net/mlx5e: Avoid unbounded peer devices when unpairing TC hairpin rules

If the peer device was already unbound, then do not attempt to modify
it's resources, otherwise we will crash on dereferencing non-existing
device.

Fixes: 5c65c564c962 ("net/mlx5e: Support offloading TC NIC hairpin flows")
Signed-off-by: Alaa Hleihel <alaa@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

1 files changed, 61 insertions, 1 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 9fed54017659..52e05f3ece50 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -2946,14 +2946,71 @@ int mlx5e_stats_flower(struct mlx5e_priv *priv,
 	return 0;
 }
 
+static void mlx5e_tc_hairpin_update_dead_peer(struct mlx5e_priv *priv,
+					      struct mlx5e_priv *peer_priv)
+{
+	struct mlx5_core_dev *peer_mdev = peer_priv->mdev;
+	struct mlx5e_hairpin_entry *hpe;
+	u16 peer_vhca_id;
+	int bkt;
+
+	if (!same_hw_devs(priv, peer_priv))
+		return;
+
+	peer_vhca_id = MLX5_CAP_GEN(peer_mdev, vhca_id);
+
+	hash_for_each(priv->fs.tc.hairpin_tbl, bkt, hpe, hairpin_hlist) {
+		if (hpe->peer_vhca_id == peer_vhca_id)
+			hpe->hp->pair->peer_gone = true;
+	}
+}
+
+static int mlx5e_tc_netdev_event(struct notifier_block *this,
+				 unsigned long event, void *ptr)
+{
+	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
+	struct mlx5e_flow_steering *fs;
+	struct mlx5e_priv *peer_priv;
+	struct mlx5e_tc_table *tc;
+	struct mlx5e_priv *priv;
+
+	if (ndev->netdev_ops != &mlx5e_netdev_ops ||
+	    event != NETDEV_UNREGISTER ||
+	    ndev->reg_state == NETREG_REGISTERED)
+		return NOTIFY_DONE;
+
+	tc = container_of(this, struct mlx5e_tc_table, netdevice_nb);
+	fs = container_of(tc, struct mlx5e_flow_steering, tc);
+	priv = container_of(fs, struct mlx5e_priv, fs);
+	peer_priv = netdev_priv(ndev);
+	if (priv == peer_priv ||
+	    !(priv->netdev->features & NETIF_F_HW_TC))
+		return NOTIFY_DONE;
+
+	mlx5e_tc_hairpin_update_dead_peer(priv, peer_priv);
+
+	return NOTIFY_DONE;
+}
+
 int mlx5e_tc_nic_init(struct mlx5e_priv *priv)
 {
 	struct mlx5e_tc_table *tc = &priv->fs.tc;
+	int err;
 
 	hash_init(tc->mod_hdr_tbl);
 	hash_init(tc->hairpin_tbl);
 
-	return rhashtable_init(&tc->ht, &tc_ht_params);
+	err = rhashtable_init(&tc->ht, &tc_ht_params);
+	if (err)
+		return err;
+
+	tc->netdevice_nb.notifier_call = mlx5e_tc_netdev_event;
+	if (register_netdevice_notifier(&tc->netdevice_nb)) {
+		tc->netdevice_nb.notifier_call = NULL;
+		mlx5_core_warn(priv->mdev, "Failed to register netdev notifier\n");
+	}
+
+	return err;
 }
 
 static void _mlx5e_tc_del_flow(void *ptr, void *arg)
@@ -2969,6 +3026,9 @@ void mlx5e_tc_nic_cleanup(struct mlx5e_priv *priv)
 {
 	struct mlx5e_tc_table *tc = &priv->fs.tc;
 
+	if (tc->netdevice_nb.notifier_call)
+		unregister_netdevice_notifier(&tc->netdevice_nb);
+
 	rhashtable_free_and_destroy(&tc->ht, _mlx5e_tc_del_flow, NULL);
 
 	if (!IS_ERR_OR_NULL(tc->t)) {