scsi: target: Make the virtual LUN 0 device

Create the device for the virtual LUN 0 using the DUMMY flag. This change
makes it possible to remove some special-casing in the INQUIRY code.

Link: https://lore.kernel.org/r/20210322200938.53300-3-k.shelekhin@yadro.comReviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Konstantin Shelekhin <k.shelekhin@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_device.c

@@ -1035,7 +1035,7 @@ int core_dev_setup_virtual_lun0(void)
 {
 	struct se_hba *hba;
 	struct se_device *dev;
-	char buf[] = "rd_pages=8,rd_nullio=1";
+	char buf[] = "rd_pages=8,rd_nullio=1,rd_dummy=1";
 	int ret;
 
 	hba = core_alloc_hba("rd_mcp", 0, HBA_FLAGS_INTERNAL_USE);

drivers/target/target_core_spc.c

@@ -701,7 +701,6 @@ static sense_reason_t
 spc_emulate_inquiry(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
-	struct se_portal_group *tpg = cmd->se_lun->lun_tpg;
 	unsigned char *rbuf;
 	unsigned char *cdb = cmd->t_task_cdb;
 	unsigned char *buf;
@@ -715,10 +714,7 @@ spc_emulate_inquiry(struct se_cmd *cmd)
 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 
-	if (dev == rcu_access_pointer(tpg->tpg_virt_lun0->lun_se_dev))
-		buf[0] = 0x3f; /* Not connected */
-	else
-		buf[0] = dev->transport->get_device_type(dev);
+	buf[0] = dev->transport->get_device_type(dev);
 
 	if (!(cdb[1] & 0x1)) {
 		if (cdb[2]) {