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Date:   Mon, 25 Jul 2022 19:05:19 +0200
From:   Guillaume Nault <gnault@redhat.com>
To:     Matthias May <matthias.may@westermo.com>
Cc:     netdev@vger.kernel.org, davem@davemloft.net,
        yoshfuji@linux-ipv6.org, dsahern@kernel.org, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, nicolas.dichtel@6wind.com,
        eyal.birger@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2 net-next] geneve: fix TOS inheriting for ipv6
Message-ID: <20220725170519.GD18808@pc-4.home>
References: <20220724003741.57816-1-matthias.may@westermo.com>
 <20220724003741.57816-3-matthias.may@westermo.com>
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In-Reply-To: <20220724003741.57816-3-matthias.may@westermo.com>
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On Sun, Jul 24, 2022 at 02:37:41AM +0200, Matthias May wrote:
> The current code uses the RT_TOS macro to cut off the 6 DSCP
> bits, down to the original 3 TOS bits.
> 
> Do not use this macro to get the prio for inheriting purposes.

Honestly, this patch is a bug fix and is suitable for the net tree
(with appropriate 'Fixes' tag).

Ideally, we'd also fix ip6_dst_lookup_tunnel() (used by bareudp
tunnels) and vxlan6_get_route().

Also, mlx5e_tc_tun_update_header_ipv6() and
mlx5e_tc_tun_create_header_ipv6() both call RT_TOS() inside
ip6_make_flowinfo() and certainly need to be fixed too.

> Signed-off-by: Matthias May <matthias.may@westermo.com>
> ---
>  drivers/net/geneve.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
> index 4c380c06f178..e1a4480e6f17 100644
> --- a/drivers/net/geneve.c
> +++ b/drivers/net/geneve.c
> @@ -877,8 +877,7 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
>  		use_cache = false;
>  	}
>  
> -	fl6->flowlabel = ip6_make_flowinfo(RT_TOS(prio),
> -					   info->key.label);
> +	fl6->flowlabel = ip6_make_flowinfo(prio, info->key.label);
>  	dst_cache = (struct dst_cache *)&info->dst_cache;
>  	if (use_cache) {
>  		dst = dst_cache_get_ip6(dst_cache, &fl6->saddr);
> -- 
> 2.35.1
>