Re: [ANNOUNCE] Generic SCSI Target Middle Level for Linux (SCST) with target drivers

Vladislav Bolkhovitin
2004-06-17T13:21:10Z

Christoph Hellwig wrote:
> On Wed, Jun 16, 2004 at 08:31:22PM +0400, Vladislav Bolkhovitin wrote:
>
> The code looks pretty neat to me, there's a few issues I'd like to see
> addresses but that doesn't make sense before the 2.4 support is dropped
> and there's an actual LLDD for 2.6. But I think for most interesting
> scenarios in the storage virtualization world your driver is pretty much
> useless because it wants to dispatch directly to a scsi device and doesn't
> go through the block layer. So no fancy volume managers/etc there to make
> interesting storage virtualization boxes.
>
For that is intended upcoming block device handler with block
layer/cache support,
which will be in its exec() method check, if requested blocks in cache,
and, if not, dispatch the commands to block layer, leaving regular
scsi_do_req() calls for tapes, changers, etc. In the similar way "_perf"
handlers work (they don't send READ/WRITE commands to SCSI devices for
performance studies).

This device handler is on our todo list. Actually, it's quite simple and
if anyone interested, he's help would be greatly appreciated.

Thanks,
Vlad