Modify1.swift

func updateDataIndex(from fromIndexPath: IndexPath, to toIndexPath: IndexPath) {
    let fromPosition = fromIndexPath.item
    let toPosition = toIndexPath.item
    let selected = cellDataList[fromPosition] as Int
    DispatchQueue.main.async {[weak self] in
        self?.cellDataList.remove(at: fromPosition)

        var newindex = toPosition
        if (newindex > self?.cellDataList.count ?? 0) {
            newindex = self?.cellDataList.count ?? 0
        }
        self?.cellDataList.insert(selected, at: newindex)

        self?.collectionView.reloadData()
        UIView.performWithoutAnimation {
            self?.collectionView.reloadSections(IndexSet(integersIn: 0...0))
        }
    }
}

func getCollectionViewColumnMaxCount() -> Int {
    return ViewController.columnCount
}

func getCollectionViewRowMaxCount() -> Int {
    return 10
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    let maxCount = getCollectionViewColumnMaxCount() * getCollectionViewRowMaxCount()
    let bufferCount = maxCount - (self.cellDataList.count % maxCount)

    return self.cellDataList.count + bufferCount
}