Re: [PATCH net] net: hns: Fix the device being used for dma mapping during TX

[Lino Sanfilippo]

Hi,

> From: Kejian Yan <yankejian@xxxxxxxxxx>
> 
> This patch fixes the device being used to DMA map skb->data.
> Erroneous device assignment causes the crash when SMMU is enabled.
> This happens during TX since buffer gets DMA mapped with device
> correspondign to net_device and gets unmapped using the device
> related to DSAF.
> 
> Signed-off-by: Kejian Yan <yankejian@xxxxxxxxxx>
> Reviewed-by: Yisen Zhuang <yisen.zhuang@xxxxxxxxxx>
> Signed-off-by: Salil Mehta <salil.mehta@xxxxxxxxxx>
> ---
>  drivers/net/ethernet/hisilicon/hns/hns_enet.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
> index 672b646..2b52a12 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
> +++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
> @@ -305,7 +305,7 @@ int hns_nic_net_xmit_hw(struct net_device *ndev,
>  			struct hns_nic_ring_data *ring_data)
>  {
>  	struct hns_nic_priv *priv = netdev_priv(ndev);
> -	struct device *dev = priv->dev;
> +	struct device *dev = ring_to_dev(ring_data->ring);
>  	struct hnae_ring *ring = ring_data->ring;
>  	struct netdev_queue *dev_queue;
>  	struct skb_frag_struct *frag;
> -- 

I would say it should be the other way around: Use priv->dev for mapping and
unmapping instead of ring_to_dev().

Regards,
Lino