Re: [Patch net-next] net_sched: add network namespace support for tc actions

On 16-02-20 07:46 PM, Cong Wang wrote:

On Sat, Feb 20, 2016 at 10:36 AM, Daniel Borkmann [off-list ref] wrote:

quoted

Do you see a way to reduce the code duplication needed across all
the action modules? I.e. that each of them now needs to register
a new per netns subsystem, etc. In other words, is there a way the
action API could be reworked to handle most of this in the tc core
framework instead?

I definitely agree.

Same here.

Initially I made a wrapper macro for the per netns API for each tc
action, but it didn't work as I thought, mostly due to the per net ops and
net_id stuffs.

So it is not as easy as it appears, it needs more work. At least the
current code is more readable than using any macro. We can always
refactor the API in the future, and as I mentioned in the changelog that
is in my plan.

Or do you have any quick and easy way to reduce the code?

I did a quick look and i am struggling with it. The patch seems largish
The issue is that we need to do this per kernel module so the code
churn maybe unavoidable; hinfo stored in act_ops complicates things.
Having said that:  All the pernet operations in your
code seem to be generic, other than to accomodate for module specific
act_ops. Is it possible to make generic pernet operations? This way
you could do things at tcf_register_action() for all actions.
The challenge seems to be in the xxx_net_id which appears(sorry didnt
look closely at the namespace code) to need to be unique id per module
and per namespace instance - otherwise i would suggest for xxx_net_id
to be part of act_ops. Could we not have an #ifdef in the namespace
core like the netfilter code does and have one level of indirection
for everything but the namespace 0?

cheers,
jamal