[PATCH net 7/7] net/mlx5e: shampo: Do not merge PSP packets

[Tariq Toukan <tariqt@nvidia.com>]

From: Cosmin Ratiu <cratiu@nvidia.com>

PSP packets are UDP-encapsulated, and enabling HW GRO (SHAMPO in mlx5)
makes it possible to merge those packets in a silly way:
IP|UDP1|PSP1|payload1|UDP2|PSP2|payload2|...

That happens because the HW GRO machinery doesn't know about PSP and
considers it part of the UDP payload.

This patch enforces no match in SW.

Fixes: 29d7f433fcec ("net/mlx5e: Add Rx data path offload")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 7bd0606a5253..5e07cc8586f6 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -2224,6 +2224,16 @@ static bool mlx5e_hw_gro_skb_has_enough_space(struct sk_buff *skb,
 		return page_size * nr_frags + data_bcnt <= GRO_LEGACY_MAX_SIZE;
 }
 
+static bool mlx5e_hw_gro_psp_match(struct sk_buff *skb, struct mlx5_cqe64 *cqe)
+{
+#ifdef CONFIG_MLX5_EN_PSP
+	/* PSP packets cannot be merged. */
+	return !mlx5e_psp_is_rx_flow(cqe);
+#else
+	return true;
+#endif
+}
+
 static void mlx5e_handle_rx_cqe_mpwrq_shampo(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe)
 {
 	u16 data_bcnt		= mpwrq_get_cqe_byte_cnt(cqe) - cqe->shampo.header_size;
@@ -2266,8 +2276,9 @@ static void mlx5e_handle_rx_cqe_mpwrq_shampo(struct mlx5e_rq *rq, struct mlx5_cq
 	}
 
 	if (*skb &&
-	    !(match && mlx5e_hw_gro_skb_has_enough_space(*skb, data_bcnt,
-							 page_size))) {
+	    !(match &&
+	      mlx5e_hw_gro_skb_has_enough_space(*skb, data_bcnt, page_size) &&
+	      mlx5e_hw_gro_psp_match(*skb, cqe))) {
 		match = false;
 		mlx5e_shampo_flush_skb(rq, cqe, match);
 	}
-- 
2.44.0