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

[Tariq Toukan]

From: Alexei Lazar <alazar@xxxxxxxxxx>

In mlx5e_init_nic_rx(), a failure subsequent to
mlx5e_create_flow_steering() initiates an error cleanup flow, where
mlx5e_destroy_flow_steering() calls mlx5e_del_vlan_rules() that contains
WARN_ON_ONCE(fs->state_destroy).
This warning fires because state_destroy is set before flow steering is
fully initialized.

To fix this, initialize NIC flow steering with state_destroy cleared,
and set state_destroy only after profile->init_rx() succeeds.
This keeps the flag cleared while mlx5e_create_flow_steering() is
building its tables, so its internal error paths can destroy partially
created flow steering without triggering the warning.

The flag is set in mlx5e_attach_netdev(), rather than in
mlx5e_init_nic_rx(), so non-NIC profiles such as representors also get
state_destroy set after a detach/attach cycle.

Previously, the 'out' label in mlx5e_attach_netdev() cleared
state_destroy on every attach failure. Now that the flag is only set
after init_rx() succeeds, the sole failure path that can observe it set
is profile->enable() failing. Handle it at err_cleanup_rx: clear
state_destroy so that cleanup_rx() can tear down flow steering without
triggering the warning, and cancel set_rx_mode_work, which enable() is
responsible for queueing, so the worker cannot run against flow steering
that is being destroyed.

Fixes: 8c7353b6f716 ("net/mlx5e: Fix VLAN cleanup flow")
Signed-off-by: Alexei Lazar <alazar@xxxxxxxxxx>
Signed-off-by: Gal Pressman <gal@xxxxxxxxxx>
Reviewed-by: Shahar Shitrit <shshitrit@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
---
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 20 +++++++++----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 38ce7d0a9001..13409f6585ba 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -6039,9 +6039,7 @@ 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);
@@ -6556,9 +6554,6 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 	int err;
 
 	clear_bit(MLX5E_STATE_DESTROYING, &priv->state);
-	if (priv->fs)
-		mlx5e_fs_set_state_destroy(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)) {
@@ -6619,6 +6614,9 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 	if (err)
 		goto err_cleanup_tx;
 
+	if (priv->fs)
+		mlx5e_fs_set_state_destroy(priv->fs, true);
+
 	if (profile->enable) {
 		err = profile->enable(priv);
 		if (err)
@@ -6630,6 +6628,10 @@ int mlx5e_attach_netdev(struct mlx5e_priv *priv)
 	return 0;
 
 err_cleanup_rx:
+	if (priv->fs) {
+		mlx5e_fs_set_state_destroy(priv->fs, false);
+		cancel_work_sync(&priv->set_rx_mode_work);
+	}
 	profile->cleanup_rx(priv);
 err_cleanup_tx:
 	profile->cleanup_tx(priv);
@@ -6637,9 +6639,6 @@ 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_state_destroy(priv->fs,
-					   !test_bit(MLX5E_STATE_DESTROYING, &priv->state));
 	cancel_work_sync(&priv->update_stats_work);
 	return err;
 }
@@ -6650,8 +6649,7 @@ void mlx5e_detach_netdev(struct mlx5e_priv *priv)
 
 	set_bit(MLX5E_STATE_DESTROYING, &priv->state);
 	if (priv->fs)
-		mlx5e_fs_set_state_destroy(priv->fs,
-					   !test_bit(MLX5E_STATE_DESTROYING, &priv->state));
+		mlx5e_fs_set_state_destroy(priv->fs, false);
 
 	if (profile->disable)
 		profile->disable(priv);

base-commit: f4377bf85887f57b59abb5479f7660a81ffe4449
-- 
2.44.0