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

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

[Salil Mehta]

From: Kejian Yan <yankejian@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 <yankejian@huawei.com>
Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@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;
-- 
1.7.9.5

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

[YUAN Linyu]

> -----Original Message-----
> From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org]
> On Behalf Of Salil Mehta
> Sent: Thursday, February 09, 2017 5:24 PM
> To: davem@davemloft.net
> Cc: salil.mehta@huawei.com; yisen.zhuang@huawei.com;
> mehta.salil.lnk@gmail.com; netdev@vger.kernel.org;
> linux-kernel@vger.kernel.org; linuxarm@huawei.com; Kejian Yan
> Subject: [PATCH net] net: hns: Fix the device being used for dma mapping during
> TX
> 
> From: Kejian Yan <yankejian@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 <yankejian@huawei.com>
> Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@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 device *dev = ring_to_dev(ring); ??????
>  	struct netdev_queue *dev_queue;
>  	struct skb_frag_struct *frag;
> --
> 1.7.9.5
> 

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

[Salil Mehta]

> -----Original Message-----
> From: YUAN Linyu [mailto:Linyu.Yuan@alcatel-sbell.com.cn]
> Sent: Thursday, February 09, 2017 9:36 AM
> To: Salil Mehta; davem@davemloft.net
> Cc: Zhuangyuzeng (Yisen); mehta.salil.lnk@gmail.com;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Linuxarm;
> Yankejian (Hackim Yim)
> Subject: RE: [PATCH net] net: hns: Fix the device being used for dma
> mapping during TX
> 
> 
> 
> > -----Original Message-----
> > From: netdev-owner@vger.kernel.org [mailto:netdev-
> owner@vger.kernel.org]
> > On Behalf Of Salil Mehta
> > Sent: Thursday, February 09, 2017 5:24 PM
> > To: davem@davemloft.net
> > Cc: salil.mehta@huawei.com; yisen.zhuang@huawei.com;
> > mehta.salil.lnk@gmail.com; netdev@vger.kernel.org;
> > linux-kernel@vger.kernel.org; linuxarm@huawei.com; Kejian Yan
> > Subject: [PATCH net] net: hns: Fix the device being used for dma
> mapping during
> > TX
> >
> > From: Kejian Yan <yankejian@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 <yankejian@huawei.com>
> > Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
> > Signed-off-by: Salil Mehta <salil.mehta@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 device *dev = ring_to_dev(ring); ??????
Yes, name of the macro is slight misnomer but this gets the dsaf device.
Hope this answers your question?

Thanks
Salil
> >  	struct netdev_queue *dev_queue;
> >  	struct skb_frag_struct *frag;
> > --
> > 1.7.9.5
> >

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

[Salil Mehta]

> -----Original Message-----
> From: Salil Mehta
> Sent: Thursday, February 09, 2017 9:48 AM
> To: 'YUAN Linyu'; davem@davemloft.net
> Cc: Zhuangyuzeng (Yisen); mehta.salil.lnk@gmail.com;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Linuxarm;
> Yankejian (Hackim Yim)
> Subject: RE: [PATCH net] net: hns: Fix the device being used for dma
> mapping during TX
> 
> > -----Original Message-----
> > From: YUAN Linyu [mailto:Linyu.Yuan@alcatel-sbell.com.cn]
> > Sent: Thursday, February 09, 2017 9:36 AM
> > To: Salil Mehta; davem@davemloft.net
> > Cc: Zhuangyuzeng (Yisen); mehta.salil.lnk@gmail.com;
> > netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Linuxarm;
> > Yankejian (Hackim Yim)
> > Subject: RE: [PATCH net] net: hns: Fix the device being used for dma
> > mapping during TX
> >
> >
> >
> > > -----Original Message-----
> > > From: netdev-owner@vger.kernel.org [mailto:netdev-
> > owner@vger.kernel.org]
> > > On Behalf Of Salil Mehta
> > > Sent: Thursday, February 09, 2017 5:24 PM
> > > To: davem@davemloft.net
> > > Cc: salil.mehta@huawei.com; yisen.zhuang@huawei.com;
> > > mehta.salil.lnk@gmail.com; netdev@vger.kernel.org;
> > > linux-kernel@vger.kernel.org; linuxarm@huawei.com; Kejian Yan
> > > Subject: [PATCH net] net: hns: Fix the device being used for dma
> > mapping during
> > > TX
> > >
> > > From: Kejian Yan <yankejian@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 <yankejian@huawei.com>
> > > Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
> > > Signed-off-by: Salil Mehta <salil.mehta@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 device *dev = ring_to_dev(ring); ??????
> Yes, name of the macro is slight misnomer but this gets the dsaf
> device.
> Hope this answers your question?

I realized this lately, I think you meant below:
  	struct hnae_ring *ring = ring_data->ring;
	struct device *dev = ring_to_dev(ring);

I will correct this and float a patch. Thanks!

Best regards
Salil
> 
> Thanks
> Salil
> > >  	struct netdev_queue *dev_queue;
> > >  	struct skb_frag_struct *frag;
> > > --
> > > 1.7.9.5
> > >

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

[Lino Sanfilippo]

Hi,

> From: Kejian Yan <yankejian@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 <yankejian@huawei.com>
> Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
> Signed-off-by: Salil Mehta <salil.mehta@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().

Regards,
Lino

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

[Salil Mehta]

> -----Original Message-----
> From: Lino Sanfilippo [mailto:LinoSanfilippo@gmx.de]
> Sent: Thursday, February 09, 2017 10:25 AM
> To: Salil Mehta
> Cc: davem@davemloft.net; Salil Mehta; Zhuangyuzeng (Yisen);
> mehta.salil.lnk@gmail.com; netdev@vger.kernel.org; linux-
> kernel@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 <yankejian@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 <yankejian@huawei.com>
> > Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
> > Signed-off-by: Salil Mehta <salil.mehta@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

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

[Lino Sanfilippo]

> Gesendet: Donnerstag, 09. Februar 2017 um 12:30 Uhr
> Von: "Salil Mehta" <salil.mehta@huawei.com>
> An: "Lino Sanfilippo" <LinoSanfilippo@gmx.de>
> Cc: "davem@davemloft.net" <davem@davemloft.net>, "Zhuangyuzeng (Yisen)" <yisen.zhuang@huawei.com>, "mehta.salil.lnk@gmail.com" <mehta.salil.lnk@gmail.com>, "netdev@vger.kernel.org" <netdev@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Linuxarm <linuxarm@huawei.com>, "Yankejian (Hackim Yim)" <yankejian@huawei.com>
> Betreff: RE: [PATCH net] net: hns: Fix the device being used for dma mapping during TX
>
> > -----Original Message-----
> > From: Lino Sanfilippo [mailto:LinoSanfilippo@gmx.de]
> > Sent: Thursday, February 09, 2017 10:25 AM
> > To: Salil Mehta
> > Cc: davem@davemloft.net; Salil Mehta; Zhuangyuzeng (Yisen);
> > mehta.salil.lnk@gmail.com; netdev@vger.kernel.org; linux-
> > kernel@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 <yankejian@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 <yankejian@huawei.com>
> > > Reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
> > > Signed-off-by: Salil Mehta <salil.mehta@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.
> 

Ok, but how can it work if we set the DMA mask of the device object of 
the plaform_device (via dma_set_mask_and_coherent in the probe() function)
and do the actual mapping with a different device object? I dont know much about
 the low level dma handling but I can imagine that the mask is required to
do the mapping correctly. 

Regards,
Lino