netdev - Re: [PATCH net-next] net: udp Allow CHECKSUM

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Date:   Tue, 29 Jan 2019 11:00:02 +0800
From:   maowenan <maowenan@...wei.com>
To:     <netdev@...r.kernel.org>, <davem@...emloft.net>,
        <edumazet@...gle.com>
Subject: Re: [PATCH net-next] net: udp Allow CHECKSUM_UNNECESSARY packets to
 do GRO.

Hi all，
Do you have any comments about this change?


On 2019/1/23 11:33, Mao Wenan wrote:
> When udp4_gro_receive() get one packet that uh->check=0,
> skb_gro_checksum_validate_zero_check() will set the
> skb->ip_summed = CHECKSUM_UNNECESSARY;
> skb->csum_level = 0;
> Then udp_gro_receive() will flush the packet which is not CHECKSUM_PARTIAL,
> It is not our expect,  because check=0 in udp header indicates this
> packet is no need to caculate checksum, we should go further to do GRO.
> 
> This patch changes the value of csum_cnt according to skb->csum_level.
> ---
>  include/linux/netdevice.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 1377d08..9c819f1 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -2764,6 +2764,7 @@ static inline void skb_gro_incr_csum_unnecessary(struct sk_buff *skb)
>  		 * during GRO. This saves work if we fallback to normal path.
>  		 */
>  		__skb_incr_checksum_unnecessary(skb);
> +		NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
>  	}
>  }
>  
>