[PATCH net V2] net/mlx5e: SHAMPO: Do not merge PSP packets

[PATCH net V2] net/mlx5e: SHAMPO: Do not merge PSP packets

[Tariq Toukan]

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|UDP|PSP1|payload1|PSP2|payload2|...

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

Reject merging when the incoming CQE has PSP marker or the pending skb
has the PSP extension.

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>
---
 .../ethernet/mellanox/mlx5/core/en_accel/en_accel.h |  6 ++++++
 .../ethernet/mellanox/mlx5/core/en_accel/psp_rxtx.h | 13 +++++++++++++
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c     |  6 ++++--
 3 files changed, 23 insertions(+), 2 deletions(-)

V2:
- Separated from the patchset.
- Moved the PSP merge check into a helper in psp_rxtx.h, with a stub
  returning true when CONFIG_MLX5_EN_PSP is off, and an en_accel.h
  wrapper, replacing the #ifdef in en_rx.c.
- Also reject merging when the pending skb already has the PSP
  extension, not only when the incoming CQE has the PSP marker.
- Fixed the commit message diagram and capitalized SHAMPO in the
  subject.

V1:
https://lore.kernel.org/all/20260917175433.4090878-8-tariqt@nvidia.com/

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/en_accel.h b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/en_accel.h
index 3f212e46fc2f..5a340f1435e6 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/en_accel.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/en_accel.h
@@ -218,6 +218,12 @@ static inline void mlx5e_accel_tx_finish(struct mlx5e_txqsq *sq,
 #endif
 }
 
+static inline bool
+mlx5e_accel_shampo_can_merge(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe)
+{
+	return mlx5e_psp_shampo_can_merge(rq->hw_gro_data->skb, cqe);
+}
+
 static inline int mlx5e_accel_init_rx(struct mlx5e_priv *priv)
 {
 	return mlx5e_ktls_init_rx(priv);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/psp_rxtx.h b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/psp_rxtx.h
index 2b080c39cc37..9fd1ee789de0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/psp_rxtx.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/psp_rxtx.h
@@ -85,6 +85,13 @@ static inline bool mlx5e_psp_is_rx_flow(struct mlx5_cqe64 *cqe)
 	return MLX5_PSP_METADATA_MARKER(be32_to_cpu(cqe->ft_metadata));
 }
 
+static inline bool
+mlx5e_psp_shampo_can_merge(struct sk_buff *skb, struct mlx5_cqe64 *cqe)
+{
+	/* PSP packets cannot be merged. */
+	return !skb_ext_exist(skb, SKB_EXT_PSP) && !mlx5e_psp_is_rx_flow(cqe);
+}
+
 bool mlx5e_psp_offload_handle_rx_skb(struct net_device *netdev, struct sk_buff *skb,
 				     struct mlx5_cqe64 *cqe);
 #else
@@ -110,6 +117,12 @@ static inline bool mlx5e_psp_is_rx_flow(struct mlx5_cqe64 *cqe)
 	return false;
 }
 
+static inline bool
+mlx5e_psp_shampo_can_merge(struct sk_buff *skb, struct mlx5_cqe64 *cqe)
+{
+	return true;
+}
+
 static inline bool mlx5e_psp_offload_handle_rx_skb(struct net_device *netdev,
 						   struct sk_buff *skb,
 						   struct mlx5_cqe64 *cqe)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 903af3b3e779..d49f26323b1e 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -49,6 +49,7 @@
 #include "en_rep.h"
 #include "en/rep/tc.h"
 #include "ipoib/ipoib.h"
+#include "en_accel/en_accel.h"
 #include "en_accel/ipsec.h"
 #include "en_accel/macsec.h"
 #include "en_accel/psp_rxtx.h"
@@ -2268,8 +2269,9 @@ 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_accel_shampo_can_merge(rq, cqe))) {
 		match = false;
 		mlx5e_shampo_flush_skb(rq, cqe, match);
 	}

base-commit: b6ef0d965fe8ce0ee4b4dcb58b3511f83003e42d
-- 
2.44.0

Re: [PATCH net V2] net/mlx5e: SHAMPO: Do not merge PSP packets

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
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 - How the issue was discovered, e.g. hit in production, hit during
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