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Date: Wed, 31 Dec 2003 23:45:14 +0200
From: Tommi Virtanen <tv@tv.debian.net>
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To: Rob Love <rml@ximian.com>
Cc: Nathan Conrad <lk@bungled.net>, Pascal Schmidt <der.eremit@email.de>,
       linux-kernel@vger.kernel.org, Greg KH <greg@kroah.com>
Subject: Re: udev and devfs - The final word
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Rob Love wrote:
>>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.
...

> The kernel uses the device number to understand what device user-space
> is trying to access.  The kernel associates the device with a device
> number.  Normally that number is static, and known a priori, so we just
> create a huge /dev directory with all possible devices and their
> assigned numbers (you can see these numbers with ls -la).

Let me try to rephrase Nathan's question more explicitly.

If user policy decides all naming, how does the kernel parse e.g. 
root=/dev/foo arguments? Or the swap partition to use for swsuspend?