Re: [PATCH 3/3] tcm ibmvscsis driver

[Brian King <brking@linux.vnet.ibm.com>]

On 02/10/2011 01:38 PM, Nicholas A. Bellinger wrote:
> On Thu, 2011-02-10 at 13:15 -0600, Brian King wrote:
>> On 02/10/2011 06:21 AM, FUJITA Tomonori wrote:
> 
> Hi Brian,
> 
> <SNIP>
> 
>>> +
>>> +static int ibmvscsis_new_cmd_map(struct se_cmd *se_cmd)
>>> +{
>>> +	struct ibmvscsis_cmnd *cmd =
>>> +		container_of(se_cmd, struct ibmvscsis_cmnd, se_cmd);
>>> +	struct scsi_cmnd *sc = &cmd->sc;
>>> +	struct iu_entry *iue = (struct iu_entry *)sc->SCp.ptr;
>>> +	struct srp_cmd *scmd = iue->sbuf->buf;
>>> +	int ret;
>>> +
>>> +	/*
>>> +	 * Allocate the necessary tasks to complete the received CDB+data
>>> +	 */
>>> +	ret = transport_generic_allocate_tasks(se_cmd, scmd->cdb);
>>> +	if (ret == -1) {
>>> +		/* Out of Resources */
>>> +		return PYX_TRANSPORT_LU_COMM_FAILURE;
>>> +	} else if (ret == -2) {
>>> +		/*
>>> +		 * Handle case for SAM_STAT_RESERVATION_CONFLICT
>>> +		 */
>>> +		if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)
>>> +			return PYX_TRANSPORT_RESERVATION_CONFLICT;
>>
>> Does this imply the driver supports scsi reservations? If it supports SCSI-2 reservations,
>> there is a capability that could be set in the capabilities MAD to advertise this
>> fact such that it can be used by the client.
>>
> 
> Absoulutely, the target core struct se_device backends being serviced as
> VSCSI LUN would normally return SCSI-3 from INQUIRY data, and support
> the full set of persistent reservations and CRH=1 (Compatible
> Reservations Handling) in drivers/target/target_core_pr.c code.
> 
> Also, we are able to explictly limit individual struct se_device
> backends to disable PR and only use the older SCSI-2 reservations, but I
> don't think we have a way to do this on a fabric module wide basis just
> yet.
> 
> Is this something we should be doing for this code..?

Disregard my previous comment. It looks like current client should handle reservations
just fine without any further changes.

Thanks,

Brian

-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center