Re: [patch net-next 0/9] Introduce devlink interface and first drivers to use it

From: Jiri Pirko <jiri@resnulli.us>
To: Andy Gospodarek <gospo@cumulusnetworks.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, idosch@mellanox.com,
	eladr@mellanox.com, yotamg@mellanox.com, ogerlitz@mellanox.com,
	yishaih@mellanox.com, dledford@redhat.com, sean.hefty@intel.com,
	hal.rosenstock@gmail.com, eugenia@mellanox.com,
	roopa@cumulusnetworks.com, nikolay@cumulusnetworks.com,
	hadarh@mellanox.com, jhs@mojatatu.com, john.fastabend@gmail.com,
	jeffrey.t.kirsher@intel.com, brouer@redhat.com,
	ivecera@redhat.com, rami.rosen@intel.com
Subject: Re: [patch net-next 0/9] Introduce devlink interface and first drivers to use it
Date: Tue, 23 Feb 2016 17:01:31 +0100	[thread overview]
Message-ID: <20160223160131.GL2140@nanopsycho.orion> (raw)
In-Reply-To: <20160223155527.GS33942@gospo.home.greyhouse.net>

Tue, Feb 23, 2016 at 04:55:28PM CET, gospo@cumulusnetworks.com wrote:
>On Tue, Feb 23, 2016 at 03:45:51PM +0100, Jiri Pirko wrote:
>> Tue, Feb 23, 2016 at 03:34:19PM CET, gospo@cumulusnetworks.com wrote:
>> 
>> <snip>
>> >> 
>> >> >> 	myhost:~$ dl port show
>> >> >> 	devlink0/1: type eth netdev ens4
>> >> >                             ^^^^^^^^^^^
>> >> >> 	devlink0/2: type ib ibdev mlx4_0
>> >> >                            ^^^^^^^^^^^^
>> >> >I think my only other question about this implementation is whether or
>> >> >not one would really want to have the true netdev/ibdev names mapped
>> >> >here.
>> >> >
>> >> >Would be as reasonable to simply specify the type (and there may be more
>> >> >types within ethernet that could be useful in multi-chip configurations)
>> >> >and then let normal infrastructure that exists today figure out how to
>> >> >map the names for the netdevs to the devices?
>> >> 
>> >> What normal infrastructure you have in mind? There is no info about
>> >> devlink port mapping to netdev/ibdev anywhere. Only here. I might be
>> >> missing something but I fail to see what's wrong with it.
>> >
>> >I was simply wondering out loud if we _really_ wanted to name netdevs
>> >this way.  I was suggesting that output could be like this:
>> >
>> >myhost:~$ dl port show
>> >devlink0/1: type eth
>> >devlink0/2: type ib 
>> >
>> >mnd that udev/systemd/biosdevname/etc would take care of naming the
>> >device whataever it wanted.  This appears to be essentially the same
>> >concern Hannes has.
>> 
>> Wait. The only thing which will be renamed by udev is "devlink0". The
>> suffixes "/1" and "/2" are direct indexes as used inside the driver.
>> 
>> And you need some link to netdev in case netdev exists - therefore
>> "netdev ens4" attribute is there. There's no other way to get the
>> mapping of "devlink0/1" to "ens4" anywhere else.
>
>So I think I had invisioned a slightly different workflow than what you
>just described.
>
>- Load PCI driver
>- Setup devlink attributes for your hardware
>- Create netdevs in network driver based on those attributes
>
>You don't need a netdev to reference any of the devlink specific
>parameters do you?

No, I have a devlink handle and a devlink port index. That is enough.