devctl attach/detach notification for disks

[Nate Nielsen]

M. Warner Losh wrote:
> In message: <20060222190919.C6B9FDCA99B at mail.npubs.com>
>             Nate Nielsen <nielsen-list at memberwebs.com> writes:
> : I'm working on a bit of code to get devctl notifications for attaching
> : and removing of disks. This would allow actions to be taken via devd
> : when a disk is attached or removed from the system.
> 
> I'm not sure I like the API changes you've made to subr_bus.  Why are
> they needed?

Currently the memory passed to devctl_queue_data is required to be
allocated via M_BUS, which is declared static in subr_bus.c. The other
option would be to put the M_BUS declaration in bus.h.

> : Currently I have the attach and detach notifications hooked into
> : disk_create() and disk_destroy() in geom_disk.c. See attached (rough)
> : patch.
> : 
> : However at these points the disks are not yet present in the /dev/
> : filesystem. Anyone have any clues or tips for a better place to hook
> : these notifications into the system?
> 
> That's one of the main reasons that this hasn't happened yet.  The
> hard part is getting all of the devices in place before sending
> notifications.  Robert Watson had a similar thing that I think solved
> some of the problems a little better...

K, well I guess this is out of my scope then. I'll just watch for umassX
and other plugabble diskish devices, and then configure them after a 5
second delay or something.

Cheers,
Nate