Re: [PATCH v3 2/3] ethdev: add compare item

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

On 1/31/2024 5:43 PM, Ori Kam wrote:
> 
> 
>> -----Original Message-----
>> From: Ferruh Yigit <ferruh.yigit@amd.com>
>> Sent: Wednesday, January 31, 2024 6:46 PM
>> Subject: Re: [PATCH v3 2/3] ethdev: add compare item
>>
>> On 1/31/2024 3:56 PM, Ori Kam wrote:
>>> Hi
>>>
>>>> -----Original Message-----
>>>> From: Suanming Mou <suanmingm@nvidia.com>
>>>> Sent: Wednesday, January 31, 2024 4:48 AM
>>>>
>>>> Hi,
>>>>
>>>>> -----Original Message-----
>>>>> From: Ferruh Yigit <ferruh.yigit@amd.com>
>>>>> Sent: Wednesday, January 31, 2024 1:34 AM
>>>>> To: Suanming Mou <suanmingm@nvidia.com>; Ori Kam
>>>> <orika@nvidia.com>;
>>>>> Aman Singh <aman.deep.singh@intel.com>; Yuying Zhang
>>>>> <yuying.zhang@intel.com>; NBU-Contact-Thomas Monjalon (EXTERNAL)
>>>>> <thomas@monjalon.net>; Andrew Rybchenko
>>>>> <andrew.rybchenko@oktetlabs.ru>
>>>>> Cc: dev@dpdk.org
>>>>> Subject: Re: [PATCH v3 2/3] ethdev: add compare item
>>>>>
>>>>> On 1/15/2024 9:13 AM, Suanming Mou wrote:
>>>>>> The new item type is added for the case user wants to match traffic
>>>>>> based on packet field compare result with other fields or immediate
>>>>>> value.
>>>>>>
>>>>>> e.g. take advantage the compare item user will be able to accumulate a
>>>>>> IPv4/TCP packet's TCP data_offset and IPv4 IHL field to a tag
>>>>>> register, then compare the tag register with IPv4 header total length
>>>>>> to understand the packet has payload or not.
>>>>>>
>>>>>
>>>>> ack, above sample makes it easier to understand.
>>>>>
>>>>> This patch is adding testpmd commands, can you please provide some
>>>> sample
>>>>> commands in commit log?
>>>>> The more samples are better, as far as I remember there was a testpmd
>>>>> documentation that documents the sample usages, can you please check
>>>> for it?
>>>
>>> [Snip ..]
>>>
>>>>>
>>>>>> +/**
>>>>>> + * @warning
>>>>>> + * @b EXPERIMENTAL: this structure may change without prior notice
>>>>>> + *
>>>>>> + * Field description for packet field.
>>>>>> + */
>>>>>> +struct rte_flow_field_data {
>>>>>> +	enum rte_flow_field_id field; /**< Field or memory type ID. */
>>>>>> +	union {
>>>>>> +		struct {
>>>>>> +			/** Encapsulation level and tag index or flex item
>>>>> handle. */
>>>>>> +			union {
>>>>>> +				struct {
>>>>>> +					/**
>>>>>> +					 * Packet encapsulation level
>>>> containing
>>>>>> +					 * the field to modify.
>>>>>> +					 *
>>>>>> +					 * - @p 0 requests the default
>>>> behavior.
>>>>>> +					 *   Depending on the packet type, it
>>>>>> +					 *   can mean outermost, innermost
>>>> or
>>>>>> +					 *   anything in between.
>>>>>> +					 *
>>>>>> +					 *   It basically stands for the
>>>>>> +					 *   innermost encapsulation level.
>>>>>> +					 *   Modification can be performed
>>>>>> +					 *   according to PMD and device
>>>>>> +					 *   capabilities.
>>>>>> +					 *
>>>>>> +					 * - @p 1 requests modification to be
>>>>>> +					 *   performed on the outermost
>>>> packet
>>>>>> +					 *   encapsulation level.
>>>>>> +					 *
>>>>>> +					 * - @p 2 and subsequent values
>>>>> request
>>>>>> +					 *   modification to be performed on
>>>>>> +					 *   the specified inner packet
>>>>>> +					 *   encapsulation level, from
>>>>>> +					 *   outermost to innermost (lower to
>>>>>> +					 *   higher values).
>>>>>> +					 *
>>>>>> +					 * Values other than @p 0 are not
>>>>>> +					 * necessarily supported.
>>>>>> +					 *
>>>>>> +					 * @note that for MPLS field,
>>>>>> +					 * encapsulation level also include
>>>>>> +					 * tunnel since MPLS may appear in
>>>>>> +					 * outer, inner or tunnel.
>>>>>> +					 */
>>>>>> +					uint8_t level;
>>>>>> +					union {
>>>>>> +						/**
>>>>>> +						 * Tag index array inside
>>>>>> +						 * encapsulation level.
>>>>>> +						 * Used for VLAN, MPLS or
>>>> TAG
>>>>> types.
>>>>>> +						 */
>>>>>> +						uint8_t tag_index;
>>>>>> +						/**
>>>>>> +						 * Geneve option identifier.
>>>>>> +						 * Relevant only for
>>>>>> +						 *
>>>>> RTE_FLOW_FIELD_GENEVE_OPT_XXXX
>>>>>> +						 * modification type.
>>>>>> +						 */
>>>>>> +						struct {
>>>>>> +							/**
>>>>>> +							 * Geneve option
>>>> type.
>>>>>> +							 */
>>>>>> +							uint8_t type;
>>>>>> +							/**
>>>>>> +							 * Geneve option
>>>> class.
>>>>>> +							 */
>>>>>> +							rte_be16_t class_id;
>>>>>> +						};
>>>>>> +					};
>>>>>> +				};
>>>>>> +				struct rte_flow_item_flex_handle
>>>> *flex_handle;
>>>>>> +			};
>>>>>> +			/** Number of bits to skip from a field. */
>>>>>> +			uint32_t offset;
>>>>>> +		};
>>>>>> +		/**
>>>>>> +		 * Immediate value for RTE_FLOW_FIELD_VALUE, presented
>>>> in
>>>>> the
>>>>>> +		 * same byte order and length as in relevant
>>>> rte_flow_item_xxx.
>>>>>> +		 * The immediate source bitfield offset is inherited from
>>>>>> +		 * the destination's one.
>>>>>> +		 */
>>>>>> +		uint8_t value[16];
>>>>>> +		/**
>>>>>> +		 * Memory address for RTE_FLOW_FIELD_POINTER, memory
>>>>> layout
>>>>>> +		 * should be the same as for relevant field in the
>>>>>> +		 * rte_flow_item_xxx structure.
>>>>>> +		 */
>>>>>> +		void *pvalue;
>>>>>> +	};
>>>>>> +};
>>>>>> +
>>>>>>
>>>>>
>>>>> I am aware that you are just moving the above struct, but it is nested too
>>>> much
>>>>> which is making it hard to read.
>>>>>
>>>>> As you are touching it, can we extract some structs and make this struct
>> less
>>>>> nested, what do you think?
>>>>> Of course it needs to be done in separate patch, as a preperation/clean-
>> up
>>>> patch
>>>>> before moving it around.
>>>>
>>>> Agree the struct maybe a bit nested. But not sure how it was discussed
>>>> before during the last new member was added... @Ori, Do you have any
>> idea
>>>> about this?
>>>>
>>>
>>> As far as I remember, it was never discussed,
>>>
>>> I think for this series we should keep it as is, and revise it later.
>>>
>>
>> If you don't want to make this set more complex with this, that is OK as
>> long as it is addressed at some point.
> 
> Agree,
> If you have suggestions, I will be more than happy to hear.
> 

For the struct?
Simply extracting the inner structs as named structs to reduce the
nested structs, does this make sense?