Re: [dpdk-dev] [PATCH v2 1/2] ethdev: replace callback getting filter operations

From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
To: Thomas Monjalon <thomas@monjalon.net>
Cc: dev@dpdk.org, Ori Kam <orika@nvidia.com>,
	Ajit Khaparde <ajit.khaparde@broadcom.com>,
	Somnath Kotur <somnath.kotur@broadcom.com>,
	Chas Williams <chas3@att.com>,
	"Min Hu (Connor)" <humin29@huawei.com>,
	Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>,
	Hemant Agrawal <hemant.agrawal@nxp.com>,
	Sachin Saxena <sachin.saxena@oss.nxp.com>,
	Jeff Guo <jia.guo@intel.com>, Haiyue Wang <haiyue.wang@intel.com>,
	John Daley <johndale@cisco.com>,
	Hyong Youb Kim <hyonkim@cisco.com>, Gaetan Rivet <grive@u256.net>,
	Ziyang Xuan <xuanziyang2@huawei.com>,
	Xiaoyun Wang <cloud.wangxiaoyun@huawei.com>,
	Guoyang Zhou <zhouguoyang@huawei.com>,
	Yisen Zhuang <yisen.zhuang@huawei.com>,
	Lijun Ou <oulijun@huawei.com>,
	Beilei Xing <beilei.xing@intel.com>,
	Jingjing Wu <jingjing.wu@intel.com>,
	Qiming Yang <qiming.yang@intel.com>,
	Qi Zhang <qi.z.zhang@intel.com>, Rosen Xu <rosen.xu@intel.com>,
	Matan Azrad <matan@nvidia.com>,
	Shahaf Shuler <shahafs@nvidia.com>,
	Viacheslav Ovsiienko <viacheslavo@nvidia.com>,
	Liron Himi <lironh@marvell.com>, Jerin Jacob <jerinj@marvell.com>,
	Nithin Dabilpuram <ndabilpuram@marvell.com>,
	Kiran Kumar K <kirankumark@marvell.com>,
	Rasesh Mody <rmody@marvell.com>,
	Shahed Shaikh <shshaikh@marvell.com>,
	Jasvinder Singh <jasvinder.singh@intel.com>,
	Cristian Dumitrescu <cristian.dumitrescu@intel.com>,
	Keith Wiles <keith.wiles@intel.com>,
	Jiawen Wu <jiawenwu@trustnetic.com>,
	Jian Wang <jianwang@trustnetic.com>,
	Ferruh Yigit <ferruh.yigit@intel.com>
Subject: Re: [dpdk-dev] [PATCH v2 1/2] ethdev: replace callback getting filter operations
Date: Mon, 15 Mar 2021 11:43:01 +0300	[thread overview]
Message-ID: <cb727e86-b4ce-a707-1fef-6e94dab4ff60@oktetlabs.ru> (raw)
In-Reply-To: <1656619.R5YYQy59bT@thomas>

On 3/15/21 10:54 AM, Thomas Monjalon wrote:
> 15/03/2021 08:18, Andrew Rybchenko:
>> On 3/12/21 8:46 PM, Thomas Monjalon wrote:
>>> --- a/lib/librte_ethdev/rte_flow.c
>>> +++ b/lib/librte_ethdev/rte_flow.c
>>> @@ -255,18 +255,19 @@ rte_flow_ops_get(uint16_t port_id, struct rte_flow_error *error)
>>>  
>>>  	if (unlikely(!rte_eth_dev_is_valid_port(port_id)))
>>>  		code = ENODEV;
>>> -	else if (unlikely(!dev->dev_ops->filter_ctrl ||
>>> -			  dev->dev_ops->filter_ctrl(dev,
>>> -						    RTE_ETH_FILTER_GENERIC,
>>> -						    RTE_ETH_FILTER_GET,
>>> -						    &ops) ||
>>> -			  !ops))
>>> -		code = ENOSYS;
>>> +	else if (unlikely(dev->dev_ops->flow_ops_get == NULL))
>>> +		code = ENOTSUP;
>>>  	else
>>> -		return ops;
>>> -	rte_flow_error_set(error, code, RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
>>> -			   NULL, rte_strerror(code));
>>> -	return NULL;
>>> +		code = dev->dev_ops->flow_ops_get(dev, &ops);
>>> +	if (code == 0 && ops == NULL)
>>> +		code = EACCES;
>> It looks something new. I think it should be mentioned in flow_ops_get
>> type documentation (similar to eth_promiscuous_enable_t) and
>> rte_flow_validate() etc functions
>> return values description.
> It is an internal function used only in rte_flow.c.
> The real consequence is to set rte_errno in a lot of rte_flow API.
> Not sure there is a good way to document the code details.
> Other codes are not documented in rte_flow.h

First of all it is a behaviour of the flow_ops_get callback and
driver developers should know that it is a legal to return 0 and
ops==NULL and know what it means.

Second, it is visible as rte_flow_validate() (and other functions
which use rte_flow_ops_get()) return value value which has
special meaning. So, should be documented.