Re: [PATCH net-next] net/smc: add support for netdevice in containers.

[Wenjia Zhang <wenjia@linux.ibm.com>]

On 12.10.23 14:17, Dust Li wrote:
> On Wed, Oct 11, 2023 at 10:48:16PM +0800, Dust Li wrote:
>> On Thu, Sep 28, 2023 at 05:04:21PM +0200, Niklas Schnelle wrote:
>>> On Mon, 2023-09-25 at 10:35 +0800, Albert Huang wrote:
>>>> If the netdevice is within a container and communicates externally
>>>> through network technologies like VXLAN, we won't be able to find
>>>> routing information in the init_net namespace. To address this issue,
>>>> we need to add a struct net parameter to the smc_ib_find_route function.
>>>> This allow us to locate the routing information within the corresponding
>>>> net namespace, ensuring the correct completion of the SMC CLC interaction.
>>>>
>>>> Signed-off-by: Albert Huang <huangjie.albert@bytedance.com>
>>>> ---
>>>>   net/smc/af_smc.c | 3 ++-
>>>>   net/smc/smc_ib.c | 7 ++++---
>>>>   net/smc/smc_ib.h | 2 +-
>>>>   3 files changed, 7 insertions(+), 5 deletions(-)
>>>>
>>>
>>> I'm trying to test this patch on s390x but I'm running into the same
>>> issue I ran into with the original SMC namespace
>>> support:https://lore.kernel.org/netdev/8701fa4557026983a9ec687cfdd7ac5b3b85fd39.camel@linux.ibm.com/
>>>
>>> Just like back then I'm using a server and a client network namespace
>>> on the same system with two ConnectX-4 VFs from the same card and port.
>>> Both TCP/IP traffic as well as user-space RDMA via "qperf … rc_bw" and
>>> `qperf … rc_lat` work between namespaces and definitely go via the
>>> card.
>>>
>>> I did use "rdma system set netns exclusive" then moved the RDMA devices
>>> into the namespaces with "rdma dev set <rdma_dev> netns <namespace>". I
>>> also verified with "ip netns exec <namespace> rdma dev"
>>> that the RDMA devices are in the network namespace and as seen by the
>>> qperf runs normal RDMA does work.
>>>
>>> For reference the smc_chck tool gives me the following output:
>>>
>>> Server started on port 37373
>>> [DEBUG] Interfaces to check: eno4378
>>> Test with target IP 10.10.93.12 and port 37373
>>>   Live test (SMC-D and SMC-R)
>>> [DEBUG] Running client: smc_run /tmp/echo-clt.x0q8iO 10.10.93.12 -p
>>> 37373
>>> [DEBUG] Client result: TCP 0x05000000/0x03030000
>>>      Failed  (TCP fallback), reasons:
>>>           Client:        0x05000000   Peer declined during handshake
>>>           Server:        0x03030000   No SMC devices found (R and D)
>>>
>>> I also checked that SMC is generally working, once I add an ISM device
>>> I do get SMC-D between the namespaces. Any ideas what could break SMC-R
>>> here?
>>
>> I missed the email :(
>>
>> Are you running SMC-Rv2 or v1 ?
> 
> Hi Niklas,
> 
> I tried your test today, and I encounter the same issue.
> But I found it's because my 2 VFs are in difference subnets,
> SMC-Rv2 work fine, SMC-Rv1 won't work, which is expected.
> When I set the 2 VFs in the same subnet, SMC-Rv1 also works.
> 
> So I'm not sure it's the same for you. Can you check it out ?
> 
> BTW, the fallback reason(SMC_CLC_DECL_NOSMCDEV) in this case
> is really not friendly, it's better to return SMC_CLC_DECL_DIFFPREFIX.
> 
> Best regards,
> Dust
> 
Thank you, Dust, for trying it out!
The reason code SMC_CLC_DECL_NOSMCDEV there could really make one 
misunderstand.

> 
>>
>> Best regards,
>> Dust
>>
>>
>>>
>>> Thanks,
>>> Niklas