Subject: Re: [PATCH net-next v13 3/3] net: hisilicon: new hip04 ethernet driver

From: Joe Perches <[email-masked]>
Date: Wed, 14 Jan 2015 00:06:22 -0800

On Wed, 2015-01-14 at 14:34 +0800, Ding Tianhong wrote:
> Support Hisilicon hip04 ethernet driver, including 100M / 1000M controller.
> The controller has no tx done interrupt, reclaim xmitted buffer in the poll.

Single comment:

> diff --git a/drivers/net/ethernet/hisilicon/hip04_eth.c b/drivers/net/ethernet/hisilicon/hip04_eth.c
[]
> +static int hip04_rx_poll(struct napi_struct *napi, int budget)
> +{
[]
> +	while (cnt && !last) {
> +		buf = priv->rx_buf[priv->rx_head];
> +		skb = build_skb(buf, priv->rx_buf_size);
> +		if (unlikely(!skb))
> +			net_dbg_ratelimited("build_skb failed\n");
> +
> +		dma_unmap_single(&ndev->dev, priv->rx_phys[priv->rx_head],
> +				 RX_BUF_SIZE, DMA_FROM_DEVICE);
> +		priv->rx_phys[priv->rx_head] = 0;
> +
> +		desc = (struct rx_desc *)skb->data;

Perhaps if (!skb) is possible, there shouldn't be
a dereference of that known null here.