From: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Date: Thu, 21 Jan 2021 21:47:07 +0800
> In some cases, we hope to construct skb directly based on the existing
> memory without copying data. In this case, the page will be placed
> directly in the skb, and the linear space of skb is empty. But
> unfortunately, many the network card does not support this operation.
> For example Mellanox Technologies MT27710 Family [ConnectX-4 Lx] will
> get the following error message:
>
> mlx5_core 0000:3b:00.1 eth1: Error cqe on cqn 0x817, ci 0x8, qn 0x1dbb, opcode 0xd, syndrome 0x1, vendor syndrome 0x68
> 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00000030: 00 00 00 00 60 10 68 01 0a 00 1d bb 00 0f 9f d2
> WQE DUMP: WQ size 1024 WQ cur size 0, WQE index 0xf, len: 64
> 00000000: 00 00 0f 0a 00 1d bb 03 00 00 00 08 00 00 00 00
> 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 00000020: 00 00 00 2b 00 08 00 00 00 00 00 05 9e e3 08 00
> 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> mlx5_core 0000:3b:00.1 eth1: ERR CQE on SQ: 0x1dbb
>
> So a priv_flag is added here to indicate whether the network card
> supports this feature.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> Suggested-by: Alexander Lobakin <alobakin@xxxxx>
Acked-by: Alexander Lobakin <alobakin@xxxxx>
> ---
> include/linux/netdevice.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index ef51725..135db8f 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -1525,6 +1525,7 @@ struct net_device_ops {
> * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
> * @IFF_L3MDEV_RX_HANDLER: only invoke the rx handler of L3 master device
> * @IFF_LIVE_RENAME_OK: rename is allowed while device is up and running
> + * @IFF_TX_SKB_NO_LINEAR: allow tx skb linear is empty
> */
> enum netdev_priv_flags {
> IFF_802_1Q_VLAN = 1<<0,
> @@ -1558,6 +1559,7 @@ enum netdev_priv_flags {
> IFF_FAILOVER_SLAVE = 1<<28,
> IFF_L3MDEV_RX_HANDLER = 1<<29,
> IFF_LIVE_RENAME_OK = 1<<30,
> + IFF_TX_SKB_NO_LINEAR = 1<<31,
> };
>
> #define IFF_802_1Q_VLAN IFF_802_1Q_VLAN
> @@ -1590,6 +1592,7 @@ enum netdev_priv_flags {
> #define IFF_FAILOVER_SLAVE IFF_FAILOVER_SLAVE
> #define IFF_L3MDEV_RX_HANDLER IFF_L3MDEV_RX_HANDLER
> #define IFF_LIVE_RENAME_OK IFF_LIVE_RENAME_OK
> +#define IFF_TX_SKB_NO_LINEAR IFF_TX_SKB_NO_LINEAR
>
> /**
> * struct net_device - The DEVICE structure.
> --
> 1.8.3.1
Thanks,
Al
