netdev - Re: [PATCH 0/2] net: stmmac: allow sharing MDIO lines

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue, 8 Aug 2023 19:38:06 +0100
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Andrew Lunn <andrew@...n.ch>, Andrew Halaney <ahalaney@...hat.com>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Jose Abreu <joabreu@...opsys.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alex Elder <elder@...aro.org>,
	Srini Kandagatla <srinivas.kandagatla@...aro.org>,
	netdev@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 0/2] net: stmmac: allow sharing MDIO lines

On Tue, Aug 08, 2023 at 08:26:22PM +0200, Bartosz Golaszewski wrote:
> When I say "device unbind", I don't just mean manual unbinding using
> sysfs. I mean any code path (rmmod, unplugging the USB, etc.) that
> leads to the device being detached from its driver. This is a
> perfectly normal situation and should work correctly.
> 
> I won't be fixing it for this series but may end up looking into
> establishing some kind of device links between MACs and their "remote"
> PHYs that would allow to safely unbind them.

I don't think you're the first to suggest that!

That gets difficult - because although the PHY may be a different
driver, the MDIO bus may be provided by the _same_ hardware as the
ethernet MAC itself. So you end up with a circular dependency - the
PHY device depends on the MDIO bus device (which is the ethernet MAC)
and then you make the ethernet MAC depend on the PHY device.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!