[PATCH 6/6] block: remove delayed holder registration

[Christoph Hellwig <hch@xxxxxx>]

Now that dm has been fixed to track of holder registrations before
add_disk, the somewhat buggy block layer code can be safely removed.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 block/genhd.c          |  4 ----
 block/holder.c         | 40 +++++++++++-----------------------------
 include/linux/blkdev.h |  5 -----
 3 files changed, 11 insertions(+), 38 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index cd90df6c775c2..7c86b161fbd0f 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -478,10 +478,6 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 		goto out_put_holder_dir;
 	}
 
-	ret = bd_register_pending_holders(disk);
-	if (ret < 0)
-		goto out_put_slave_dir;
-
 	ret = blk_register_queue(disk);
 	if (ret)
 		goto out_put_slave_dir;
diff --git a/block/holder.c b/block/holder.c
index 4923a77ebecdc..c183553503b07 100644
--- a/block/holder.c
+++ b/block/holder.c
@@ -79,6 +79,9 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	struct bd_holder_disk *holder;
 	int ret = 0;
 
+	if (WARN_ON_ONCE(!disk->slave_dir))
+		return -EINVAL;
+
 	mutex_lock(&disk->open_mutex);
 
 	WARN_ON_ONCE(!bdev->bd_holder);
@@ -98,12 +101,10 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	INIT_LIST_HEAD(&holder->list);
 	holder->bdev = bdev;
 	holder->refcnt = 1;
-	if (disk->slave_dir) {
-		ret = __link_disk_holder(bdev, disk);
-		if (ret) {
-			kfree(holder);
-			goto out_unlock;
-		}
+	ret = __link_disk_holder(bdev, disk);
+	if (ret) {
+		kfree(holder);
+		goto out_unlock;
 	}
 
 	list_add(&holder->list, &disk->slave_bdevs);
@@ -140,11 +141,13 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 {
 	struct bd_holder_disk *holder;
 
+	if (WARN_ON_ONCE(!disk->slave_dir))
+		return;
+
 	mutex_lock(&disk->open_mutex);
 	holder = bd_find_holder_disk(bdev, disk);
 	if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
-		if (disk->slave_dir)
-			__unlink_disk_holder(bdev, disk);
+		__unlink_disk_holder(bdev, disk);
 		kobject_put(bdev->bd_holder_dir);
 		list_del_init(&holder->list);
 		kfree(holder);
@@ -152,24 +155,3 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
 	mutex_unlock(&disk->open_mutex);
 }
 EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
-
-int bd_register_pending_holders(struct gendisk *disk)
-{
-	struct bd_holder_disk *holder;
-	int ret;
-
-	mutex_lock(&disk->open_mutex);
-	list_for_each_entry(holder, &disk->slave_bdevs, list) {
-		ret = __link_disk_holder(holder->bdev, disk);
-		if (ret)
-			goto out_undo;
-	}
-	mutex_unlock(&disk->open_mutex);
-	return 0;
-
-out_undo:
-	list_for_each_entry_continue_reverse(holder, &disk->slave_bdevs, list)
-		__unlink_disk_holder(holder->bdev, disk);
-	mutex_unlock(&disk->open_mutex);
-	return ret;
-}
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 50e358a19d986..5a208d6def879 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -839,7 +839,6 @@ void set_capacity(struct gendisk *disk, sector_t size);
 #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
 int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
 void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
-int bd_register_pending_holders(struct gendisk *disk);
 #else
 static inline int bd_link_disk_holder(struct block_device *bdev,
 				      struct gendisk *disk)
@@ -850,10 +849,6 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev,
 					 struct gendisk *disk)
 {
 }
-static inline int bd_register_pending_holders(struct gendisk *disk)
-{
-	return 0;
-}
 #endif /* CONFIG_BLOCK_HOLDER_DEPRECATED */
 
 dev_t part_devt(struct gendisk *disk, u8 partno);
-- 
2.30.2