net/mlx5: limit inner RSS expansion for MPLS

If user wants to do MPLS inner RSS and only provides pattern
till MPLS without inner items [1], RSS expansion will expand flows
into 13 sub-flows[2] which is too many and it impacts flow insert
rate, stack usage becomes large as well.

This expansion into 13 sub-flows seems not worthy of and it can
be significantly reduced (i.e, 7 sub-flows [3]) by user providing
at least one inner L2/L3 item [4].

[1]:
pattern eth / ipv4 / udp / mpls / end actions rss type tcp udp ip
end level 2 / end

[2]:
eth / ipv4 / udp / mpls
eth / ipv4 / udp / mpls / ipv4
eth / ipv4 / udp / mpls / ipv4 / udp
eth / ipv4 / udp / mpls / ipv4 / tcp
eth / ipv4 / udp / mpls / ipv6
eth / ipv4 / udp / mpls / ipv6 / udp
eth / ipv4 / udp / mpls / ipv6 / tcp
eth / ipv4 / udp / mpls / eth / ipv4
eth / ipv4 / udp / mpls / eth / ipv4 / udp
eth / ipv4 / udp / mpls / eth / ipv4 / tcp
eth / ipv4 / udp / mpls / eth / ipv6
eth / ipv4 / udp / mpls / eth / ipv6 / udp
eth / ipv4 / udp / mpls / eth / ipv6 / tcp

[3]:
eth / ipv4 / udp / mpls / eth
eth / ipv4 / udp / mpls / eth / ipv4 / udp
eth / ipv4 / udp / mpls / eth / ipv4 / tcp
eth / ipv4 / udp / mpls / eth / ipv6
eth / ipv4 / udp / mpls / eth / ipv6 / udp
eth / ipv4 / udp / mpls / eth / ipv6 / tcp

[4]:
pattern eth / ipv4 / udp / mpls / eth / end actions rss type tcp udp ip
level 2 / end

Signed-off-by: Xiaoyu Min <jackmin@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>

diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index 00fc37e..8b53156 100644 (file)
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -1674,6 +1674,13 @@ mlx5_flow_validate_action_rss(const struct rte_flow_action *action,
                                          RTE_FLOW_ERROR_TYPE_ACTION_CONF, NULL,
                                          "RSS on eCPRI is not supported now");
        }
+       if ((item_flags & MLX5_FLOW_LAYER_MPLS) &&
+           !(item_flags &
+             (MLX5_FLOW_LAYER_INNER_L2 | MLX5_FLOW_LAYER_INNER_L3)) &&
+           rss->level > 1)
+               return rte_flow_error_set(error, EINVAL,
+                                         RTE_FLOW_ERROR_TYPE_ITEM, NULL,
+                                         "MPLS inner RSS needs to specify inner L2/L3 items after MPLS in pattern");
        return 0;
 }