Subject: Re: [PATCH net-next 06/12] ipv4: Unmask upper DSCP bits when building flow key

From: Guillaume Nault <[email-masked]>
Date: Tue, 27 Aug 2024 16:51:49 +0200

On Tue, Aug 27, 2024 at 02:18:07PM +0300, Ido Schimmel wrote:
> build_sk_flow_key() and __build_flow_key() are used to build an IPv4
> flow key before calling one of the FIB lookup APIs.
> 
> Unmask the upper DSCP bits so that in the future the lookup could be
> performed according to the full DSCP value.
> 
> Remove IPTOS_RT_MASK since it is no longer used.
> 
> Signed-off-by: Ido Schimmel <[email-masked]>
> ---
>  include/net/route.h | 2 --
>  net/ipv4/route.c    | 4 ++--
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/include/net/route.h b/include/net/route.h
> index b896f086ec8e..1789f1e6640b 100644
> --- a/include/net/route.h
> +++ b/include/net/route.h
> @@ -266,8 +266,6 @@ static inline void ip_rt_put(struct rtable *rt)
>  	dst_release(&rt->dst);
>  }
>  
> -#define IPTOS_RT_MASK	(IPTOS_TOS_MASK & ~3)
> -

IPTOS_RT_MASK is still used by xfrm_get_tos() (net/xfrm/xfrm_policy.c).
To preserve bisectablility, this chunk should be moved to the next
patch. Or just swap patch 6 and 7, whatever you prefer :).