Re: "block" symlink in sysfs for a multifunction device

[Jeremy Katz <katzj@redhat.com>]

On Wed, 2005-12-14 at 15:42 -0800, Greg KH wrote:
> On Wed, Dec 14, 2005 at 03:26:15PM -0800, Pete Zaitcev wrote:
> > On Tue, 13 Dec 2005 21:50:19 -0800, Greg KH <greg@kroah.com> wrote:
> > > $ ls -l /sys/block/uba/device/
> > > -r--r--r--  1 root root 4096 Dec 13 21:31 bNumEndpoints
> > > lrwxrwxrwx  1 root root    0 Dec 13 21:31 block:uba -> ../../../../../../block/uba
> > > lrwxrwxrwx  1 root root    0 Dec 13 21:31 block:ubb -> ../../../../../../block/ubb
> > > lrwxrwxrwx  1 root root    0 Dec 13 21:31 block:ubc -> ../../../../../../block/ubc
> > > lrwxrwxrwx  1 root root    0 Dec 13 21:31 block:ubd -> ../../../../../../block/ubd
> > 
> > Greg, Jeremy is not happy about this.
> > 
> > > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=175563
> > > ------- Additional Comments From katzj@redhat.com  2005-12-14 18:05 EST -------
> > > Actually, this is problematic.  It makes it so that the single device directory
> > > corresponds to more than one device which we can't handle with kudzu :-(
> 
> Well, how do you handle it for class devices then?

We don't have any where we need to handle it at present.  

> And if this isn't acceptable, what would be?

By going this route, it really feels like you're hacking around your own
rule of a single value per file :-)  Except that instead of having a
file that I read five values from, it's five files with naming
heuristics to get five values.  Which is, in a lot of ways, worse.

I'd much rather see the fact that there are multiple devices be handled
by having each device with its own unique directory.  This then keeps
all of the abstractions which currently exist.

Jeremy