[dpdk-stable] [PATCH 19.11 3/4] net/mlx5: limit inner RSS expansion for MPLS

[Xiaoyu Min]

[ upstream commit a26cc30fa0463fb6707b0caea1a288dc54c09b0f ]

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 at nvidia.com>
Acked-by: Matan Azrad <matan at nvidia.com>
---
 drivers/net/mlx5/mlx5_flow.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
index 0f0c779ca..494555b16 100644
--- a/drivers/net/mlx5/mlx5_flow.c
+++ b/drivers/net/mlx5/mlx5_flow.c
@@ -1229,6 +1229,13 @@ mlx5_flow_validate_action_rss(const struct rte_flow_action *action,
 					  RTE_FLOW_ERROR_TYPE_ACTION_CONF, NULL,
 					  "inner RSS is not supported for "
 					  "non-tunnel flows");
+	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;
 }
 
-- 
2.32.0