Re: [RFC] Asynchronous scsi scanning

[Matthew Wilcox <matthew@wil.cx>]

On Thu, May 11, 2006 at 01:49:26PM -0500, Mike Christie wrote:
> > 2) Unless it's serialised (in which case it still takes two hours to
> > boot), you lose drive numbering.
> 
> Drive numbering refers to the bus, target numbering right?

No, I mean sda, sdb, sdc, etc.

> Currently
> when you scan a host you are serialized at the host level because of the
> host->scan_mutex aren't we? So for each host addition hotplug event you
> can scan that host with the command above, and then you can scan all
> your hosts in parallel and the drive numbering is not affected is it? I
> thought, your patch is basically creating a kernel thread and running
> scan host selected, which grabs the scan_mutex, with all wild cards.
> What I suggested ends up calling scan host selected with all wild cards
> but from userspace.

The trick is to avoid adding the sdevs to sysfs until all prior sdevs
have been added.  I don't see a good way to do that from userspace.