Re: [PATCH-WIP] convert CPU sysdev class to a real subsytem (needed for CPU modaliases)

[Greg KH <greg@kroah.com>]

On Thu, Dec 08, 2011 at 02:58:37AM +0100, Kay Sievers wrote:
> This patch is work-in-progress and just posted to coordinate with Andi
> Kleen's current export of CPU modaliases. It boots my x86_64 workstation
> fine, nothing else is tested.
> 
> The CPU subsystem from a sysdev_class to a plain driver-core subsystem
> (currently called 'bus').
> 
> With the CPUs as normal devices, userspace will pick the events up
> properly and udev is able to coldplug the devices during bootup, which
> will allow proper module autoloading based on MODALIAS.
> 
>   $ tree /sys/bus/cpu/
>   /sys/bus/cpu/
>   ├── devices
>   │   ├── cpu0 -> ../../../devices/system/cpu/cpu0
>   │   ├── cpu1 -> ../../../devices/system/cpu/cpu1
>   │   ├── cpu2 -> ../../../devices/system/cpu/cpu2
>   │   └── cpu3 -> ../../../devices/system/cpu/cpu3
>   ...
>   └── uevent
> 
> The needed bits to easily convert the remaining sysdev class users to a
> plain subsystem and plain devices have been added to the driver core.
> Sysdev drivers have never been 'drivers' in the driver-core sense, and
> they can be now ported-over to subsys_interfaces. The end goal is to
> finally remove all of the ugly sysdev hack from the system.
> 
> Greg, I guess we need a bit of your time, to make a plan and get the
> remaining things sorted out. We are planning and fiddling for years
> already here, and we should finally get the stuff out. :)

I agree, I want this to get done finally.

> Greg, I think with the subsys_interfaces we do not need the
> 'multi-driver-binding' anymore, seems we can get away with the
> interfaces only. Classes which need to convert to buses because the
> class interface is not extensible can be easily converted now. The only
> missing piece is the 'glue directory'. We should be able to unify
> classes and buses internally with all that stuff.

Ah, good, I was stalled on this because of the multi-driver-binding
stuff.  If that's not needed, I'll gladly take any patches for this.

So, what do I need to do here?  Your patch looks good at first glance,
the interface logic looks sane, is that all that we really need to do to
the core?

thanks,

greg k-h