scsi: target: core: Add the VERSION DESCRIPTOR fields to the INQUIRY data

Extend the standard INQUIRY data to 96 bytes and fill in the VERSION
DESCRIPTOR fields.

The layout follows SPC-4:

 - SCSI architecture standard
 - SCSI transport protocol standard
 - SCSI primary command set standard
 - SCSI device type command set standard

All version descriptor values are defined as "no version claimed" because
some initiators fail to recognize anything else.

[mkp: whitespace]

Link: https://lore.kernel.org/r/20210513192804.1252142-3-k.shelekhin@yadro.comReviewed-by: NRoman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: NKonstantin Shelekhin <k.shelekhin@yadro.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_spc.c

@@ -47,10 +47,32 @@ static void spc_fill_alua_data(struct se_lun *lun, unsigned char *buf)
 	spin_unlock(&lun->lun_tg_pt_gp_lock);
 }
 
+static u16
+spc_find_scsi_transport_vd(int proto_id)
+{
+	switch (proto_id) {
+	case SCSI_PROTOCOL_FCP:
+		return SCSI_VERSION_DESCRIPTOR_FCP4;
+	case SCSI_PROTOCOL_ISCSI:
+		return SCSI_VERSION_DESCRIPTOR_ISCSI;
+	case SCSI_PROTOCOL_SAS:
+		return SCSI_VERSION_DESCRIPTOR_SAS3;
+	case SCSI_PROTOCOL_SBP:
+		return SCSI_VERSION_DESCRIPTOR_SBP3;
+	case SCSI_PROTOCOL_SRP:
+		return SCSI_VERSION_DESCRIPTOR_SRP;
+	default:
+		pr_warn("Cannot find VERSION DESCRIPTOR value for unknown SCSI"
+			" transport PROTOCOL IDENTIFIER %#x\n", proto_id);
+		return 0;
+	}
+}
+
 sense_reason_t
 spc_emulate_inquiry_std(struct se_cmd *cmd, unsigned char *buf)
 {
 	struct se_lun *lun = cmd->se_lun;
+	struct se_portal_group *tpg = lun->lun_tpg;
 	struct se_device *dev = cmd->se_dev;
 	struct se_session *sess = cmd->se_sess;
 
@@ -108,7 +130,17 @@ spc_emulate_inquiry_std(struct se_cmd *cmd, unsigned char *buf)
 	       strnlen(dev->t10_wwn.model, INQUIRY_MODEL_LEN));
 	memcpy(&buf[32], dev->t10_wwn.revision,
 	       strnlen(dev->t10_wwn.revision, INQUIRY_REVISION_LEN));
-	buf[4] = 31; /* Set additional length to 31 */
+
+	/*
+	 * Set the VERSION DESCRIPTOR fields
+	 */
+	put_unaligned_be16(SCSI_VERSION_DESCRIPTOR_SAM5, &buf[58]);
+	put_unaligned_be16(spc_find_scsi_transport_vd(tpg->proto_id), &buf[60]);
+	put_unaligned_be16(SCSI_VERSION_DESCRIPTOR_SPC4, &buf[62]);
+	if (cmd->se_dev->transport->get_device_type(dev) == TYPE_DISK)
+		put_unaligned_be16(SCSI_VERSION_DESCRIPTOR_SBC3, &buf[64]);
+
+	buf[4] = 91; /* Set additional length to 91 */
 
 	return 0;
 }

include/scsi/scsi_proto.h

@@ -341,4 +341,16 @@ enum zbc_zone_cond {
 	ZBC_ZONE_COND_OFFLINE		= 0xf,
 };
 
+/* Version descriptor values for INQUIRY */
+enum scsi_version_descriptor {
+	SCSI_VERSION_DESCRIPTOR_FCP4	= 0x0a40,
+	SCSI_VERSION_DESCRIPTOR_ISCSI	= 0x0960,
+	SCSI_VERSION_DESCRIPTOR_SAM5	= 0x00a0,
+	SCSI_VERSION_DESCRIPTOR_SAS3	= 0x0c60,
+	SCSI_VERSION_DESCRIPTOR_SBC3	= 0x04c0,
+	SCSI_VERSION_DESCRIPTOR_SBP3	= 0x0980,
+	SCSI_VERSION_DESCRIPTOR_SPC4	= 0x0460,
+	SCSI_VERSION_DESCRIPTOR_SRP	= 0x0940
+};
+
 #endif /* _SCSI_PROTO_H_ */