Re: [PATCH net 2/4] net: ll_temac: Add more error handling of dma_map_single() calls

[David Miller]

From: Esben Haabendal <esben@xxxxxxxxxx>
Date: Wed, 19 Feb 2020 11:54:00 +0100

> @@ -863,12 +865,13 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
>  	skb_dma_addr = dma_map_single(ndev->dev.parent, skb->data,
>  				      skb_headlen(skb), DMA_TO_DEVICE);
>  	cur_p->len = cpu_to_be32(skb_headlen(skb));
> +	if (WARN_ON_ONCE(dma_mapping_error(ndev->dev.parent, skb_dma_addr)))
> +		return NETDEV_TX_BUSY;

The appropriate behavior in this situation is to drop the packet and return
NETDEV_TX_OK.