[8547] in linux-scsi channel archive
Re: SCSI_IOCTL_GET_IDLUN changes in lk 2.3/2.4
daemon@ATHENA.MIT.EDU (Douglas Gilbert)
Wed Apr 5 00:46:57 2000
Message-ID: <38EAB45B.73F0B1B@interlog.com>
Date: Tue, 04 Apr 2000 23:34:51 -0400
From: Douglas Gilbert <dgilbert@interlog.com>
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To: schilling@fokus.gmd.de
Cc: linux-scsi@vger.rutgers.edu
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schilling@fokus.gmd.de wrote:
>
> >From dgilbert@interlog.com Sat Apr 1 18:14:22 2000
>
> >A recent posting on the SANE newsgroup reported the "scsi_info"
> >program failing. A cause for this failure on a recent 2.3 series
> >kernel is that the SCSI_IOCTL_GET_IDLUN ioctl made available
> >by the SCSI mid-level code (and hence to all scsi device
> >file descriptors) has changed. The cdrecord application is
> >also effected by this change.
>
> >> "four_in_one" is made up as follows:
> >> (scsi_device_id | (lun << 8) | (channel << 16) | (host_no << 24))
> >> These 4 components are assumed (or masked) to be 1 byte each.
> >>
> >> The 'host_no' element is a change in lk 2.3/2.4 kernels. [In the lk 2.2
> >> series and prior it was 'low_inode & 0xff' of the /proc pseudo file system
> >> entry corresponding to the adapter/host.] This change makes the use of the
> >> SCSI_IOCTL_GET_BUS_NUMBER ioctl superfluous.
>
> As cdrecord only uses this number to have one more criteria to do the mapping,
> I would assume that cdrecord will work as before.
>
> Did you definitely observe problems?
No, I was just aware that the libscg code used it. Best that
you know about it.
BTW Several failures of cdrecord have been reported on the
linux-kernel newsgroup using 2.3.99-pre* . As far as I could
see they are associated with the change that makes shm a file
system and those people not mounting it.
Also the device pseudo file system (devfs) can make a real
mess of apps that scan for sg devices although in cdrecord's
case the /dev/cdroms subdirectory looks promising. Luckily
devfs is optional and it will be a brave distribution that
first makes it the default.
Doug Gilbert
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