[PATCH 1/1][SRU][B] net: hns3: pad the short frame before sending to the hardware

[Andrea Righi]

On Thu, Feb 20, 2020 at 05:22:49PM +0800, Taihsiang Ho (tai271828) wrote:
> From: Yunsheng Lin <linyunsheng at huawei.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1860320
> 
> The hardware can not handle short frames below or equal to 32
> bytes according to the hardware user manual, and it will trigger
> a RAS error when the frame's length is below 33 bytes.
> 
> This patch pads the SKB when skb->len is below 33 bytes before
> sending it to hardware.
> 
> Fixes: 76ad4f0ee747 ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
> Signed-off-by: Yunsheng Lin <linyunsheng at huawei.com>
> Signed-off-by: Huazhong Tan <tanhuazhong at huawei.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> (backported from commit 36c67349a1a1c88b9cf11d7ca7762ababdb38867)
> Signed-off-by: Taihsiang Ho (tai271828) <taihsiang.ho at canonical.com>
> ---
>  drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> index a6b834c6d323..c699d3d47633 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> @@ -32,6 +32,18 @@ static const char hns3_driver_string[] =
>  static const char hns3_copyright[] = "Copyright (c) 2017 Huawei Corporation.";
>  static struct hnae3_client client;
>  
> +static int debug = -1;
> +module_param(debug, int, 0);
> +MODULE_PARM_DESC(debug, " Network interface message level setting");
> +
> +#define DEFAULT_MSG_LEVEL (NETIF_MSG_PROBE | NETIF_MSG_LINK | \
> +			   NETIF_MSG_IFDOWN | NETIF_MSG_IFUP)
> +
> +#define HNS3_INNER_VLAN_TAG	1
> +#define HNS3_OUTER_VLAN_TAG	2

^ Do we really need this part? IIUC the part below should be enough, or
am I missing something?

Thanks,
-Andrea

> +
> +#define HNS3_MIN_TX_LEN		33U
> +
>  /* hns3_pci_tbl - PCI Device ID Table
>   *
>   * Last entry must be all 0s
> @@ -1224,6 +1236,10 @@ netdev_tx_t hns3_nic_net_xmit(struct sk_buff *skb, struct net_device *netdev)
>  	int ret;
>  	int i;
>  
> +	/* Hardware can only handle short frames above 32 bytes */
> +	if (skb_put_padto(skb, HNS3_MIN_TX_LEN))
> +		return NETDEV_TX_OK;
> +
>  	/* Prefetch the data used later */
>  	prefetch(skb->data);
>  
> -- 
> 2.17.1
> 
> 
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