Re: [PATCH] adding PCI bus information to SCSI layer

From: Ingo Oeser (ingo.oeser@informatik.tu-chemnitz.de)
Date: Wed May 02 2001 - 10:03:03 EST


On Tue, May 01, 2001 at 09:32:41PM +0100, Alan Cox wrote:
> Having thought over the issues I plan to maintain a 32bit dev_t kernel with
> conventional mknod behaviour, even if Linus won't. One very interesting item
> that Peter Anvin noted is that its not clear in POSIX that
>
> mknod /dev/ttyF00 c 100 100
>
> open("/dev/ttyF00/speed=9600,clocal");
>
> is illegal. That may be a nice way to get much of the desired
> behaviour without totally breaking compatibility

Ouch!

How is that supposed to work with the dcache?

1. Does POSIX state, that "/" is the directory/entry[1] separator?
2. Can a device node be an directory?

If 1. and not 2., there is no way to implement it like that.

I don't know how people call this, if they call sth. like DevFS
"crappy", but I would be very surprised, if they call it "clean".

Just think of:

test -r /dev/ttyF00/speed=9600,clocal && cat /dev/ttyF00/speed=9600,clocal

Or the equivalent in C in most of the programs, which read sth.

POSIX might not forbid this, because common sense already does ;-)

Regards

Ingo Oeser

[1] entry := directory | file

-- 
10.+11.03.2001 - 3. Chemnitzer LinuxTag <http://www.tu-chemnitz.de/linux/tag>
         <<<<<<<<<<<<     been there and had much fun   >>>>>>>>>>>>
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