static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
 {
-       struct btrfs_block_group *block_group = ctl->private;
+       struct btrfs_block_group *block_group = ctl->block_group;
        u64 max_bytes;
        u64 bitmap_bytes;
        u64 extent_bytes;
 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
                      struct btrfs_free_space *info)
 {
-       struct btrfs_block_group *block_group = ctl->private;
+       struct btrfs_block_group *block_group = ctl->block_group;
        struct btrfs_fs_info *fs_info = block_group->fs_info;
        bool forced = false;
 
                return 0;
 
        if (ctl->op == &free_space_op)
-               block_group = ctl->private;
+               block_group = ctl->block_group;
 again:
        /*
         * Since we link bitmaps right into the cluster we need to see if we
        spin_lock_init(&ctl->tree_lock);
        ctl->unit = fs_info->sectorsize;
        ctl->start = block_group->start;
-       ctl->private = block_group;
+       ctl->block_group = block_group;
        ctl->op = &free_space_op;
        ctl->free_space_bytes = RB_ROOT_CACHED;
        INIT_LIST_HEAD(&ctl->trimming_ranges);
 {
        spin_lock(&ctl->tree_lock);
        __btrfs_remove_free_space_cache_locked(ctl);
-       if (ctl->private)
-               btrfs_discard_update_discardable(ctl->private);
+       if (ctl->block_group)
+               btrfs_discard_update_discardable(ctl->block_group);
        spin_unlock(&ctl->tree_lock);
 }
 
 
        s32 discardable_extents[BTRFS_STAT_NR_ENTRIES];
        s64 discardable_bytes[BTRFS_STAT_NR_ENTRIES];
        const struct btrfs_free_space_op *op;
-       void *private;
+       struct btrfs_block_group *block_group;
        struct mutex cache_writeout_mutex;
        struct list_head trimming_ranges;
 };