}
 
 static ssize_t mtk_btcvsd_snd_read(struct mtk_btcvsd_snd *bt,
-                                  char __user *buf,
+                                  struct iov_iter *buf,
                                   size_t count)
 {
        ssize_t read_size = 0, read_count = 0, cur_read_idx, cont;
-       unsigned int cur_buf_ofs = 0;
        unsigned long avail;
        unsigned long flags;
        unsigned int packet_size = bt->rx->packet_size;
                if (read_size > cont)
                        read_size = cont;
 
-               if (copy_to_user(buf + cur_buf_ofs,
-                                bt->rx_packet_buf + cur_read_idx,
-                                read_size)) {
-                       dev_warn(bt->dev, "%s(), copy_to_user fail\n",
+               if (copy_to_iter(bt->rx_packet_buf + cur_read_idx,
+                                read_size, buf) != read_size) {
+                       dev_warn(bt->dev, "%s(), copy_to_iter fail\n",
                                 __func__);
                        return -EFAULT;
                }
                spin_unlock_irqrestore(&bt->rx_lock, flags);
 
                read_count += read_size;
-               cur_buf_ofs += read_size;
                count -= read_size;
        }
 
 }
 
 static ssize_t mtk_btcvsd_snd_write(struct mtk_btcvsd_snd *bt,
-                                   char __user *buf,
+                                   struct iov_iter *buf,
                                    size_t count)
 {
        int written_size = count, avail, cur_write_idx, write_size, cont;
-       unsigned int cur_buf_ofs = 0;
        unsigned long flags;
        unsigned int packet_size = bt->tx->packet_size;
 
                if (write_size > cont)
                        write_size = cont;
 
-               if (copy_from_user(bt->tx_packet_buf +
-                                  cur_write_idx,
-                                  buf + cur_buf_ofs,
-                                  write_size)) {
-                       dev_warn(bt->dev, "%s(), copy_from_user fail\n",
+               if (copy_from_iter(bt->tx_packet_buf + cur_write_idx,
+                                  write_size, buf) != write_size) {
+                       dev_warn(bt->dev, "%s(), copy_from_iter fail\n",
                                 __func__);
                        return -EFAULT;
                }
                spin_lock_irqsave(&bt->tx_lock, flags);
                bt->tx->packet_w += write_size / packet_size;
                spin_unlock_irqrestore(&bt->tx_lock, flags);
-               cur_buf_ofs += write_size;
                count -= write_size;
        }
 
 static int mtk_pcm_btcvsd_copy(struct snd_soc_component *component,
                               struct snd_pcm_substream *substream,
                               int channel, unsigned long pos,
-                              void __user *buf, unsigned long count)
+                              struct iov_iter *buf, unsigned long count)
 {
        struct mtk_btcvsd_snd *bt = snd_soc_component_get_drvdata(component);
 
        .prepare        = mtk_pcm_btcvsd_prepare,
        .trigger        = mtk_pcm_btcvsd_trigger,
        .pointer        = mtk_pcm_btcvsd_pointer,
-       .copy_user      = mtk_pcm_btcvsd_copy,
+       .copy           = mtk_pcm_btcvsd_copy,
 };
 
 static int mtk_btcvsd_snd_probe(struct platform_device *pdev)