Re: Multi-LUN CD changer simultaneous access problem.

[Chiaki Ishikawa]

X-PMC-CI-e-mail-id: 12062 

>FWIW, I solved the LUN-based changer problem in FreeBSD/CAM by adding a
>sort-of scheduler to the CD driver.  All CD devices that are part of a
>changer are grouped together, and commands can only be issued to one LUN
>at a time.

It sounds to me a good solution. The choice of time quantum seems also
reasonable.
I am not a kernel hacker, but probably the
checking of data structure to see if there are pending
requests to different LUNs on the same target by traversing the
linked list as mentioned in Eric Youngdale's post 
is functionally equivalent to what you describe here.

Alan Cox has been mentioning partial overhaul of SCSI code and so I am 
not sure where the fix should go in (and also when).



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