netdev - Re: [PATCH net-next] net/sched: cls_flower: Add user specified data

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Date:   Mon, 9 Jan 2017 10:23:31 -0800
From:   John Fastabend <john.fastabend@...il.com>
To:     Jiri Pirko <jiri@...nulli.us>, Jamal Hadi Salim <jhs@...atatu.com>
Cc:     Paul Blakey <paulb@...lanox.com>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        Jiri Pirko <jiri@...lanox.com>,
        Hadar Hen Zion <hadarh@...lanox.com>,
        Or Gerlitz <ogerlitz@...lanox.com>,
        Roi Dayan <roid@...lanox.com>, Roman Mashak <mrv@...atatu.com>,
        Simon Horman <simon.horman@...ronome.com>
Subject: Re: [PATCH net-next] net/sched: cls_flower: Add user specified data

On 17-01-08 09:19 AM, Jiri Pirko wrote:
> Mon, Jan 02, 2017 at 11:21:41PM CET, jhs@...atatu.com wrote:
>> On 17-01-02 01:23 PM, John Fastabend wrote:
>>
>>>
>>> Additionally I would like to point out this is an arbitrary length binary
>>> blob (for undefined use, without even a specified encoding) that gets pushed
>>> between user space and hardware ;) This seemed to get folks fairly excited in
>>> the past.
>>>
>>
>> The binary blob size is a little strange - but i think there is value
>> in storing some "cookie" field. The challenge is whether the kernel
>> gets to intepret it; in which case encoding must be specified. Or
>> whether we should leave it up to user space - in which something
>> like tc could standardize its own encodings.
> 
> This should never be interpreted by kernel. I think this would be good
> to make clear in the comment in the code.
> 

Ah OK I had assumed you would be pushing this via tc_cls_flower_offload into
the driver in a follow up patch. But if it lives in kernel space as opaque
cookie guess its no different then other id fields order/prio/cookie.

Thanks for clarifying.