Re: [PATCH 0/7] driver core: export MAJOR/MINOR to the hotplug env

[Kay Sievers <kay.sievers@vrfy.org>]

On Tue, Feb 01, 2005 at 02:56:25PM -0800, Greg KH wrote:
> On Sun, Jan 23, 2005 at 05:19:11AM +0100, Kay Sievers wrote:
> > This patch sequence moves the creation of the sysfs "dev" file of the class
> > devices into the driver core. The struct class_device contains a dev_t
> > value now. If set, the driver core will create the "dev" file containing
> > the major/minor numbers automatically.
> > 
> > The MAJOR/MINOR values are also exported to the hotplug environment. This
> > makes it easy for userspace, especially udev to know if it should wait for
> > a "dev" file to create a device node or if it can just ignore the event.
> > We currently carry a compiled in blacklist around for that reason.
> > 
> > It would also be possible to run some "tiny udev" while sysfs is not
> > available - just by reading the hotplug call or the netlink-uevent.
> 
> This is great, thanks for doing this.  I've applied all of these patches
> to my trees, and they'll show up in the next -mm release.

Fine, thanks.

> Hm, that class_simple interface is looking like the way we should move
> toward, as it's "simple" to use, instead of the more complex class code.
> I'll have to look at migrating more code to use it over time, or move
> that interface back into the class code itself...

Nice idea! What about keeping a list of devices belonging to a
specific class in an own list in 'struct class' and maintaining that list
with class_device_add(), class_device_del()?

A class driver may use that list to keep track of its own devices if
wanted and class_simple would not be needed anymore as everything
would be available in the core.

Thanks,
Kay