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

[Ye Xiaolong <xiaolong.ye@intel.com>]

Hi, Ferruh

Thanks for the comments.

On 03/28, Ferruh Yigit wrote:
>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?

Will add.

>
><...>
>
>> +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?

Got it, I'll put them together.

>
>> +
>> +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?

Will do.

>
><...>
>
>> +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?

I've mentioned the single queue limitation in af_xdp.rst, or you mean we also
need to comment it here?

>
><...>
>
>> +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?
>
><...>

Will do.

>
>> +	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.
>
><...>

Got it, will do.

>
>> +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

Got it.

>
>> +			      "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"?

Will do.

>
><...>
>
>> @@ -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?

Will remove it since Bjorn hasn't sent the fix patch to kernel community.

Thanks,
Xiaolong