Re: [dpdk-stable] patch 'net/mlx5: workaround drop action with old kernel' has been queued to stable release 20.11.3

[Luca Boccassi <bluca@debian.org>]

Hi,

Please triple-check this one, as the merge conflict was not trivial -
there's no __flow_dv_adjust_buf_size() in 20.11.
Thank you.

On Thu, 2021-08-05 at 10:53 +0100, luca.boccassi@gmail.com wrote:
> Hi,
> 
> FYI, your patch has been queued to stable release 20.11.3
> 
> Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
> It will be pushed if I get no objections before 08/07/21. So please
> shout if anyone has objections.
> 
> Also note that after the patch there's a diff of the upstream commit vs the
> patch applied to the branch. This will indicate if there was any rebasing
> needed to apply to the stable branch. If there were code changes for rebasing
> (ie: not only metadata diffs), please double check that the rebase was
> correctly done.
> 
> Queued patches are on a temporary branch at:
> https://github.com/bluca/dpdk-stable
> 
> This queued commit can be viewed at:
> https://github.com/bluca/dpdk-stable/commit/53193aeeba442cc83bf58aec6449778ced80c465
> 
> Thanks.
> 
> Luca Boccassi
> 
> ---
> From 53193aeeba442cc83bf58aec6449778ced80c465 Mon Sep 17 00:00:00 2001
> From: Suanming Mou <suanmingm@nvidia.com>
> Date: Mon, 2 Aug 2021 17:30:24 +0300
> Subject: [PATCH] net/mlx5: workaround drop action with old kernel
> 
> [ upstream commit 45633c460c223a67dd1a7cc084c3eceb5e17687c ]
> 
> Currently, there are two types of drop action implementation
> in the PMD. One is the DR (Direct Rules) dummy placeholder drop
> action and another is the dedicated dummy queue drop action.
> When creates flow on the root table with DR drop action, the
> action will be converted to MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP
> Verbs attribute in rdma-core.
> 
> In some inbox systems, MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP Verbs
> attribute may not be supported in the kernel driver. Create flow
> with drop action on the root table will be failed as it is not
> supported. In this case, the dummy queue drop action should be
> used instead of DR dummy placeholder drop action.
> 
> This commit adds the DR drop action support detect on the root
> table. If MLX5_IB_ATTR_CREATE_FLOW_FLAGS_DROP Verbs is not
> supported in the system, a dummy queue will be used as drop
> action.
> 
> Fixes: da845ae9d7c1 ("net/mlx5: fix drop action for Direct Rules/Verbs")
> 
> Signed-off-by: Suanming Mou <suanmingm@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>
> ---
>  drivers/net/mlx5/linux/mlx5_os.c | 27 ++++++++++++
>  drivers/net/mlx5/mlx5.h          |  1 +
>  drivers/net/mlx5/mlx5_flow.h     |  1 +
>  drivers/net/mlx5/mlx5_flow_dv.c  | 70 +++++++++++++++++++++++++++++++-
>  4 files changed, 98 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mlx5/linux/mlx5_os.c b/drivers/net/mlx5/linux/mlx5_os.c
> index b191fd740e..e4843f1c6d 100644
> --- a/drivers/net/mlx5/linux/mlx5_os.c
> +++ b/drivers/net/mlx5/linux/mlx5_os.c
> @@ -651,6 +651,32 @@ mlx5_flow_counter_mode_config(struct rte_eth_dev *dev __rte_unused)
>  #endif
>  }
>  
> +/**
> + * DR flow drop action support detect.
> + *
> + * @param dev
> + *   Pointer to rte_eth_dev structure.
> + *
> + */
> +static void
> +mlx5_flow_drop_action_config(struct rte_eth_dev *dev __rte_unused)
> +{
> +#ifdef HAVE_MLX5DV_DR
> +	struct mlx5_priv *priv = dev->data->dev_private;
> +
> +	if (!priv->config.dv_flow_en || !priv->sh->dr_drop_action)
> +		return;
> +	/**
> +	 * DR supports drop action placeholder when it is supported;
> +	 * otherwise, use the queue drop action.
> +	 */
> +	if (mlx5_flow_discover_dr_action_support(dev))
> +		priv->root_drop_action = priv->drop_queue.hrxq->action;
> +	else
> +		priv->root_drop_action = priv->sh->dr_drop_action;
> +#endif
> +}
> +
>  /**
>   * Spawn an Ethernet device from Verbs information.
>   *
> @@ -1587,6 +1613,7 @@ err_secondary:
>  	}
>  	rte_spinlock_init(&priv->shared_act_sl);
>  	mlx5_flow_counter_mode_config(eth_dev);
> +	mlx5_flow_drop_action_config(eth_dev);
>  	if (priv->config.dv_flow_en)
>  		eth_dev->data->dev_flags |= RTE_ETH_DEV_FLOW_OPS_THREAD_SAFE;
>  	return eth_dev;
> diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
> index 831838768a..1946110f7c 100644
> --- a/drivers/net/mlx5/mlx5.h
> +++ b/drivers/net/mlx5/mlx5.h
> @@ -969,6 +969,7 @@ struct mlx5_priv {
>  	unsigned int reta_idx_n; /* RETA index size. */
>  	struct mlx5_drop drop_queue; /* Flow drop queues. */
>  	uint32_t flows; /* RTE Flow rules. */
> +	void *root_drop_action; /* Pointer to root drop action. */
>  	uint32_t ctrl_flows; /* Control flow rules. */
>  	rte_spinlock_t flow_list_lock;
>  	struct mlx5_obj_ops obj_ops; /* HW objects operations. */
> diff --git a/drivers/net/mlx5/mlx5_flow.h b/drivers/net/mlx5/mlx5_flow.h
> index 9b72cde5ff..56af30c2bb 100644
> --- a/drivers/net/mlx5/mlx5_flow.h
> +++ b/drivers/net/mlx5/mlx5_flow.h
> @@ -1429,6 +1429,7 @@ int mlx5_flow_meter_flush(struct rte_eth_dev *dev,
>  			  struct rte_mtr_error *error);
>  int mlx5_flow_dv_discover_counter_offset_support(struct rte_eth_dev *dev);
>  int mlx5_shared_action_flush(struct rte_eth_dev *dev);
> +int mlx5_flow_discover_dr_action_support(struct rte_eth_dev *dev);
>  void mlx5_release_tunnel_hub(struct mlx5_dev_ctx_shared *sh, uint16_t port_id);
>  int mlx5_alloc_tunnel_hub(struct mlx5_dev_ctx_shared *sh);
>  
> diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
> index 1b9637ac44..1793683421 100644
> --- a/drivers/net/mlx5/mlx5_flow_dv.c
> +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> @@ -10840,7 +10840,9 @@ flow_dv_apply(struct rte_eth_dev *dev, struct rte_flow *flow,
>  #ifdef HAVE_MLX5DV_DR
>  				/* DR supports drop action placeholder. */
>  				MLX5_ASSERT(priv->sh->dr_drop_action);
> -				dv->actions[n++] = priv->sh->dr_drop_action;
> +				dv->actions[n++] = dv->group ?
> +					priv->sh->dr_drop_action :
> +					priv->root_drop_action;
>  #else
>  				/* For DV we use the explicit drop queue. */
>  				MLX5_ASSERT(priv->drop_queue.hrxq);
> @@ -12567,6 +12569,72 @@ error:
>  	flow_dv_destroy_policer_rules(dev, fm, attr);
>  	return -1;
>  }
> +/**
> + * Check whether the DR drop action is supported on the root table or not.
> + *
> + * Create a simple flow with DR drop action on root table to validate
> + * if DR drop action on root table is supported or not.
> + *
> + * @param[in] dev
> + *   Pointer to rte_eth_dev structure.
> + *
> + * @return
> + *   0 on success, a negative errno value otherwise and rte_errno is set.
> + */
> +int
> +mlx5_flow_discover_dr_action_support(struct rte_eth_dev *dev)
> +{
> +	struct mlx5_priv *priv = dev->data->dev_private;
> +	struct mlx5_dev_ctx_shared *sh = priv->sh;
> +	struct mlx5_flow_dv_match_params mask = {
> +		.size = sizeof(mask.buf),
> +	};
> +	struct mlx5_flow_dv_match_params value = {
> +		.size = sizeof(value.buf),
> +	};
> +	struct mlx5dv_flow_matcher_attr dv_attr = {
> +		.type = IBV_FLOW_ATTR_NORMAL,
> +		.priority = 0,
> +		.match_criteria_enable = 0,
> +		.match_mask = (void *)&mask,
> +	};
> +	struct mlx5_flow_tbl_resource *tbl = NULL;
> +	void *matcher = NULL;
> +	void *flow = NULL;
> +	int ret = -1;
> +
> +	tbl = flow_dv_tbl_resource_get(dev, 0, 0, 0, false, NULL,
> +					0, 0, NULL);
> +	if (!tbl)
> +		goto err;
> +	dv_attr.match_criteria_enable = flow_dv_matcher_enable(mask.buf);
> +	ret = mlx5_flow_os_create_flow_matcher(sh->ctx, &dv_attr, tbl->obj,
> +					       &matcher);
> +	if (ret)
> +		goto err;
> +	ret = mlx5_flow_os_create_flow(matcher, (void *)&value, 1,
> +				       &sh->dr_drop_action, &flow);
> +err:
> +	/*
> +	 * If DR drop action is not supported on root table, flow create will
> +	 * be failed with EOPNOTSUPP or EPROTONOSUPPORT.
> +	 */
> +	if (!flow) {
> +		if (matcher &&
> +		    (errno == EPROTONOSUPPORT || errno == EOPNOTSUPP))
> +			DRV_LOG(INFO, "DR drop action is not supported in root table.");
> +		else
> +			DRV_LOG(ERR, "Unexpected error in DR drop action support detection");
> +		ret = -1;
> +	} else {
> +		claim_zero(mlx5_flow_os_destroy_flow(flow));
> +	}
> +	if (matcher)
> +		claim_zero(mlx5_flow_os_destroy_flow_matcher(matcher));
> +	if (tbl)
> +		flow_dv_tbl_resource_release(MLX5_SH(dev), tbl);
> +	return ret;
> +}
>  
>  /**
>   * Validate the batch counter support in root table.