Re: [patch net-next v7 09/13] net: sched: allow ingress and clsact qdiscs to share filter blocks

[Roopa Prabhu <roopa@cumulusnetworks.com>]

On Thu, Jan 11, 2018 at 7:07 AM, Jiri Pirko <jiri@resnulli.us> wrote:
> Thu, Jan 11, 2018 at 03:46:09PM CET, jhs@mojatatu.com wrote:
>>On 18-01-11 09:41 AM, Jiri Pirko wrote:
>>> Thu, Jan 11, 2018 at 03:37:08PM CET, jhs@mojatatu.com wrote:
>>> > On 18-01-11 09:24 AM, Jiri Pirko wrote:
>>> > > Thu, Jan 11, 2018 at 02:36:01PM CET, jhs@mojatatu.com wrote:
>>> > > > On 18-01-09 09:07 AM, Jiri Pirko wrote:
>>> > > > > From: Jiri Pirko <jiri@mellanox.com>
>>> > > > >
>>> > > > > Benefit from the previously introduced shared filter blocks
>>> > > > > infrastructure and allow ingress and clsact qdisc instances to share
>>> > > > > filter blocks. The block index is coming from userspace as qdisc option.
>>> > > >
>>> > > > Didnt quiet follow why ingress is special and needs attributes to
>>> > > > set the block but other qdiscs didnt.
>>> > >
>>> > > Jamal, again, other qdiscs does not support block sharing. This patchset
>>> > > only adds support for sharing of block for ingress and clsact qdiscs.
>>> > > Later on, other qdiscs could also support block sharing.
>>> > >
>>> >
>>> > Can you stop a config which says:
>>> > tc qdisc add dev ens9 root block 22 handle 1:0 prio ?
>>>
>>> Please see the iproute2 patches. Parsing of "block" command line option
>>> is done inside q_ingress.c
>>>
>>
>>I only looked at the kernel code. Good you can stop it at tc
>>but the API does not stop it (unless you expect the rest of the
>>world to only use tc).
>
> Jamal, apparently, you did not looked at the kernel code either :)
> Look at the changes done in net/sched/sch_ingress.c - there is where the
> parsing of block attr takes place.
>
>
>>Really - there is no reason for this API to be only via ingress qdisc
>>attributes. You can add a check in cls api to reject any parent that is
>>not either of the clsacts + ingress (depending on tc doesnt sound
>>right).
>
> I was thinking to take this direction originally. To have another
> generic attr called TCA_BLOCK or something that would be used when qdisc
> is created. For ingress, what would work. But for clsact, you need to be
> able to specify 2 block during qdisc creation - one for ingress, one for
> egress. That's when I realized this has to be per-qdisc-type attr.


yeah, see the problem...but.., would it help if we just introduce two
generic attrs TCA_BLOCK_INGRESS and TCA_BLOCK_EGRESS instead of having
to duplicate these attrs at every qdisc ?.
and add proper validation depending on qdisc type..