mlx5: do not use RT_TOS for IPv6 flowlabel

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2161351
Upstream Status: linux.git

commit bcb0da7
Author: Matthias May <matthias.may@westermo.com>
Date:   Fri Aug 5 21:19:05 2022 +0200

    mlx5: do not use RT_TOS for IPv6 flowlabel

    According to Guillaume Nault RT_TOS should never be used for IPv6.

    Quote:
    RT_TOS() is an old macro used to interprete IPv4 TOS as described in
    the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4
    code, although, given the current state of the code, most of the
    existing calls have no consequence.

    But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS"
    field to be interpreted the RFC 1349 way. There's no historical
    compatibility to worry about.

    Fixes: ce99f6b ("net/mlx5e: Support SRIOV TC encapsulation offloads for IPv6 tunnels")
    Acked-by: Guillaume Nault <gnault@redhat.com>
    Signed-off-by: Matthias May <matthias.may@westermo.com>
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Guillaume Nault <gnault@redhat.com>

Author: Guillaume Nault

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c

@@ -506,7 +506,7 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
 	int err;
 
 	attr.ttl = tun_key->ttl;
-	attr.fl.fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tun_key->tos), tun_key->label);
+	attr.fl.fl6.flowlabel = ip6_make_flowinfo(tun_key->tos, tun_key->label);
 	attr.fl.fl6.daddr = tun_key->u.ipv6.dst;
 	attr.fl.fl6.saddr = tun_key->u.ipv6.src;
 
@@ -620,7 +620,7 @@ int mlx5e_tc_tun_update_header_ipv6(struct mlx5e_priv *priv,
 
 	attr.ttl = tun_key->ttl;
 
-	attr.fl.fl6.flowlabel = ip6_make_flowinfo(RT_TOS(tun_key->tos), tun_key->label);
+	attr.fl.fl6.flowlabel = ip6_make_flowinfo(tun_key->tos, tun_key->label);
 	attr.fl.fl6.daddr = tun_key->u.ipv6.dst;
 	attr.fl.fl6.saddr = tun_key->u.ipv6.src;