scsi: target: use an enum to track emulate_ua_intlck_ctrl

The emulate_ua_intlck_ctrl device attribute accepts values of 0, 1 or 2 via
ConfigFS, which map to unit attention interlocks control codes in the MODE
SENSE control Mode Page.  Use an enum to track these values so that it's
clear that, unlike the remaining emulate_X attributes,
emulate_ua_intlck_ctrl isn't boolean.

Link: https://marc.info/?l=target-devel&m=158227825428798Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_configfs.c

@@ -684,7 +684,9 @@ static ssize_t emulate_ua_intlck_ctrl_store(struct config_item *item,
 	if (ret < 0)
 		return ret;
 
-	if (val != 0 && val != 1 && val != 2) {
+	if (val != TARGET_UA_INTLCK_CTRL_CLEAR
+	 && val != TARGET_UA_INTLCK_CTRL_NO_CLEAR
+	 && val != TARGET_UA_INTLCK_CTRL_ESTABLISH_UA) {
 		pr_err("Illegal value %d\n", val);
 		return -EINVAL;
 	}

drivers/target/target_core_device.c

@@ -767,7 +767,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
 	dev->dev_attrib.emulate_fua_write = 1;
 	dev->dev_attrib.emulate_fua_read = 1;
 	dev->dev_attrib.emulate_write_cache = DA_EMULATE_WRITE_CACHE;
-	dev->dev_attrib.emulate_ua_intlck_ctrl = DA_EMULATE_UA_INTLLCK_CTRL;
+	dev->dev_attrib.emulate_ua_intlck_ctrl = TARGET_UA_INTLCK_CTRL_CLEAR;
 	dev->dev_attrib.emulate_tas = DA_EMULATE_TAS;
 	dev->dev_attrib.emulate_tpu = DA_EMULATE_TPU;
 	dev->dev_attrib.emulate_tpws = DA_EMULATE_TPWS;

drivers/target/target_core_spc.c

@@ -847,8 +847,17 @@ static int spc_modesense_control(struct se_cmd *cmd, u8 pc, u8 *p)
 	 * for a BUSY, TASK SET FULL, or RESERVATION CONFLICT status regardless
 	 * to the number of commands completed with one of those status codes.
 	 */
-	p[4] = (dev->dev_attrib.emulate_ua_intlck_ctrl == 2) ? 0x30 :
-	       (dev->dev_attrib.emulate_ua_intlck_ctrl == 1) ? 0x20 : 0x00;
+	switch (dev->dev_attrib.emulate_ua_intlck_ctrl) {
+	case TARGET_UA_INTLCK_CTRL_ESTABLISH_UA:
+		p[4] = 0x30;
+		break;
+	case TARGET_UA_INTLCK_CTRL_NO_CLEAR:
+		p[4] = 0x20;
+		break;
+	default:	/* TARGET_UA_INTLCK_CTRL_CLEAR */
+		p[4] = 0x00;
+		break;
+	}
 	/*
 	 * From spc4r17, section 7.4.6 Control mode Page
 	 *

drivers/target/target_core_transport.c

@@ -1879,7 +1879,8 @@ void transport_generic_request_failure(struct se_cmd *cmd,
 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
 		 */
 		if (cmd->se_sess &&
-		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
+		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl
+					== TARGET_UA_INTLCK_CTRL_ESTABLISH_UA) {
 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
 					       cmd->orig_fe_lun, 0x2C,
 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);

drivers/target/target_core_ua.c

@@ -199,6 +199,8 @@ bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
 	struct se_node_acl *nacl;
 	struct se_ua *ua = NULL, *ua_p;
 	int head = 1;
+	bool dev_ua_intlck_clear = (dev->dev_attrib.emulate_ua_intlck_ctrl
+						== TARGET_UA_INTLCK_CTRL_CLEAR);
 
 	if (WARN_ON_ONCE(!sess))
 		return false;
@@ -229,7 +231,7 @@ bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
 		 * highest priority UNIT_ATTENTION and ASC/ASCQ without
 		 * clearing it.
 		 */
-		if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
+		if (!dev_ua_intlck_clear) {
 			*asc = ua->ua_asc;
 			*ascq = ua->ua_ascq;
 			break;
@@ -254,8 +256,8 @@ bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
 		" INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
 		" reported ASC: 0x%02x, ASCQ: 0x%02x\n",
 		nacl->se_tpg->se_tpg_tfo->fabric_name,
-		(dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
-		"Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
+		dev_ua_intlck_clear ? "Releasing" : "Reporting",
+		dev->dev_attrib.emulate_ua_intlck_ctrl,
 		cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
 
 	return head == 0;

include/target/target_core_base.h

@@ -74,8 +74,6 @@
 #define DA_EMULATE_MODEL_ALIAS			0
 /* Emulation for WriteCache and SYNCHRONIZE_CACHE */
 #define DA_EMULATE_WRITE_CACHE			0
-/* Emulation for UNIT ATTENTION Interlock Control */
-#define DA_EMULATE_UA_INTLLCK_CTRL		0
 /* Emulation for TASK_ABORTED status (TAS) by default */
 #define DA_EMULATE_TAS				1
 /* Emulation for Thin Provisioning UNMAP using block/blk-lib.c:blkdev_issue_discard() */
@@ -433,6 +431,13 @@ enum target_prot_type {
 	TARGET_DIF_TYPE3_PROT,
 };
 
+/* Emulation for UNIT ATTENTION Interlock Control */
+enum target_ua_intlck_ctrl {
+	TARGET_UA_INTLCK_CTRL_CLEAR = 0,
+	TARGET_UA_INTLCK_CTRL_NO_CLEAR = 1,
+	TARGET_UA_INTLCK_CTRL_ESTABLISH_UA = 2,
+};
+
 enum target_core_dif_check {
 	TARGET_DIF_CHECK_GUARD  = 0x1 << 0,
 	TARGET_DIF_CHECK_APPTAG = 0x1 << 1,
@@ -668,7 +673,7 @@ struct se_dev_attrib {
 	bool		emulate_fua_write;
 	bool		emulate_fua_read;	/* deprecated */
 	bool		emulate_write_cache;
-	int		emulate_ua_intlck_ctrl;
+	enum target_ua_intlck_ctrl emulate_ua_intlck_ctrl;
 	bool		emulate_tas;
 	bool		emulate_tpu;
 	bool		emulate_tpws;