static int btmtksdio_rx_packet()

in btmtksdio.c [355:450]

• 62 lines of code
• 12 McCabe index (conditional complexity)

static int btmtksdio_rx_packet(struct btmtksdio_dev *bdev, u16 rx_size)
{
	const struct h4_recv_pkt *pkts = mtk_recv_pkts;
	int pkts_count = ARRAY_SIZE(mtk_recv_pkts);
	struct mtkbtsdio_hdr *sdio_hdr;
	int err, i, pad_size;
	struct sk_buff *skb;
	u16 dlen;

	if (rx_size < sizeof(*sdio_hdr))
		return -EILSEQ;

	/* A SDIO packet is exactly containing a Bluetooth packet */
	skb = bt_skb_alloc(rx_size, GFP_KERNEL);
	if (!skb)
		return -ENOMEM;

	skb_put(skb, rx_size);

	err = sdio_readsb(bdev->func, skb->data, MTK_REG_CRDR, rx_size);
	if (err < 0)
		goto err_kfree_skb;

	sdio_hdr = (void *)skb->data;

	/* We assume the default error as -EILSEQ simply to make the error path
	 * be cleaner.
	 */
	err = -EILSEQ;

	if (rx_size != le16_to_cpu(sdio_hdr->len)) {
		bt_dev_err(bdev->hdev, "Rx size in sdio header is mismatched ");
		goto err_kfree_skb;
	}

	hci_skb_pkt_type(skb) = sdio_hdr->bt_type;

	/* Remove MediaTek SDIO header */
	skb_pull(skb, sizeof(*sdio_hdr));

	/* We have to dig into the packet to get payload size and then know how
	 * many padding bytes at the tail, these padding bytes should be removed
	 * before the packet is indicated to the core layer.
	 */
	for (i = 0; i < pkts_count; i++) {
		if (sdio_hdr->bt_type == (&pkts[i])->type)
			break;
	}

	if (i >= pkts_count) {
		bt_dev_err(bdev->hdev, "Invalid bt type 0x%02x",
			   sdio_hdr->bt_type);
		goto err_kfree_skb;
	}

	/* Remaining bytes cannot hold a header*/
	if (skb->len < (&pkts[i])->hlen) {
		bt_dev_err(bdev->hdev, "The size of bt header is mismatched");
		goto err_kfree_skb;
	}

	switch ((&pkts[i])->lsize) {
	case 1:
		dlen = skb->data[(&pkts[i])->loff];
		break;
	case 2:
		dlen = get_unaligned_le16(skb->data +
						  (&pkts[i])->loff);
		break;
	default:
		goto err_kfree_skb;
	}

	pad_size = skb->len - (&pkts[i])->hlen -  dlen;

	/* Remaining bytes cannot hold a payload */
	if (pad_size < 0) {
		bt_dev_err(bdev->hdev, "The size of bt payload is mismatched");
		goto err_kfree_skb;
	}

	/* Remove padding bytes */
	skb_trim(skb, skb->len - pad_size);

	/* Complete frame */
	(&pkts[i])->recv(bdev->hdev, skb);

	bdev->hdev->stat.byte_rx += rx_size;

	return 0;

err_kfree_skb:
	kfree_skb(skb);

	return err;
}