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mlx5en: Implement dummy receive queue, RQ, for dropping packets.

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What is a drop RQ and why is it needed?

The RSS indirection table, also called the RQT, selects the
destination RQ based on the receive queue number, RQN. The RQT is
frequently referred to by flow steering rules to distribute traffic
among multiple RQs. The problem is that the RQs cannot be destroyed
before the RQT referring them is destroyed too. Further, TLS RX
rules may still be referring to the RQT even if the link went
down. Because there is no magic RQN for dropping packets, we create
a dummy RQ, also called drop RQ, which sole purpose is to drop all
received packets. When the link goes down this RQN is filled in all
RQT entries, of the main RQT, so the real RQs which are about to be
destroyed can be released and the TLS RX rules can be sustained.

MFC after:	1 week
Sponsored by:	NVIDIA Networking
This commit is contained in:
Hans Petter Selasky 2022-02-01 16:20:06 +01:00
parent a60f953424
commit 27b778ae55
2 changed files with 93 additions and 0 deletions
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1
sys/dev/mlx5/mlx5_en/en.h
View File

@ -1018,6 +1018,7 @@ struct mlx5e_priv {
#define PRIV_LOCKED(priv) sx_xlocked(&(priv)->state_lock)
#define PRIV_ASSERT_LOCKED(priv) sx_assert(&(priv)->state_lock, SA_XLOCKED)
struct sx state_lock; /* Protects Interface state */
struct mlx5e_rq drop_rq;
u32 pdn;
u32 tdn;
struct mlx5_core_mkey mr;

92
sys/dev/mlx5/mlx5_en/mlx5_en_main.c
View File

@ -1479,6 +1479,88 @@ mlx5e_close_rq_wait(struct mlx5e_rq *rq)
mlx5e_destroy_rq(rq);
}
/*
* What is a drop RQ and why is it needed?
*
* The RSS indirection table, also called the RQT, selects the
* destination RQ based on the receive queue number, RQN. The RQT is
* frequently referred to by flow steering rules to distribute traffic
* among multiple RQs. The problem is that the RQs cannot be destroyed
* before the RQT referring them is destroyed too. Further, TLS RX
* rules may still be referring to the RQT even if the link went
* down. Because there is no magic RQN for dropping packets, we create
* a dummy RQ, also called drop RQ, which sole purpose is to drop all
* received packets. When the link goes down this RQN is filled in all
* RQT entries, of the main RQT, so the real RQs which are about to be
* destroyed can be released and the TLS RX rules can be sustained.
*/
static void
mlx5e_open_drop_rq_comp(struct mlx5_core_cq *mcq __unused, struct mlx5_eqe *eqe __unused)
{
}
static int
mlx5e_open_drop_rq(struct mlx5e_priv *priv,
struct mlx5e_rq *drop_rq)
{
struct mlx5e_cq_param param_cq = {};
struct mlx5e_rq_param param_rq = {};
void *rqc_wq = MLX5_ADDR_OF(rqc, param_rq.rqc, wq);
int err;
/* set basic CQ parameters needed */
MLX5_SET(cqc, param_cq.cqc, log_cq_size, 0);
MLX5_SET(cqc, param_cq.cqc, uar_page, priv->mdev->priv.uar->index);
/* open receive completion queue */
err = mlx5e_open_cq(priv, &param_cq, &drop_rq->cq,
&mlx5e_open_drop_rq_comp, 0);
if (err)
goto err_done;
/* set basic WQ parameters needed */
MLX5_SET(wq, rqc_wq, wq_type, MLX5_WQ_TYPE_LINKED_LIST);
MLX5_SET(wq, rqc_wq, end_padding_mode, MLX5_WQ_END_PAD_MODE_ALIGN);
MLX5_SET(wq, rqc_wq, log_wq_stride, ilog2(sizeof(struct mlx5e_rx_wqe) + sizeof(struct mlx5_wqe_data_seg)));
MLX5_SET(wq, rqc_wq, log_wq_sz, 0);
MLX5_SET(wq, rqc_wq, pd, priv->pdn);
param_rq.wq.linear = 1;
err = mlx5_wq_ll_create(priv->mdev, &param_rq.wq, rqc_wq, &drop_rq->wq,
&drop_rq->wq_ctrl);
if (err)
goto err_close_cq;
err = mlx5e_enable_rq(drop_rq, &param_rq);
if (err)
goto err_wq_destroy;
err = mlx5e_modify_rq(drop_rq, MLX5_RQC_STATE_RST, MLX5_RQC_STATE_RDY);
if (err)
goto err_disable_rq;
return (err);
err_disable_rq:
mlx5e_disable_rq(drop_rq);
err_wq_destroy:
mlx5_wq_destroy(&drop_rq->wq_ctrl);
err_close_cq:
mlx5e_close_cq(&drop_rq->cq);
err_done:
return (err);
}
static void
mlx5e_close_drop_rq(struct mlx5e_rq *drop_rq)
{
mlx5e_modify_rq(drop_rq, MLX5_RQC_STATE_RDY, MLX5_RQC_STATE_ERR);
mlx5e_disable_rq(drop_rq);
mlx5_wq_destroy(&drop_rq->wq_ctrl);
mlx5e_close_cq(&drop_rq->cq);
}
void
mlx5e_free_sq_db(struct mlx5e_sq *sq)
{
@ -4450,6 +4532,12 @@ mlx5e_create_ifp(struct mlx5_core_dev *mdev)
goto err_rl_init;
}
err = mlx5e_open_drop_rq(priv, &priv->drop_rq);
if (err) {
if_printf(ifp, "%s: mlx5e_open_drop_rq failed\n", __func__);
goto err_tls_init;
}
/* set default MTU */
mlx5e_set_dev_port_mtu(ifp, ifp->if_mtu);
@ -4577,6 +4665,9 @@ mlx5e_create_ifp(struct mlx5_core_dev *mdev)
return (priv);
err_tls_init:
mlx5e_tls_cleanup(priv);
err_rl_init:
mlx5e_rl_cleanup(priv);
@ -4672,6 +4763,7 @@ mlx5e_destroy_ifp(struct mlx5_core_dev *mdev, void *vpriv)
ifmedia_removeall(&priv->media);
ether_ifdetach(ifp);
mlx5e_close_drop_rq(&priv->drop_rq);
mlx5e_tls_cleanup(priv);
mlx5e_rl_cleanup(priv);