Re: [PATCH RFC v2 net-next 02/25] net/ipv6: Refactor address dump to push inet6_fill_args to in6_dump_addrs

On Tue, 2 Oct 2018 09:11:17 -0600, David Ahern wrote:

Generically speaking a filter modifies the output based on the input.
Specifying a target namespace is an input to the dump that modifies the
output.

That's conventionally called "algorithm" :-)

Let's just say we have a different understanding of what "filter" is.
Perhaps we should look at it from a different side. What is the use
case of having NLM_F_DUMP_FILTERED set for IFA_TARGET_NETNSID? How is
this going to be used by applications?

Yes, you can do it in userspace which is what iproute2 has done to this
point, but it is grossly inefficient and that inefficiency has
implications at scale.

You can't do that with IFA_TARGET_NETNSID. Which is my point. Without
the flag, you don't get a list of all interfaces in all net name spaces.

 Jiri