md/md-bitmap: merge bitmap_unplug() 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 <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240826074452.1490072-33-yukuai1@huaweicloud.comSigned-off-by: Song Liu <song@kernel.org>

drivers/md/md-bitmap.c

@@ -1087,7 +1087,7 @@ static void bitmap_unplug_async(struct bitmap *bitmap)
 	wait_for_completion(&done);
 }
 
-void md_bitmap_unplug(struct mddev *mddev, bool sync)
+static void bitmap_unplug(struct mddev *mddev, bool sync)
 {
 	struct bitmap *bitmap = mddev->bitmap;
 
@@ -1099,7 +1099,6 @@ void md_bitmap_unplug(struct mddev *mddev, bool sync)
 	else
 		bitmap_unplug_async(bitmap);
 }
-EXPORT_SYMBOL_GPL(md_bitmap_unplug);
 
 static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
 
@@ -2754,6 +2753,7 @@ static struct bitmap_operations bitmap_ops = {
 	.flush			= bitmap_flush,
 	.write_all		= bitmap_write_all,
 	.dirty_bits		= bitmap_dirty_bits,
+	.unplug			= bitmap_unplug,
 
 	.startwrite		= bitmap_startwrite,
 	.endwrite		= bitmap_endwrite,

drivers/md/md-bitmap.h

@@ -254,6 +254,7 @@ struct bitmap_operations {
 	void (*write_all)(struct mddev *mddev);
 	void (*dirty_bits)(struct mddev *mddev, unsigned long s,
 			   unsigned long e);
+	void (*unplug)(struct mddev *mddev, bool sync);
 
 	int (*startwrite)(struct mddev *mddev, sector_t offset,
 			  unsigned long sectors, bool behind);
@@ -277,7 +278,6 @@ struct bitmap_operations {
 void mddev_set_bitmap_ops(struct mddev *mddev);
 
 /* these are exported */
-void md_bitmap_unplug(struct mddev *mddev, bool sync);
 void md_bitmap_daemon_work(struct mddev *mddev);
 
 int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,

drivers/md/md.c

@@ -4715,7 +4715,7 @@ bitmap_store(struct mddev *mddev, const char *buf, size_t len)
 		mddev->bitmap_ops->dirty_bits(mddev, chunk, end_chunk);
 		buf = skip_spaces(end);
 	}
-	md_bitmap_unplug(mddev, true); /* flush the bits to disk */
+	mddev->bitmap_ops->unplug(mddev, true); /* flush the bits to disk */
 out:
 	mddev_unlock(mddev);
 	return len;

drivers/md/raid1-10.c

@@ -168,7 +168,7 @@ static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
  */
 static inline void raid1_prepare_flush_writes(struct mddev *mddev)
 {
-	md_bitmap_unplug(mddev, current->bio_list == NULL);
+	mddev->bitmap_ops->unplug(mddev, current->bio_list == NULL);
 }
 
 /*

drivers/md/raid5.c

@@ -6768,7 +6768,7 @@ static void raid5d(struct md_thread *thread)
 			/* Now is a good time to flush some bitmap updates */
 			conf->seq_flush++;
 			spin_unlock_irq(&conf->device_lock);
-			md_bitmap_unplug(mddev, true);
+			mddev->bitmap_ops->unplug(mddev, true);
 			spin_lock_irq(&conf->device_lock);
 			conf->seq_write = conf->seq_flush;
 			activate_bit_delay(conf, conf->temp_inactive_list);