md/md-bitmap: merge md_bitmap_enabled() into bitmap_operations

So that the implementation won't be exposed, and it'll be possible
to invent a new bitmap by replacing bitmap_operations.

Signed-off-by: Yu Kuai <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Song Liu <[e-mail]>

drivers/md/md-bitmap.c

···
 	return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
 }
 
+static bool __bitmap_enabled(struct bitmap *bitmap)
+{
+	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)
  *
···
 	int dirty, need_write;
 	int writing = 0;
 
-	if (!md_bitmap_enabled(bitmap))
+	if (!__bitmap_enabled(bitmap))
 		return;
 
 	/* look at each page to see if there are any set bits that need to be
···
 };
 
 static struct bitmap_operations bitmap_ops = {
+	.enabled		= bitmap_enabled,
 	.create			= bitmap_create,
 	.resize			= bitmap_resize,
 	.load			= bitmap_load,

drivers/md/md-bitmap.h

···
 };
 
 struct bitmap_operations {
+	bool (*enabled)(struct mddev *mddev);
 	int (*create)(struct mddev *mddev, int slot);
 	int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize,
 		      bool init);
···
 /* the bitmap API */
 void mddev_set_bitmap_ops(struct mddev *mddev);
 
-static inline bool md_bitmap_enabled(struct bitmap *bitmap)
-{
-	return bitmap && bitmap->storage.filemap &&
-	       !test_bit(BITMAP_STALE, &bitmap->flags);
-}
-
 #endif
-
 #endif

drivers/md/raid1-10.c

···
 	 * If bitmap is not enabled, it's safe to submit the io directly, and
 	 * this can get optimal performance.
 	 */
-	if (!md_bitmap_enabled(mddev->bitmap)) {
+	if (!mddev->bitmap_ops->enabled(mddev)) {
 		raid1_submit_write(bio);
 		return true;
 	}