netdev - Re: Component API not right for DSA?

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]

Message-ID: <ZurZ8sj4N9b0yUtx@shell.armlinux.org.uk>
Date: Wed, 18 Sep 2024 14:47:30 +0100
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Vladimir Oltean <vladimir.oltean@....com>
Cc: Andrew Lunn <andrew@...n.ch>, Florian Fainelli <f.fainelli@...il.com>,
	Saravana Kannan <saravanak@...gle.com>, netdev@...r.kernel.org
Subject: Re: Component API not right for DSA?

On Wed, Sep 18, 2024 at 02:10:08PM +0300, Vladimir Oltean wrote:
> This is all great, but then I realized that, for addressing issue #2,
> it is no better than what we currently have. Namely, by default the tree
> looks like this:
> 
...
> 
> but after this operation:
> 
> $ echo d0032004.mdio-mii:11 > /sys/bus/mdio_bus/devices/d0032004.mdio-mii\:11/driver/unbind
> $ cat /sys/kernel/debug/device_component/dsa_tree.0.auto
> aggregate_device name                                  status
> -------------------------------------------------------------
> dsa_tree.0.auto                                     not bound
> 
> device name                                            status
> -------------------------------------------------------------
> (unknown)                                      not registered
> d0032004.mdio-mii:10                                not bound
> d0032004.mdio-mii:12                                not bound
> 
> the tree (component master) is unbound, its unbind() method calls
> component_unbind_all(), and this also unbinds the other switches.

Correct. As author of the component helper... The component helper was
designed for an overall device that is made up of multiple component
devices that are themselves drivers, and _all_ need to be present in
order for the overall device to be functional. It is not intended to
address cases where an overall device has optional components.

The helper was originally written to address that problem for the
Freescale i.MX IPU, which had been sitting in staging for considerable
time, and was blocked from being moved out because of issues with this
that weren't solvable at the time (we didn't have device links back
then, which probably could've been used instead.)

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