Re: [PATCH] RDMA/rxe: Check the last packet by RXE_END_MASK

["yangx.jy@fujitsu.com" <yangx.jy@fujitsu.com>]

On 2022/1/15 11:38, Yanjun Zhu wrote:
>
> 在 2022/1/12 11:58, yangx.jy@fujitsu.com 写道:
>> On 2022/1/12 9:19, Yanjun Zhu wrote:
>>> 在 2022/1/11 23:16, Haakon Bugge 写道:
>>>>> On 11 Jan 2022, at 15:42, Yanjun Zhu <yanjun.zhu@linux.dev> wrote:
>>>>>
>>>>>
>>>>> 在 2022/1/10 13:17, yangx.jy@fujitsu.com 写道:
>>>>>> On 2022/1/7 19:49, Yanjun Zhu wrote:
>>>>>>> It seems that it does not mean to check the last packet. It means
>>>>>>> that
>>>>>>> it receives a MSN response.
>>>>>> Hi Yanjun,
>>>>>>
>>>>>> Checking the last packet is a way to indicate that responder has
>>>>>> completed an entire request(including multiple packets) and then
>>>>>> increases a msn.
>>>>> Hi, Xiao
>>>>>
>>>>> What does the msn mean?
>>>> Message Sequence Number.
>>> Thanks, Haakon
>>>
>>> I am reading the following from the spec.
>>>
>>> "
>>>
>>> C9-148: An HCA responder using Reliable Connection service shall
>>> initialize
>>>
>>> its MSN value to zero. The responder shall increment its MSN
>>> whenever it has successfully completed processing a new, valid request
>>> message. The MSN shall not be incremented for duplicate requests. The
>>> incremented MSN shall be returned in the last or only packet of an RDMA
>>> READ or Atomic response. For RDMA READ requests, the responder
>>> may increment its MSN after it has completed validating the request and
>>> before it has begun transmitting any of the requested data, and may
>>> return
>>> the incremented MSN in the AETH of the first response packet. The MSN
>>> shall be incremented only once for any given request message.
>>>
>>> "
>>>
>>> It seems that the above describe how to handle MSN increment in 
>>> details.
>> Hi Yanjun,
>>
>> Sorry for the late reply.
>>
>> Right, 9.7.7.1 GENERATING MSN VALUE section explains Message Sequence
>
> Does your commit take into account of duplicate requests?
Hi Yanjun,

Responder will check duplicate requests by check_psn() and process them 
by duplicate_request().
According to the logic of duplicate_request(), responder doesn't 
increase msn for duplicate requests.

Best Regards,
Xiao Yang
>
> Zhu Yanjun
>
>> Number(MSN).
>>
>> Best Regards,
>> Xiao Yang
>>> Zhu Yanjun
>>>
>>>>
>>>> Thxs, Håkon
>>>>
>>>>> Thanks a lot.
>>>>>
>>>>> Zhu Yanjun
>>>>>
>>>>>> Best Regards,
>>>>>> Xiao Yang