netdev - Re: [PATCH net-next 1/4] net: use indirect calls helpers for ptype hook

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Date:   Fri, 31 May 2019 17:02:05 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org
Cc:     "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH net-next 1/4] net: use indirect calls helpers for ptype
 hook



On 5/3/19 8:01 AM, Paolo Abeni wrote:
> This avoids an indirect call per RX IPv6/IPv4 packet.
> Note that we don't want to use the indirect calls helper for taps.
> 
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>
> ---
>  net/core/dev.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 22f2640f559a..108ac8137b9b 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -4987,7 +4987,8 @@ static int __netif_receive_skb_one_core(struct sk_buff *skb, bool pfmemalloc)
>  
>  	ret = __netif_receive_skb_core(skb, pfmemalloc, &pt_prev);
>  	if (pt_prev)
> -		ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
> +		ret = INDIRECT_CALL_INET(pt_prev->func, ipv6_rcv, ip_rcv, skb,
> +					 skb->dev, pt_prev, orig_dev);
>  	return ret;
>  }
>  
> @@ -5033,7 +5034,8 @@ static inline void __netif_receive_skb_list_ptype(struct list_head *head,
>  	else
>  		list_for_each_entry_safe(skb, next, head, list) {
>  			skb_list_del_init(skb);
> -			pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
> +			INDIRECT_CALL_INET(pt_prev->func, ipv6_rcv, ip_rcv, skb,
> +					   skb->dev, pt_prev, orig_dev);

IPv4 has ip_list_rcv() and IPv6 has ipv6_list_rcv(),
so the code  invoking ->list_func() should run,
meaning this part of the patch was not needed.

if (pt_prev->list_func != NULL)
    pt_prev->list_func(head, pt_prev, orig_dev);

Maybe you want instead have INDIRECT_CALL_INET() for the list_func() calls.