Re: [PATCH net-next 0/2] Fix phy_link_topology initialization

From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Nathan Chancellor <nathan@kernel.org>,
	davem@davemloft.net, Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>
Cc: "Maxime Chevallier" <maxime.chevallier@bootlin.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	thomas.petazzoni@bootlin.com, "Andrew Lunn" <andrew@lunn.ch>,
	"Eric Dumazet" <edumazet@google.com>,
	linux-arm-kernel@lists.infradead.org,
	"Christophe Leroy" <christophe.leroy@csgroup.eu>,
	"Herve Codina" <herve.codina@bootlin.com>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	"Heiner Kallweit" <hkallweit1@gmail.com>,
	"Vladimir Oltean" <vladimir.oltean@nxp.com>,
	"Köry Maincent" <kory.maincent@bootlin.com>,
	"Jesse Brandeburg" <jesse.brandeburg@intel.com>,
	"Marek Behún" <kabel@kernel.org>,
	"Piergiorgio Beruto" <piergiorgio.beruto@gmail.com>,
	"Oleksij Rempel" <o.rempel@pengutronix.de>,
	"Nicolò Veronese" <nicveronese@gmail.com>,
	"Simon Horman" <horms@kernel.org>,
	mwojtas@chromium.org, "Antoine Tenart" <atenart@kernel.org>
Subject: Re: [PATCH net-next 0/2] Fix phy_link_topology initialization
Date: Mon, 13 May 2024 10:15:48 +0100	[thread overview]
Message-ID: <ZkHaRD8WGrhrzemn@shell.armlinux.org.uk> (raw)
In-Reply-To: <20240513063636.GA652533@thelio-3990X>

On Sun, May 12, 2024 at 11:36:36PM -0700, Nathan Chancellor wrote:
> Hi Maxime,
> 
> On Tue, May 07, 2024 at 12:28:19PM +0200, Maxime Chevallier wrote:
> > Nathan and Heiner reported issues that occur when phylib and phy drivers
> > built as modules expect the phy_link_topology to be initialized, due to
> > wrong use of IS_REACHABLE.
> > 
> > This small fixup series addresses that by moving the initialization code
> > into net/core/dev.c, but at the same time implementing lazy
> > initialization to only allocate the topology upon the first PHY
> > insertion.
> > 
> > This needed some refactoring, namely pass the netdevice itself as a
> > parameter for phy_link_topology helpers.
> > 
> > Thanks Heiner for the help on untangling this, and Nathan for the
> > report.
> 
> Are you able to prioritize getting this series merged? This has been a
> problem in -next for over a month now and the merge window is now open.
> I would hate to see this regress in mainline, as my main system may be
> affected by it (not sure, I got a new test machine that got bit by it in
> addition to the other two I noticed it on).

... and Maxime has been working on trying to get an acceptable fix for
it over that time, with to-and-fro discussions. Maxime still hasn't got
an ack from Heiner for the fixes, and changes are still being
requested.

I think, sadly, the only way forward at this point would be to revert
the original commit. I've just tried reverting 6916e461e793 in my
net-next tree and it's possible, although a little noisy:

$ git revert 6916e461e793
Performing inexact rename detection: 100% (8904/8904), done.
Auto-merging net/core/dev.c
Auto-merging include/uapi/linux/ethtool.h
Removing include/linux/phy_link_topology_core.h
Removing include/linux/phy_link_topology.h
Auto-merging include/linux/phy.h
Auto-merging include/linux/netdevice.h
Removing drivers/net/phy/phy_link_topology.c
Auto-merging drivers/net/phy/phy_device.c
Auto-merging MAINTAINERS
hint: Waiting for your editor to close the file...

I haven't checked whether that ends up with something that's buildable.

Any views Jakub/Dave/Paolo?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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