diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/qos.c b/drivers/net/ethernet/mellanox/mlx5/core/en/qos.c index c1e07496c89c..ff45840581e3 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/qos.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/qos.c @@ -50,7 +50,6 @@ static int mlx5e_find_unused_qos_qid(struct mlx5e_priv *priv) struct mlx5e_qos_node { struct hlist_node hnode; - struct rcu_head rcu; struct mlx5e_qos_node *parent; u64 rate; u32 bw_share; @@ -132,7 +131,11 @@ static void mlx5e_sw_node_delete(struct mlx5e_priv *priv, struct mlx5e_qos_node __clear_bit(node->qid, priv->htb.qos_used_qids); mlx5e_update_tx_netdev_queues(priv); } - kfree_rcu(node, rcu); + /* Make sure this qid is no longer selected by mlx5e_select_queue, so + * that mlx5e_reactivate_qos_sq can safely restart the netdev TX queue. + */ + synchronize_net(); + kfree(node); } /* TX datapath API */ @@ -273,10 +276,18 @@ static int mlx5e_open_qos_sq(struct mlx5e_priv *priv, struct mlx5e_channels *chs static void mlx5e_activate_qos_sq(struct mlx5e_priv *priv, struct mlx5e_qos_node *node) { struct mlx5e_txqsq *sq; + u16 qid; sq = mlx5e_get_qos_sq(priv, node->qid); - WRITE_ONCE(priv->txq2sq[mlx5e_qid_from_qos(&priv->channels, node->qid)], sq); + qid = mlx5e_qid_from_qos(&priv->channels, node->qid); + + /* If it's a new queue, it will be marked as started at this point. + * Stop it before updating txq2sq. + */ + mlx5e_tx_disable_queue(netdev_get_tx_queue(priv->netdev, qid)); + + priv->txq2sq[qid] = sq; /* Make the change to txq2sq visible before the queue is started. * As mlx5e_xmit runs under a spinlock, there is an implicit ACQUIRE, @@ -299,8 +310,13 @@ static void mlx5e_deactivate_qos_sq(struct mlx5e_priv *priv, u16 qid) qos_dbg(priv->mdev, "Deactivate QoS SQ qid %u\n", qid); mlx5e_deactivate_txqsq(sq); - /* The queue is disabled, no synchronization with datapath is needed. */ priv->txq2sq[mlx5e_qid_from_qos(&priv->channels, qid)] = NULL; + + /* Make the change to txq2sq visible before the queue is started again. + * As mlx5e_xmit runs under a spinlock, there is an implicit ACQUIRE, + * which pairs with this barrier. + */ + smp_wmb(); } static void mlx5e_close_qos_sq(struct mlx5e_priv *priv, u16 qid) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c index 9c91ef0e1ed2..726661774979 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c @@ -691,8 +691,21 @@ netdev_tx_t mlx5e_xmit(struct sk_buff *skb, struct net_device *dev) struct mlx5e_txqsq *sq; u16 pi; + /* All changes to txq2sq are performed in sync with mlx5e_xmit, when the + * queue being changed is disabled, and smp_wmb guarantees that the + * changes are visible before mlx5e_xmit tries to read from txq2sq. It + * guarantees that the value of txq2sq[qid] doesn't change while + * mlx5e_xmit is running on queue number qid. smb_wmb is paired with + * HARD_TX_LOCK around ndo_start_xmit, which serves as an ACQUIRE. + */ sq = priv->txq2sq[skb_get_queue_mapping(skb)]; if (unlikely(!sq)) { + /* Two cases when sq can be NULL: + * 1. The HTB node is registered, and mlx5e_select_queue + * selected its queue ID, but the SQ itself is not yet created. + * 2. HTB SQ creation failed. Similar to the previous case, but + * the SQ won't be created. + */ dev_kfree_skb_any(skb); return NETDEV_TX_OK; }