Re: [PATCH] net: macb: Disable macb pad and fcs for fragmented packets

[Claudiu.Beznea]

On 09.05.2022 15:15, Harini Katakam wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> data_len in skbuff represents bytes resident in fragment lists or
> unmapped page buffers. For such packets, when data_len is non-zero,
> skb_put cannot be used - this will throw a kernel bug. Hence do not
> use macb_pad_and_fcs for such fragments.
> 
> Signed-off-by: Harini Katakam <harini.katakam@xxxxxxxxxx>
> Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxxxxx>

Reviewed-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>


> ---
>  drivers/net/ethernet/cadence/macb_main.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 6434e74c04f1..0b03305ad6a0 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -1995,7 +1995,8 @@ static unsigned int macb_tx_map(struct macb *bp,
>                         ctrl |= MACB_BF(TX_LSO, lso_ctrl);
>                         ctrl |= MACB_BF(TX_TCP_SEQ_SRC, seq_ctrl);
>                         if ((bp->dev->features & NETIF_F_HW_CSUM) &&
> -                           skb->ip_summed != CHECKSUM_PARTIAL && !lso_ctrl)
> +                           skb->ip_summed != CHECKSUM_PARTIAL && !lso_ctrl &&
> +                           (skb->data_len == 0))
>                                 ctrl |= MACB_BIT(TX_NOCRC);
>                 } else
>                         /* Only set MSS/MFS on payload descriptors
> @@ -2091,9 +2092,11 @@ static int macb_pad_and_fcs(struct sk_buff **skb, struct net_device *ndev)
>         struct sk_buff *nskb;
>         u32 fcs;
> 
> +       /* Not available for GSO and fragments */
>         if (!(ndev->features & NETIF_F_HW_CSUM) ||
>             !((*skb)->ip_summed != CHECKSUM_PARTIAL) ||
> -           skb_shinfo(*skb)->gso_size) /* Not available for GSO */
> +           skb_shinfo(*skb)->gso_size ||
> +           ((*skb)->data_len > 0))
>                 return 0;
> 
>         if (padlen <= 0) {
> --
> 2.17.1
>