Re: [PATCH] fix pktcdvd breakage from commit e105b8bfc769b0545b6f0f395179d1e43cbee822

On Sun, Nov 30, 2008 at 15:13, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
On Sun, Nov 30, 2008 at 02:57:14PM +0100, Kay Sievers wrote:
"It" being udev, presumably?

Yes, udev, mdev, and a few other tools people use to populate /dev
from the kernel supplied device information.

What a mess... How does drivers/usb/core/devio.c avoid essentially the same
problem?

It's a special case, where two "struct device" have the same dev_t,
but they both point to and handle the same device, so it's fine. The
usb_device class is deprecated, no recent distro uses it, and will be
removed some day.

Would that happened to udev as well... Yeah, I know, but one can dream ;-/

If there are two devices with the same dev_t, and udev is configured
to create the same names in /dev, it will create the node for the
first event, and reuse is for the second identical event. There is no
problem here.

Bloody wonderful. So we have
* userland-exposed layout of directory trees created by pktcdvd
* uevent mess generated by device_create() and *also* userland-exposed

So we need to preserve the layout, with the easiest way probably being "add
one more ktype and use kobject_init_and_add() instead of that device_create()".
Sigh...

What do you mean? We just need to replace the bogus "pd->pkt_dev" with
MKDEV(0, 0) and we are fine.

Kay
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