Re: [PATCH net-next 1/1] net sched qdisc: pass netlink message flags in event notification

[Roman Mashak <mrv@mojatatu.com>]

Cong Wang <xiyou.wangcong@gmail.com> writes:

> On Mon, Oct 30, 2017 at 11:07 AM, Roman Mashak <mrv@mojatatu.com> wrote:
>> Cong Wang <xiyou.wangcong@gmail.com> writes:
>>
>>> On Sat, Oct 28, 2017 at 8:36 PM, Roman Mashak <mrv@mojatatu.com> wrote:
>>>> Cong Wang <xiyou.wangcong@gmail.com> writes:
>>>
>>> Hmm, I thought you use RTM_NEWQDISC+RTM_DELQDISC to
>>> determine it is replacement, no?
>>
>> Create is RTM_NEWQDISC and NLM_F_EXCL|NLM_F_CREATE, replacement is
>> RTM_NEWQDISC and NLM_F_REPLACE in netlink flags.
>
> Is there any reason we can't use RTM_NEWQDISC+RTM_DELQDISC
> rather than NLM_F_REPLACE to determine it is replacement?
>

I'm not sure this would be valid semantics for replace operation, look at
the rfc3549:

Additional flag bits for NEW requests
          NLM_F_REPLACE   Replace existing matching config object with
                          this request.

> Note, RTM_NEWQDISC+RTM_DELQDISC are put in a same
> message not two.

Hmm, could you clarify how do you expect to put two event IDs in nlmsg_type?