[ovs-dev] [PATCH V2 1/1] dpif-netlink: Log eth type 0x1234 not offloadable

Eli Britstein elibr at mellanox.com
Tue Jul 30 10:23:07 UTC 2019


On 7/30/2019 1:10 PM, Ilya Maximets wrote:
> On 03.07.2019 7:58, Eli Britstein wrote:
>> Ethernet type 0x1234 is used for testing and not being offloadable. For
>> testing offloadable features, log about using this value.
>>
>> Signed-off-by: Eli Britstein <elibr at mellanox.com>
>> Acked-by: Roi Dayan <roid at mellanox.com>
>> Signed-off-by: Eli Britstein <elibr at mellanox.com>
>> Acked-by: Ben Pfaff <blp at ovn.org>
>> ---
>>   lib/dpif-netlink.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
>> index ba80a0079..a0d51ae61 100644
>> --- a/lib/dpif-netlink.c
>> +++ b/lib/dpif-netlink.c
>> @@ -2007,6 +2007,7 @@ parse_flow_put(struct dpif_netlink *dpif, struct dpif_flow_put *put)
>>   
>>       /* When we try to install a dummy flow from a probed feature. */
>>       if (match.flow.dl_type == htons(0x1234)) {
>> +        VLOG_INFO_RL(&rl, "eth 0x1234 is special and not offloadable");
>>           return EOPNOTSUPP;
>>       }
> But what is the purpose of this patch?  What is the use case?
RH wanted to test that dl_type is offloaded. Coincidentally, they used 
0x1234, and it was not offloaded, and they didn't understand why, and 
suggested a log message.
>
> Actually, it looks like we need to just remove above 'if' statement
> entirely.  Just a few lines above there is a check if we are probing
> or installing real flow:
>
>     if (put->flags & DPIF_FP_PROBE) {
>         return EOPNOTSUPP;
>     }
>
> So, we will never get there while probing.  But why we're restricting
> this flow type from being offloaded?  'netdev_flow_put' will refuse
> to offload if it doesn't know that flow type, but this shouldn't be
> done here.
>
> In case we have a dummy flow without DPIF_FP_PROBE flag set, we need
> to fix upper layers.  Is it the case?

I didn't look into it why we restrict it and if there is a real reason 
why in this layer. You may be right, but I don't know.

>
> Best regards, Ilya Maximets.


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