Commit 9cf88808 authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Daniel Borkmann
Browse files

net/mlx5e: Fix concurrency issues between config flow and XSK 



After disabling resources necessary for XSK (the XDP program, channels,
XSK queues), use synchronize_rcu to wait until the XSK wakeup function
finishes, before freeing the resources.

Suspend XSK wakeups during switching channels. If the XDP program is
being removed, synchronize_rcu before closing the old channels to allow
XSK wakeup to complete.

Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191217162023.16011-3-maximmi@mellanox.com
parent 06870682

drivers/net/ethernet/mellanox/mlx5/core/en.h

+1 −1
Original line number Diff line number Diff line
@@ -760,7 +760,7 @@ enum { 
	MLX5E_STATE_OPENED,

	MLX5E_STATE_DESTROYING,

	MLX5E_STATE_XDP_TX_ENABLED,

	MLX5E_STATE_XDP_OPEN,

	MLX5E_STATE_XDP_ACTIVE,

};



struct mlx5e_rqt {

drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h

+9 −13
Original line number Diff line number Diff line
@@ -75,12 +75,18 @@ int mlx5e_xdp_xmit(struct net_device *dev, int n, struct xdp_frame **frames, 
static inline void mlx5e_xdp_tx_enable(struct mlx5e_priv *priv)

{

	set_bit(MLX5E_STATE_XDP_TX_ENABLED, &priv->state);



	if (priv->channels.params.xdp_prog)

		set_bit(MLX5E_STATE_XDP_ACTIVE, &priv->state);

}



static inline void mlx5e_xdp_tx_disable(struct mlx5e_priv *priv)

{

	if (priv->channels.params.xdp_prog)

		clear_bit(MLX5E_STATE_XDP_ACTIVE, &priv->state);



	clear_bit(MLX5E_STATE_XDP_TX_ENABLED, &priv->state);

	/* let other device's napi(s) see our new state */

	/* Let other device's napi(s) and XSK wakeups see our new state. */

	synchronize_rcu();

}
@@ -89,19 +95,9 @@ static inline bool mlx5e_xdp_tx_is_enabled(struct mlx5e_priv *priv) 
	return test_bit(MLX5E_STATE_XDP_TX_ENABLED, &priv->state);

}



static inline void mlx5e_xdp_set_open(struct mlx5e_priv *priv)

{

	set_bit(MLX5E_STATE_XDP_OPEN, &priv->state);

}



static inline void mlx5e_xdp_set_closed(struct mlx5e_priv *priv)

{

	clear_bit(MLX5E_STATE_XDP_OPEN, &priv->state);

}



static inline bool mlx5e_xdp_is_open(struct mlx5e_priv *priv)

static inline bool mlx5e_xdp_is_active(struct mlx5e_priv *priv)

{

	return test_bit(MLX5E_STATE_XDP_OPEN, &priv->state);

	return test_bit(MLX5E_STATE_XDP_ACTIVE, &priv->state);

}



static inline void mlx5e_xmit_xdp_doorbell(struct mlx5e_xdpsq *sq)

drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c

+1 −0
Original line number Diff line number Diff line
@@ -144,6 +144,7 @@ void mlx5e_close_xsk(struct mlx5e_channel *c) 
{

	clear_bit(MLX5E_CHANNEL_STATE_XSK, c->state);

	napi_synchronize(&c->napi);

	synchronize_rcu(); /* Sync with the XSK wakeup. */



	mlx5e_close_rq(&c->xskrq);

	mlx5e_close_cq(&c->xskrq.cq);

drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c

+1 −1
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ int mlx5e_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags) 
	struct mlx5e_channel *c;

	u16 ix;



	if (unlikely(!mlx5e_xdp_is_open(priv)))

	if (unlikely(!mlx5e_xdp_is_active(priv)))

		return -ENETDOWN;



	if (unlikely(!mlx5e_qid_get_ch_if_in_group(params, qid, MLX5E_RQ_GROUP_XSK, &ix)))

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

+1 −18
Original line number Diff line number Diff line
@@ -3000,12 +3000,9 @@ void mlx5e_timestamp_init(struct mlx5e_priv *priv) 
int mlx5e_open_locked(struct net_device *netdev)

{

	struct mlx5e_priv *priv = netdev_priv(netdev);

	bool is_xdp = priv->channels.params.xdp_prog;

	int err;



	set_bit(MLX5E_STATE_OPENED, &priv->state);

	if (is_xdp)

		mlx5e_xdp_set_open(priv);



	err = mlx5e_open_channels(priv, &priv->channels);

	if (err)
@@ -3020,8 +3017,6 @@ int mlx5e_open_locked(struct net_device *netdev) 
	return 0;



err_clear_state_opened_flag:

	if (is_xdp)

		mlx5e_xdp_set_closed(priv);

	clear_bit(MLX5E_STATE_OPENED, &priv->state);

	return err;

}
@@ -3053,8 +3048,6 @@ int mlx5e_close_locked(struct net_device *netdev) 
	if (!test_bit(MLX5E_STATE_OPENED, &priv->state))

		return 0;



	if (priv->channels.params.xdp_prog)

		mlx5e_xdp_set_closed(priv);

	clear_bit(MLX5E_STATE_OPENED, &priv->state);



	netif_carrier_off(priv->netdev);
@@ -4371,16 +4364,6 @@ static int mlx5e_xdp_allowed(struct mlx5e_priv *priv, struct bpf_prog *prog) 
	return 0;

}



static int mlx5e_xdp_update_state(struct mlx5e_priv *priv)

{

	if (priv->channels.params.xdp_prog)

		mlx5e_xdp_set_open(priv);

	else

		mlx5e_xdp_set_closed(priv);



	return 0;

}



static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog)

{

	struct mlx5e_priv *priv = netdev_priv(netdev);
@@ -4415,7 +4398,7 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog) 
		mlx5e_set_rq_type(priv->mdev, &new_channels.params);

		old_prog = priv->channels.params.xdp_prog;



		err = mlx5e_safe_switch_channels(priv, &new_channels, mlx5e_xdp_update_state);

		err = mlx5e_safe_switch_channels(priv, &new_channels, NULL);

		if (err)

			goto unlock;

	} else {

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