Re: [dpdk-dev] [PATCH v7 1/5] net/af_xdp: introduce AF XDP PMD driver

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 3/27/2019 9:00 AM, Xiaolong Ye wrote:
> Add a new PMD driver for AF_XDP which is a proposed faster version of
> AF_PACKET interface in Linux. More info about AF_XDP, please refer to [1]
> [2].
> 
> This is the vanilla version PMD which just uses a raw buffer registered as
> the umem.
> 
> [1] https://fosdem.org/2018/schedule/event/af_xdp/
> [2] https://lwn.net/Articles/745934/
> 
> Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>

Hi Xiaolong,

Mostly looks good, only there are a few comments on minor issues, can you please
check them?

<...>

> @@ -474,6 +474,12 @@ M: John W. Linville <linville@tuxdriver.com>
>  F: drivers/net/af_packet/
>  F: doc/guides/nics/features/afpacket.ini
>  
> +Linux AF_XDP
> +M: Xiaolong Ye <xiaolong.ye@intel.com>
> +M: Qi Zhang <qi.z.zhang@intel.com>
> +F: drivers/net/af_xdp/
> +F: doc/guides/nics/features/af_xdp.rst

Can you please add .ini file too?

<...>

> +static const char * const valid_arguments[] = {
> +	ETH_AF_XDP_IFACE_ARG,
> +	ETH_AF_XDP_QUEUE_IDX_ARG,
> +	NULL
> +};

Minor issue, but can you please keep close the .*ARG defines and this structure,
either move this up or move defines down just above this struct?

> +
> +static struct rte_eth_link pmd_link = {
> +	.link_speed = ETH_SPEED_NUM_10G,
> +	.link_duplex = ETH_LINK_FULL_DUPLEX,
> +	.link_status = ETH_LINK_DOWN,
> +	.link_autoneg = ETH_LINK_AUTONEG
> +};

Can this variable be const?

<...>

> +static void
> +eth_dev_info(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
> +{
> +	struct pmd_internals *internals = dev->data->dev_private;
> +
> +	dev_info->if_index = internals->if_index;
> +	dev_info->max_mac_addrs = 1;
> +	dev_info->max_rx_pktlen = ETH_FRAME_LEN;
> +	dev_info->max_rx_queues = 1;
> +	dev_info->max_tx_queues = 1;

What do you think documenting the only single queue supported limitation?

<...>

> +static void remove_xdp_program(struct pmd_internals *internals)
> +{

According coding convention it should be:

static void
remove_xdp_program(struct pmd_internals *internals)
{

There is a usage of mixture, can you please update them according convention?

<...>

> +	if (parse_parameters(kvlist, if_name, &xsk_queue_idx) < 0) {
> +		AF_XDP_LOG(ERR, "Invalid kvargs value\n");
> +		return -EINVAL;
> +	}

At this point we don't know if the user provided a "if_name" value, needs a way
to confirm mandantory devargs provided before continue.

<...>

> +RTE_PMD_REGISTER_VDEV(net_af_xdp, pmd_af_xdp_drv);
> +RTE_PMD_REGISTER_PARAM_STRING(eth_af_xdp,

s/eth_af_xdp/net_af_xdp

> +			      "iface=<string> "
> +			      "queue=<int> ");
> +
> +RTE_INIT(af_xdp_init_log)
> +{
> +	af_xdp_logtype = rte_log_register("pmd.net.xdp");

why not "pmd.net.af_xdp"?

<...>

> @@ -143,6 +143,7 @@ _LDLIBS-$(CONFIG_RTE_LIBRTE_DPAA2_MEMPOOL)  += -lrte_mempool_dpaa2
>  endif
>  
>  _LDLIBS-$(CONFIG_RTE_LIBRTE_PMD_AF_PACKET)  += -lrte_pmd_af_packet
> +_LDLIBS-$(CONFIG_RTE_LIBRTE_PMD_AF_XDP)     += -lrte_pmd_af_xdp -lelf -lbpf

Is "-lelf" still required?