> -----Original Message----- > From: Lino Sanfilippo [mailto:linosanfili...@gmx.de] > Sent: Thursday, February 09, 2017 10:25 AM > To: Salil Mehta > Cc: da...@davemloft.net; Salil Mehta; Zhuangyuzeng (Yisen); > mehta.salil....@gmail.com; netdev@vger.kernel.org; linux- > ker...@vger.kernel.org; Linuxarm; Yankejian (Hackim Yim) > Subject: Re: [PATCH net] net: hns: Fix the device being used for dma > mapping during TX > > Hi, > > > From: Kejian Yan <yankej...@huawei.com> > > > > 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 <yankej...@huawei.com> > > Reviewed-by: Yisen Zhuang <yisen.zhu...@huawei.com> > > Signed-off-by: Salil Mehta <salil.me...@huawei.com> > > --- > > 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(). Yes, you got it right. Ideally, it should be per-port and for legacy reasons we have it this way. In the current design, we have SMMU node per-dsaf and I guess we will not land in the right dma-ops if we use per-netdev platform-device/device right now.
Best regards Salil > > Regards, > Lino
