[PATCH] net: fec: fix receive VLAN CTAG HW acceleration issue

[PATCH] net: fec: fix receive VLAN CTAG HW acceleration issue

[Fugang Duan]

The current driver support receive VLAN CTAG HW acceleration feature
(NETIF_F_HW_VLAN_CTAG_RX) through software simulation. There calls the
api .skb_copy_to_linear_data_offset() to skip the VLAN tag, but there
have overlap between the two memory data point range. The patch just fix
the issue.

Reported-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Fugang Duan <B38611@freescale.com>
---
 drivers/net/ethernet/freescale/fec_main.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 9bb6220..c9b1dbb 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1475,12 +1475,14 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
 			/* Push and remove the vlan tag */
 			struct vlan_hdr *vlan_header =
 					(struct vlan_hdr *) (data + ETH_HLEN);
+			unsigned char eth_hdr[12];
 			vlan_tag = ntohs(vlan_header->h_vlan_TCI);
 
 			vlan_packet_rcvd = true;
 
+			memcpy(eth_hdr, data, 2 * ETH_ALEN);
 			skb_copy_to_linear_data_offset(skb, VLAN_HLEN,
-						       data, (2 * ETH_ALEN));
+						       eth_hdr, (2 * ETH_ALEN));
 			skb_pull(skb, VLAN_HLEN);
 		}
 
-- 
1.7.8

Re: [PATCH] net: fec: fix receive VLAN CTAG HW acceleration issue

[Michael Grzeschik]

On Tue, Mar 10, 2015 at 06:30:42PM +0800, Fugang Duan wrote:
> The current driver support receive VLAN CTAG HW acceleration feature
> (NETIF_F_HW_VLAN_CTAG_RX) through software simulation. There calls the
> api .skb_copy_to_linear_data_offset() to skip the VLAN tag, but there
> have overlap between the two memory data point range. The patch just fix
> the issue.
> 
> Reported-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> Signed-off-by: Fugang Duan <B38611@freescale.com>
> ---
>  drivers/net/ethernet/freescale/fec_main.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 9bb6220..c9b1dbb 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1475,12 +1475,14 @@ fec_enet_rx_queue(struct net_device *ndev, int budget, u16 queue_id)
>  			/* Push and remove the vlan tag */
>  			struct vlan_hdr *vlan_header =
>  					(struct vlan_hdr *) (data + ETH_HLEN);
> +			unsigned char eth_hdr[12];
>  			vlan_tag = ntohs(vlan_header->h_vlan_TCI);
>  
>  			vlan_packet_rcvd = true;
>  
> +			memcpy(eth_hdr, data, 2 * ETH_ALEN);
>  			skb_copy_to_linear_data_offset(skb, VLAN_HLEN,
> -						       data, (2 * ETH_ALEN));
> +						       eth_hdr, (2 * ETH_ALEN));
>  			skb_pull(skb, VLAN_HLEN);
>  		}
>  
> -- 
> 1.7.8

why not just use memmove instead of the skb_copy_to_linear_data_offset?

memmove(skb->data + VLAN_HLEN, data, (2 * ETH_ALEN));

Michael

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RE: [PATCH] net: fec: fix receive VLAN CTAG HW acceleration issue

[fugang.duan]

From: Michael Grzeschik <mgr@pengutronix.de> Sent: Tuesday, March 10, 2015 7:05 PM
> To: Duan Fugang-B38611
> Cc: davem@davemloft.net; netdev@vger.kernel.org; kernel@pengutronix.de
> Subject: Re: [PATCH] net: fec: fix receive VLAN CTAG HW acceleration
> issue
> 
> On Tue, Mar 10, 2015 at 06:30:42PM +0800, Fugang Duan wrote:
> > The current driver support receive VLAN CTAG HW acceleration feature
> > (NETIF_F_HW_VLAN_CTAG_RX) through software simulation. There calls the
> > api .skb_copy_to_linear_data_offset() to skip the VLAN tag, but there
> > have overlap between the two memory data point range. The patch just
> > fix the issue.
> >
> > Reported-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> > Signed-off-by: Fugang Duan <B38611@freescale.com>
> > ---
> >  drivers/net/ethernet/freescale/fec_main.c |    4 +++-
> >  1 files changed, 3 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/freescale/fec_main.c
> > b/drivers/net/ethernet/freescale/fec_main.c
> > index 9bb6220..c9b1dbb 100644
> > --- a/drivers/net/ethernet/freescale/fec_main.c
> > +++ b/drivers/net/ethernet/freescale/fec_main.c
> > @@ -1475,12 +1475,14 @@ fec_enet_rx_queue(struct net_device *ndev, int
> budget, u16 queue_id)
> >  			/* Push and remove the vlan tag */
> >  			struct vlan_hdr *vlan_header =
> >  					(struct vlan_hdr *) (data + ETH_HLEN);
> > +			unsigned char eth_hdr[12];
> >  			vlan_tag = ntohs(vlan_header->h_vlan_TCI);
> >
> >  			vlan_packet_rcvd = true;
> >
> > +			memcpy(eth_hdr, data, 2 * ETH_ALEN);
> >  			skb_copy_to_linear_data_offset(skb, VLAN_HLEN,
> > -						       data, (2 * ETH_ALEN));
> > +						       eth_hdr, (2 * ETH_ALEN));
> >  			skb_pull(skb, VLAN_HLEN);
> >  		}
> >
> > --
> > 1.7.8
> 
> why not just use memmove instead of the skb_copy_to_linear_data_offset?
> 
> memmove(skb->data + VLAN_HLEN, data, (2 * ETH_ALEN));
> 
> Michael


Good suggestion. Thanks. 

Regards,
Andy

Re: [PATCH] net: fec: fix receive VLAN CTAG HW acceleration issue

[David Miller]

From: Fugang Duan <b38611@freescale.com>
Date: Tue, 10 Mar 2015 18:30:42 +0800

> The current driver support receive VLAN CTAG HW acceleration feature
> (NETIF_F_HW_VLAN_CTAG_RX) through software simulation. There calls the
> api .skb_copy_to_linear_data_offset() to skip the VLAN tag, but there
> have overlap between the two memory data point range. The patch just fix
> the issue.
> 
> Reported-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
> Signed-off-by: Fugang Duan <B38611@freescale.com>

How about simply using.... memmove()?