[PATCH net V2] net/mlx5e: Fix false WARN_ON_ONCE in flow steering cleanup on RX init failure

[PATCH net V2] net/mlx5e: Fix false WARN_ON_ONCE in flow steering cleanup on RX init failure

[Tariq Toukan]

From: Alexei Lazar <alazar@nvidia.com>

mlx5e_attach_netdev() sets rx_mode_active before calling init_rx(), so
any init_rx() failure after mlx5e_create_flow_steering() has succeeded
makes mlx5e_destroy_flow_steering() trip
WARN_ON_ONCE(fs->rx_mode_active) in mlx5e_del_vlan_rules().

Hit in internal regression testing, so kthread creation failed
with -EINTR:

  WARNING: CPU: 3 PID: 170 at drivers/net/ethernet/mellanox/mlx5/core/en_fs.c:564 mlx5e_del_vlan_rules+0x295/0x2b0 [mlx5_core]
  mlx5e_destroy_flow_steering+0x34/0xc0 [mlx5_core]
  mlx5e_init_nic_rx+0x137/0x200 [mlx5_core]
  mlx5e_attach_netdev+0x105/0x360 [mlx5_core]

Fix it by creating NIC flow steering with rx_mode_active cleared and
setting it only after profile->init_rx() succeeds. This also lets the
internal error paths of mlx5e_create_flow_steering() destroy partially
created steering without warning. The flag is set in
mlx5e_attach_netdev() rather than mlx5e_init_nic_rx() so that non-NIC
profiles, such as representors, also get it set after a detach/attach
cycle.

Fixes: 8c7353b6f716 ("net/mlx5e: Fix VLAN cleanup flow")
Signed-off-by: Alexei Lazar <alazar@nvidia.com>
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 23 ++++++++-----------
 1 file changed, 9 insertions(+), 14 deletions(-)

V2:
- Rebased.
- Updated commit message.

V1:
https://lore.kernel.org/all/20261026072253.4118892-1-tariqt@nvidia.com/

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 72bca10c579d..990d2fa6a914 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -6041,9 +6041,7 @@ static int mlx5e_nic_init(struct mlx5_core_dev *mdev,
 	priv->dfs_root = debugfs_create_dir("nic",
 					    mlx5_debugfs_get_dev_root(mdev));
 
-	fs = mlx5e_fs_init(priv->profile, mdev,
-			   !test_bit(MLX5E_STATE_DESTROYING, &priv->state),
-			   priv->dfs_root);
+	fs = mlx5e_fs_init(priv->profile, mdev, false, priv->dfs_root);
 	if (!fs) {
 		err = -ENOMEM;
 		mlx5_core_err(mdev, "FS initialization failed, %d\n", err);
@@ -6558,10 +6556,6 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 	int err;
 
 	clear_bit(MLX5E_STATE_DESTROYING, &priv->state);
-	if (priv->fs)
-		mlx5e_fs_set_rx_mode_active(priv->fs,
-					    !test_bit(MLX5E_STATE_DESTROYING,
-						      &priv->state));
 
 	/* Validate the max_wqe_size_sq capability. */
 	if (WARN_ON_ONCE(mlx5e_get_max_sq_wqebbs(priv->mdev) < MLX5E_MAX_TX_WQEBBS)) {
@@ -6622,6 +6616,9 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 	if (err)
 		goto err_cleanup_tx;
 
+	if (priv->fs)
+		mlx5e_fs_set_rx_mode_active(priv->fs, true);
+
 	if (profile->enable) {
 		err = profile->enable(priv);
 		if (err)
@@ -6633,6 +6630,10 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 	return 0;
 
 err_cleanup_rx:
+	if (priv->fs) {
+		mlx5e_fs_set_rx_mode_active(priv->fs, false);
+		cancel_work_sync(&priv->set_rx_mode_work);
+	}
 	profile->cleanup_rx(priv);
 err_cleanup_tx:
 	profile->cleanup_tx(priv);
@@ -6640,10 +6641,6 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 out:
 	mlx5e_reset_channels(priv->netdev);
 	set_bit(MLX5E_STATE_DESTROYING, &priv->state);
-	if (priv->fs)
-		mlx5e_fs_set_rx_mode_active(priv->fs,
-					    !test_bit(MLX5E_STATE_DESTROYING,
-						      &priv->state));
 	cancel_work_sync(&priv->update_stats_work);
 	return err;
 }
@@ -6654,9 +6651,7 @@ void mlx5e_detach_netdev(struct mlx5e_priv *priv)
 
 	set_bit(MLX5E_STATE_DESTROYING, &priv->state);
 	if (priv->fs)
-		mlx5e_fs_set_rx_mode_active(priv->fs,
-					    !test_bit(MLX5E_STATE_DESTROYING,
-						      &priv->state));
+		mlx5e_fs_set_rx_mode_active(priv->fs, false);
 
 	if (profile->disable)
 		profile->disable(priv);

base-commit: b71c101bbb9814d163c00234d43c41f0a17907d4
-- 
2.44.0