net/mlx5e: Protect hairpin hash table with mutex

To remove dependency on rtnl lock, protect hairpin hash table from
concurrent modifications with new "hairpin_tbl_lock" mutex.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h b/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
index 4518ce1..100506a 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
@@ -17,6 +17,7 @@ struct mlx5e_tc_table {
        struct rhashtable               ht;
 
        DECLARE_HASHTABLE(mod_hdr_tbl, 8);
+       struct mutex hairpin_tbl_lock; /* protects hairpin_tbl */
        DECLARE_HASHTABLE(hairpin_tbl, 8);
 
        struct notifier_block     netdevice_nb;

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 0abfa9b..a7acb7f 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -652,15 +652,16 @@ static void mlx5e_hairpin_put(struct mlx5e_priv *priv,
                              struct mlx5e_hairpin_entry *hpe)
 {
        /* no more hairpin flows for us, release the hairpin pair */
-       if (!refcount_dec_and_test(&hpe->refcnt))
+       if (!refcount_dec_and_mutex_lock(&hpe->refcnt, &priv->fs.tc.hairpin_tbl_lock))
                return;
+       hash_del(&hpe->hairpin_hlist);
+       mutex_unlock(&priv->fs.tc.hairpin_tbl_lock);
 
        netdev_dbg(priv->netdev, "del hairpin: peer %s\n",
                   dev_name(hpe->hp->pair->peer_mdev->device));
 
        WARN_ON(!list_empty(&hpe->flows));
        mlx5e_hairpin_destroy(hpe->hp);
-       hash_del(&hpe->hairpin_hlist);
        kfree(hpe);
 }
 
@@ -729,13 +730,17 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
                                     extack);
        if (err)
                return err;
+
+       mutex_lock(&priv->fs.tc.hairpin_tbl_lock);
        hpe = mlx5e_hairpin_get(priv, peer_id, match_prio);
        if (hpe)
                goto attach_flow;
 
        hpe = kzalloc(sizeof(*hpe), GFP_KERNEL);
-       if (!hpe)
-               return -ENOMEM;
+       if (!hpe) {
+               err = -ENOMEM;
+               goto create_hairpin_err;
+       }
 
        spin_lock_init(&hpe->flows_lock);
        INIT_LIST_HEAD(&hpe->flows);
@@ -784,6 +789,8 @@ attach_flow:
        } else {
                flow->nic_attr->hairpin_tirn = hpe->hp->tirn;
        }
+       mutex_unlock(&priv->fs.tc.hairpin_tbl_lock);
+
        flow->hpe = hpe;
        spin_lock(&hpe->flows_lock);
        list_add(&flow->hairpin, &hpe->flows);
@@ -792,6 +799,7 @@ attach_flow:
        return 0;
 
 create_hairpin_err:
+       mutex_unlock(&priv->fs.tc.hairpin_tbl_lock);
        kfree(hpe);
        return err;
 }
@@ -3768,10 +3776,12 @@ static void mlx5e_tc_hairpin_update_dead_peer(struct mlx5e_priv *priv,
 
        peer_vhca_id = MLX5_CAP_GEN(peer_mdev, vhca_id);
 
+       mutex_lock(&priv->fs.tc.hairpin_tbl_lock);
        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;
        }
+       mutex_unlock(&priv->fs.tc.hairpin_tbl_lock);
 }
 
 static int mlx5e_tc_netdev_event(struct notifier_block *this,
@@ -3808,6 +3818,7 @@ int mlx5e_tc_nic_init(struct mlx5e_priv *priv)
 
        mutex_init(&tc->t_lock);
        hash_init(tc->mod_hdr_tbl);
+       mutex_init(&tc->hairpin_tbl_lock);
        hash_init(tc->hairpin_tbl);
 
        err = rhashtable_init(&tc->ht, &tc_ht_params);
@@ -3839,6 +3850,8 @@ void mlx5e_tc_nic_cleanup(struct mlx5e_priv *priv)
        if (tc->netdevice_nb.notifier_call)
                unregister_netdevice_notifier(&tc->netdevice_nb);
 
+       mutex_destroy(&tc->hairpin_tbl_lock);
+
        rhashtable_destroy(&tc->ht);
 
        if (!IS_ERR_OR_NULL(tc->t)) {