[v2,3/6] ethdev: add API to get hairpin peer ports list

  After hairpin queues are configured, in general, the application will
maintain the ports topology and even the queues configuration for
hairpin. But sometimes it will not.

If there is no hot-plug, it is easy to bind and unbind hairpin among
all the ports. The application can just connect or disconnect the
hairpin egress ports to / from all the probed ingress ports. Then
all the connections could be handled properly.

But with hot-plug / hot-unplug, one port could be probed and removed
dynamically. With two ports hairpin, all the connections from and to
this port should be handled after start(bind) or before stop(unbind).
It is necessary to know the hairpin topology with this port.

This API will return the ports list with the actual peer ports number
after configuration. Either peer RX or TX ports will be gotten with
this function call.

Signed-off-by: Bing Zhao <bingz@nvidia.com>
---
 lib/librte_ethdev/rte_ethdev.c           | 24 ++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev.h           | 27 +++++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev_driver.h    | 30 ++++++++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev_version.map |  1 +
 4 files changed, 82 insertions(+)
  

Hi Bing,

PSB,
Best,
Ori
> -----Original Message-----
> From: Bing Zhao <bingz@nvidia.com>
> Sent: Thursday, October 8, 2020 11:52 AM
> Subject: [PATCH v2 3/6] ethdev: add API to get hairpin peer ports list
> 
> After hairpin queues are configured, in general, the application will
> maintain the ports topology and even the queues configuration for
> hairpin. But sometimes it will not.
> 
> If there is no hot-plug, it is easy to bind and unbind hairpin among
> all the ports. The application can just connect or disconnect the
> hairpin egress ports to / from all the probed ingress ports. Then
> all the connections could be handled properly.
> 
> But with hot-plug / hot-unplug, one port could be probed and removed
> dynamically. With two ports hairpin, all the connections from and to
> this port should be handled after start(bind) or before stop(unbind).
> It is necessary to know the hairpin topology with this port.
> 
> This API will return the ports list with the actual peer ports number
> after configuration. Either peer RX or TX ports will be gotten with
> this function call.
> 
> Signed-off-by: Bing Zhao <bingz@nvidia.com>
> ---
>  lib/librte_ethdev/rte_ethdev.c           | 24 ++++++++++++++++++++++++
>  lib/librte_ethdev/rte_ethdev.h           | 27 +++++++++++++++++++++++++++
>  lib/librte_ethdev/rte_ethdev_driver.h    | 30
> ++++++++++++++++++++++++++++++
>  lib/librte_ethdev/rte_ethdev_version.map |  1 +
>  4 files changed, 82 insertions(+)
> 
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index a4adeff..ea7892a 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -2208,6 +2208,30 @@ struct rte_eth_dev *
>  	return ret;
>  }
> 
> +int
> +rte_eth_hairpin_get_peer_ports(uint16_t cur_port, uint16_t *peer_ports,
> +			       bool direction)
> +{
> +	struct rte_eth_dev *dev;
> +	int ret;
> +
> +	if (!peer_ports)
> +		return -EINVAL;
> +
> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(cur_port, -EINVAL);
> +	dev = &rte_eth_devices[cur_port];
> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops-
> >hairpin_get_peer_ports,
> +				-ENOTSUP);
> +
> +	ret = (*dev->dev_ops->hairpin_get_peer_ports)(dev, peer_ports,
> +						      direction);
> +	if (ret < 0)
> +		RTE_ETHDEV_LOG(ERR, "Failed to get %d hairpin peer %s
> ports",
> +			       cur_port, direction ? "RX" : "TX");
> +
> +	return ret;
> +}
> +
>  void
>  rte_eth_tx_buffer_drop_callback(struct rte_mbuf **pkts, uint16_t unsent,
>  		void *userdata __rte_unused)
> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
> index 94a981c..6680de2 100644
> --- a/lib/librte_ethdev/rte_ethdev.h
> +++ b/lib/librte_ethdev/rte_ethdev.h
> @@ -2134,6 +2134,33 @@ int rte_eth_tx_queue_setup(uint16_t port_id,
> uint16_t tx_queue_id,
>   * @warning
>   * @b EXPERIMENTAL: this API may change, or be removed, without prior
> notice
>   *
> + * Get all the hairpin peer RX / TX ports of the current port.
> + * The caller should ensure that the array is large enough to save the ports
> + * list.
> + *
> + * @param cur_port
> + *   The current port identifier of the Ethernet device.
> + * @param peer_ports
> + *   Pointer to the array to save the peer ports list *
> + * @param direction
> + *   Current port to peer port direction
> + *   true - current used as TX to get all peer RX ports.
> + *   false - current used as RX to get all peer TX ports.
> + *
> + * @return
> + *   - (0 or positive) actual peer ports number.
> + *   - (-EINVAL) if bad parameter.
> + *   - (-ENOTSUP) if hardware doesn't support.
> + *   - Others detailed errors from PMD drivers.
> + */
> +__rte_experimental
> +int rte_eth_hairpin_get_peer_ports(uint16_t cur_port, uint16_t *peer_ports,
> +				   bool direction);
> +

I think direction should be changed to int, or change the name to ingress, also
I think we should add the peer_ports array size, so in case the application
didn't allocate enough space it will simply end in error.

> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change, or be removed, without prior
> notice
> + *
>   * Bind all hairpin TX queues of one port to the RX queues of the peer port.
>   * It is only allowed to call this API after all hairpin queues are configured
>   * properly and the devices of TX and peer RX are in started state.
> diff --git a/lib/librte_ethdev/rte_ethdev_driver.h
> b/lib/librte_ethdev/rte_ethdev_driver.h
> index f8eb879..ecca9d6 100644
> --- a/lib/librte_ethdev/rte_ethdev_driver.h
> +++ b/lib/librte_ethdev/rte_ethdev_driver.h
> @@ -576,6 +576,34 @@ typedef int (*eth_tx_hairpin_queue_setup_t)
> 
>  /**
>   * @internal
> + * Get all hairpin TX/RX peer ports of the current device, if any.
> + *
> + * @param dev
> + *   ethdev handle of port.
> + * @param peer_ports
> + *   array to save the ports list.
> + * @param direction
> + *   value to decide the current to peer direction
> + *   true - used as TX to get all peer RX ports.
> + *   false - used as RX to get all peer TX ports.
> + *
> + * @return
> + *   Negative errno value on error, 0 or positive on success.
> + *
> + * @retval 0
> + *   Success, no peer ports.
> + * @retval >0
> + *   Actual number of the peer ports.
> + * @retval -ENOTSUP
> + *   Get peer ports API is not supported.
> + * @retval -EINVAL
> + *   One of the parameters is invalid.
> + */
> +typedef int (*hairpin_get_peer_ports_t)(struct rte_eth_dev *dev,
> +					uint16_t *peer_ports, bool direction);
> +
> +/**
> + * @internal
>   * Bind all hairpin TX queues of one port to the RX queues of the peer port.
>   *
>   * @param dev
> @@ -761,6 +789,8 @@ struct eth_dev_ops {
>  	/**< Set up device RX hairpin queue. */
>  	eth_tx_hairpin_queue_setup_t tx_hairpin_queue_setup;
>  	/**< Set up device TX hairpin queue. */
> +	hairpin_get_peer_ports_t hairpin_get_peer_ports;
> +	/**< Get hairpin peer ports list. */
>  	eth_hairpin_bind_t hairpin_bind;
>  	/**< Bind all hairpin TX queues of device to the peer port RX queues. */
>  	eth_hairpin_unbind_t hairpin_unbind;
> diff --git a/lib/librte_ethdev/rte_ethdev_version.map
> b/lib/librte_ethdev/rte_ethdev_version.map
> index 18efe4e..1019e28 100644
> --- a/lib/librte_ethdev/rte_ethdev_version.map
> +++ b/lib/librte_ethdev/rte_ethdev_version.map
> @@ -228,6 +228,7 @@ EXPERIMENTAL {
> 
>  	# added in 20.11
>  	rte_eth_hairpin_bind;
> +	rte_eth_hairpin_get_peer_ports;
>  	rte_eth_hairpin_unbind;
>  	rte_eth_link_speed_to_str;
>  	rte_eth_link_to_str;
> --
> 1.8.3.1