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>

1 files changed, 411 insertions, 507 deletions

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(struct se_cmd *cmd)
 		return 0;
 
 	if (dev->dev_reserved_node_acl != sess->se_node_acl)
-		return -EBUSY;
+		return TCM_RESERVATION_CONFLICT;
 
 	if (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS_WITH_ISID) {
 		if (dev->dev_res_bin_isid != sess->sess_bin_isid)
-			return -EBUSY;
+			return TCM_RESERVATION_CONFLICT;
 	}
 
 	return 0;
@@ -165,32 +166,28 @@ static int target_check_scsi2_reservation_conflict(struct se_cmd *cmd)
 		pr_err("Received legacy SPC-2 RESERVE/RELEASE"
 			" while active SPC-3 registrations exist,"
 			" returning RESERVATION_CONFLICT\n");
-		cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
 		return -EBUSY;
 	}
 
 	return 0;
 }
 
-int target_scsi2_reservation_release(struct se_cmd *cmd)
+sense_reason_t
+target_scsi2_reservation_release(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_session *sess = cmd->se_sess;
 	struct se_portal_group *tpg;
-	int ret = 0, rc;
+	int rc;
 
 	if (!sess || !sess->se_tpg)
 		goto out;
 	rc = target_check_scsi2_reservation_conflict(cmd);
 	if (rc == 1)
 		goto out;
-	else if (rc < 0) {
-		cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-		ret = -EINVAL;
-		goto out;
-	}
+	if (rc < 0)
+		return TCM_RESERVATION_CONFLICT;
 
-	ret = 0;
 	spin_lock(&dev->dev_reservation_lock);
 	if (!dev->dev_reserved_node_acl || !sess)
 		goto out_unlock;
@@ -216,25 +213,24 @@ int target_scsi2_reservation_release(struct se_cmd *cmd)
 out_unlock:
 	spin_unlock(&dev->dev_reservation_lock);
 out:
-	if (!ret)
-		target_complete_cmd(cmd, GOOD);
-	return ret;
+	target_complete_cmd(cmd, GOOD);
+	return 0;
 }
 
-int target_scsi2_reservation_reserve(struct se_cmd *cmd)
+sense_reason_t
+target_scsi2_reservation_reserve(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_session *sess = cmd->se_sess;
 	struct se_portal_group *tpg;
-	int ret = 0, rc;
+	sense_reason_t ret = 0;
+	int rc;
 
 	if ((cmd->t_task_cdb[1] & 0x01) &&
 	    (cmd->t_task_cdb[1] & 0x02)) {
 		pr_err("LongIO and Obselete Bits set, returning"
 				" ILLEGAL_REQUEST\n");
-		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
-		ret = -EINVAL;
-		goto out;
+		return TCM_UNSUPPORTED_SCSI_OPCODE;
 	}
 	/*
 	 * This is currently the case for target_core_mod passthrough struct se_cmd
@@ -245,13 +241,10 @@ int target_scsi2_reservation_reserve(struct se_cmd *cmd)
 	rc = target_check_scsi2_reservation_conflict(cmd);
 	if (rc == 1)
 		goto out;
-	else if (rc < 0) {
-		cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-		ret = -EINVAL;
-		goto out;
-	}
 
-	ret = 0;
+	if (rc < 0)
+		return TCM_RESERVATION_CONFLICT;
+
 	tpg = sess->se_tpg;
 	spin_lock(&dev->dev_reservation_lock);
 	if (dev->dev_reserved_node_acl &&
@@ -265,8 +258,7 @@ int target_scsi2_reservation_reserve(struct se_cmd *cmd)
 			" from %s \n", cmd->se_lun->unpacked_lun,
 			cmd->se_deve->mapped_lun,
 			sess->se_node_acl->initiatorname);
-		cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-		ret = -EINVAL;
+		ret = TCM_RESERVATION_CONFLICT;
 		goto out_unlock;
 	}
 
@@ -536,7 +528,8 @@ static int core_scsi3_pr_seq_non_holder(
 	return 1; /* Conflict by default */
 }
 
-static int target_scsi3_pr_reservation_check(struct se_cmd *cmd)
+static sense_reason_t
+target_scsi3_pr_reservation_check(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_session *sess = cmd->se_sess;
@@ -562,7 +555,7 @@ static int target_scsi3_pr_reservation_check(struct se_cmd *cmd)
 
 check_nonholder:
 	if (core_scsi3_pr_seq_non_holder(cmd, pr_reg_type))
-		return -EBUSY;
+		return TCM_RESERVATION_CONFLICT;
 	return 0;
 }
 
@@ -1435,7 +1428,8 @@ static void core_scsi3_lunacl_undepend_item(struct se_dev_entry *se_deve)
 	smp_mb__after_atomic_dec();
 }
 
-static int core_scsi3_decode_spec_i_port(
+static sense_reason_t
+core_scsi3_decode_spec_i_port(
 	struct se_cmd *cmd,
 	struct se_portal_group *tpg,
 	unsigned char *l_isid,
@@ -1457,8 +1451,9 @@ static int core_scsi3_decode_spec_i_port(
 	unsigned char *buf;
 	unsigned char *ptr, *i_str = NULL, proto_ident, tmp_proto_ident;
 	char *iport_ptr = NULL, dest_iport[64], i_buf[PR_REG_ISID_ID_LEN];
+	sense_reason_t ret;
 	u32 tpdl, tid_len = 0;
-	int ret, dest_local_nexus, prf_isid;
+	int dest_local_nexus, prf_isid;
 	u32 dest_rtpi = 0;
 
 	memset(dest_iport, 0, 64);
@@ -1473,8 +1468,7 @@ static int core_scsi3_decode_spec_i_port(
 	tidh_new = kzalloc(sizeof(struct pr_transport_id_holder), GFP_KERNEL);
 	if (!tidh_new) {
 		pr_err("Unable to allocate tidh_new\n");
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 	INIT_LIST_HEAD(&tidh_new->dest_list);
 	tidh_new->dest_tpg = tpg;
@@ -1486,8 +1480,7 @@ static int core_scsi3_decode_spec_i_port(
 				sa_res_key, all_tg_pt, aptpl);
 	if (!local_pr_reg) {
 		kfree(tidh_new);
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -ENOMEM;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 	tidh_new->dest_pr_reg = local_pr_reg;
 	/*
@@ -1501,12 +1494,16 @@ static int core_scsi3_decode_spec_i_port(
 	if (cmd->data_length < 28) {
 		pr_warn("SPC-PR: Received PR OUT parameter list"
 			" length too small: %u\n", cmd->data_length);
-		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-		ret = -EINVAL;
+		ret = TCM_INVALID_PARAMETER_LIST;
 		goto out;
 	}
 
 	buf = transport_kmap_data_sg(cmd);
+	if (!buf) {
+		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+		goto out;
+	}
+
 	/*
 	 * For a PERSISTENT RESERVE OUT specify initiator ports payload,
 	 * first extract TransportID Parameter Data Length, and make sure
@@ -1521,9 +1518,8 @@ static int core_scsi3_decode_spec_i_port(
 		pr_err("SPC-3 PR: Illegal tpdl: %u + 28 byte header"
 			" does not equal CDB data_length: %u\n", tpdl,
 			cmd->data_length);
-		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-		ret = -EINVAL;
-		goto out;
+		ret = TCM_INVALID_PARAMETER_LIST;
+		goto out_unmap;
 	}
 	/*
 	 * Start processing the received transport IDs using the
@@ -1566,16 +1562,13 @@ static int core_scsi3_decode_spec_i_port(
 			smp_mb__after_atomic_inc();
 			spin_unlock(&dev->se_port_lock);
 
-			ret = core_scsi3_tpg_depend_item(tmp_tpg);
-			if (ret != 0) {
+			if (core_scsi3_tpg_depend_item(tmp_tpg)) {
 				pr_err(" core_scsi3_tpg_depend_item()"
 					" for tmp_tpg\n");
 				atomic_dec(&tmp_tpg->tpg_pr_ref_count);
 				smp_mb__after_atomic_dec();
-				cmd->scsi_sense_reason =
-					TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-				ret = -EINVAL;
-				goto out;
+				ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+				goto out_unmap;
 			}
 			/*
 			 * Locate the destination initiator ACL to be registered
@@ -1597,17 +1590,14 @@ static int core_scsi3_decode_spec_i_port(
 				continue;
 			}
 
-			ret = core_scsi3_nodeacl_depend_item(dest_node_acl);
-			if (ret != 0) {
+			if (core_scsi3_nodeacl_depend_item(dest_node_acl)) {
 				pr_err("configfs_depend_item() failed"
 					" for dest_node_acl->acl_group\n");
 				atomic_dec(&dest_node_acl->acl_pr_ref_count);
 				smp_mb__after_atomic_dec();
 				core_scsi3_tpg_undepend_item(tmp_tpg);
-				cmd->scsi_sense_reason =
-					TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-				ret = -EINVAL;
-				goto out;
+				ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+				goto out_unmap;
 			}
 
 			dest_tpg = tmp_tpg;
@@ -1624,9 +1614,8 @@ static int core_scsi3_decode_spec_i_port(
 		if (!dest_tpg) {
 			pr_err("SPC-3 PR SPEC_I_PT: Unable to locate"
 					" dest_tpg\n");
-			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-			ret = -EINVAL;
-			goto out;
+			ret = TCM_INVALID_PARAMETER_LIST;
+			goto out_unmap;
 		}
 
 		pr_debug("SPC-3 PR SPEC_I_PT: Got %s data_length: %u tpdl: %u"
@@ -1639,9 +1628,8 @@ static int core_scsi3_decode_spec_i_port(
 				" %u for Transport ID: %s\n", tid_len, ptr);
 			core_scsi3_nodeacl_undepend_item(dest_node_acl);
 			core_scsi3_tpg_undepend_item(dest_tpg);
-			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-			ret = -EINVAL;
-			goto out;
+			ret = TCM_INVALID_PARAMETER_LIST;
+			goto out_unmap;
 		}
 		/*
 		 * Locate the desintation struct se_dev_entry pointer for matching
@@ -1658,23 +1646,19 @@ static int core_scsi3_decode_spec_i_port(
 
 			core_scsi3_nodeacl_undepend_item(dest_node_acl);
 			core_scsi3_tpg_undepend_item(dest_tpg);
-			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-			ret = -EINVAL;
-			goto out;
+			ret = TCM_INVALID_PARAMETER_LIST;
+			goto out_unmap;
 		}
 
-		ret = core_scsi3_lunacl_depend_item(dest_se_deve);
-		if (ret < 0) {
+		if (core_scsi3_lunacl_depend_item(dest_se_deve)) {
 			pr_err("core_scsi3_lunacl_depend_item()"
 					" failed\n");
 			atomic_dec(&dest_se_deve->pr_ref_count);
 			smp_mb__after_atomic_dec();
 			core_scsi3_nodeacl_undepend_item(dest_node_acl);
 			core_scsi3_tpg_undepend_item(dest_tpg);
-			cmd->scsi_sense_reason =
-				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-			ret = -EINVAL;
-			goto out;
+			ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+			goto out_unmap;
 		}
 
 		pr_debug("SPC-3 PR SPEC_I_PT: Located %s Node: %s"
@@ -1710,10 +1694,8 @@ static int core_scsi3_decode_spec_i_port(
 			core_scsi3_lunacl_undepend_item(dest_se_deve);
 			core_scsi3_nodeacl_undepend_item(dest_node_acl);
 			core_scsi3_tpg_undepend_item(dest_tpg);
-			cmd->scsi_sense_reason =
-				TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-			ret = -ENOMEM;
-			goto out;
+			ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+			goto out_unmap;
 		}
 		INIT_LIST_HEAD(&tidh_new->dest_list);
 		tidh_new->dest_tpg = dest_tpg;
@@ -1744,9 +1726,8 @@ static int core_scsi3_decode_spec_i_port(
 			core_scsi3_nodeacl_undepend_item(dest_node_acl);
 			core_scsi3_tpg_undepend_item(dest_tpg);
 			kfree(tidh_new);
-			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-			ret = -EINVAL;
-			goto out;
+			ret = TCM_INVALID_PARAMETER_LIST;
+			goto out_unmap;
 		}
 		tidh_new->dest_pr_reg = dest_pr_reg;
 		list_add_tail(&tidh_new->dest_list, &tid_dest_list);
@@ -1804,8 +1785,9 @@ static int core_scsi3_decode_spec_i_port(
 	}
 
 	return 0;
-out:
+out_unmap:
 	transport_kunmap_data_sg(cmd);
+out:
 	/*
 	 * For the failure case, release everything from tid_dest_list
 	 * including *dest_pr_reg and the configfs dependances..
@@ -2020,14 +2002,15 @@ static int __core_scsi3_write_aptpl_to_file(
 	return 0;
 }
 
-static int core_scsi3_update_and_write_aptpl(
-	struct se_device *dev,
-	unsigned char *in_buf,
-	u32 in_pr_aptpl_buf_len)
+static int
+core_scsi3_update_and_write_aptpl(struct se_device *dev, unsigned char *in_buf,
+		u32 in_pr_aptpl_buf_len)
 {
 	unsigned char null_buf[64], *buf;
 	u32 pr_aptpl_buf_len;
-	int ret, clear_aptpl_metadata = 0;
+	int clear_aptpl_metadata = 0;
+	int ret;
+
 	/*
 	 * Can be called with a NULL pointer from PROUT service action CLEAR
 	 */
@@ -2049,25 +2032,17 @@ static int core_scsi3_update_and_write_aptpl(
 				clear_aptpl_metadata);
 	if (ret != 0)
 		return ret;
+
 	/*
 	 * __core_scsi3_write_aptpl_to_file() will call strlen()
 	 * on the passed buf to determine pr_aptpl_buf_len.
 	 */
-	ret = __core_scsi3_write_aptpl_to_file(dev, buf, 0);
-	if (ret != 0)
-		return ret;
-
-	return ret;
+	return __core_scsi3_write_aptpl_to_file(dev, buf, 0);
 }
 
-static int core_scsi3_emulate_pro_register(
-	struct se_cmd *cmd,
-	u64 res_key,
-	u64 sa_res_key,
-	int aptpl,
-	int all_tg_pt,
-	int spec_i_pt,
-	int ignore_key)
+static sense_reason_t
+core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
+		int aptpl, int all_tg_pt, int spec_i_pt, int ignore_key)
 {
 	struct se_session *se_sess = cmd->se_sess;
 	struct se_device *dev = cmd->se_dev;
@@ -2079,12 +2054,12 @@ static int core_scsi3_emulate_pro_register(
 	/* Used for APTPL metadata w/ UNREGISTER */
 	unsigned char *pr_aptpl_buf = NULL;
 	unsigned char isid_buf[PR_REG_ISID_LEN], *isid_ptr = NULL;
-	int pr_holder = 0, ret = 0, type;
+	sense_reason_t ret;
+	int pr_holder = 0, type;
 
 	if (!se_sess || !se_lun) {
 		pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 	se_tpg = se_sess->se_tpg;
 	se_deve = se_sess->se_node_acl->device_list[cmd->orig_fe_lun];
@@ -2103,8 +2078,7 @@ static int core_scsi3_emulate_pro_register(
 		if (res_key) {
 			pr_warn("SPC-3 PR: Reservation Key non-zero"
 				" for SA REGISTER, returning CONFLICT\n");
-			cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-			return -EINVAL;
+			return TCM_RESERVATION_CONFLICT;
 		}
 		/*
 		 * Do nothing but return GOOD status.
@@ -2118,15 +2092,13 @@ static int core_scsi3_emulate_pro_register(
 			 * Port Endpoint that the PRO was received from on the
 			 * Logical Unit of the SCSI device server.
 			 */
-			ret = core_scsi3_alloc_registration(cmd->se_dev,
+			if (core_scsi3_alloc_registration(cmd->se_dev,
 					se_sess->se_node_acl, se_deve, isid_ptr,
 					sa_res_key, all_tg_pt, aptpl,
-					ignore_key, 0);
-			if (ret != 0) {
+					ignore_key, 0)) {
 				pr_err("Unable to allocate"
 					" struct t10_pr_registration\n");
-				cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-				return -EINVAL;
+				return TCM_INVALID_PARAMETER_LIST;
 			}
 		} else {
 			/*
@@ -2160,201 +2132,192 @@ static int core_scsi3_emulate_pro_register(
 		pr_reg = core_scsi3_locate_pr_reg(cmd->se_dev,
 				se_sess->se_node_acl, se_sess);
 
-		ret = core_scsi3_update_and_write_aptpl(cmd->se_dev,
+		if (core_scsi3_update_and_write_aptpl(cmd->se_dev,
 				&pr_reg->pr_aptpl_buf[0],
-				pr_tmpl->pr_aptpl_buf_len);
-		if (!ret) {
+				pr_tmpl->pr_aptpl_buf_len)) {
 			pr_tmpl->pr_aptpl_active = 1;
 			pr_debug("SPC-3 PR: Set APTPL Bit Activated for REGISTER\n");
 		}
 
-		core_scsi3_put_pr_reg(pr_reg);
-		return ret;
-	} else {
-		/*
-		 * Locate the existing *pr_reg via struct se_node_acl pointers
-		 */
-		pr_reg = pr_reg_e;
-		type = pr_reg->pr_res_type;
-
-		if (!ignore_key) {
-			if (res_key != pr_reg->pr_res_key) {
-				pr_err("SPC-3 PR REGISTER: Received"
-					" res_key: 0x%016Lx does not match"
-					" existing SA REGISTER res_key:"
-					" 0x%016Lx\n", res_key,
-					pr_reg->pr_res_key);
-				core_scsi3_put_pr_reg(pr_reg);
-				cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-				return -EINVAL;
-			}
+		goto out_put_pr_reg;
+	}
+
+	/*
+	 * Locate the existing *pr_reg via struct se_node_acl pointers
+	 */
+	pr_reg = pr_reg_e;
+	type = pr_reg->pr_res_type;
+
+	if (!ignore_key) {
+		if (res_key != pr_reg->pr_res_key) {
+			pr_err("SPC-3 PR REGISTER: Received"
+				" res_key: 0x%016Lx does not match"
+				" existing SA REGISTER res_key:"
+				" 0x%016Lx\n", res_key,
+				pr_reg->pr_res_key);
+			ret = TCM_RESERVATION_CONFLICT;
+			goto out_put_pr_reg;
 		}
-		if (spec_i_pt) {
-			pr_err("SPC-3 PR UNREGISTER: SPEC_I_PT"
-				" set while sa_res_key=0\n");
-			core_scsi3_put_pr_reg(pr_reg);
-			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-			return -EINVAL;
+	}
+
+	if (spec_i_pt) {
+		pr_err("SPC-3 PR UNREGISTER: SPEC_I_PT"
+			" set while sa_res_key=0\n");
+		ret = TCM_INVALID_PARAMETER_LIST;
+		goto out_put_pr_reg;
+	}
+
+	/*
+	 * An existing ALL_TG_PT=1 registration being released
+	 * must also set ALL_TG_PT=1 in the incoming PROUT.
+	 */
+	if (pr_reg->pr_reg_all_tg_pt && !(all_tg_pt)) {
+		pr_err("SPC-3 PR UNREGISTER: ALL_TG_PT=1"
+			" registration exists, but ALL_TG_PT=1 bit not"
+			" present in received PROUT\n");
+		ret = TCM_INVALID_CDB_FIELD;
+		goto out_put_pr_reg;
+	}
+
+	/*
+	 * Allocate APTPL metadata buffer used for UNREGISTER ops
+	 */
+	if (aptpl) {
+		pr_aptpl_buf = kzalloc(pr_tmpl->pr_aptpl_buf_len,
+					GFP_KERNEL);
+		if (!pr_aptpl_buf) {
+			pr_err("Unable to allocate"
+				" pr_aptpl_buf\n");
+			ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+			goto out_put_pr_reg;
 		}
-		/*
-		 * An existing ALL_TG_PT=1 registration being released
-		 * must also set ALL_TG_PT=1 in the incoming PROUT.
-		 */
-		if (pr_reg->pr_reg_all_tg_pt && !(all_tg_pt)) {
-			pr_err("SPC-3 PR UNREGISTER: ALL_TG_PT=1"
-				" registration exists, but ALL_TG_PT=1 bit not"
-				" present in received PROUT\n");
-			core_scsi3_put_pr_reg(pr_reg);
-			cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
-			return -EINVAL;
+	}
+
+	/*
+	 * sa_res_key=0 Unregister Reservation Key for registered I_T
+	 * Nexus sa_res_key=1 Change Reservation Key for registered I_T
+	 * Nexus.
+	 */
+	if (!sa_res_key) {
+		pr_holder = core_scsi3_check_implict_release(
+				cmd->se_dev, pr_reg);
+		if (pr_holder < 0) {
+			kfree(pr_aptpl_buf);
+			ret = TCM_RESERVATION_CONFLICT;
+			goto out_put_pr_reg;
 		}
+
+		spin_lock(&pr_tmpl->registration_lock);
 		/*
-		 * Allocate APTPL metadata buffer used for UNREGISTER ops
+		 * Release all ALL_TG_PT=1 for the matching SCSI Initiator Port
+		 * and matching pr_res_key.
 		 */
-		if (aptpl) {
-			pr_aptpl_buf = kzalloc(pr_tmpl->pr_aptpl_buf_len,
-						GFP_KERNEL);
-			if (!pr_aptpl_buf) {
-				pr_err("Unable to allocate"
-					" pr_aptpl_buf\n");
-				core_scsi3_put_pr_reg(pr_reg);
-				cmd->scsi_sense_reason =
-					TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-				return -EINVAL;
+		if (pr_reg->pr_reg_all_tg_pt) {
+			list_for_each_entry_safe(pr_reg_p, pr_reg_tmp,
+					&pr_tmpl->registration_list,
+					pr_reg_list) {
+
+				if (!pr_reg_p->pr_reg_all_tg_pt)
+					continue;
+				if (pr_reg_p->pr_res_key != res_key)
+					continue;
+				if (pr_reg == pr_reg_p)
+					continue;
+				if (strcmp(pr_reg->pr_reg_nacl->initiatorname,
+					   pr_reg_p->pr_reg_nacl->initiatorname))
+					continue;
+
+				__core_scsi3_free_registration(dev,
+						pr_reg_p, NULL, 0);
 			}
 		}
+
 		/*
-		 * sa_res_key=0 Unregister Reservation Key for registered I_T
-		 * Nexus sa_res_key=1 Change Reservation Key for registered I_T
-		 * Nexus.
+		 * Release the calling I_T Nexus registration now..
 		 */
-		if (!sa_res_key) {
-			pr_holder = core_scsi3_check_implict_release(
-					cmd->se_dev, pr_reg);
-			if (pr_holder < 0) {
-				kfree(pr_aptpl_buf);
-				core_scsi3_put_pr_reg(pr_reg);
-				cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-				return -EINVAL;
-			}
-
-			spin_lock(&pr_tmpl->registration_lock);
-			/*
-			 * Release all ALL_TG_PT=1 for the matching SCSI Initiator Port
-			 * and matching pr_res_key.
-			 */
-			if (pr_reg->pr_reg_all_tg_pt) {
-				list_for_each_entry_safe(pr_reg_p, pr_reg_tmp,
-						&pr_tmpl->registration_list,
-						pr_reg_list) {
-
-					if (!pr_reg_p->pr_reg_all_tg_pt)
-						continue;
+		__core_scsi3_free_registration(cmd->se_dev, pr_reg, NULL, 1);
 
-					if (pr_reg_p->pr_res_key != res_key)
-						continue;
-
-					if (pr_reg == pr_reg_p)
-						continue;
-
-					if (strcmp(pr_reg->pr_reg_nacl->initiatorname,
-						   pr_reg_p->pr_reg_nacl->initiatorname))
-						continue;
-
-					__core_scsi3_free_registration(dev,
-							pr_reg_p, NULL, 0);
-				}
-			}
-			/*
-			 * Release the calling I_T Nexus registration now..
-			 */
-			__core_scsi3_free_registration(cmd->se_dev, pr_reg,
-							NULL, 1);
-			/*
-			 * From spc4r17, section 5.7.11.3 Unregistering
-			 *
-			 * If the persistent reservation is a registrants only
-			 * type, the device server shall establish a unit
-			 * attention condition for the initiator port associated
-			 * with every registered I_T nexus except for the I_T
-			 * nexus on which the PERSISTENT RESERVE OUT command was
-			 * received, with the additional sense code set to
-			 * RESERVATIONS RELEASED.
-			 */
-			if (pr_holder &&
-			   ((type == PR_TYPE_WRITE_EXCLUSIVE_REGONLY) ||
-			    (type == PR_TYPE_EXCLUSIVE_ACCESS_REGONLY))) {
-				list_for_each_entry(pr_reg_p,
-						&pr_tmpl->registration_list,
-						pr_reg_list) {
-
-					core_scsi3_ua_allocate(
-						pr_reg_p->pr_reg_nacl,
-						pr_reg_p->pr_res_mapped_lun,
-						0x2A,
-						ASCQ_2AH_RESERVATIONS_RELEASED);
-				}
+		/*
+		 * From spc4r17, section 5.7.11.3 Unregistering
+		 *
+		 * If the persistent reservation is a registrants only
+		 * type, the device server shall establish a unit
+		 * attention condition for the initiator port associated
+		 * with every registered I_T nexus except for the I_T
+		 * nexus on which the PERSISTENT RESERVE OUT command was
+		 * received, with the additional sense code set to
+		 * RESERVATIONS RELEASED.
+		 */
+		if (pr_holder &&
+		   (type == PR_TYPE_WRITE_EXCLUSIVE_REGONLY ||
+		    type == PR_TYPE_EXCLUSIVE_ACCESS_REGONLY)) {
+			list_for_each_entry(pr_reg_p,
+					&pr_tmpl->registration_list,
+					pr_reg_list) {
+
+				core_scsi3_ua_allocate(
+					pr_reg_p->pr_reg_nacl,
+					pr_reg_p->pr_res_mapped_lun,
+					0x2A,
+					ASCQ_2AH_RESERVATIONS_RELEASED);
 			}
-			spin_unlock(&pr_tmpl->registration_lock);
+		}
+		spin_unlock(&pr_tmpl->registration_lock);
 
-			if (!aptpl) {
-				pr_tmpl->pr_aptpl_active = 0;
-				core_scsi3_update_and_write_aptpl(dev, NULL, 0);
-				pr_debug("SPC-3 PR: Set APTPL Bit Deactivated"
-						" for UNREGISTER\n");
-				return 0;
-			}
+		if (!aptpl) {
+			pr_tmpl->pr_aptpl_active = 0;
+			core_scsi3_update_and_write_aptpl(dev, NULL, 0);
+			pr_debug("SPC-3 PR: Set APTPL Bit Deactivated"
+					" for UNREGISTER\n");
+			return 0;
+		}
 
-			ret = core_scsi3_update_and_write_aptpl(dev,
-					&pr_aptpl_buf[0],
-					pr_tmpl->pr_aptpl_buf_len);
-			if (!ret) {
-				pr_tmpl->pr_aptpl_active = 1;
-				pr_debug("SPC-3 PR: Set APTPL Bit Activated"
-						" for UNREGISTER\n");
-			}
+		if (!core_scsi3_update_and_write_aptpl(dev, &pr_aptpl_buf[0],
+				pr_tmpl->pr_aptpl_buf_len)) {
+			pr_tmpl->pr_aptpl_active = 1;
+			pr_debug("SPC-3 PR: Set APTPL Bit Activated"
+					" for UNREGISTER\n");
+		}
 
-			kfree(pr_aptpl_buf);
-			return ret;
-		} else {
-			/*
-			 * Increment PRgeneration counter for struct se_device"
-			 * upon a successful REGISTER, see spc4r17 section 6.3.2
-			 * READ_KEYS service action.
-			 */
-			pr_reg->pr_res_generation = core_scsi3_pr_generation(
-							cmd->se_dev);
-			pr_reg->pr_res_key = sa_res_key;
-			pr_debug("SPC-3 PR [%s] REGISTER%s: Changed Reservation"
-				" Key for %s to: 0x%016Lx PRgeneration:"
-				" 0x%08x\n", cmd->se_tfo->get_fabric_name(),
-				(ignore_key) ? "_AND_IGNORE_EXISTING_KEY" : "",
-				pr_reg->pr_reg_nacl->initiatorname,
-				pr_reg->pr_res_key, pr_reg->pr_res_generation);
-
-			if (!aptpl) {
-				pr_tmpl->pr_aptpl_active = 0;
-				core_scsi3_update_and_write_aptpl(dev, NULL, 0);
-				core_scsi3_put_pr_reg(pr_reg);
-				pr_debug("SPC-3 PR: Set APTPL Bit Deactivated"
-						" for REGISTER\n");
-				return 0;
-			}
+		goto out_free_aptpl_buf;
+	}
 
-			ret = core_scsi3_update_and_write_aptpl(dev,
-					&pr_aptpl_buf[0],
-					pr_tmpl->pr_aptpl_buf_len);
-			if (!ret) {
-				pr_tmpl->pr_aptpl_active = 1;
-				pr_debug("SPC-3 PR: Set APTPL Bit Activated"
-						" for REGISTER\n");
-			}
+	/*
+	 * Increment PRgeneration counter for struct se_device"
+	 * upon a successful REGISTER, see spc4r17 section 6.3.2
+	 * READ_KEYS service action.
+	 */
+	pr_reg->pr_res_generation = core_scsi3_pr_generation(cmd->se_dev);
+	pr_reg->pr_res_key = sa_res_key;
+	pr_debug("SPC-3 PR [%s] REGISTER%s: Changed Reservation"
+		" Key for %s to: 0x%016Lx PRgeneration:"
+		" 0x%08x\n", cmd->se_tfo->get_fabric_name(),
+		(ignore_key) ? "_AND_IGNORE_EXISTING_KEY" : "",
+		pr_reg->pr_reg_nacl->initiatorname,
+		pr_reg->pr_res_key, pr_reg->pr_res_generation);
 
-			kfree(pr_aptpl_buf);
-			core_scsi3_put_pr_reg(pr_reg);
-		}
+	if (!aptpl) {
+		pr_tmpl->pr_aptpl_active = 0;
+		core_scsi3_update_and_write_aptpl(dev, NULL, 0);
+		pr_debug("SPC-3 PR: Set APTPL Bit Deactivated"
+				" for REGISTER\n");
+		ret = 0;
+		goto out_put_pr_reg;
 	}
-	return 0;
+
+	if (!core_scsi3_update_and_write_aptpl(dev, &pr_aptpl_buf[0],
+						pr_tmpl->pr_aptpl_buf_len)) {
+		pr_tmpl->pr_aptpl_active = 1;
+		pr_debug("SPC-3 PR: Set APTPL Bit Activated"
+			" for REGISTER\n");
+	}
+
+out_free_aptpl_buf:
+	kfree(pr_aptpl_buf);
+	ret = 0;
+out_put_pr_reg:
+	core_scsi3_put_pr_reg(pr_reg);
+	return ret;
 }
 
 unsigned char *core_scsi3_pr_dump_type(int type)
@@ -2379,26 +2342,23 @@ unsigned char *core_scsi3_pr_dump_type(int type)
 	return "Unknown SPC-3 PR Type";
 }
 
-static int core_scsi3_pro_reserve(
-	struct se_cmd *cmd,
-	struct se_device *dev,
-	int type,
-	int scope,
-	u64 res_key)
+static sense_reason_t
+core_scsi3_pro_reserve(struct se_cmd *cmd, int type, int scope, u64 res_key)
 {
+	struct se_device *dev = cmd->se_dev;
 	struct se_session *se_sess = cmd->se_sess;
 	struct se_lun *se_lun = cmd->se_lun;
 	struct t10_pr_registration *pr_reg, *pr_res_holder;
 	struct t10_reservation *pr_tmpl = &dev->t10_pr;
 	char i_buf[PR_REG_ISID_ID_LEN];
-	int ret, prf_isid;
+	sense_reason_t ret;
+	int prf_isid;
 
 	memset(i_buf, 0, PR_REG_ISID_ID_LEN);
 
 	if (!se_sess || !se_lun) {
 		pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 	/*
 	 * Locate the existing *pr_reg via struct se_node_acl pointers
@@ -2408,8 +2368,7 @@ static int core_scsi3_pro_reserve(
 	if (!pr_reg) {
 		pr_err("SPC-3 PR: Unable to locate"
 			" PR_REGISTERED *pr_reg for RESERVE\n");
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 	/*
 	 * From spc4r17 Section 5.7.9: Reserving:
@@ -2424,9 +2383,8 @@ static int core_scsi3_pro_reserve(
 		pr_err("SPC-3 PR RESERVE: Received res_key: 0x%016Lx"
 			" does not match existing SA REGISTER res_key:"
 			" 0x%016Lx\n", res_key, pr_reg->pr_res_key);
-		core_scsi3_put_pr_reg(pr_reg);
-		cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-		return -EINVAL;
+		ret = TCM_RESERVATION_CONFLICT;
+		goto out_put_pr_reg;
 	}
 	/*
 	 * From spc4r17 Section 5.7.9: Reserving:
@@ -2440,9 +2398,8 @@ static int core_scsi3_pro_reserve(
 	 */
 	if (scope != PR_SCOPE_LU_SCOPE) {
 		pr_err("SPC-3 PR: Illegal SCOPE: 0x%02x\n", scope);
-		core_scsi3_put_pr_reg(pr_reg);
-		cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
-		return -EINVAL;
+		ret = TCM_INVALID_PARAMETER_LIST;
+		goto out_put_pr_reg;
 	}
 	/*
 	 * See if we have an existing PR reservation holder pointer at
@@ -2473,9 +2430,8 @@ static int core_scsi3_pro_reserve(
 				pr_res_holder->pr_reg_nacl->initiatorname);
 
 			spin_unlock(&dev->dev_reservation_lock);
-			core_scsi3_put_pr_reg(pr_reg);
-			cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-			return -EINVAL;
+			ret = TCM_RESERVATION_CONFLICT;
+			goto out_put_pr_reg;
 		}
 		/*
 		 * From spc4r17 Section 5.7.9: Reserving:
@@ -2497,9 +2453,8 @@ static int core_scsi3_pro_reserve(
 				pr_res_holder->pr_reg_nacl->initiatorname);
 
 			spin_unlock(&dev->dev_reservation_lock);
-			core_scsi3_put_pr_reg(pr_reg);
-			cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-			return -EINVAL;
+			ret = TCM_RESERVATION_CONFLICT;
+			goto out_put_pr_reg;
 		}
 		/*
 		 * From spc4r17 Section 5.7.9: Reserving:
@@ -2512,8 +2467,8 @@ static int core_scsi3_pro_reserve(
 		 * shall completethe command with GOOD status.
 		 */
 		spin_unlock(&dev->dev_reservation_lock);
-		core_scsi3_put_pr_reg(pr_reg);
-		return 0;
+		ret = 0;
+		goto out_put_pr_reg;
 	}
 	/*
 	 * Otherwise, our *pr_reg becomes the PR reservation holder for said
@@ -2537,27 +2492,24 @@ static int core_scsi3_pro_reserve(
 	spin_unlock(&dev->dev_reservation_lock);
 
 	if (pr_tmpl->pr_aptpl_active) {
-		ret = core_scsi3_update_and_write_aptpl(cmd->se_dev,
+		if (!core_scsi3_update_and_write_aptpl(cmd->se_dev,
 				&pr_reg->pr_aptpl_buf[0],
-				pr_tmpl->pr_aptpl_buf_len);
-		if (!ret)
+				pr_tmpl->pr_aptpl_buf_len)) {
 			pr_debug("SPC-3 PR: Updated APTPL metadata"
 					" for RESERVE\n");
+		}
 	}
 
+	ret = 0;
+out_put_pr_reg:
 	core_scsi3_put_pr_reg(pr_reg);
-	return 0;
+	return ret;
 }
 
-static int core_scsi3_emulate_pro_reserve(
-	struct se_cmd *cmd,
-	int type,
-	int scope,
-	u64 res_key)
+static sense_reason_t
+core_scsi3_emulate_pro_reserve(struct se_cmd *cmd, int type, int scope,
+		u64 res_key)
 {
-	struct se_device *dev = cmd->se_dev;
-	int ret = 0;
-
 	switch (type) {
 	case PR_TYPE_WRITE_EXCLUSIVE:
 	case PR_TYPE_EXCLUSIVE_ACCESS:
@@ -2565,16 +2517,12 @@ static int core_scsi3_emulate_pro_reserve(
 	case PR_TYPE_EXCLUSIVE_ACCESS_REGONLY:
 	case PR_TYPE_WRITE_EXCLUSIVE_ALLREG:
 	case PR_TYPE_EXCLUSIVE_ACCESS_ALLREG:
-		ret = core_scsi3_pro_reserve(cmd, dev, type, scope, res_key);
-		break;
+		return core_scsi3_pro_reserve(cmd, type, scope, res_key);
 	default:
 		pr_err("SPC-3 PR: Unknown Service Action RESERVE Type:"
 			" 0x%02x\n", type);
-		cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
-		return -EINVAL;
+		return TCM_INVALID_CDB_FIELD;
 	}
-
-	return ret;
 }
 
 /*
@@ -2612,23 +2560,21 @@ static void __core_scsi3_complete_pro_release(
 	pr_reg->pr_res_holder = pr_reg->pr_res_type = pr_reg->pr_res_scope = 0;
 }
 
-static int core_scsi3_emulate_pro_release(
-	struct se_cmd *cmd,
-	int type,
-	int scope,
-	u64 res_key)
+static sense_reason_t
+core_scsi3_emulate_pro_release(struct se_cmd *cmd, int type, int scope,
+		u64 res_key)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_session *se_sess = cmd->se_sess;
 	struct se_lun *se_lun = cmd->se_lun;
 	struct t10_pr_registration *pr_reg, *pr_reg_p, *pr_res_holder;
 	struct t10_reservation *pr_tmpl = &dev->t10_pr;
-	int ret, all_reg = 0;
+	int all_reg = 0;
+	sense_reason_t ret = 0;
 
 	if (!se_sess || !se_lun) {
 		pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 	/*
 	 * Locate the existing *pr_reg via struct se_node_acl pointers
@@ -2637,8 +2583,7 @@ static int core_scsi3_emulate_pro_release(
 	if (!pr_reg) {
 		pr_err("SPC-3 PR: Unable to locate"
 			" PR_REGISTERED *pr_reg for RELEASE\n");
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	}
 	/*
 	 * From spc4r17 Section 5.7.11.2 Releasing:
@@ -2659,7 +2604,6 @@ static int core_scsi3_emulate_pro_release(
 		 * No persistent reservation, return GOOD status.
 		 */
 		spin_unlock(&dev->dev_reservation_lock);
-		core_scsi3_put_pr_reg(pr_reg);
 		return 0;
 	}
 	if ((pr_res_holder->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||
@@ -2673,9 +2617,9 @@ static int core_scsi3_emulate_pro_release(
 		 * persistent reservation holder. return GOOD status.
 		 */
 		spin_unlock(&dev->dev_reservation_lock);
-		core_scsi3_put_pr_reg(pr_reg);
-		return 0;
+		goto out_put_pr_reg;
 	}
+
 	/*
 	 * From spc4r17 Section 5.7.11.2 Releasing:
 	 *
@@ -2695,9 +2639,8 @@ static int core_scsi3_emulate_pro_release(
 			" does not match existing SA REGISTER res_key:"
 			" 0x%016Lx\n", res_key, pr_reg->pr_res_key);
 		spin_unlock(&dev->dev_reservation_lock);
-		core_scsi3_put_pr_reg(pr_reg);
-		cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-		return -EINVAL;
+		ret = TCM_RESERVATION_CONFLICT;
+		goto out_put_pr_reg;
 	}
 	/*
 	 * From spc4r17 Section 5.7.11.2 Releasing and above:
@@ -2718,9 +2661,8 @@ static int core_scsi3_emulate_pro_release(
 			pr_res_holder->pr_reg_nacl->initiatorname);
 
 		spin_unlock(&dev->dev_reservation_lock);
-		core_scsi3_put_pr_reg(pr_reg);
-		cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-		return -EINVAL;
+		ret = TCM_RESERVATION_CONFLICT;
+		goto out_put_pr_reg;
 	}
 	/*
 	 * In response to a persistent reservation release request from the
@@ -2773,20 +2715,18 @@ static int core_scsi3_emulate_pro_release(
 
 write_aptpl:
 	if (pr_tmpl->pr_aptpl_active) {
-		ret = core_scsi3_update_and_write_aptpl(cmd->se_dev,
-				&pr_reg->pr_aptpl_buf[0],
-				pr_tmpl->pr_aptpl_buf_len);
-		if (!ret)
+		if (!core_scsi3_update_and_write_aptpl(cmd->se_dev,
+			&pr_reg->pr_aptpl_buf[0], pr_tmpl->pr_aptpl_buf_len)) {
 			pr_debug("SPC-3 PR: Updated APTPL metadata for RELEASE\n");
+		}
 	}
-
+out_put_pr_reg:
 	core_scsi3_put_pr_reg(pr_reg);
-	return 0;
+	return ret;
 }
 
-static int core_scsi3_emulate_pro_clear(
-	struct se_cmd *cmd,
-	u64 res_key)
+static sense_reason_t
+core_scsi3_emulate_pro_clear(struct se_cmd *cmd, u64 res_key)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_node_acl *pr_reg_nacl;
@@ -2803,8 +2743,7 @@ static int core_scsi3_emulate_pro_clear(
 	if (!pr_reg_n) {
 		pr_err("SPC-3 PR: Unable to locate"
 			" PR_REGISTERED *pr_reg for CLEAR\n");
-		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-		return -EINVAL;
+		return TCM_LOG