From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jamal Hadi Salim <jhs@mojatatu.com>
Subject: Re: [patch net-next v2 8/9] switchdev: introduce Netlink API
Date: Tue, 23 Sep 2014 07:09:10 -0400
Message-ID: <542154D6.3050406@mojatatu.com>
References: <20140919154946.GH1980@nanopsycho.orion> <541C6E6D.9000109@mojatatu.com> <541CAA3C.5080105@intel.com> <20140920081426.GE1821@nanopsycho.orion> <20140920105354.GA29419@casper.infradead.org> <CAADnVQK0wT2Fjqdg+C=ruSt8jF6sKeMo7cFj7K1fsu7-1u5g=g@mail.gmail.com> <20140922081341.GA20905@casper.infradead.org> <CA+mtBx-ZvkZ2ALGLsLEN7Cgn9gN_rY36ZhuqYC3mZ9WVxjFDaQ@mail.gmail.com> <20140922221727.GA4708@casper.infradead.org> <CA+mtBx9ZVQ5r5Hzy9-uEnk+iu+HKkOP4+VANC06Xf8VvTxktwQ@mail.gmail.com> <20140922225305.GB4708@casper.infradead.org> <CA+mtBx94TrLzQrZDo58d9ktma3ZioOpO=2FAODMRoiyiuYkQ9Q@mail.gmail.com> <5420CEAC.2070104@gmail.com>
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Cc: Thomas Graf <tgraf@suug.ch>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Jiri Pirko <jiri@resnulli.us>,
	John Fastabend <john.r.fastabend@intel.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Neil Horman <nhorman@tuxdriver.com>,
	Andy Gospodarek <andy@greyhouse.net>,
	Daniel Borkmann <dborkman@redhat.com>,
	Or Gerlitz <ogerlitz@mellanox.com>,
	Jesse Gross <jesse@nicira.com>,
	Pravin Shelar <pshelar@nicira.com>,
	Andy Zhou <azhou@nicira.com>,
	Ben Hutchings <ben@decadent.org.uk>,
	Stephen Hemminger <stephen@networkplumber.org>,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
	Vladislav Yasevich <vyasevic@redhat.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Eric Dumazet <edumazet@google.com>,
	Scott Feldman <sfeldma@cumulusnetworks.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Roopa Prabhu <roopa@cumulusnetworks.com>,
	John
To: John Fastabend <john.fastabend@gmail.com>,
	Tom Herbert <therbert@google.com>
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On 09/22/14 21:36, John Fastabend wrote:

> n-tuple has some deficiencies,
>
>      - its not possible to get the capabilities to learn what
>        fields are supported by the device, what actions, etc.
>
>      - its ioctl based so we have to poll the device
>
>      - only supports a single table, where we have devices with
>        multiple tables
>
>      - sort of the same as above but it doesn't allow creating new
>        tables or destroying old tables.
>
> I probably missed a few others

A few more I can think of which are generic:
The whole event subsystem allowing multi-user sync or monitoring
offered by netlink is missing because ethtool ioctl go
directly to the driver.
The synchronous interface vs async offered by netlink offers
a more effective user programmability.
The ioctl binary interface whose extensibility is a pain (dont
let Stephen H hear you mention ioctls for just this one reason).

> but those are the main ones that I
> would like to address. Granted other than the ioctl line the rest could
> be solved by extending the existing interface. However I would just
> assume port it to ndo_ops and netlink then extend the existing ioctl
> seeing it needs a reasonable overall to support the above anyways.
>
> We could port the ethtool ops over to the new interface to
> simplify drivers.

Indeed.

cheers,
jamal

> .John
>