From: Jianbo Liu <jianbol@nvidia.com>

An optimization for promiscuous mode adds a high-priority steering
table with a single catch-all rule to steer all traffic directly to
the TTC table.

However, a gap exists between the creation of this table and the
insertion of the catch-all rule. Packets arriving in this brief window
would miss as no rule was inserted yet, unnecessarily incrementing the
'rx_steer_missed_packets' counter and dropped.

This patch resolves the issue by introducing a new prio for this
table, placing it between MLX5E_TC_PRIO and MLX5E_NIC_PRIO. By doing
so, packets arriving during the window now fall through to the next
prio (at MLX5E_NIC_PRIO) instead of being dropped.

Fixes: 1c46d7409f30 ("net/mlx5e: Optimize promiscuous mode")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/fs.h   |  9 +++++++--
 drivers/net/ethernet/mellanox/mlx5/core/en_fs.c   |  2 +-
 drivers/net/ethernet/mellanox/mlx5/core/fs_core.c | 13 +++++++++----
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h b/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
index b5c3a2a9d2a5..9560fcba643f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
@@ -18,7 +18,8 @@ enum {
 
 enum {
 	MLX5E_TC_PRIO = 0,
-	MLX5E_NIC_PRIO
+	MLX5E_PROMISC_PRIO,
+	MLX5E_NIC_PRIO,
 };
 
 struct mlx5e_flow_table {
@@ -68,9 +69,13 @@ struct mlx5e_l2_table {
 				 MLX5_HASH_FIELD_SEL_DST_IP   |\
 				 MLX5_HASH_FIELD_SEL_IPSEC_SPI)
 
-/* NIC prio FTS */
+/* NIC promisc FT level */
 enum {
 	MLX5E_PROMISC_FT_LEVEL,
+};
+
+/* NIC prio FTS */
+enum {
 	MLX5E_VLAN_FT_LEVEL,
 	MLX5E_L2_FT_LEVEL,
 	MLX5E_TTC_FT_LEVEL,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
index 04a969128161..265c4ca85f7d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_fs.c
@@ -780,7 +780,7 @@ static int mlx5e_create_promisc_table(struct mlx5e_flow_steering *fs)
 	ft_attr.max_fte = MLX5E_PROMISC_TABLE_SIZE;
 	ft_attr.autogroup.max_num_groups = 1;
 	ft_attr.level = MLX5E_PROMISC_FT_LEVEL;
-	ft_attr.prio = MLX5E_NIC_PRIO;
+	ft_attr.prio = MLX5E_PROMISC_PRIO;
 
 	ft->t = mlx5_create_auto_grouped_flow_table(fs->ns, &ft_attr);
 	if (IS_ERR(ft->t)) {
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index a8046200d376..3dd9a6f40709 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -113,13 +113,16 @@
 #define ETHTOOL_PRIO_NUM_LEVELS 1
 #define ETHTOOL_NUM_PRIOS 11
 #define ETHTOOL_MIN_LEVEL (KERNEL_MIN_LEVEL + ETHTOOL_NUM_PRIOS)
-/* Promiscuous, Vlan, mac, ttc, inner ttc, {UDP/ANY/aRFS/accel/{esp, esp_err}}, IPsec policy,
+/* Vlan, mac, ttc, inner ttc, {UDP/ANY/aRFS/accel/{esp, esp_err}}, IPsec policy,
  * {IPsec RoCE MPV,Alias table},IPsec RoCE policy
  */
-#define KERNEL_NIC_PRIO_NUM_LEVELS 11
+#define KERNEL_NIC_PRIO_NUM_LEVELS 10
 #define KERNEL_NIC_NUM_PRIOS 1
-/* One more level for tc */
-#define KERNEL_MIN_LEVEL (KERNEL_NIC_PRIO_NUM_LEVELS + 1)
+/* One more level for tc, and one more for promisc */
+#define KERNEL_MIN_LEVEL (KERNEL_NIC_PRIO_NUM_LEVELS + 2)
+
+#define KERNEL_NIC_PROMISC_NUM_PRIOS 1
+#define KERNEL_NIC_PROMISC_NUM_LEVELS 1
 
 #define KERNEL_NIC_TC_NUM_PRIOS  1
 #define KERNEL_NIC_TC_NUM_LEVELS 3
@@ -187,6 +190,8 @@ static struct init_tree_node {
 			   ADD_NS(MLX5_FLOW_TABLE_MISS_ACTION_DEF,
 				  ADD_MULTIPLE_PRIO(KERNEL_NIC_TC_NUM_PRIOS,
 						    KERNEL_NIC_TC_NUM_LEVELS),
+				  ADD_MULTIPLE_PRIO(KERNEL_NIC_PROMISC_NUM_PRIOS,
+						    KERNEL_NIC_PROMISC_NUM_LEVELS),
 				  ADD_MULTIPLE_PRIO(KERNEL_NIC_NUM_PRIOS,
 						    KERNEL_NIC_PRIO_NUM_LEVELS))),
 		  ADD_PRIO(0, BY_PASS_MIN_LEVEL, 0, FS_CHAINING_CAPS,
-- 
2.31.1

On 7/10/2025 6:53 AM, Tariq Toukan wrote:
> From: Jianbo Liu <jianbol@nvidia.com>
> 
> An optimization for promiscuous mode adds a high-priority steering
> table with a single catch-all rule to steer all traffic directly to
> the TTC table.
> 
> However, a gap exists between the creation of this table and the
> insertion of the catch-all rule. Packets arriving in this brief window
> would miss as no rule was inserted yet, unnecessarily incrementing the
> 'rx_steer_missed_packets' counter and dropped.
> 
> This patch resolves the issue by introducing a new prio for this
> table, placing it between MLX5E_TC_PRIO and MLX5E_NIC_PRIO. By doing
> so, packets arriving during the window now fall through to the next
> prio (at MLX5E_NIC_PRIO) instead of being dropped.
> 
> Fixes: 1c46d7409f30 ("net/mlx5e: Optimize promiscuous mode")
> Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
> Reviewed-by: Mark Bloch <mbloch@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> ---

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>