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Date: Fri, 13 Jun 2025 09:53:47 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Petr Machata <petrm@nvidia.com>
Cc: "David S. Miller" <davem@davemloft.net>, Eric Dumazet
 <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, David Ahern
 <dsahern@gmail.com>, <netdev@vger.kernel.org>, Simon Horman
 <horms@kernel.org>, Nikolay Aleksandrov <razor@blackwall.org>, Ido Schimmel
 <idosch@nvidia.com>, <mlxsw@nvidia.com>
Subject: Re: [PATCH net-next v2 08/14] net: ipv6: ip6mr: Extract a helper
 out of ip6mr_forward2()
Message-ID: <20250613095347.59328a33@kernel.org>
In-Reply-To: <0bef079626b34bc6531d83d79e0fd5c056ee17da.1749757582.git.petrm@nvidia.com>
References: <cover.1749757582.git.petrm@nvidia.com>
	<0bef079626b34bc6531d83d79e0fd5c056ee17da.1749757582.git.petrm@nvidia.com>
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On Thu, 12 Jun 2025 22:10:42 +0200 Petr Machata wrote:
> -static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
> -			  struct sk_buff *skb, int vifi)
> +static int ip6mr_prepare_xmit(struct net *net, struct mr_table *mrt,
> +			      struct sk_buff *skb, int vifi)
>  {
>  	struct vif_device *vif = &mrt->vif_table[vifi];
> -	struct net_device *indev = skb->dev;
>  	struct net_device *vif_dev;
>  	struct ipv6hdr *ipv6h;
>  	struct dst_entry *dst;
> @@ -2098,6 +2097,20 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
>  
>  	ipv6h = ipv6_hdr(skb);
>  	ipv6h->hop_limit--;
> +	return 0;
> +
> +out_free:
> +	kfree_skb(skb);
> +	return -1;
> +}

ipmr_prepare_xmit() does not free the skb on error, and ip6mr_prepare_xmit() 
does. The v6 version does lead to slightly cleaner code, but I wonder
if its worth the asymmetry ?