# Re: \[PATCH v5 12/17\] net: sgi: ioc3-eth: use dma-direct for dma allocations

- From: Jakub Kicinski \<hidden\>
- Date: 2019-08-20 00:07:48 
- List: netdev
- Page: https://ratatoskr.run/netdev/2019/08/5692352
- Thread: https://ratatoskr.run/linux-doc/2019/08/5691925/t.md

```text
On Mon, 19 Aug 2019 18:31:35 +0200, Thomas Bogendoerfer wrote:
> @@ -1386,18 +1427,24 @@ static netdev_tx_t ioc3_start_xmit(struct sk_buff *skb, struct net_device *dev)
>  		unsigned long b2 = (data | 0x3fffUL) + 1UL;
>  		unsigned long s1 = b2 - data;
>  		unsigned long s2 = data + len - b2;
> +		dma_addr_t d;
>  
>  		desc->cmd    = cpu_to_be32(len | ETXD_INTWHENDONE |
>  					   ETXD_B1V | ETXD_B2V | w0);
>  		desc->bufcnt = cpu_to_be32((s1 << ETXD_B1CNT_SHIFT) |
>  					   (s2 << ETXD_B2CNT_SHIFT));
> -		desc->p1     = cpu_to_be64(ioc3_map(skb->data, 1));
> -		desc->p2     = cpu_to_be64(ioc3_map((void *)b2, 1));
> +		d = dma_map_single(ip->dma_dev, skb->data, s1, DMA_TO_DEVICE);

You'll need to check the DMA address with dma_mapping_error(dev, addr),
otherwise static checkers will get upset.

> +		desc->p1     = cpu_to_be64(ioc3_map(d, PCI64_ATTR_PREF));
> +		d = dma_map_single(ip->dma_dev, (void *)b2, s1, DMA_TO_DEVICE);
> +		desc->p2     = cpu_to_be64(ioc3_map(d, PCI64_ATTR_PREF));
```