diff --git a/block/sed-opal.c b/block/sed-opal.c
index c5dff6199bd6..0348fb896a5d 100644
--- a/block/sed-opal.c
+++ b/block/sed-opal.c
@@ -655,7 +655,7 @@ static int cmd_finalize(struct opal_dev *cmd, u32 hsn, u32 tsn)
 	struct opal_header *hdr;
 	int err = 0;
 
-	/* close parameter list */
+	/* close the parameter list opened from cmd_start */
 	add_token_u8(&err, cmd, OPAL_ENDLIST);
 
 	add_token_u8(&err, cmd, OPAL_ENDOFDATA);
@@ -1000,6 +1000,27 @@ static void clear_opal_cmd(struct opal_dev *dev)
 	memset(dev->cmd, 0, IO_BUFFER_LENGTH);
 }
 
+static int cmd_start(struct opal_dev *dev, const u8 *uid, const u8 *method)
+{
+	int err = 0;
+
+	clear_opal_cmd(dev);
+	set_comid(dev, dev->comid);
+
+	add_token_u8(&err, dev, OPAL_CALL);
+	add_token_bytestring(&err, dev, uid, OPAL_UID_LENGTH);
+	add_token_bytestring(&err, dev, method, OPAL_METHOD_LENGTH);
+
+	/*
+	 * Every method call is followed by its parameters enclosed within
+	 * OPAL_STARTLIST and OPAL_ENDLIST tokens. We automatically open the
+	 * parameter list here and close it later in cmd_finalize.
+	 */
+	add_token_u8(&err, dev, OPAL_STARTLIST);
+
+	return err;
+}
+
 static int start_opal_session_cont(struct opal_dev *dev)
 {
 	u32 hsn, tsn;
@@ -1062,20 +1083,13 @@ static int finalize_and_send(struct opal_dev *dev, cont_fn cont)
 static int gen_key(struct opal_dev *dev, void *data)
 {
 	u8 uid[OPAL_UID_LENGTH];
-	int err = 0;
-
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	int err;
 
 	memcpy(uid, dev->prev_data, min(sizeof(uid), dev->prev_d_len));
 	kfree(dev->prev_data);
 	dev->prev_data = NULL;
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, uid, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_GENKEY],
-			     OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
+	err = cmd_start(dev, uid, opalmethod[OPAL_GENKEY]);
 
 	if (err) {
 		pr_debug("Error building gen key command\n");
@@ -1113,21 +1127,14 @@ static int get_active_key_cont(struct opal_dev *dev)
 static int get_active_key(struct opal_dev *dev, void *data)
 {
 	u8 uid[OPAL_UID_LENGTH];
-	int err = 0;
+	int err;
 	u8 *lr = data;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
-
 	err = build_locking_range(uid, sizeof(uid), *lr);
 	if (err)
 		return err;
 
-	err = 0;
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, uid, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_GET], OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
+	err = cmd_start(dev, uid, opalmethod[OPAL_GET]);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, 3); /* startCloumn */
@@ -1150,13 +1157,10 @@ static int generic_lr_enable_disable(struct opal_dev *dev,
 				     u8 *uid, bool rle, bool wle,
 				     bool rl, bool wl)
 {
-	int err = 0;
+	int err;
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, uid, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_SET], OPAL_UID_LENGTH);
+	err = cmd_start(dev, uid, opalmethod[OPAL_SET]);
 
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, OPAL_VALUES);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
@@ -1203,10 +1207,7 @@ static int setup_locking_range(struct opal_dev *dev, void *data)
 	u8 uid[OPAL_UID_LENGTH];
 	struct opal_user_lr_setup *setup = data;
 	u8 lr;
-	int err = 0;
-
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	int err;
 
 	lr = setup->session.opal_key.lr;
 	err = build_locking_range(uid, sizeof(uid), lr);
@@ -1216,12 +1217,8 @@ static int setup_locking_range(struct opal_dev *dev, void *data)
 	if (lr == 0)
 		err = enable_global_lr(dev, uid, setup);
 	else {
-		add_token_u8(&err, dev, OPAL_CALL);
-		add_token_bytestring(&err, dev, uid, OPAL_UID_LENGTH);
-		add_token_bytestring(&err, dev, opalmethod[OPAL_SET],
-				     OPAL_UID_LENGTH);
+		err = cmd_start(dev, uid, opalmethod[OPAL_SET]);
 
-		add_token_u8(&err, dev, OPAL_STARTLIST);
 		add_token_u8(&err, dev, OPAL_STARTNAME);
 		add_token_u8(&err, dev, OPAL_VALUES);
 		add_token_u8(&err, dev, OPAL_STARTLIST);
@@ -1265,22 +1262,15 @@ static int start_generic_opal_session(struct opal_dev *dev,
 				      u8 key_len)
 {
 	u32 hsn;
-	int err = 0;
+	int err;
 
 	if (key == NULL && auth != OPAL_ANYBODY_UID)
 		return OPAL_INVAL_PARAM;
 
-	clear_opal_cmd(dev);
-
-	set_comid(dev, dev->comid);
 	hsn = GENERIC_HOST_SESSION_NUM;
+	err = cmd_start(dev, opaluid[OPAL_SMUID_UID],
+			opalmethod[OPAL_STARTSESSION]);
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_SMUID_UID],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_STARTSESSION],
-			     OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u64(&err, dev, hsn);
 	add_token_bytestring(&err, dev, opaluid[sp_type], OPAL_UID_LENGTH);
 	add_token_u8(&err, dev, 1);
@@ -1360,30 +1350,21 @@ static int start_auth_opal_session(struct opal_dev *dev, void *data)
 	u8 *key = session->opal_key.key;
 	u32 hsn = GENERIC_HOST_SESSION_NUM;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
-
-	if (session->sum) {
+	if (session->sum)
 		err = build_locking_user(lk_ul_user, sizeof(lk_ul_user),
 					 session->opal_key.lr);
-		if (err)
-			return err;
-
-	} else if (session->who != OPAL_ADMIN1 && !session->sum) {
+	else if (session->who != OPAL_ADMIN1 && !session->sum)
 		err = build_locking_user(lk_ul_user, sizeof(lk_ul_user),
 					 session->who - 1);
-		if (err)
-			return err;
-	} else
+	else
 		memcpy(lk_ul_user, opaluid[OPAL_ADMIN1_UID], OPAL_UID_LENGTH);
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_SMUID_UID],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_STARTSESSION],
-			     OPAL_UID_LENGTH);
+	if (err)
+		return err;
+
+	err = cmd_start(dev, opaluid[OPAL_SMUID_UID],
+			opalmethod[OPAL_STARTSESSION]);
 
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u64(&err, dev, hsn);
 	add_token_bytestring(&err, dev, opaluid[OPAL_LOCKINGSP_UID],
 			     OPAL_UID_LENGTH);
@@ -1407,17 +1388,10 @@ static int start_auth_opal_session(struct opal_dev *dev, void *data)
 
 static int revert_tper(struct opal_dev *dev, void *data)
 {
-	int err = 0;
+	int err;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
-
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_ADMINSP_UID],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_REVERT],
-			     OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
+	err = cmd_start(dev, opaluid[OPAL_ADMINSP_UID],
+			opalmethod[OPAL_REVERT]);
 	if (err) {
 		pr_debug("Error building REVERT TPER command.\n");
 		return err;
@@ -1430,18 +1404,12 @@ static int internal_activate_user(struct opal_dev *dev, void *data)
 {
 	struct opal_session_info *session = data;
 	u8 uid[OPAL_UID_LENGTH];
-	int err = 0;
-
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	int err;
 
 	memcpy(uid, opaluid[OPAL_USER1_UID], OPAL_UID_LENGTH);
 	uid[7] = session->who;
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, uid, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_SET], OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
+	err = cmd_start(dev, uid, opalmethod[OPAL_SET]);
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, OPAL_VALUES);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
@@ -1464,19 +1432,12 @@ static int erase_locking_range(struct opal_dev *dev, void *data)
 {
 	struct opal_session_info *session = data;
 	u8 uid[OPAL_UID_LENGTH];
-	int err = 0;
-
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	int err;
 
 	if (build_locking_range(uid, sizeof(uid), session->opal_key.lr) < 0)
 		return -ERANGE;
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, uid, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_ERASE],
-			     OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
+	err = cmd_start(dev, uid, opalmethod[OPAL_ERASE]);
 
 	if (err) {
 		pr_debug("Error building Erase Locking Range Command.\n");
@@ -1488,16 +1449,11 @@ static int erase_locking_range(struct opal_dev *dev, void *data)
 static int set_mbr_done(struct opal_dev *dev, void *data)
 {
 	u8 *mbr_done_tf = data;
-	int err = 0;
+	int err;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	err = cmd_start(dev, opaluid[OPAL_MBRCONTROL],
+			opalmethod[OPAL_SET]);
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_MBRCONTROL],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_SET], OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, OPAL_VALUES);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
@@ -1519,16 +1475,11 @@ static int set_mbr_done(struct opal_dev *dev, void *data)
 static int set_mbr_enable_disable(struct opal_dev *dev, void *data)
 {
 	u8 *mbr_en_dis = data;
-	int err = 0;
+	int err;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	err = cmd_start(dev, opaluid[OPAL_MBRCONTROL],
+			opalmethod[OPAL_SET]);
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_MBRCONTROL],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_SET], OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, OPAL_VALUES);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
@@ -1550,16 +1501,10 @@ static int set_mbr_enable_disable(struct opal_dev *dev, void *data)
 static int generic_pw_cmd(u8 *key, size_t key_len, u8 *cpin_uid,
 			  struct opal_dev *dev)
 {
-	int err = 0;
+	int err;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	err = cmd_start(dev, cpin_uid, opalmethod[OPAL_SET]);
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, cpin_uid, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_SET],
-			     OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, OPAL_VALUES);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
@@ -1616,10 +1561,7 @@ static int add_user_to_lr(struct opal_dev *dev, void *data)
 	u8 lr_buffer[OPAL_UID_LENGTH];
 	u8 user_uid[OPAL_UID_LENGTH];
 	struct opal_lock_unlock *lkul = data;
-	int err = 0;
-
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	int err;
 
 	memcpy(lr_buffer, opaluid[OPAL_LOCKINGRANGE_ACE_RDLOCKED],
 	       OPAL_UID_LENGTH);
@@ -1634,12 +1576,8 @@ static int add_user_to_lr(struct opal_dev *dev, void *data)
 
 	user_uid[7] = lkul->session.who;
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, lr_buffer, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_SET],
-			     OPAL_UID_LENGTH);
+	err = cmd_start(dev, lr_buffer, opalmethod[OPAL_SET]);
 
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, OPAL_VALUES);
 
@@ -1693,9 +1631,6 @@ static int lock_unlock_locking_range(struct opal_dev *dev, void *data)
 	u8 read_locked = 1, write_locked = 1;
 	int err = 0;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
-
 	if (build_locking_range(lr_buffer, sizeof(lr_buffer),
 				lkul->session.opal_key.lr) < 0)
 		return -ERANGE;
@@ -1717,10 +1652,8 @@ static int lock_unlock_locking_range(struct opal_dev *dev, void *data)
 		return OPAL_INVAL_PARAM;
 	}
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, lr_buffer, OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_SET], OPAL_UID_LENGTH);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
+	err = cmd_start(dev, lr_buffer, opalmethod[OPAL_SET]);
+
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, OPAL_VALUES);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
@@ -1791,17 +1724,10 @@ static int activate_lsp(struct opal_dev *dev, void *data)
 	struct opal_lr_act *opal_act = data;
 	u8 user_lr[OPAL_UID_LENGTH];
 	u8 uint_3 = 0x83;
-	int err = 0, i;
-
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
-
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_LOCKINGSP_UID],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_ACTIVATE],
-			     OPAL_UID_LENGTH);
+	int err, i;
 
+	err = cmd_start(dev, opaluid[OPAL_LOCKINGSP_UID],
+			opalmethod[OPAL_ACTIVATE]);
 
 	if (opal_act->sum) {
 		err = build_locking_range(user_lr, sizeof(user_lr),
@@ -1809,7 +1735,6 @@ static int activate_lsp(struct opal_dev *dev, void *data)
 		if (err)
 			return err;
 
-		add_token_u8(&err, dev, OPAL_STARTLIST);
 		add_token_u8(&err, dev, OPAL_STARTNAME);
 		add_token_u8(&err, dev, uint_3);
 		add_token_u8(&err, dev, 6);
@@ -1824,8 +1749,6 @@ static int activate_lsp(struct opal_dev *dev, void *data)
 		}
 		add_token_u8(&err, dev, OPAL_ENDLIST);
 		add_token_u8(&err, dev, OPAL_ENDNAME);
-	} else {
-		add_token_u8(&err, dev, OPAL_STARTLIST);
 	}
 
 	if (err) {
@@ -1859,17 +1782,11 @@ static int get_lsp_lifecycle_cont(struct opal_dev *dev)
 /* Determine if we're in the Manufactured Inactive or Active state */
 static int get_lsp_lifecycle(struct opal_dev *dev, void *data)
 {
-	int err = 0;
+	int err;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
+	err = cmd_start(dev, opaluid[OPAL_LOCKINGSP_UID],
+			opalmethod[OPAL_GET]);
 
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_LOCKINGSP_UID],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_GET], OPAL_UID_LENGTH);
-
-	add_token_u8(&err, dev, OPAL_STARTLIST);
 	add_token_u8(&err, dev, OPAL_STARTLIST);
 
 	add_token_u8(&err, dev, OPAL_STARTNAME);
@@ -1919,19 +1836,12 @@ static int get_msid_cpin_pin_cont(struct opal_dev *dev)
 
 static int get_msid_cpin_pin(struct opal_dev *dev, void *data)
 {
-	int err = 0;
+	int err;
 
-	clear_opal_cmd(dev);
-	set_comid(dev, dev->comid);
-
-	add_token_u8(&err, dev, OPAL_CALL);
-	add_token_bytestring(&err, dev, opaluid[OPAL_C_PIN_MSID],
-			     OPAL_UID_LENGTH);
-	add_token_bytestring(&err, dev, opalmethod[OPAL_GET], OPAL_UID_LENGTH);
+	err = cmd_start(dev, opaluid[OPAL_C_PIN_MSID],
+			opalmethod[OPAL_GET]);
 
 	add_token_u8(&err, dev, OPAL_STARTLIST);
-	add_token_u8(&err, dev, OPAL_STARTLIST);
-
 	add_token_u8(&err, dev, OPAL_STARTNAME);
 	add_token_u8(&err, dev, 3); /* Start Column */
 	add_token_u8(&err, dev, 3); /* PIN */