[PATCH 6.6 062/122] net/mlx5e: Do not produce metadata freelist entries in Tx port ts WQE xmit

Greg Kroah-Hartman
2024-04-15T14:35:16Z

From: Rahul Rameshbabu <rrameshbabu@nvidia.com>

[ Upstream commit 86b0ca5b118d3a0bae5e5645a13e66f8a4f6c525 ]

Free Tx port timestamping metadata entries in the NAPI poll context and
consume metadata enties in the WQE xmit path. Do not free a Tx port
timestamping metadata entry in the WQE xmit path even in the error path to
avoid a race between two metadata entry producers.

Fixes: 3178308ad4ca ("net/mlx5e: Make tx_port_ts logic resilient to out-of-order CQEs")
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20240409190820.227554-10-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h | 8 +++++++-
drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 7 +++----
2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h
index 7b700d0f956a8..b171cd8f11e04 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.h
@@ -95,9 +95,15 @@ static inline void mlx5e_ptp_metadata_fifo_push(struct mlx5e_ptp_metadata_fifo *
}

static inline u8
+mlx5e_ptp_metadata_fifo_peek(struct mlx5e_ptp_metadata_fifo *fifo)
+{
+ return fifo->data[fifo->mask & fifo->cc];
+}
+
+static inline void
mlx5e_ptp_metadata_fifo_pop(struct mlx5e_ptp_metadata_fifo *fifo)
{
- return fifo->data[fifo->mask & fifo->cc++];
+ fifo->cc++;
}

static inline void
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 1ead69c5f5fa3..24cbd44dae93c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -398,6 +398,8 @@ mlx5e_txwqe_complete(struct mlx5e_txqsq *sq, struct sk_buff *skb,
(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))) {
u8 metadata_index = be32_to_cpu(eseg->flow_table_metadata);

+ mlx5e_ptp_metadata_fifo_pop(&sq->ptpsq->metadata_freelist);
+
mlx5e_skb_cb_hwtstamp_init(skb);
mlx5e_ptp_metadata_map_put(&sq->ptpsq->metadata_map, skb,
metadata_index);
@@ -496,9 +498,6 @@ mlx5e_sq_xmit_wqe(struct mlx5e_txqsq *sq, struct sk_buff *skb,

err_drop:
stats->dropped++;
- if (unlikely(sq->ptpsq && (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP)))
- mlx5e_ptp_metadata_fifo_push(&sq->ptpsq->metadata_freelist,
- be32_to_cpu(eseg->flow_table_metadata));
dev_kfree_skb_any(skb);
mlx5e_tx_flush(sq);
}
@@ -657,7 +656,7 @@ static void mlx5e_cqe_ts_id_eseg(struct mlx5e_ptpsq *ptpsq, struct sk_buff *skb,
{
if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))
eseg->flow_table_metadata =
- cpu_to_be32(mlx5e_ptp_metadata_fifo_pop(&ptpsq->metadata_freelist));
+ cpu_to_be32(mlx5e_ptp_metadata_fifo_peek(&ptpsq->metadata_freelist));
}

static void mlx5e_txwqe_build_eseg(struct mlx5e_priv *priv, struct mlx5e_txqsq *sq,
--
2.43.0