Re: [BK PATCHES] add ata scsi driver

Jeff Garzik
2003-05-27T16:03:11Z

On Tue, May 27, 2003 at 12:00:28PM -0400, James Bottomley wrote:
> On Tue, 2003-05-27 at 11:50, Jeff Garzik wrote:
> > Oh, no question. My main interest is having a persistent id for a
> > device's media. Then Linux can use that to allow mapping in case device
> > names or majors change at each boot (and similar situations).
>
> Well, OK, that's not an in-kernel issue.

It's definitely an in-kernel issue, because the mapping is in-kernel now:

<major,minor> -> queue

> My current thought for this is that deriving the unique name can be
> awfully device specific (even in SCSI there are several fallback methods
> plus the usual black/white list of things that don't quite return
> entirely unique objects).

Agreed. And kernel assistance is likely necessary in many cases to
obtain the unique id, even if it's only userspace that's reading it.

> Thus, I think the derivation probably belongs
> in userspace as part of hotplug. Once the unique ID is determined, it
> could be written to a well known place in the sysfs tree for all the
> rest of the OS (things like udev for persistent device naming) to use.

Agreed, with the above proviso.

Jeff