From mboxrd@z Thu Jan  1 00:00:00 1970
From: Willem Riede <wrlk@riede.org>
Subject: Re: devices with more than one node
Date: Sun, 18 Jan 2004 17:08:02 -0500
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In-Reply-To: <4006499A.4070302@torque.net> (from dougg@torque.net on Thu, Jan 15, 2004 at 03:04:42 -0500)
List-Id: linux-scsi@vger.kernel.org
To: dougg@torque.net
Cc: linux-scsi@vger.kernel.org, Kai.Makisara@kolumbus.fi

On 2004.01.15 03:04, Douglas Gilbert wrote:
> 
> To test it I modded scsi_debug to fake OnStream tape
> drives and ran a 2.6.1-mm2 kernel. The attached
> output of "cd /sys/class; tree scsi* osst" is instructive.
> Two peculiar entries are:
>      scsi_generic/sg0/driver -> ../../../bus/scsi/drivers/osst
>      scsi_generic/sg1/driver -> ../../../bus/scsi/drivers/osst
> 
> This symlink only appears if the osst driver is loaded
> _before_ the sg driver! It is also left dangling by
> "rmmod osst". 

I see the same with real OnStream tape drives.
It appears that when an upper level driver like osst is
(un)loaded, your (sg) attach doesn't get a chance to
reconsider...

By the way, I notice that st produces links in scsi_device
that osst doesn't - 0:0:3:0 and 3:0:0:0 are OnStream drives:

scsi_device
|-- 0:0:3:0
|   `-- device -> ../../../devices/pci0000:00/0000:00:0e.0/host0/0:0:3:0
|-- 0:0:6:0
|   `-- device -> ../../../devices/pci0000:00/0000:00:0e.0/host0/0:0:6:0
|-- 1:0:0:0
|   |-- device -> ../../../devices/pci0000:00/0000:00:0e.1/host1/1:0:0:0
|   `-- driver -> ../../../bus/scsi/drivers/sd
|-- 1:0:1:0
|   |-- device -> ../../../devices/pci0000:00/0000:00:0e.1/host1/1:0:1:0
|   `-- driver -> ../../../bus/scsi/drivers/sd
|-- 2:0:0:0
|   |-- device -> ../../../devices/pci0000:00/0000:00:07.1/ide0/0.1/host2/2:0:0:0
|   `-- driver -> ../../../bus/scsi/drivers/st
|-- 3:0:0:0
|   `-- device -> ../../../devices/pci0000:00/0000:00:07.1/ide1/1.0/host3/3:0:0:0
`-- 4:0:0:0
    |-- device -> ../../../devices/pci0000:00/0000:00:07.1/ide1/1.1/host4/4:0:0:0
    `-- driver -> ../../../bus/scsi/drivers/st

Should I emulate what st does to create these entries?

Thanks, Willem Riede.