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From: Saeed Mahameed <saeed@kernel.org>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org, Tariq Toukan <tariqt@nvidia.com>,
	Maxim Mikityanskiy <maximmi@nvidia.com>,
	Saeed Mahameed <saeedm@nvidia.com>
Subject: [net-next 12/15] net/mlx5e: Use READ_ONCE/WRITE_ONCE for DCBX trust state
Date: Mon, 14 Feb 2022 22:32:26 -0800	[thread overview]
Message-ID: <20220215063229.737960-13-saeed@kernel.org> (raw)
In-Reply-To: <20220215063229.737960-1-saeed@kernel.org>

From: Maxim Mikityanskiy <maximmi@nvidia.com>

trust_state can be written while mlx5e_select_queue() is reading it. To
avoid inconsistencies, use READ_ONCE and WRITE_ONCE for access and
updates, and touch the variable only once per operation.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/selq.c  |  2 +-
 drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c | 12 +++++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c b/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c
index aab2046da45b..b8f1a955944d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/selq.c
@@ -113,7 +113,7 @@ static int mlx5e_get_dscp_up(struct mlx5e_priv *priv, struct sk_buff *skb)
 static int mlx5e_get_up(struct mlx5e_priv *priv, struct sk_buff *skb)
 {
 #ifdef CONFIG_MLX5_CORE_EN_DCB
-	if (priv->dcbx_dp.trust_state == MLX5_QPTS_TRUST_DSCP)
+	if (READ_ONCE(priv->dcbx_dp.trust_state) == MLX5_QPTS_TRUST_DSCP)
 		return mlx5e_get_dscp_up(priv, skb);
 #endif
 	if (skb_vlan_tag_present(skb))
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c b/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
index a4c8d8d00d5a..d659fe07d464 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_dcbnl.c
@@ -1142,7 +1142,7 @@ static int mlx5e_update_trust_state_hw(struct mlx5e_priv *priv, void *context)
 	err = mlx5_set_trust_state(priv->mdev, *trust_state);
 	if (err)
 		return err;
-	priv->dcbx_dp.trust_state = *trust_state;
+	WRITE_ONCE(priv->dcbx_dp.trust_state, *trust_state);
 
 	return 0;
 }
@@ -1187,16 +1187,18 @@ static int mlx5e_set_dscp2prio(struct mlx5e_priv *priv, u8 dscp, u8 prio)
 static int mlx5e_trust_initialize(struct mlx5e_priv *priv)
 {
 	struct mlx5_core_dev *mdev = priv->mdev;
+	u8 trust_state;
 	int err;
 
-	priv->dcbx_dp.trust_state = MLX5_QPTS_TRUST_PCP;
-
-	if (!MLX5_DSCP_SUPPORTED(mdev))
+	if (!MLX5_DSCP_SUPPORTED(mdev)) {
+		WRITE_ONCE(priv->dcbx_dp.trust_state, MLX5_QPTS_TRUST_PCP);
 		return 0;
+	}
 
-	err = mlx5_query_trust_state(priv->mdev, &priv->dcbx_dp.trust_state);
+	err = mlx5_query_trust_state(priv->mdev, &trust_state);
 	if (err)
 		return err;
+	WRITE_ONCE(priv->dcbx_dp.trust_state, trust_state);
 
 	mlx5e_params_calc_trust_tx_min_inline_mode(priv->mdev, &priv->channels.params,
 						   priv->dcbx_dp.trust_state);
-- 
2.34.1


  parent reply	other threads:[~2022-02-15  6:33 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-15  6:32 [pull request][net-next 00/15] mlx5 updates 2022-02-14 Saeed Mahameed
2022-02-15  6:32 ` [net-next 01/15] net/mlx5e: Remove unused tstamp SQ field Saeed Mahameed
2022-02-15 10:50   ` patchwork-bot+netdevbpf
2022-02-15  6:32 ` [net-next 02/15] net/mlx5e: Read max WQEBBs on the SQ from firmware Saeed Mahameed
2022-02-15  6:32 ` [net-next 03/15] net/mlx5e: Use FW limitation for max MPW WQEBBs Saeed Mahameed
2022-02-15  6:32 ` [net-next 04/15] net/mlx5e: Cleanup of start/stop all queues Saeed Mahameed
2022-02-15  6:32 ` [net-next 05/15] net/mlx5e: Disable TX queues before registering the netdev Saeed Mahameed
2022-02-15  6:32 ` [net-next 06/15] net/mlx5e: Use a barrier after updating txq2sq Saeed Mahameed
2022-02-15  6:32 ` [net-next 07/15] net/mlx5e: Sync txq2sq updates with mlx5e_xmit for HTB queues Saeed Mahameed
2022-02-15  6:32 ` [net-next 08/15] net/mlx5e: Introduce select queue parameters Saeed Mahameed
2022-02-15  6:32 ` [net-next 09/15] net/mlx5e: Move mlx5e_select_queue to en/selq.c Saeed Mahameed
2022-02-15  6:32 ` [net-next 10/15] net/mlx5e: Use select queue parameters to sync with control flow Saeed Mahameed
2022-02-15  6:32 ` [net-next 11/15] net/mlx5e: Move repeating code that gets TC prio into a function Saeed Mahameed
2022-02-15  6:32 ` Saeed Mahameed [this message]
2022-02-15  6:32 ` [net-next 13/15] net/mlx5e: Optimize mlx5e_select_queue Saeed Mahameed
2022-02-15  6:32 ` [net-next 14/15] net/mlx5e: Optimize modulo in mlx5e_select_queue Saeed Mahameed
2022-02-15  6:32 ` [net-next 15/15] net/mlx5e: Optimize the common case condition " Saeed Mahameed

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