Re: udev and devfs - The final word

Nathan Conrad
2003-12-31T22:01:12Z

One thing that I'm confused about with respect to device files is how
kernel arguments are supposed to work. Now, we _seem_ to have a
mish-mash of different ways to tell the kernel which device to open as
a console, which device to use as a suspend device, etc.... Now, all
of the device names are being migrated to userland. How is the kernel
supposed to determine which device to use when it is told use
/dev/hda3 or /dev/ide/host0/something/part3 as the suspend partition?
The kernel no longer knows to which device this string this device is
connected.

(I have not looked into how these parameters are parsed; this is pure
speculation)

One solution that I see if the device names are totally removed from
the kernel is specifying these parameters as sysfs paths. Would this
work? Or is there a better way?

-Nathan

On Wed, Dec 31, 2003 at 03:19:22PM -0500, Rob Love wrote:
> On Wed, 2003-12-31 at 14:23, Greg KH wrote:
>
> > What benefit would there be in "random" numbers? More compressed number
> > space by giving out numbers sequentially?
>
> That is one advantage.
>
> > Or less having to work with the numbers because they become just
> > cookies and never need to be inspected except in very small parts of
> > the kernel?
>
> Yup, especially this one. It is not so much "let's make the device
> numbers random" but "let's just not care what they are."
>
> We can get to the point where we don't even need the explicit concept of
> device numbers, but just "any old unique value" to use as a cookie. The
> kernel can pull that number from anywhere, and notify user-space via
> udev ala hotplug.
>
> Rob Love
>
>
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Nathan J. Conrad Campus phone #5930
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