Message-ID: <41487558.7010404@pobox.com>
Date: Wed, 15 Sep 2004 13:01:12 -0400
From: Jeff Garzik <jgarzik@pobox.com>
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To: Mark Lord <lsml@rtr.ca>
CC: dougg@torque.net, Linux Kernel <linux-kernel@vger.kernel.org>,
       Jens Axboe <axboe@suse.de>
Subject: Re: [PATCH] New QStor SATA/RAID Driver for 2.6.9-rc2
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Mark Lord wrote:
> Currently on Linux, that interface is called "SCSI".
> I think it might not be unreasonable to gradually evolve
> the SCSI host interface to include, say, a non-translating
> queuecommand() method, and associated pals.
[...]
> We practically have that already today.
> The SCSI mid-layer is a nice generic block device glue system.
> We just need perhaps to make it less SCSI-specific.


You seem to have independent reached the same conclusion I did :)

To be specific, SCSI provides LLD infrastructure that block does not:
1) infrastructure for queueing, retrying, and timing out requests
2) an error handling thread.
3) a standard method of addressing attached devices
4) a standard method of submitting raw commands from userspace

It is my goal to shift this infrastructure from SCSI to block over time. 
  There is a fair amount of queueing infrastructure now in 2.6 (part of 
#1), and Jens already has test code for #4.

I had hoped to start working on this in 2.7, but with the new dev model 
2.7 is postponed indefinitely....  so I guess I'll start working on it 
sooner rather than later :)

	Jeff


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