Re: [PATCH v3 3/5] net: Let the active time stamping layer be selectable.

From: Jakub Kicinski <kuba@kernel.org>
To: Richard Cochran <richardcochran@gmail.com>
Cc: "Vladimir Oltean" <vladimir.oltean@nxp.com>,
	"Köry Maincent" <kory.maincent@bootlin.com>,
	"Oleksij Rempel" <o.rempel@pengutronix.de>,
	"Horatiu Vultur" <horatiu.vultur@microchip.com>,
	"Michael Walle" <michael@walle.cc>,
	"Andrew Lunn" <andrew@lunn.ch>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	"Heiner Kallweit" <hkallweit1@gmail.com>,
	netdev@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-omap@vger.kernel.org,
	"Maxime Chevallier" <maxime.chevallier@bootlin.com>,
	thomas.petazzoni@bootlin.com,
	"Russell King" <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Paolo Abeni" <pabeni@redhat.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Jay Vosburgh" <j.vosburgh@gmail.com>,
	"Veaceslav Falico" <vfalico@gmail.com>,
	"Andy Gospodarek" <andy@greyhouse.net>,
	"Claudiu Manoil" <claudiu.manoil@nxp.com>,
	"Alexandre Belloni" <alexandre.belloni@bootlin.com>,
	UNGLinuxDriver@microchip.com,
	"Minghao Chi" <chi.minghao@zte.com.cn>,
	"Jie Wang" <wangjie125@huawei.com>,
	"Oleksij Rempel" <linux@rempel-privat.de>,
	"Sean Anderson" <sean.anderson@seco.com>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	"Wolfram Sang" <wsa+renesas@sang-engineering.com>,
	"Alexander Lobakin" <alexandr.lobakin@intel.com>,
	"Marco Bonelli" <marco@mebeim.net>
Subject: Re: [PATCH v3 3/5] net: Let the active time stamping layer be selectable.
Date: Fri, 17 Mar 2023 21:03:06 -0700	[thread overview]
Message-ID: <20230317210306.346e80ea@kernel.org> (raw)
In-Reply-To: <ZBUyST3kDP1ZE1lF@hoboy.vegasvil.org>

On Fri, 17 Mar 2023 20:38:49 -0700 Richard Cochran wrote:
> On Fri, Mar 17, 2023 at 05:21:50PM +0200, Vladimir Oltean wrote:
> > On Thu, Mar 16, 2023 at 04:09:20PM +0100, Köry Maincent wrote:  
> > > Was there any useful work that could be continued on managing timestamp through
> > > NDOs. As it seem we will made some change to the timestamp API, maybe it is a
> > > good time to also take care of this.  
> > 
> > Not to my knowledge. Yes, I agree that it would be a good time to add an
> > NDO for hwtimestamping (while keeping the ioctl fallback), then
> > transitioning as many devices as we can, and removing the fallback when
> > the transition is complete.  
> 
> Um, user space ABI cannot be removed.

NDO meaning a dedicated callback in struct net_device_ops, so at least
for netdevs we can copy the data from user space, validate in the core
and then call the driver with a normal kernel pointer. So just an
internal refactoring, no uAPI changes.