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

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
......@@ -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 {
......
......@@ -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)
......
......@@ -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);
......
......@@ -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)))
......
......@@ -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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