target: pass sense_reason as a return value

Pass the sense reason as an explicit return value from the I/O submission
path instead of storing it in struct se_cmd and using negative return
values.  This cleans up a lot of the code pathes, and with the sparse
annotations for the new sense_reason_t type allows for much better
error checking.

(nab: Convert spc_emulate_modesense + spc_emulate_modeselect to use
      sense_reason_t with Roland's MODE SELECT changes)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

18 files changed, 783 insertions, 991 deletions

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 035c2c76253..093fb601027 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -767,9 +767,8 @@ static int iscsit_handle_scsi_cmd(
 	struct iscsi_conn *conn,
 	unsigned char *buf)
 {
-	int	data_direction, cmdsn_ret = 0, immed_ret, ret, transport_ret;
-	int	dump_immediate_data = 0, send_check_condition = 0, payload_length;
-	struct iscsi_cmd	*cmd = NULL;
+	int data_direction, payload_length, cmdsn_ret = 0, immed_ret;
+	struct iscsi_cmd *cmd = NULL;
 	struct iscsi_scsi_req *hdr;
 	int iscsi_task_attr;
 	int sam_task_attr;
@@ -956,38 +955,26 @@ done:
 		" ExpXferLen: %u, Length: %u, CID: %hu\n", hdr->itt,
 		hdr->cmdsn, hdr->data_length, payload_length, conn->cid);
 
-	/*
-	 * The CDB is going to an se_device_t.
-	 */
-	ret = transport_lookup_cmd_lun(&cmd->se_cmd,
-				       scsilun_to_int(&hdr->lun));
-	if (ret < 0) {
-		if (cmd->se_cmd.scsi_sense_reason == TCM_NON_EXISTENT_LUN) {
-			pr_debug("Responding to non-acl'ed,"
-				" non-existent or non-exported iSCSI LUN:"
-				" 0x%016Lx\n", get_unaligned_le64(&hdr->lun));
+	cmd->sense_reason = transport_lookup_cmd_lun(&cmd->se_cmd,
+						     scsilun_to_int(&hdr->lun));
+	if (cmd->sense_reason)
+		goto attach_cmd;
+
+	cmd->sense_reason = target_setup_cmd_from_cdb(&cmd->se_cmd, hdr->cdb);
+	if (cmd->sense_reason) {
+		if (cmd->sense_reason == TCM_OUT_OF_RESOURCES) {
+			return iscsit_add_reject_from_cmd(
+					ISCSI_REASON_BOOKMARK_NO_RESOURCES,
+					1, 1, buf, cmd);
 		}
-		send_check_condition = 1;
+
 		goto attach_cmd;
 	}
 
-	transport_ret = target_setup_cmd_from_cdb(&cmd->se_cmd, hdr->cdb);
-	if (transport_ret == -ENOMEM) {
+	if (iscsit_build_pdu_and_seq_lists(cmd, payload_length) < 0) {
 		return iscsit_add_reject_from_cmd(
-				ISCSI_REASON_BOOKMARK_NO_RESOURCES,
-				1, 1, buf, cmd);
-	} else if (transport_ret < 0) {
-		/*
-		 * Unsupported SAM Opcode.  CHECK_CONDITION will be sent
-		 * in iscsit_execute_cmd() during the CmdSN OOO Execution
-		 * Mechinism.
-		 */
-		send_check_condition = 1;
-	} else {
-		if (iscsit_build_pdu_and_seq_lists(cmd, payload_length) < 0)
-			return iscsit_add_reject_from_cmd(
-				ISCSI_REASON_BOOKMARK_NO_RESOURCES,
-				1, 1, buf, cmd);
+			ISCSI_REASON_BOOKMARK_NO_RESOURCES,
+			1, 1, buf, cmd);
 	}
 
 attach_cmd:
@@ -1000,11 +987,12 @@ attach_cmd:
 	 */
 	core_alua_check_nonop_delay(&cmd->se_cmd);
 
-	ret = iscsit_allocate_iovecs(cmd);
-	if (ret < 0)
+	if (iscsit_allocate_iovecs(cmd) < 0) {
 		return iscsit_add_reject_from_cmd(
 				ISCSI_REASON_BOOKMARK_NO_RESOURCES,
 				1, 0, buf, cmd);
+	}
+
 	/*
 	 * Check the CmdSN against ExpCmdSN/MaxCmdSN here if
 	 * the Immediate Bit is not set, and no Immediate
@@ -1031,10 +1019,7 @@ attach_cmd:
 	 * If no Immediate Data is attached, it's OK to return now.
 	 */
 	if (!cmd->immediate_data) {
-		if (send_check_condition)
-			return 0;
-
-		if (cmd->unsolicited_data) {
+		if (!cmd->sense_reason && cmd->unsolicited_data) {
 			iscsit_set_dataout_sequence_values(cmd);
 
 			spin_lock_bh(&cmd->dataout_timeout_lock);
@@ -1050,19 +1035,17 @@ attach_cmd:
 	 * thread.  They are processed in CmdSN order by
 	 * iscsit_check_received_cmdsn() below.
 	 */
-	if (send_check_condition) {
+	if (cmd->sense_reason) {
 		immed_ret = IMMEDIATE_DATA_NORMAL_OPERATION;
-		dump_immediate_data = 1;
 		goto after_immediate_data;
 	}
 	/*
 	 * Call directly into transport_generic_new_cmd() to perform
 	 * the backend memory allocation.
 	 */
-	ret = transport_generic_new_cmd(&cmd->se_cmd);
-	if (ret < 0) {
+	cmd->sense_reason = transport_generic_new_cmd(&cmd->se_cmd);
+	if (cmd->sense_reason) {
 		immed_ret = IMMEDIATE_DATA_NORMAL_OPERATION;
-		dump_immediate_data = 1;
 		goto after_immediate_data;
 	}
 
@@ -1079,7 +1062,7 @@ after_immediate_data:
 		 * Special case for Unsupported SAM WRITE Opcodes
 		 * and ImmediateData=Yes.
 		 */
-		if (dump_immediate_data) {
+		if (cmd->sense_reason) {
 			if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
 				return -1;
 		} else if (cmd->unsolicited_data) {
@@ -1272,8 +1255,7 @@ static int iscsit_handle_data_out(struct iscsi_conn *conn, unsigned char *buf)
 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
 
 		spin_lock_irqsave(&se_cmd->t_state_lock, flags);
-		if (!(se_cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) ||
-		     (se_cmd->se_cmd_flags & SCF_SCSI_CDB_EXCEPTION))
+		if (!(se_cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE))
 			dump_unsolicited_data = 1;
 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
 
@@ -1742,7 +1724,6 @@ static int iscsit_handle_task_mgt_cmd(
 		ret = transport_lookup_tmr_lun(&cmd->se_cmd,
 					       scsilun_to_int(&hdr->lun));
 		if (ret < 0) {
-			cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 			se_tmr->response = ISCSI_TMF_RSP_NO_LUN;
 			goto attach;
 		}
@@ -1751,10 +1732,8 @@ static int iscsit_handle_task_mgt_cmd(
 	switch (function) {
 	case ISCSI_TM_FUNC_ABORT_TASK:
 		se_tmr->response = iscsit_tmr_abort_task(cmd, buf);
-		if (se_tmr->response != ISCSI_TMF_RSP_COMPLETE) {
-			cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+		if (se_tmr->response)
 			goto attach;
-		}
 		break;
 	case ISCSI_TM_FUNC_ABORT_TASK_SET:
 	case ISCSI_TM_FUNC_CLEAR_ACA:
@@ -1763,14 +1742,12 @@ static int iscsit_handle_task_mgt_cmd(
 		break;
 	case ISCSI_TM_FUNC_TARGET_WARM_RESET:
 		if (iscsit_tmr_task_warm_reset(conn, tmr_req, buf) < 0) {
-			cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 			se_tmr->response = ISCSI_TMF_RSP_AUTH_FAILED;
 			goto attach;
 		}
 		break;
 	case ISCSI_TM_FUNC_TARGET_COLD_RESET:
 		if (iscsit_tmr_task_cold_reset(conn, tmr_req, buf) < 0) {
-			cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 			se_tmr->response = ISCSI_TMF_RSP_AUTH_FAILED;
 			goto attach;
 		}
@@ -1781,7 +1758,7 @@ static int iscsit_handle_task_mgt_cmd(
 		 * Perform sanity checks on the ExpDataSN only if the
 		 * TASK_REASSIGN was successful.
 		 */
-		if (se_tmr->response != ISCSI_TMF_RSP_COMPLETE)
+		if (se_tmr->response)
 			break;
 
 		if (iscsit_check_task_reassign_expdatasn(tmr_req, conn) < 0)
@@ -1792,7 +1769,6 @@ static int iscsit_handle_task_mgt_cmd(
 	default:
 		pr_err("Unknown TMR function: 0x%02x, protocol"
 			" error.\n", function);
-		cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 		se_tmr->response = ISCSI_TMF_RSP_NOT_SUPPORTED;
 		goto attach;
 	}
diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index 21048dbf7d1..7a333d28d9a 100644
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -474,7 +474,7 @@ struct iscsi_cmd {
 	struct scatterlist	*first_data_sg;
 	u32			first_data_sg_off;
 	u32			kmapped_nents;
-
+	sense_reason_t		sense_reason;
 }  ____cacheline_aligned;
 
 struct iscsi_tmr_req {
diff --git a/drivers/target/iscsi/iscsi_target_erl1.c b/drivers/target/iscsi/iscsi_target_erl1.c
index 21f29d91a8c..0b52a237130 100644
--- a/drivers/target/iscsi/iscsi_target_erl1.c
+++ b/drivers/target/iscsi/iscsi_target_erl1.c
@@ -929,11 +929,10 @@ int iscsit_execute_cmd(struct iscsi_cmd *cmd, int ooo)
 	case ISCSI_OP_SCSI_CMD:
 		/*
 		 * Go ahead and send the CHECK_CONDITION status for
-		 * any SCSI CDB exceptions that may have occurred, also
-		 * handle the SCF_SCSI_RESERVATION_CONFLICT case here as well.
+		 * any SCSI CDB exceptions that may have occurred.
 		 */
-		if (se_cmd->se_cmd_flags & SCF_SCSI_CDB_EXCEPTION) {
-			if (se_cmd->scsi_sense_reason == TCM_RESERVATION_CONFLICT) {
+		if (cmd->sense_reason) {
+			if (cmd->sense_reason == TCM_RESERVATION_CONFLICT) {
 				cmd->i_state = ISTATE_SEND_STATUS;
 				spin_unlock_bh(&cmd->istate_lock);
 				iscsit_add_cmd_to_response_queue(cmd, cmd->conn,
@@ -956,7 +955,7 @@ int iscsit_execute_cmd(struct iscsi_cmd *cmd, int ooo)
 			 * exception
 			 */
 			return transport_send_check_condition_and_sense(se_cmd,
-					se_cmd->scsi_sense_reason, 0);
+					cmd->sense_reason, 0);
 		}
 		/*
 		 * Special case for delayed CmdSN with Immediate
@@ -1013,7 +1012,7 @@ int iscsit_execute_cmd(struct iscsi_cmd *cmd, int ooo)
 		iscsit_add_cmd_to_response_queue(cmd, cmd->conn, cmd->i_state);
 		break;
 	case ISCSI_OP_SCSI_TMFUNC:
-		if (se_cmd->se_cmd_flags & SCF_SCSI_CDB_EXCEPTION) {
+		if (cmd->se_cmd.se_tmr_req->response) {
 			spin_unlock_bh(&cmd->istate_lock);
 			iscsit_add_cmd_to_response_queue(cmd, cmd->conn,
 					cmd->i_state);
diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index b3302a9200a..e62dc529e51 100644
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -41,7 +41,7 @@
 #include "target_core_alua.h"
 #include "target_core_ua.h"
 
-static int core_alua_check_transition(int state, int *primary);
+static sense_reason_t core_alua_check_transition(int state, int *primary);
 static int core_alua_set_tg_pt_secondary_state(
 		struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
 		struct se_port *port, int explict, int offline);
@@ -59,7 +59,8 @@ struct t10_alua_lu_gp *default_lu_gp;
  *
  * See spc4r17 section 6.27
  */
-int target_emulate_report_target_port_groups(struct se_cmd *cmd)
+sense_reason_t
+target_emulate_report_target_port_groups(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_port *port;
@@ -68,6 +69,7 @@ int target_emulate_report_target_port_groups(struct se_cmd *cmd)
 	unsigned char *buf;
 	u32 rd_len = 0, off;
 	int ext_hdr = (cmd->t_task_cdb[1] & 0x20);
+
 	/*
 	 * Skip over RESERVED area to first Target port group descriptor
 	 * depending on the PARAMETER DATA FORMAT type..
@@ -81,10 +83,11 @@ int target_emulate_report_target_port_groups(struct se_cmd *cmd)
 		pr_warn("REPORT TARGET PORT GROUPS allocation length %u too"
 			" small for %s header\n", cmd->data_length,
 			(ext_hdr) ? "extended" : "normal");
-		cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
-		return -EINVAL;
+		return TCM_INVALID_CDB_FIELD;
 	}
 	buf = transport_kmap_data_sg(cmd);
+	if (!buf)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 
 	spin_lock(&dev->t10_alua.tg_pt_gps_lock);
 	list_for_each_entry(tg_pt_gp, &dev->t10_alua.tg_pt_gps_list,
@@ -200,7 +203,8 @@ int target_emulate_report_target_port_groups(struct se_cmd *cmd)
  *
  * See spc4r17 section 6.35
  */
-int target_emulate_set_target_port_groups(struct se_cmd *cmd)
+sense_reason_t
+target_emulate_set_target_port_groups(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_port *port, *l_port = cmd->se_lun->lun_sep;
@@ -209,22 +213,23 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem, *l_tg_pt_gp_mem;
 	unsigned char *buf;
 	unsigned char *ptr;
+	sense_reason_t rc;
 	u32 len = 4; /* Skip over RESERVED area in header */
-	int alua_access_state, primary = 0, rc;
+	int alua_access_state, primary = 0;
 	u16 tg_pt_id, rtpi;
 
-	if (!l_port) {
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
-	}
+	if (!l_port)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
 	if (cmd->data_length < 4) {
 		pr_warn("SET TARGET PORT GROUPS parameter list length %u too"
 			" small\n", cmd->data_length);
-		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-		return -EINVAL;
+		return TCM_INVALID_PARAMETER_LIST;
 	}
 
 	buf = transport_kmap_data_sg(cmd);
+	if (!buf)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 
 	/*
 	 * Determine if explict ALUA via SET_TARGET_PORT_GROUPS is allowed
@@ -233,8 +238,7 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 	l_tg_pt_gp_mem = l_port->sep_alua_tg_pt_gp_mem;
 	if (!l_tg_pt_gp_mem) {
 		pr_err("Unable to access l_port->sep_alua_tg_pt_gp_mem\n");
-		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
-		rc = -EINVAL;
+		rc = TCM_UNSUPPORTED_SCSI_OPCODE;
 		goto out;
 	}
 	spin_lock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
@@ -242,24 +246,22 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 	if (!l_tg_pt_gp) {
 		spin_unlock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
 		pr_err("Unable to access *l_tg_pt_gp_mem->tg_pt_gp\n");
-		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
-		rc = -EINVAL;
+		rc = TCM_UNSUPPORTED_SCSI_OPCODE;
 		goto out;
 	}
-	rc = (l_tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA);
 	spin_unlock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
 
-	if (!rc) {
+	if (l_tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA) {
 		pr_debug("Unable to process SET_TARGET_PORT_GROUPS"
 				" while TPGS_EXPLICT_ALUA is disabled\n");
-		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
-		rc = -EINVAL;
+		rc = TCM_UNSUPPORTED_SCSI_OPCODE;
 		goto out;
 	}
 
 	ptr = &buf[4]; /* Skip over RESERVED area in header */
 
 	while (len < cmd->data_length) {
+		bool found = false;
 		alua_access_state = (ptr[0] & 0x0f);
 		/*
 		 * Check the received ALUA access state, and determine if
@@ -267,7 +269,7 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 		 * access state.
 		 */
 		rc = core_alua_check_transition(alua_access_state, &primary);
-		if (rc != 0) {
+		if (rc) {
 			/*
 			 * If the SET TARGET PORT GROUPS attempts to establish
 			 * an invalid combination of target port asymmetric
@@ -278,11 +280,9 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 			 * REQUEST, and the additional sense code set to INVALID
 			 * FIELD IN PARAMETER LIST.
 			 */
-			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-			rc = -EINVAL;
 			goto out;
 		}
-		rc = -1;
+
 		/*
 		 * If the ASYMMETRIC ACCESS STATE field (see table 267)
 		 * specifies a primary target port asymmetric access state,
@@ -314,11 +314,13 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 
 				atomic_inc(&tg_pt_gp->tg_pt_gp_ref_cnt);
 				smp_mb__after_atomic_inc();
+
 				spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
 
-				rc = core_alua_do_port_transition(tg_pt_gp,
+				if (!core_alua_do_port_transition(tg_pt_gp,
 						dev, l_port, nacl,
-						alua_access_state, 1);
+						alua_access_state, 1))
+					found = true;
 
 				spin_lock(&dev->t10_alua.tg_pt_gps_lock);
 				atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
@@ -326,15 +328,6 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 				break;
 			}
 			spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
-			/*
-			 * If not matching target port group ID can be located
-			 * throw an exception with ASCQ: INVALID_PARAMETER_LIST
-			 */
-			if (rc != 0) {
-				cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-				rc = -EINVAL;
-				goto out;
-			}
 		} else {
 			/*
 			 * Extact the RELATIVE TARGET PORT IDENTIFIER to identify
@@ -353,25 +346,22 @@ int target_emulate_set_target_port_groups(struct se_cmd *cmd)
 					continue;
 
 				tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
+
 				spin_unlock(&dev->se_port_lock);
 
-				rc = core_alua_set_tg_pt_secondary_state(
-						tg_pt_gp_mem, port, 1, 1);
+				if (!core_alua_set_tg_pt_secondary_state(
+						tg_pt_gp_mem, port, 1, 1))
+					found = true;
 
 				spin_lock(&dev->se_port_lock);
 				break;
 			}
 			spin_unlock(&dev->se_port_lock);
-			/*
-			 * If not matching relative target port identifier can
-			 * be located, throw an exception with ASCQ:
-			 * INVALID_PARAMETER_LIST
-			 */
-			if (rc != 0) {
-				cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-				rc = -EINVAL;
-				goto out;
-			}
+		}
+
+		if (!found) {
+			rc = TCM_INVALID_PARAMETER_LIST;
+			goto out;
 		}
 
 		ptr += 4;
@@ -526,7 +516,8 @@ static inline int core_alua_state_transition(
  * return 0: Used to signal success
  * reutrn -1: Used to signal failure, and invalid cdb field
  */
-int target_alua_state_check(struct se_cmd *cmd)
+sense_reason_t
+target_alua_state_check(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	unsigned char *cdb = cmd->t_task_cdb;
@@ -599,8 +590,7 @@ int target_alua_state_check(struct se_cmd *cmd)
 	default:
 		pr_err("Unknown ALUA access state: 0x%02x\n",
 				out_alua_state);
-		ret = -EINVAL;
-		break;
+		return TCM_INVALID_CDB_FIELD;
 	}
 
 out:
@@ -617,15 +607,17 @@ out:
 
 		cmd->scsi_asc = 0x04;
 		cmd->scsi_ascq = alua_ascq;
+		return TCM_CHECK_CONDITION_NOT_READY;
 	}
 
-	return ret;
+	return 0;
 }
 
 /*
  * Check implict and explict ALUA state change request.
  */
-static int core_alua_check_transition(int state, int *primary)
+static sense_reason_t
+core_alua_check_transition(int state, int *primary)
 {
 	switch (state) {
 	case ALUA_ACCESS_STATE_ACTIVE_OPTMIZED:
@@ -647,7 +639,7 @@ static int core_alua_check_transition(int state, int *primary)
 		break;
 	default:
 		pr_err("Unknown ALUA access state: 0x%02x\n", state);
-		return -EINVAL;
+		return TCM_INVALID_PARAMETER_LIST;
 	}
 
 	return 0;
diff --git a/drivers/target/target_core_alua.h b/drivers/target/target_core_alua.h
index a2af8aa15b9..e539c3e7f4a 100644
--- a/drivers/target/target_core_alua.h
+++ b/drivers/target/target_core_alua.h
@@ -72,8 +72,8 @@ extern struct kmem_cache *t10_alua_lu_gp_mem_cache;
 extern struct kmem_cache *t10_alua_tg_pt_gp_cache;
 extern struct kmem_cache *t10_alua_tg_pt_gp_mem_cache;
 
-extern int target_emulate_report_target_port_groups(struct se_cmd *);
-extern int target_emulate_set_target_port_groups(struct se_cmd *);
+extern sense_reason_t target_emulate_report_target_port_groups(struct se_cmd *);
+extern sense_reason_t target_emulate_set_target_port_groups(struct se_cmd *);
 extern int core_alua_check_nonop_delay(struct se_cmd *);
 extern int core_alua_do_port_transition(struct t10_alua_tg_pt_gp *,
 				struct se_device *, struct se_port *,
@@ -132,6 +132,6 @@ extern ssize_t core_alua_show_secondary_write_metadata(struct se_lun *,
 extern ssize_t core_alua_store_secondary_write_metadata(struct se_lun *,
 					const char *, size_t);
 extern int core_setup_alua(struct se_device *);
-extern int target_alua_state_check(struct se_cmd *cmd);
+extern sense_reason_t target_alua_state_check(struct se_cmd *cmd);
 
 #endif /* TARGET_CORE_ALUA_H */
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 066e8159afc..599374e6d24 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -54,18 +54,16 @@ static struct se_hba *lun0_hba;
 /* not static, needed by tpg.c */
 struct se_device *g_lun0_dev;
 
-int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
+sense_reason_t
+transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
 {
 	struct se_lun *se_lun = NULL;
 	struct se_session *se_sess = se_cmd->se_sess;
 	struct se_device *dev;
 	unsigned long flags;
 
-	if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
-		se_cmd->scsi_sense_reason = TCM_NON_EXISTENT_LUN;
-		se_cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
-		return -ENODEV;
-	}
+	if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG)
+		return TCM_NON_EXISTENT_LUN;
 
 	spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags);
 	se_cmd->se_deve = se_sess->se_node_acl->device_list[unpacked_lun];
@@ -77,14 +75,12 @@ int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
 
 		if ((se_cmd->data_direction == DMA_TO_DEVICE) &&
 		    (deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)) {
-			se_cmd->scsi_sense_reason = TCM_WRITE_PROTECTED;
-			se_cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 			pr_err("TARGET_CORE[%s]: Detected WRITE_PROTECTED LUN"
 				" Access for 0x%08x\n",
 				se_cmd->se_tfo->get_fabric_name(),
 				unpacked_lun);
 			spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags);
-			return -EACCES;
+			return TCM_WRITE_PROTECTED;
 		}
 
 		if (se_cmd->data_direction == DMA_TO_DEVICE)
@@ -109,23 +105,18 @@ int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
 		 * MappedLUN=0 exists for this Initiator Port.
 		 */
 		if (unpacked_lun != 0) {
-			se_cmd->scsi_sense_reason = TCM_NON_EXISTENT_LUN;
-			se_cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 			pr_err("TARGET_CORE[%s]: Detected NON_EXISTENT_LUN"
 				" Access for 0x%08x\n",
 				se_cmd->se_tfo->get_fabric_name(),
 				unpacked_lun);
-			return -ENODEV;
+			return TCM_NON_EXISTENT_LUN;
 		}
 		/*
 		 * Force WRITE PROTECT for virtual LUN 0
 		 */
 		if ((se_cmd->data_direction != DMA_FROM_DEVICE) &&
-		    (se_cmd->data_direction != DMA_NONE)) {
-			se_cmd->scsi_sense_reason = TCM_WRITE_PROTECTED;
-			se_cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
-			return -EACCES;
-		}
+		    (se_cmd->data_direction != DMA_NONE))
+			return TCM_WRITE_PROTECTED;
 
 		se_lun = &se_sess->se_tpg->tpg_virt_lun0;
 		se_cmd->se_lun = &se_sess->se_tpg->tpg_virt_lun0;
@@ -162,11 +153,8 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
 	struct se_tmr_req *se_tmr = se_cmd->se_tmr_req;
 	unsigned long flags;
 
-	if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
-		se_cmd->scsi_sense_reason = TCM_NON_EXISTENT_LUN;
-		se_cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+	if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG)
 		return -ENODEV;
-	}
 
 	spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags);
 	se_cmd->se_deve = se_sess->se_node_acl->device_list[unpacked_lun];
@@ -186,7 +174,6 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
 			" Access for 0x%08x\n",
 			se_cmd->se_tfo->get_fabric_name(),
 			unpacked_lun);
-		se_cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 		return -ENODEV;
 	}
 
diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 342a6a6dcca..3ccef831a64 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -309,7 +309,8 @@ static int fd_do_writev(struct se_cmd *cmd, struct scatterlist *sgl,
 	return 1;
 }
 
-static int fd_execute_sync_cache(struct se_cmd *cmd)
+static sense_reason_t
+fd_execute_sync_cache(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct fd_dev *fd_dev = FD_DEV(dev);
@@ -345,17 +346,16 @@ static int fd_execute_sync_cache(struct se_cmd *cmd)
 	if (immed)
 		return 0;
 
-	if (ret) {
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	if (ret)
 		target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
-	} else {
+	else
 		target_complete_cmd(cmd, SAM_STAT_GOOD);
-	}
 
 	return 0;
 }
 
-static int fd_execute_rw(struct se_cmd *cmd)
+static sense_reason_t
+fd_execute_rw(struct se_cmd *cmd)
 {
 	struct scatterlist *sgl = cmd->t_data_sg;
 	u32 sgl_nents = cmd->t_data_nents;
@@ -388,10 +388,9 @@ static int fd_execute_rw(struct se_cmd *cmd)
 		}
 	}
 
-	if (ret < 0) {
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return ret;
-	}
+	if (ret < 0)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
 	if (ret)
 		target_complete_cmd(cmd, SAM_STAT_GOOD);
 	return 0;
@@ -515,7 +514,8 @@ static struct sbc_ops fd_sbc_ops = {
 	.execute_sync_cache	= fd_execute_sync_cache,
 };
 
-static int fd_parse_cdb(struct se_cmd *cmd)
+static sense_reason_t
+fd_parse_cdb(struct se_cmd *cmd)
 {
 	return sbc_parse_cdb(cmd, &fd_sbc_ops);
 }
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 17fc01d6bae..53f4501819f 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -261,13 +261,10 @@ static void iblock_end_io_flush(struct bio *bio, int err)
 		pr_err("IBLOCK: cache flush failed: %d\n", err);
 
 	if (cmd) {
-		if (err) {
-			cmd->scsi_sense_reason =
-				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+		if (err)
 			target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
-		} else {
+		else
 			target_complete_cmd(cmd, SAM_STAT_GOOD);
-		}
 	}
 
 	bio_put(bio);
@@ -277,7 +274,8 @@ static void iblock_end_io_flush(struct bio *bio, int err)
  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
  * always flush the whole cache.
  */
-static int iblock_execute_sync_cache(struct se_cmd *cmd)
+static sense_reason_t
+iblock_execute_sync_cache(struct se_cmd *cmd)
 {
 	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 	int immed = (cmd->t_task_cdb[1] & 0x2);
@@ -299,7 +297,8 @@ static int iblock_execute_sync_cache(struct se_cmd *cmd)
 	return 0;
 }
 
-static int iblock_execute_unmap(struct se_cmd *cmd)
+static sense_reason_t
+iblock_execute_unmap(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
@@ -307,17 +306,18 @@ static int iblock_execute_unmap(struct se_cmd *cmd)
 	sector_t lba;
 	int size;
 	u32 range;
-	int ret = 0;
-	int dl, bd_dl;
+	sense_reason_t ret = 0;
+	int dl, bd_dl, err;
 
 	if (cmd->data_length < 8) {
 		pr_warn("UNMAP parameter list length %u too small\n",
 			cmd->data_length);
-		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-		return -EINVAL;
+		return TCM_INVALID_PARAMETER_LIST;
 	}
 
 	buf = transport_kmap_data_sg(cmd);
+	if (!buf)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 
 	dl = get_unaligned_be16(&buf[0]);
 	bd_dl = get_unaligned_be16(&buf[2]);
@@ -330,8 +330,7 @@ static int iblock_execute_unmap(struct se_cmd *cmd)
 		size = bd_dl;
 
 	if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
-		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-		ret = -EINVAL;
+		ret = TCM_INVALID_PARAMETER_LIST;
 		goto err;
 	}
 
@@ -347,22 +346,21 @@ static int iblock_execute_unmap(struct se_cmd *cmd)
 				 (unsigned long long)lba, range);
 
 		if (range > dev->dev_attrib.max_unmap_lba_count) {
-			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-			ret = -EINVAL;
+			ret = TCM_INVALID_PARAMETER_LIST;
 			goto err;
 		}
 
 		if (lba + range > dev->transport->get_blocks(dev) + 1) {
-			cmd->scsi_sense_reason = TCM_ADDRESS_OUT_OF_RANGE;
-			ret = -EINVAL;
+			ret = TCM_ADDRESS_OUT_OF_RANGE;
 			goto err;
 		}
 
-		ret = blkdev_issue_discard(ib_dev->ibd_bd, lba, range,
+		err = blkdev_issue_discard(ib_dev->ibd_bd, lba, range,
 					   GFP_KERNEL, 0);
-		if (ret < 0) {
+		if (err < 0) {
 			pr_err("blkdev_issue_discard() failed: %d\n",
-					ret);
+					err);
+			ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 			goto err;
 		}
 
@@ -377,7 +375,8 @@ err:
 	return ret;
 }
 
-static int iblock_execute_write_same(struct se_cmd *cmd)
+static sense_reason_t
+iblock_execute_write_same(struct se_cmd *cmd)
 {
 	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 	int ret;
@@ -387,7 +386,7 @@ static int iblock_execute_write_same(struct se_cmd *cmd)
 				   0);
 	if (ret < 0) {
 		pr_debug("blkdev_issue_discard() failed for WRITE_SAME\n");
-		return ret;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 
 	target_complete_cmd(cmd, GOOD);
@@ -552,7 +551,8 @@ static void iblock_submit_bios(struct bio_list *list, int rw)
 	blk_finish_plug(&plug);
 }
 
-static int iblock_execute_rw(struct se_cmd *cmd)
+static sense_reason_t
+iblock_execute_rw(struct se_cmd *cmd)
 {
 	struct scatterlist *sgl = cmd->t_data_sg;
 	u32 sgl_nents = cmd->t_data_nents;
@@ -598,8 +598,7 @@ static int iblock_execute_rw(struct se_cmd *cmd)
 	else {
 		pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 				" %u\n", dev->dev_attrib.block_size);
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -ENOSYS;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 
 	ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
@@ -659,9 +658,8 @@ fail_put_bios:
 		bio_put(bio);
 fail_free_ibr:
 	kfree(ibr);
-	cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 fail:
-	return -ENOMEM;
+	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 }
 
 static sector_t iblock_get_blocks(struct se_device *dev)
@@ -706,7 +704,8 @@ static struct sbc_ops iblock_sbc_ops = {
 	.execute_unmap		= iblock_execute_unmap,
 };
 
-static int iblock_parse_cdb(struct se_cmd *cmd)
+static sense_reason_t
+iblock_parse_cdb(struct se_cmd *cmd)
 {
 	return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 }
diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index 2f37720c4db..bc9c5228484 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -101,7 +101,7 @@ int	transport_dump_vpd_ident(struct t10_vpd *, unsigned char *, int);
 bool	target_stop_cmd(struct se_cmd *cmd, unsigned long *flags);
 int	transport_clear_lun_from_sessions(struct se_lun *);
 void	transport_send_task_abort(struct se_cmd *);
-int	target_cmd_size_check(struct se_cmd *cmd, unsigned int size);
+sense_reason_t	target_cmd_size_check(struct se_cmd *cmd, unsigned int size);
 void	target_qf_do_work(struct work_struct *work);
 
 /* target_core_stat.c */
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index f561a08ff8e..ffbe0ea9bba 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -68,7 +68,8 @@ int core_pr_dump_initiator_port(
 static void __core_scsi3_complete_pro_release(struct se_device *, struct se_node_acl *,
 			struct t10_pr_registration *, int);
 
-static int target_scsi2_reservation_check(struct se_cmd *cmd)
+static sense_reason_t
+target_scsi2_reservation_check(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_session *sess = cmd->se_sess;
@@ -86,11 +87,11 @@ static int target_scsi2_reservation_check(struc