Re: [RFC v2 16/21] tcm: Add PSCSI subsystem plugin

[Vladislav Bolkhovitin <vst@vlnb.net>]

Boaz Harrosh, on 11/02/2010 05:23 PM wrote:

[...]

>> +	 * Some pseudo SCSI HBAs do not fill in sector_size
>> +	 * correctly. (See ide-scsi.c)  So go ahead and setup sane
>> +	 * values.
>> +	 */
>> +	if (!sd->sector_size) {
>> +		switch (sd->type) {
>> +		case TYPE_DISK:
>> +			sd->sector_size = 512;
>> +			break;
>> +		case TYPE_ROM:
>> +			sd->sector_size = 2048;
>> +			break;
>> +		case TYPE_TAPE: /* The Tape may not be in the drive */
>> +			break;
>> +		case TYPE_MEDIUM_CHANGER: /* Control CDBs only */
>> +			break;
>> +		default:
>> +			printk(KERN_ERR "Unable to set sector_size for %d\n",
>> +					sd->type);
>> +			return NULL;
> 
> What about sector-less devices? OSD, Scanners, printers ...

[...]

>> +	/*
>> +	 * For TYPE_TAPE, attempt to determine blocksize with MODE_SENSE.
>> +	 */
>> +	if (sd->type == TYPE_TAPE) {
> 
> Just as a future note:
> One of the things I'm missing from LIO is the notion of SCSI_TYPE or SCSI
> class. So things like this can be done in a plugin manner as per TYPE
> Like in the Kernel we have the ULDs for that.

This is exactly how it is done in SCST.

Also SCST well handles sector-less devices.

Vlad