netdev - Re: [PATCH net-next 1/2] net: remove skb->vlan

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Date:   Wed, 9 Nov 2022 08:36:37 -0800
From:   Yonghong Song <yhs@...a.com>
To:     Eric Dumazet <edumazet@...gle.com>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Andrii Nakryiko <andrii@...nel.org>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org, eric.dumazet@...il.com
Subject: Re: [PATCH net-next 1/2] net: remove skb->vlan_present



On 11/9/22 1:57 AM, Eric Dumazet wrote:
> skb->vlan_present seems redundant.
> 
> We can instead derive it from this boolean expression:
> 
> vlan_present = skb->vlan_proto != 0 || skb->vlan_tci != 0
> 
> Add a new union, to access both fields in a single load/store
> when possible.
> 
> 	union {
> 		u32	vlan_all;
> 		struct {
> 		__be16	vlan_proto;
> 		__u16	vlan_tci;
> 		};
> 	};
> 
> This allows following patch to remove a conditional test in GRO stack.
> 
> Note:
>    We move remcsum_offload to keep TC_AT_INGRESS_MASK
>    and SKB_MONO_DELIVERY_TIME_MASK unchanged.
> 
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

Ack except the sparc jit part:

Acked-by: Yonghong Song <yhs@...com>