Date:   Fri, 29 Sep 2023 00:42:17 +0800
From:   Wen Gu <guwen@...ux.alibaba.com>
To:     Alexandra Winter <wintera@...ux.ibm.com>, kgraul@...ux.ibm.com,
        wenjia@...ux.ibm.com, jaka@...ux.ibm.com, davem@...emloft.net,
        edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com
Cc:     schnelle@...ux.ibm.com, gbayer@...ux.ibm.com, pasic@...ux.ibm.com,
        alibuda@...ux.alibaba.com, tonylu@...ux.alibaba.com,
        dust.li@...ux.alibaba.com, linux-s390@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v4 00/18] net/smc: implement virtual ISM
 extension and loopback-ism



On 2023/9/27 23:16, Alexandra Winter wrote:
> 
> 
> On 24.09.23 17:16, Wen Gu wrote:
>> Wen Gu (18):
>>    net/smc: decouple ism_dev from SMC-D device dump
>>    net/smc: decouple ism_dev from SMC-D DMB registration
>>    net/smc: extract v2 check helper from SMC-D device registration
>>    net/smc: support SMCv2.x supplemental features negotiation
>>    net/smc: reserve CHID range for SMC-D virtual device
>>    net/smc: extend GID to 128bits only for virtual ISM device
>>    net/smc: disable SEID on non-s390 architecture
>>    net/smc: enable virtual ISM device feature bit
>>    net/smc: introduce SMC-D loopback device
>>    net/smc: implement ID-related operations of loopback
>>    net/smc: implement some unsupported operations of loopback
>>    net/smc: implement DMB-related operations of loopback
>>    net/smc: register loopback device as SMC-Dv2 device
>>    net/smc: add operation for getting DMB attribute
>>    net/smc: add operations for DMB attach and detach
>>    net/smc: avoid data copy from sndbuf to peer RMB in SMC-D
>>    net/smc: modify cursor update logic when sndbuf mapped to RMB
>>    net/smc: add interface implementation of loopback device
>>
>>   drivers/s390/net/ism_drv.c    |  20 +-
>>   include/net/smc.h             |  32 ++-
>>   include/uapi/linux/smc.h      |   3 +
>>   include/uapi/linux/smc_diag.h |   2 +
>>   net/smc/Kconfig               |  13 ++
>>   net/smc/Makefile              |   2 +-
>>   net/smc/af_smc.c              |  88 ++++++--
>>   net/smc/smc.h                 |   7 +
>>   net/smc/smc_cdc.c             |  56 ++++-
>>   net/smc/smc_cdc.h             |   1 +
>>   net/smc/smc_clc.c             |  64 ++++--
>>   net/smc/smc_clc.h             |  10 +-
>>   net/smc/smc_core.c            | 111 +++++++++-
>>   net/smc/smc_core.h            |   9 +-
>>   net/smc/smc_diag.c            |  11 +-
>>   net/smc/smc_ism.c             | 100 ++++++---
>>   net/smc/smc_ism.h             |  24 ++-
>>   net/smc/smc_loopback.c        | 489 ++++++++++++++++++++++++++++++++++++++++++
>>   net/smc/smc_loopback.h        |  54 +++++
>>   net/smc/smc_pnet.c            |   4 +-
>>   20 files changed, 996 insertions(+), 104 deletions(-)
>>   create mode 100644 net/smc/smc_loopback.c
>>   create mode 100644 net/smc/smc_loopback.h
> 
> 
> Hello Wen Gu,
> 
> I applied and built your patches and noticed some things that you may want to consider in the next version:
> 
> Series should be split up [2]
> 
> Several lines exceed 80 columns [1][3]
> 
> 'git clang-format HEAD~18' finds several formatting issues.
> 	Maybe not all of them need to be fixed.
> 
> codespell *.patch
> 0006-net-smc-extend-GID-to-128bits-only-for-virtual-ISM-d.patch:7: protocal ==> protocol
> 
> With your patches applied I get some new warnings [4]:
> Seems there are some ntoh conversions missing
> 
>    CHECK   net/smc/af_smc.c
> net/smc/af_smc.c:723:32: warning: cast to restricted __be64
> net/smc/af_smc.c:1427:52: warning: cast to restricted __be64
>    CHECK   net/smc/smc_pnet.c
>    CHECK   net/smc/smc_ib.c
>    CHECK   net/smc/smc_clc.c
> net/smc/smc_clc.c:954:72: warning: incorrect type in argument 1 (different base types)
> net/smc/smc_clc.c:954:72:    expected unsigned short [usertype] chid
> net/smc/smc_clc.c:954:72:    got restricted __be16 [usertype] chid
> net/smc/smc_clc.c:1050:29: warning: incorrect type in assignment (different base types)
> net/smc/smc_clc.c:1050:29:    expected unsigned long long [usertype] gid
> net/smc/smc_clc.c:1050:29:    got restricted __be64 [usertype]
> net/smc/smc_clc.c:1051:31: warning: incorrect type in assignment (different base types)
> net/smc/smc_clc.c:1051:31:    expected unsigned long long [usertype] token
> net/smc/smc_clc.c:1051:31:    got restricted __be64 [usertype]
> 
> 
> [1] linux/Documentation/process/coding-style.rst
> [2] https://www.kernel.org/doc/html/v6.3/process/maintainer-netdev.html?highlight=network
> [3] scripts/checkpatch.pl --strict --max-line-length=80 --git HEAD-18
> [4] make C=2 CF=-D__CHECK_ENDIAN__ M=net/smc -Wunused-function -Wimplicit-fallthrough -Wincompatible-function-pointer-types-strict
> 
> 

Hi Sandy,

Thank you very much for your detailed comments. They are really helpful.
I will check and fix them in my next version.

> 
> When I installed the patches, I noticed that
>> smcd info
> showed an SEID, even though I had no ISM device --> good
> 

Yes, virtual ISM device will return the right SEID (same as that returned
by ISM device) on s390 arch.

> 
>> smcd device
> FID  Type  PCI-ID        PCHID  InUse  #LGs  PNET-ID
> 0000 0                   0000   Yes       2
> 
> This needs some improvements.., but I'm not sure what is the best way to display virtual smcd interfaces in the smc-tools.
> 

Right. My idea is to add the display of the device's name and GID
along with the PCI information (all zero) to indicate it's virtual
smcd device.

> 
> I was able to do SMC transfers via the smcd-loopback feature :-D
> 

Glad to hear this. I will improve the issues you mentioned in the next
version and next version will be split up.

Thank you very much.
Wen Gu

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