Matthias Fuchs wrote:
> This patch adds support for the esd USB2 CAN interface.
[snip]
> +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
> +static int esd_usb2_start_xmit(struct sk_buff *skb, struct net_device
> *netdev)
> +#else
> +static netdev_tx_t esd_usb2_start_xmit(struct sk_buff *skb,
> + struct net_device *netdev)
> +#endif
> +{
> + struct esd_usb2_net_priv *priv = netdev_priv(netdev);
> + struct esd_usb2 *dev = priv->usb2;
> + struct esd_tx_urb_context *context = NULL;
> + struct net_device_stats *stats = &netdev->stats;
> + struct can_frame *cf = (struct can_frame *)skb->data;
> + struct esd_usb2_msg *msg;
> + struct urb *urb;
> + u8 *buf;
> + int i, err;
> + int ret = NETDEV_TX_OK;
> + size_t size = sizeof(struct esd_usb2_msg);
> +
> + /* create a URB, and a buffer for it, and copy the data to the URB */
> + urb = usb_alloc_urb(0, GFP_ATOMIC);
> + if (!urb) {
> + dev_err(ND2D(netdev), "No memory left for URBs\n");
> + stats->tx_dropped++;
> + if (skb)
> + kfree_skb(skb);
skb cannot be zero.
> + goto nourbmem;
> + }
> +
> + buf = usb_buffer_alloc(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
> + if (!buf) {
> + dev_err(ND2D(netdev), "No memory left for USB buffer\n");
> + stats->tx_dropped++;
> + if (skb)
> + kfree_skb(skb);
Ditto.
> + goto nobufmem;
> + }
> +
> + msg = (struct esd_usb2_msg *)buf;
> +
> + msg->msg.hdr.len = 3; /* minimal length */
> + msg->msg.hdr.cmd = CMD_CAN_TX;
> + msg->msg.tx.net = priv->index;
> + msg->msg.tx.dlc = cf->can_dlc;
> + msg->msg.tx.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
> +
> + if (cf->can_id & CAN_RTR_FLAG)
> + msg->msg.tx.dlc |= ESD_RTR;
> +
> + if (cf->can_id & CAN_EFF_FLAG)
> + msg->msg.tx.id |= cpu_to_le32(ESD_EXTID);
> +
> + for (i = 0; i < cf->can_dlc; i++)
> + msg->msg.tx.data[i] = cf->data[i];
> +
> + msg->msg.hdr.len += (cf->can_dlc + 3) >> 2;
> +
> + for (i = 0; i < MAX_TX_URBS; i++) {
> + if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
> + context = &priv->tx_contexts[i];
> + break;
> + }
> + }
> +
> + /*
> + * This may never happen.
> + */
> + if (!context) {
> + dev_warn(ND2D(netdev), "couldn't find free context\n");
> + ret = NETDEV_TX_BUSY;
> + if (skb)
> + kfree_skb(skb);
If you return with NETDEV_TX_BUSY, you should *not* free the skb as the
upper layer will retry later.
> + goto releasebuf;
> + }
> +
> + context->priv = priv;
> + context->echo_index = i;
> + context->dlc = cf->can_dlc;
> +
> + /* hnd must not be 0 */
> + msg->msg.tx.hnd = 0x80000000 | i; /* returned in TX done message */
> +
> + usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
> + msg->msg.hdr.len << 2,
> + esd_usb2_write_bulk_callback, context);
> +
> + urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
> +
> + usb_anchor_urb(urb, &priv->tx_submitted);
> +
> + can_put_echo_skb(skb, netdev, context->echo_index);
> +
> + atomic_inc(&priv->active_tx_jobs);
> +
> + err = usb_submit_urb(urb, GFP_ATOMIC);
> + if (err) {
> + can_free_echo_skb(netdev, context->echo_index);
> +
> + atomic_dec(&priv->active_tx_jobs);
> + usb_unanchor_urb(urb);
> +
> + stats->tx_dropped++;
> +
> + if (err == -ENODEV)
> + netif_device_detach(netdev);
> + else
> + dev_warn(ND2D(netdev), "failed tx_urb %d\n", err);
> +
> + goto releasebuf;
> + }
> +
> + netdev->trans_start = jiffies;
> +
> + /* Slow down tx path */
> + if (atomic_read(&priv->active_tx_jobs) >= MAX_TX_URBS)
> + netif_stop_queue(netdev);
> +
> + /*
> + * Release our reference to this URB, the USB core will eventually free
> + * it entirely.
> + */
> + usb_free_urb(urb);
> +
> + return NETDEV_TX_OK;
> +
> +releasebuf:
> + usb_buffer_free(dev->udev, size, buf, urb->transfer_dma);
> +
> +nobufmem:
> + usb_free_urb(urb);
> +
> +nourbmem:
> + return ret;
> +}
> +
Puh, to avoid another round, I fixed the issues above and another one
reported by checkpatch and commited the patch with your signed-of-by
line. Please check.
Thanks for your contribution.
Wolfgang.
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