[PATCH net-next 08/13] net/mlx5: LAG, block RoCE and VF LAG for SD devices

From: Tariq Toukan

Date: Wed May 27 2026 - 09:06:06 EST


From: Shay Drory <shayd@xxxxxxxxxx>

Socket Direct devices manage their own LAG via SD LAG infrastructure.
Block the standard netdev-event-driven LAG path (RoCE LAG and VF LAG)
for SD devices to prevent conflicting LAG configurations.

Expose mlx5_sd_is_supported() as a public helper that encapsulates all
SD eligibility checks. Use it in mlx5_lag_dev_alloc() to skip netdev
notifier registration for SD-capable devices at alloc time. Some sd
code is reordered to expose the new function, no logic is changed.

Signed-off-by: Shay Drory <shayd@xxxxxxxxxx>
Reviewed-by: Mark Bloch <mbloch@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
---
.../net/ethernet/mellanox/mlx5/core/lag/lag.c | 13 ++--
.../net/ethernet/mellanox/mlx5/core/lib/sd.c | 60 ++++++++++++++-----
.../net/ethernet/mellanox/mlx5/core/lib/sd.h | 11 ++++
3 files changed, 63 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
index 3decb49e9f19..a2c7e2927431 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c
@@ -293,11 +293,14 @@ static struct mlx5_lag *mlx5_lag_dev_alloc(struct mlx5_core_dev *dev)
INIT_DELAYED_WORK(&ldev->bond_work, mlx5_do_bond_work);
INIT_WORK(&ldev->speed_update_work, mlx5_mpesw_speed_update_work);

- ldev->nb.notifier_call = mlx5_lag_netdev_event;
- write_pnet(&ldev->net, mlx5_core_net(dev));
- if (register_netdevice_notifier_net(read_pnet(&ldev->net), &ldev->nb)) {
- ldev->nb.notifier_call = NULL;
- mlx5_core_err(dev, "Failed to register LAG netdev notifier\n");
+ if (!mlx5_sd_is_supported(dev)) {
+ ldev->nb.notifier_call = mlx5_lag_netdev_event;
+ write_pnet(&ldev->net, mlx5_core_net(dev));
+ if (register_netdevice_notifier_net(read_pnet(&ldev->net),
+ &ldev->nb)) {
+ ldev->nb.notifier_call = NULL;
+ mlx5_core_err(dev, "Failed to register LAG netdev notifier\n");
+ }
}
ldev->mode = MLX5_LAG_MODE_NONE;

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c
index e341d814873a..8991db3a19cf 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c
@@ -115,7 +115,28 @@ static bool ft_create_alias_supported(struct mlx5_core_dev *dev)
return true;
}

-static bool mlx5_sd_is_supported(struct mlx5_core_dev *dev, u8 host_buses)
+static int mlx5_query_sd(struct mlx5_core_dev *dev, bool *sdm,
+ u8 *host_buses)
+{
+ u32 out[MLX5_ST_SZ_DW(mpir_reg)];
+ int err;
+
+ err = mlx5_query_mpir_reg(dev, out);
+ if (err)
+ return err;
+
+ *sdm = MLX5_GET(mpir_reg, out, sdm);
+ *host_buses = MLX5_GET(mpir_reg, out, host_buses);
+
+ return 0;
+}
+
+static u32 mlx5_sd_group_id(struct mlx5_core_dev *dev, u8 sd_group)
+{
+ return (u32)((MLX5_CAP_GEN(dev, native_port_num) << 8) | sd_group);
+}
+
+static bool mlx5_sd_caps_supported(struct mlx5_core_dev *dev, u8 host_buses)
{
/* Honor the SW implementation limit */
if (host_buses > MLX5_SD_MAX_GROUP_SZ)
@@ -142,25 +163,32 @@ static bool mlx5_sd_is_supported(struct mlx5_core_dev *dev, u8 host_buses)
return true;
}

-static int mlx5_query_sd(struct mlx5_core_dev *dev, bool *sdm,
- u8 *host_buses)
+bool mlx5_sd_is_supported(struct mlx5_core_dev *dev)
{
- u32 out[MLX5_ST_SZ_DW(mpir_reg)];
+ u8 host_buses, sd_group;
+ bool sdm;
int err;

- err = mlx5_query_mpir_reg(dev, out);
- if (err)
- return err;
+ /* Feature is currently implemented for PFs only */
+ if (!mlx5_core_is_pf(dev))
+ return false;

- *sdm = MLX5_GET(mpir_reg, out, sdm);
- *host_buses = MLX5_GET(mpir_reg, out, host_buses);
+ /* Block on embedded CPU PFs */
+ if (mlx5_core_is_ecpf(dev))
+ return false;

- return 0;
-}
+ err = mlx5_query_nic_vport_sd_group(dev, &sd_group);
+ if (err || !sd_group)
+ return false;

-static u32 mlx5_sd_group_id(struct mlx5_core_dev *dev, u8 sd_group)
-{
- return (u32)((MLX5_CAP_GEN(dev, native_port_num) << 8) | sd_group);
+ if (!MLX5_CAP_MCAM_REG(dev, mpir))
+ return false;
+
+ err = mlx5_query_sd(dev, &sdm, &host_buses);
+ if (err || !sdm)
+ return false;
+
+ return mlx5_sd_caps_supported(dev, host_buses);
}

static int sd_init(struct mlx5_core_dev *dev)
@@ -198,8 +226,8 @@ static int sd_init(struct mlx5_core_dev *dev)

group_id = mlx5_sd_group_id(dev, sd_group);

- if (!mlx5_sd_is_supported(dev, host_buses)) {
- sd_warn(dev, "can't support requested netdev combining for group id 0x%x), skipping\n",
+ if (!mlx5_sd_caps_supported(dev, host_buses)) {
+ sd_warn(dev, "can't support requested netdev combining for group id 0x%x, skipping\n",
group_id);
return 0;
}
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h
index 2ab259095d7e..bf59903ab23f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h
@@ -4,6 +4,8 @@
#ifndef __MLX5_LIB_SD_H__
#define __MLX5_LIB_SD_H__

+#include <linux/types.h>
+
#define MLX5_SD_MAX_GROUP_SZ 2

struct mlx5_sd;
@@ -18,6 +20,15 @@ struct auxiliary_device *mlx5_sd_get_adev(struct mlx5_core_dev *dev,
void mlx5_sd_put_adev(struct auxiliary_device *actual_adev,
struct auxiliary_device *adev);

+#ifdef CONFIG_MLX5_CORE_EN
+bool mlx5_sd_is_supported(struct mlx5_core_dev *dev);
+#else
+static inline bool mlx5_sd_is_supported(struct mlx5_core_dev *dev)
+{
+ return false;
+}
+#endif
+
int mlx5_sd_init(struct mlx5_core_dev *dev);
void mlx5_sd_cleanup(struct mlx5_core_dev *dev);

--
2.44.0