[PATCH net V2 09/11] net/mlx5e: Update and set Xon/Xoff upon MTU set

Mark Bloch
2025-08-25T14:35:52Z

From: Alexei Lazar <alazar@nvidia.com>

Xon/Xoff sizes are derived from calculation that include the MTU size.
Set Xon/Xoff when MTU is set.
If Xon/Xoff fails, set the previous MTU.

Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration")
Signed-off-by: Alexei Lazar <alazar@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
---
.../mellanox/mlx5/core/en/port_buffer.h | 12 ++++++++++++
.../net/ethernet/mellanox/mlx5/core/en_main.c | 17 ++++++++++++++++-
2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.h b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.h
index f4a19ffbb641..66d276a1be83 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.h
@@ -66,11 +66,23 @@ struct mlx5e_port_buffer {
struct mlx5e_bufferx_reg buffer[MLX5E_MAX_NETWORK_BUFFER];
};

+#ifdef CONFIG_MLX5_CORE_EN_DCB
int mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
u32 change, unsigned int mtu,
struct ieee_pfc *pfc,
u32 *buffer_size,
u8 *prio2buffer);
+#else
+static inline int
+mlx5e_port_manual_buffer_config(struct mlx5e_priv *priv,
+ u32 change, unsigned int mtu,
+ void *pfc,
+ u32 *buffer_size,
+ u8 *prio2buffer)
+{
+ return 0;
+}
+#endif

int mlx5e_port_query_buffer(struct mlx5e_priv *priv,
struct mlx5e_port_buffer *port_buffer);
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 21bb88c5d3dc..15eded36b872 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -49,6 +49,7 @@
#include "en.h"
#include "en/dim.h"
#include "en/txrx.h"
+#include "en/port_buffer.h"
#include "en_tc.h"
#include "en_rep.h"
#include "en_accel/ipsec.h"
@@ -3040,9 +3041,11 @@ int mlx5e_set_dev_port_mtu(struct mlx5e_priv *priv)
struct mlx5e_params *params = &priv->channels.params;
struct net_device *netdev = priv->netdev;
struct mlx5_core_dev *mdev = priv->mdev;
- u16 mtu;
+ u16 mtu, prev_mtu;
int err;

+ mlx5e_query_mtu(mdev, params, &prev_mtu);
+
err = mlx5e_set_mtu(mdev, params, params->sw_mtu);
if (err)
return err;
@@ -3052,6 +3055,18 @@ int mlx5e_set_dev_port_mtu(struct mlx5e_priv *priv)
netdev_warn(netdev, "%s: VPort MTU %d is different than netdev mtu %d\n",
__func__, mtu, params->sw_mtu);

+ if (mtu != prev_mtu && MLX5_BUFFER_SUPPORTED(mdev)) {
+ err = mlx5e_port_manual_buffer_config(priv, 0, mtu,
+ NULL, NULL, NULL);
+ if (err) {
+ netdev_warn(netdev, "%s: Failed to set Xon/Xoff values with MTU %d (err %d), setting back to previous MTU %d\n",
+ __func__, mtu, err, prev_mtu);
+
+ mlx5e_set_mtu(mdev, params, prev_mtu);
+ return err;
+ }
+ }
+
params->sw_mtu = mtu;
return 0;
}
--
2.34.1