Re: PATCH: exclude certain commands from emulated SCSI hosts

[James Bottomley <James.Bottomley@steeleye.com>]

On Sat, 2003-04-05 at 13:27, Matthew Dharm wrote:
> I don't think this will work.  I see two problems:
> 
> (1) You can't filter TEST_UNIT_READY (opcode 0).  Not a big deal, but a
> theoretical problem.

Yes, TUR has been mandatory since SCSI-1, so I didn't think this would
be a problem.  Any end signal can be used, zero was the least line of
resistance.

> (2) We need to be able to filter at the originator.  For example,
> MODE_SENSE is perfectly fine to send to a CD-ROM, but not to a hard-disk.
> We can't make that distinction with your code, unless we put the filtering
> code not in queuecommand but in places like sd.c.... or we need to change
> the filter to also take a device type.

What's wrong with

-		if(scsi_filter_cmd(SCp, &filter)) {
+		if(SCp->device->type == TYPE_DISK && scsi_filter_cmd(SCp, &filter)) {

?

The whole idea is to provide a filter library that the emulated HBA
drivers can use to cope with standard commands they don't like rather
than add extra code to the mid-layer main code paths.

James




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