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

From: Vladislav Bolkhovitin
Date: Thu Nov 04 2010 - 09:15:10 EST


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
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