Re: [PATCH rdma-next 07/11] RDMA/erdma: Add verbs implementation

[Cheng Xu <chengyou@linux.alibaba.com>]

On 12/22/21 8:46 PM, Bernard Metzler wrote:
>> -----Original Message-----
>> From: Cheng Xu <chengyou@linux.alibaba.com>
>> Sent: Wednesday, 22 December 2021 04:11
>> To: Bernard Metzler <BMT@zurich.ibm.com>; Leon Romanovsky
>> <leon@kernel.org>
>> Cc: jgg@ziepe.ca; dledford@redhat.com; linux-rdma@vger.kernel.org;
>> KaiShen@linux.alibaba.com; tonylu@linux.alibaba.com
>> Subject: [EXTERNAL] Re: [PATCH rdma-next 07/11] RDMA/erdma: Add verbs
>> implementation
>>
>>
>>
>> On 12/21/21 11:20 PM, Bernard Metzler wrote:
>>>> -----Original Message-----
>>>> From: Leon Romanovsky <leon@kernel.org>
>>>> Sent: Tuesday, 21 December 2021 14:32
>>>> To: Cheng Xu <chengyou@linux.alibaba.com>
>>>> Cc: jgg@ziepe.ca; dledford@redhat.com; linux-rdma@vger.kernel.org;
>>>> KaiShen@linux.alibaba.com; tonylu@linux.alibaba.com
>>>> Subject: [EXTERNAL] Re: [PATCH rdma-next 07/11] RDMA/erdma: Add verbs
>>>> implementation
>>>>
>>>> On Tue, Dec 21, 2021 at 10:48:54AM +0800, Cheng Xu wrote:
>>>>> The RDMA verbs implementation of erdma is divided into three files:
>>>>> erdma_qp.c, erdma_cq.c, and erdma_verbs.c. Internal used functions and
>>>>> datapath functions of QP/CQ are put in erdma_qp.c and erdma_cq.c, the
>>>> reset
>>>>> is in erdma_verbs.c.
>>>>>
>>>>> Signed-off-by: Cheng Xu <chengyou@linux.alibaba.com>
>>>>> ---
>>>>>    drivers/infiniband/hw/erdma/erdma_cq.c    |  201 +++
>>>>>    drivers/infiniband/hw/erdma/erdma_qp.c    |  624 +++++++++
>>>>>    drivers/infiniband/hw/erdma/erdma_verbs.c | 1477
>> +++++++++++++++++++++
>>>>>    3 files changed, 2302 insertions(+)
>>>>>    create mode 100644 drivers/infiniband/hw/erdma/erdma_cq.c
>>>>>    create mode 100644 drivers/infiniband/hw/erdma/erdma_qp.c
>>>>>    create mode 100644 drivers/infiniband/hw/erdma/erdma_verbs.c
>>>>
>>>>
>>>> Please no inline functions in .c files and no void casting for the
>>>> return values of functions.
>>>>
>>>> <...>
>>>>
>>>>> diff --git a/drivers/infiniband/hw/erdma/erdma_qp.c
>>>> b/drivers/infiniband/hw/erdma/erdma_qp.c
>>>>> new file mode 100644
>>>>> index 000000000000..8c02215cee04
>>>>> --- /dev/null
>>>>> +++ b/drivers/infiniband/hw/erdma/erdma_qp.c
>>>>> @@ -0,0 +1,624 @@
>>>>> +// SPDX-License-Identifier: GPL-2.0
>>>>> +/*
>>>>> + * Authors: Cheng Xu <chengyou@linux.alibaba.com>
>>>>> + *          Kai Shen <kaishen@linux.alibaba.com>
>>>>> + * Copyright (c) 2020-2021, Alibaba Group.
>>>>> + *
>>>>> + * Authors: Bernard Metzler <bmt@zurich.ibm.com>
>>>>> + *          Fredy Neeser <nfd@zurich.ibm.com>
>>>>> + * Copyright (c) 2008-2016, IBM Corporation
>>>>
>>>> What does it mean?
>>>>
>>>
>>> Significant parts of the driver have been taken from siw it seems.
>>> Probably really from an old version of it.
>>> In that case I would have recommended to take the upstream siw
>>> code, which has been cleaned from those issues we now see again
>>> (including debugfs code, extern definitions, inline in .c code,
>>> casting issues, etc etc.). Why starting in 2020 with
>>> code from 2016, if better code is available?
>>>
>>> Bernard.
>>
>> First of all, thank you for developing siw, Bernard and Fredy, so we
>> can build our erdma based on your work.
> 
> You are welcome.
> You probably got the code from https://github.com/zrlio/softiwarp
> where I stopped pushing updates 4 years ago. By then, I started working
> on making it acceptable for upstream. As said, I highly recommend taking
> it from there, since the community already invested time and effort to
> make the code better, and finally acceptable. If you do so, please also
> update the copyright notice.

Thank you, and I will follow your recommendation.

> Fredy isn't part of it since almost 10 years, and is not reachable
> via the email provided. And, by 2016, his contributions were limited to
> the siw_cm.c code only.
> 
> 
> 
>> At the beginning, we started developing erdma driver in kernel
>> 4.9/4.19/5.10, and didn't know the upstream siw version since it is in
> 
> 
> siw is in the Linux kernel since v5.3
> 

Yes, I got it wrong.

Thanks,
Cheng Xu

>> the newer kernel version. As a result, we develop erdma based on the
>> older version.
>> Thank you for your recommendation. We will check the differences and
>> take the upstream siw code if needed.
>>
>> Thanks,
>> Cheng Xu