Re: scsi_add_device() broken? (was Re: SBP2 hotplug doesn't update /proc/partitions)

["B. D. Elliott" <bde@nwlink.com>]

On Thu, Jun 12, 2003 at 10:40:44PM -0400, Ben Collins wrote:
> On Thu, Jun 12, 2003 at 03:52:43PM -0400, Ben Collins wrote:
> > On Thu, Jun 12, 2003 at 12:28:00PM -0700, Torrey Hoffman wrote:
> > > I am now running 2.5.70-bk15, and with slab debugging turned off SBP2
> > > mostly works.  However, I just had an interesting glitch show up.
> > > 
> > > I plugged in a 120 GB drive which had two VFAT partitions, mounted them,
> > > copied some data to them, unmounted them, and unplugged the drive.  
> > > That worked perfectly. (This was the first use of SBP2 after booting.)
> > > 
> > > Then I plugged in a 250 GB drive with a single reiserfs partition.  The
> > > SBP2 driver detected the drive correctly, but the kernel's idea of what
> > > partitions are available was not updated.  
> > > 
> > > /proc/partitions still has the old, stale data from the 120 GB drive and
> > > looks like this: (skipping my hda partitions)
> > 
> > Sounds like the scsi layer is keeping stale info. I'd say this is
> > suspiciously similar to what's causing your oops in your later email.
> > Track down where the stale info comes from, and I think you'll find the
> > cause of both your problems.
> 
> scsi0 : SCSI emulation for IEEE-1394 SBP-2 Devices
> ieee1394: sbp2: Query logins to SBP-2 device successful
> ieee1394: sbp2: Maximum concurrent logins supported: 1
> ieee1394: sbp2: Number of active logins: 0
> ieee1394: sbp2: Logged into SBP-2 device
> ieee1394: sbp2: Node[02:1023]: Max speed [S400] - Max payload [2048]
>   Vendor: FireWire  Model:  1394 Disk Drive  Rev: G603
>   Type:   Direct-Access                      ANSI SCSI revision: 02
> SCSI device sda: 240121728 512-byte hdwr sectors (122942 MB)
> sda: cache data unavailable
> sda: assuming drive cache: write through
>  sda: unknown partition table
> devfs_mk_dir: invalid argument.<5>Attached scsi disk sda at scsi0, channel 0, id 0, lun 0

This particular error occurs because the scsi/host*/bus*/target*/lun* path
hasn't yet been set up in scsi_add_lun before calling scsi_device_register.
This also occurs for usb disk registration.  (I don't know why this doesn't
happen for devices that register at boot time.)  Moving the call to
scsi_device_register (at scsi_scan.c:622) after the sprintf appears to fix
both the usb and ieee1934 problems.

> Note, the "unknown partition table" is ok for me, because I am using a
> whole-disk filesystem. However, the devfs_mk_dir() error is suspicious.
> Note, I use devfs. 2.5.69+bk (just before 2.6.70) things worked fine.
> Now, /dev/sda is not being created. Nothing in /dev/scsi/ either, but:
> 
> hopper:~# cat /proc/scsi/sbp2/0
> Host scsi0             : SBP-2 IEEE-1394 (ohci1394)
> Driver version         : $Rev: 942 $ Ben Collins <bcollins@debian.org>

A side note here:  The "$Rev: 942..." message is marked as __devinitdata
which causes an oops on sparc64 when attempting the above "cat", as the
mapping for that data is apparently deleted after module initialization.

> Module options         :
>   max_speed            : S400
>   max_sectors          : 255
>   serialize_io         : no
>   exclusive_login      : no
> 
> Attached devices       :
>   [Channel: 00, Id: 00, Lun: 00]  Direct-Access     FireWire  1394 Disk Drive
> 
> 
> Also, /sys/bus/scsi/devices/0:0:0:0 exists, with a block link to sda.
> 
> I suspect this is a problem where scsi_add_device() is not doing all the
> stuff it needs to (does anything besides ieee1394 use scsi_add_device
> and scsi_remove_device?).
> 
> 
> -- 
> Debian     - http://www.debian.org/
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-- 
B. D. Elliott   bde@nwlink.com