Re: [PATCH net-next 04/12] net: sched: add tcf_block_setup()

[Jiri Pirko <jiri@resnulli.us>]

Wed, Jun 26, 2019 at 03:16:26PM CEST, pablo@netfilter.org wrote:
>On Wed, Jun 26, 2019 at 02:12:56PM +0200, Jiri Pirko wrote:
>> Tue, Jun 25, 2019 at 10:31:54AM CEST, pablo@netfilter.org wrote:
>> >On Fri, Jun 21, 2019 at 07:16:03PM +0200, Jiri Pirko wrote:
>> >> Thu, Jun 20, 2019 at 09:49:09PM CEST, pablo@netfilter.org wrote:
>> >> 
>> >> [...]
>> >> 
>> >> > 
>> >> >+static LIST_HEAD(tcf_block_cb_list);
>> >> 
>> >> I still don't like the global list. Have to go throught the code more
>> >> carefully, but why you can't pass the priv/ctx from tc/netfilter. From
>> >> tc it would be tcf_block as it is now, from netfilter something else.
>> >
>> >This tcf_block_cb_list should go away at some point, once drivers know
>> >how to deal with multiple subsystems using the setup block
>> >infrastructure. As I said in my previous email, only one can set up
>> >the block at this stage, the ones coming later will hit busy.
>> 
>> The driver should know if it can bind or is busy. Also, the bind cmd
>> should contain type of binder (tc/nft/whatever) or perhaps rather binder
>> priority (according to the hook order in rx/tx).
>
>OK, so I see two possible paths then:
>
>#1 Add global list and allow one single subsystem to bind by now. Then
>   later, in a follow up patchset. Add binder type and priority once
>   there is a driver that can handle the three subsystems, remove
>   this global list and each driver deals/knows what to do from the
>   binder path.
>
>#2 Remove the global list now, each driver maintains a list of flow blocks
>   internally, allow one single flow block by now. This will need a bit more
>   code, since there will be code in the driver to maintain the list of
>   existing flow blocks, per driver, instead of global. So it will be
>   a per-driver global local to check if there is a flow block with
>   this [ cb, cb_ident ] already in place.
>
>#1 is almost ready - it's this batch :-) -  then #2 may need more code -
>this batch is slightly large.
>
>I understand though that path #2 may make it easier for the first
>driver client allowing for the three subsystems to bind.
>
>Let me know what path your prefer.

I definitelly prefer #2. Thanks!


>
>Thanks for reviewing.