220,14 @@ static inline char *bmname(struct bitmap *bitmap)
 	return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
 }
 
-static bool __bitmap_enabled(struct bitmap *bitmap)
+static bool bitmap_enabled(void *data)
 {
+	struct bitmap *bitmap = data;
+
 	return bitmap->storage.filemap &&
 	       !test_bit(BITMAP_STALE, &bitmap->flags);
 }
 
-static bool bitmap_enabled(struct mddev *mddev)
-{
-	struct bitmap *bitmap = mddev->bitmap;
-
-	if (!bitmap)
-		return false;
-
-	return __bitmap_enabled(bitmap);
-}
-
 /*
  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
  *
@@ -1232,7 +1224,7 @@ static void __bitmap_unplug(struct bitmap *bitmap)
 	int dirty, need_write;
 	int writing = 0;
 
-	if (!__bitmap_enabled(bitmap))
+	if (!bitmap_enabled(bitmap))
 		return;
 
 	/* look at each page to see if there are any set bits that need to be
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 5a2aa1324df0..3b242ee10856 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -71,7 +71,7 @@ struct md_bitmap_stats {
 };
 
 struct bitmap_operations {
-	bool (*enabled)(struct mddev *mddev);
+	bool (*enabled)(void *data);
 	int (*create)(struct mddev *mddev, int slot);
 	int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize);
 
@@ -116,4 +116,21 @@ struct bitmap_operations {
 /* the bitmap API */
 void mddev_set_bitmap_ops(struct mddev *mddev);
 
+static inline bool md_bitmap_registered(struct mddev *mddev)
+{
+	return mddev->bitmap_ops != NULL;
+}
+
+static inline bool md_bitmap_enabled(struct mddev *mddev)
+{
+	/* bitmap_ops must be registered before creating bitmap. */
+	if (!md_bitmap_registered(mddev))
+		return false;
+
+	if (!mddev->bitmap)
+		return false;
+
+	return mddev->bitmap_ops->enabled(mddev->bitmap);
+}
+
 #endif
diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c
index 4378d3250bd7..6b8b7b7f1678 100644
--- a/drivers/md/raid1-10.c
+++ b/drivers/md/raid1-10.c
@@ -140,7 +140,7 @@ static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
 	 * If bitmap is not enabled, it's safe to submit the io directly, and
 	 * this can get optimal performance.
 	 */
-	if (!mddev->bitmap_ops->enabled(mddev)) {
+	if (!md_bitmap_enabled(mddev)) {
 		raid1_submit_write(bio);
 		return true;
 	}
-- 
2.39.2