Re: LANANA: To Pending Device Number Registrants

Alexander Viro
2001-05-15T20:15:18Z

On Tue, 15 May 2001, James Simmons wrote:

> > only one _device_node_, you can have multiple fd's. In fact, you can, with
> > the Linux VFS layer, fairly easily do things like
> >
> > mknod /dev/fd0 c X Y
> >
> > and then use
> >
> > fd = open("/dev/fd0/colourspace", O_RDWR);
>
> Yipes!! I have to say UNIX has a tendency to teach you ioctl is the only
> way. I have never thought outside of the box nor see anyone else in this
> manner. This is absolutely brillant!!! I can see alot of possibilties with
> this.

The thing being, why thet hell create these device/directory hybrids?
Driver can export a tree and we mount it on fb0. After that you have
the whole set - yes, /dev/fb0/colourspace, etc. - no problem. And no
need to do mknod, BTW. Yes, we'll need to use /dev/fb0/frame for
frame itself. BFD...

You see, as soon as you want slightly more structured stuff (deeper than
one level) you need the dentry tree, yodda, yodda. IOW, you need a
filesystem anyway and it's easy to implement. Want me to do framebufferfs?
Would make a nice demo. No majors. No minors. No ioctls. Less code than
in current tree. ~3 days to implement.