target: Address legacy PYX_TRANSPORT_* return code breakage

This patch removes legacy usage of PYX_TRANSPORT_* return codes in a number
of locations and addresses cases where transport_generic_request_failure()
was returning the incorrect sense upon CHECK_CONDITION status after the
v3.1 converson to use errno return codes.

This includes the conversion of transport_generic_request_failure() to
process cmd->scsi_sense_reason and handle extra TCM_RESERVATION_CONFLICT
before calling transport_send_check_condition_and_sense() to queue up
response status.  It also drops PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES legacy
usgae, and returns TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE w/ a response
for these cases.

transport_generic_allocate_tasks(), transport_generic_new_cmd(), backend
SCF_SCSI_DATA_SG_IO_CDB ->do_task(), and emulated ->execute_task() have
all been updated to set se_cmd->scsi_sense_reason and return errno codes
universally upon failure.  This includes cmd->scsi_sense_reason assignment
in target_core_alua.c, target_core_pr.c and target_core_cdb.c emulation code.

Finally it updates fabric modules to remove the legacy usage, and for
TFO->new_cmd_map() callers forwards return values outside of fabric code.
iscsi-target has also been updated to remove a handful of special cases
related to the cleanup and signaling QUEUE_FULL handling w/ ft_write_pending()

(v2: Drop extra SCF_SCSI_CDB_EXCEPTION check during failure from
     transport_generic_new_cmd, and re-add missing task->task_error_status
     assignment in transport_complete_task)

Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target.c

@@ -1017,11 +1017,6 @@ static int iscsit_handle_scsi_cmd(
 				" non-existent or non-exported iSCSI LUN:"
 				" 0x%016Lx\n", get_unaligned_le64(&hdr->lun));
 		}
-		if (ret == PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES)
-			return iscsit_add_reject_from_cmd(
-					ISCSI_REASON_BOOKMARK_NO_RESOURCES,
-					1, 1, buf, cmd);
-
 		send_check_condition = 1;
 		goto attach_cmd;
 	}
@@ -1123,7 +1118,7 @@ static int iscsit_handle_scsi_cmd(
 	 * the backend memory allocation.
 	 */
 	ret = transport_generic_new_cmd(&cmd->se_cmd);
-	if ((ret < 0) || (cmd->se_cmd.se_cmd_flags & SCF_SE_CMD_FAILED)) {
+	if (ret < 0) {
 		immed_ret = IMMEDIATE_DATA_NORMAL_OPERATION;
 		dump_immediate_data = 1;
 		goto after_immediate_data;
@@ -1341,7 +1336,7 @@ static int iscsit_handle_data_out(struct iscsi_conn *conn, unsigned char *buf)
 
 		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_SE_CMD_FAILED))
+		     (se_cmd->se_cmd_flags & SCF_SCSI_CDB_EXCEPTION))
 			dump_unsolicited_data = 1;
 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
 

drivers/target/iscsi/iscsi_target_erl1.c

@@ -938,8 +938,7 @@ int iscsit_execute_cmd(struct iscsi_cmd *cmd, int ooo)
 		 * handle the SCF_SCSI_RESERVATION_CONFLICT case here as well.
 		 */
 		if (se_cmd->se_cmd_flags & SCF_SCSI_CDB_EXCEPTION) {
-			if (se_cmd->se_cmd_flags &
-					SCF_SCSI_RESERVATION_CONFLICT) {
+			if (se_cmd->scsi_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,

drivers/target/loopback/tcm_loop.c

@@ -148,22 +148,8 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
 	 * Allocate the necessary tasks to complete the received CDB+data
 	 */
 	ret = transport_generic_allocate_tasks(se_cmd, sc->cmnd);
-	if (ret == -ENOMEM) {
-		/* Out of Resources */
-		return PYX_TRANSPORT_LU_COMM_FAILURE;
-	} else if (ret == -EINVAL) {
-		/*
-		 * Handle case for SAM_STAT_RESERVATION_CONFLICT
-		 */
-		if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)
-			return PYX_TRANSPORT_RESERVATION_CONFLICT;
-		/*
-		 * Otherwise, return SAM_STAT_CHECK_CONDITION and return
-		 * sense data.
-		 */
-		return PYX_TRANSPORT_USE_SENSE_REASON;
-	}
-
+	if (ret != 0)
+		return ret;
 	/*
 	 * For BIDI commands, pass in the extra READ buffer
 	 * to transport_generic_map_mem_to_cmd() below..
@@ -194,12 +180,8 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
 	}
 
 	/* Tell the core about our preallocated memory */
-	ret = transport_generic_map_mem_to_cmd(se_cmd, scsi_sglist(sc),
+	return transport_generic_map_mem_to_cmd(se_cmd, scsi_sglist(sc),
 			scsi_sg_count(sc), sgl_bidi, sgl_bidi_count);
-	if (ret < 0)
-		return PYX_TRANSPORT_LU_COMM_FAILURE;
-
-	return 0;
 }
 
 /*

drivers/target/target_core_alua.c

@@ -191,9 +191,10 @@ int target_emulate_set_target_port_groups(struct se_task *task)
 	int alua_access_state, primary = 0, rc;
 	u16 tg_pt_id, rtpi;
 
-	if (!l_port)
-		return PYX_TRANSPORT_LU_COMM_FAILURE;
-
+	if (!l_port) {
+		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+		return -EINVAL;
+	}
 	buf = transport_kmap_first_data_page(cmd);
 
 	/*
@@ -203,15 +204,17 @@ int target_emulate_set_target_port_groups(struct se_task *task)
 	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");
-		rc = PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+		rc = -EINVAL;
 		goto out;
 	}
 	spin_lock(&l_tg_pt_gp_mem->tg_pt_gp_mem_lock);
 	l_tg_pt_gp = l_tg_pt_gp_mem->tg_pt_gp;
 	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");
-		rc = PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+		rc = -EINVAL;
 		goto out;
 	}
 	rc = (l_tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICT_ALUA);
@@ -220,7 +223,8 @@ int target_emulate_set_target_port_groups(struct se_task *task)
 	if (!rc) {
 		pr_debug("Unable to process SET_TARGET_PORT_GROUPS"
 				" while TPGS_EXPLICT_ALUA is disabled\n");
-		rc = PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+		rc = -EINVAL;
 		goto out;
 	}
 
@@ -245,7 +249,8 @@ int target_emulate_set_target_port_groups(struct se_task *task)
 			 * REQUEST, and the additional sense code set to INVALID
 			 * FIELD IN PARAMETER LIST.
 			 */
-			rc = PYX_TRANSPORT_INVALID_PARAMETER_LIST;
+			cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+			rc = -EINVAL;
 			goto out;
 		}
 		rc = -1;
@@ -298,7 +303,8 @@ int target_emulate_set_target_port_groups(struct se_task *task)
 			 * throw an exception with ASCQ: INVALID_PARAMETER_LIST
 			 */
 			if (rc != 0) {
-				rc = PYX_TRANSPORT_INVALID_PARAMETER_LIST;
+				cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+				rc = -EINVAL;
 				goto out;
 			}
 		} else {
@@ -335,7 +341,8 @@ int target_emulate_set_target_port_groups(struct se_task *task)
 			 * INVALID_PARAMETER_LIST
 			 */
 			if (rc != 0) {
-				rc = PYX_TRANSPORT_INVALID_PARAMETER_LIST;
+				cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+				rc = -EINVAL;
 				goto out;
 			}
 		}

drivers/target/target_core_cdb.c

@@ -703,6 +703,7 @@ int target_emulate_inquiry(struct se_task *task)
 	if (cmd->data_length < 4) {
 		pr_err("SCSI Inquiry payload length: %u"
 			" too small for EVPD=1\n", cmd->data_length);
+		cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
 		return -EINVAL;
 	}
 
@@ -719,6 +720,7 @@ int target_emulate_inquiry(struct se_task *task)
 	}
 
 	pr_err("Unknown VPD Code: 0x%02x\n", cdb[2]);
+	cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
 	ret = -EINVAL;
 
 out_unmap:
@@ -969,7 +971,8 @@ int target_emulate_modesense(struct se_task *task)
 	default:
 		pr_err("MODE SENSE: unimplemented page/subpage: 0x%02x/0x%02x\n",
 		       cdb[2] & 0x3f, cdb[3]);
-		return PYX_TRANSPORT_UNKNOWN_MODE_PAGE;
+		cmd->scsi_sense_reason = TCM_UNKNOWN_MODE_PAGE;
+		return -EINVAL;
 	}
 	offset += length;
 
@@ -1027,7 +1030,8 @@ int target_emulate_request_sense(struct se_task *task)
 	if (cdb[1] & 0x01) {
 		pr_err("REQUEST_SENSE description emulation not"
 			" supported\n");
-		return PYX_TRANSPORT_INVALID_CDB_FIELD;
+		cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+		return -ENOSYS;
 	}
 
 	buf = transport_kmap_first_data_page(cmd);
@@ -1100,7 +1104,8 @@ int target_emulate_unmap(struct se_task *task)
 	if (!dev->transport->do_discard) {
 		pr_err("UNMAP emulation not supported for: %s\n",
 				dev->transport->name);
-		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+		return -ENOSYS;
 	}
 
 	/* First UNMAP block descriptor starts at 8 byte offset */
@@ -1157,7 +1162,8 @@ int target_emulate_write_same(struct se_task *task)
 	if (!dev->transport->do_discard) {
 		pr_err("WRITE_SAME emulation not supported"
 				" for: %s\n", dev->transport->name);
-		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+		return -ENOSYS;
 	}
 
 	if (cmd->t_task_cdb[0] == WRITE_SAME)
@@ -1193,11 +1199,13 @@ int target_emulate_write_same(struct se_task *task)
 int target_emulate_synchronize_cache(struct se_task *task)
 {
 	struct se_device *dev = task->task_se_cmd->se_dev;
+	struct se_cmd *cmd = task->task_se_cmd;
 
 	if (!dev->transport->do_sync_cache) {
 		pr_err("SYNCHRONIZE_CACHE emulation not supported"
 			" for: %s\n", dev->transport->name);
-		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+		return -ENOSYS;
 	}
 
 	dev->transport->do_sync_cache(task);

drivers/target/target_core_device.c

@@ -708,7 +708,7 @@ int target_report_luns(struct se_task *se_task)
 
 	se_task->task_scsi_status = GOOD;
 	transport_complete_task(se_task, 1);
-	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+	return 0;
 }
 
 /*	se_release_device_for_hba():

drivers/target/target_core_file.c

@@ -449,13 +449,15 @@ static int fd_do_task(struct se_task *task)
 
 	}
 
-	if (ret < 0)
+	if (ret < 0) {
+		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 		return ret;
+	}
 	if (ret) {
 		task->task_scsi_status = GOOD;
 		transport_complete_task(task, 1);
 	}
-	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+	return 0;
 }
 
 /*	fd_free_task(): (Part of se_subsystem_api_t template)

drivers/target/target_core_iblock.c

@@ -554,12 +554,15 @@ static int iblock_do_task(struct se_task *task)
 	else {
 		pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 				" %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
-		return PYX_TRANSPORT_LU_COMM_FAILURE;
+		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+		return -ENOSYS;
 	}
 
 	bio = iblock_get_bio(task, block_lba, sg_num);
-	if (!bio)
-		return PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
+	if (!bio) {
+		cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+		return -ENOMEM;
+	}
 
 	bio_list_init(&list);
 	bio_list_add(&list, bio);
@@ -588,12 +591,13 @@ static int iblock_do_task(struct se_task *task)
 		submit_bio(rw, bio);
 	blk_finish_plug(&plug);
 
-	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+	return 0;
 
 fail:
 	while ((bio = bio_list_pop(&list)))
 		bio_put(bio);
-	return PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
+	cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	return -ENOMEM;
 }
 
 static u32 iblock_get_device_rev(struct se_device *dev)