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>

3 files changed, 38 insertions, 37 deletions

diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index e57f738..aa86809 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -31,17 +31,17 @@ struct se_subsystem_api {
 				   struct scatterlist *,
 				   unsigned char *);
 
-	int (*parse_cdb)(struct se_cmd *cmd);
+	sense_reason_t (*parse_cdb)(struct se_cmd *cmd);
 	u32 (*get_device_type)(struct se_device *);
 	sector_t (*get_blocks)(struct se_device *);
 	unsigned char *(*get_sense_buffer)(struct se_cmd *);
 };
 
 struct sbc_ops {
-	int (*execute_rw)(struct se_cmd *cmd);
-	int (*execute_sync_cache)(struct se_cmd *cmd);
-	int (*execute_write_same)(struct se_cmd *cmd);
-	int (*execute_unmap)(struct se_cmd *cmd);
+	sense_reason_t (*execute_rw)(struct se_cmd *cmd);
+	sense_reason_t (*execute_sync_cache)(struct se_cmd *cmd);
+	sense_reason_t (*execute_write_same)(struct se_cmd *cmd);
+	sense_reason_t (*execute_unmap)(struct se_cmd *cmd);
 };
 
 int	transport_subsystem_register(struct se_subsystem_api *);
@@ -49,11 +49,11 @@ void	transport_subsystem_release(struct se_subsystem_api *);
 
 void	target_complete_cmd(struct se_cmd *, u8);
 
-int	spc_parse_cdb(struct se_cmd *cmd, unsigned int *size);
-int	spc_emulate_report_luns(struct se_cmd *cmd);
+sense_reason_t	spc_parse_cdb(struct se_cmd *cmd, unsigned int *size);
+sense_reason_t	spc_emulate_report_luns(struct se_cmd *cmd);
 int	spc_get_write_same_sectors(struct se_cmd *cmd);
 
-int	sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops);
+sense_reason_t	sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops);
 u32	sbc_get_device_rev(struct se_device *dev);
 u32	sbc_get_device_type(struct se_device *dev);
 
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 11b0a68..5350f6e 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -144,8 +144,6 @@ enum se_cmd_flags_table {
 	SCF_EMULATED_TASK_SENSE		= 0x00000004,
 	SCF_SCSI_DATA_CDB		= 0x00000008,
 	SCF_SCSI_TMR_CDB		= 0x00000010,
-	SCF_SCSI_CDB_EXCEPTION		= 0x00000020,
-	SCF_SCSI_RESERVATION_CONFLICT	= 0x00000040,
 	SCF_FUA				= 0x00000080,
 	SCF_SE_LUN_CMD			= 0x00000100,
 	SCF_BIDI			= 0x00000400,
@@ -167,27 +165,32 @@ enum transport_lunflags_table {
 };
 
 /*
- * Used by transport_send_check_condition_and_sense() and se_cmd->scsi_sense_reason
+ * Used by transport_send_check_condition_and_sense()
  * to signal which ASC/ASCQ sense payload should be built.
  */
+typedef unsigned __bitwise__ sense_reason_t;
+
 enum tcm_sense_reason_table {
-	TCM_NON_EXISTENT_LUN			= 0x01,
-	TCM_UNSUPPORTED_SCSI_OPCODE		= 0x02,
-	TCM_INCORRECT_AMOUNT_OF_DATA		= 0x03,
-	TCM_UNEXPECTED_UNSOLICITED_DATA		= 0x04,
-	TCM_SERVICE_CRC_ERROR			= 0x05,
-	TCM_SNACK_REJECTED			= 0x06,
-	TCM_SECTOR_COUNT_TOO_MANY		= 0x07,
-	TCM_INVALID_CDB_FIELD			= 0x08,
-	TCM_INVALID_PARAMETER_LIST		= 0x09,
-	TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE	= 0x0a,
-	TCM_UNKNOWN_MODE_PAGE			= 0x0b,
-	TCM_WRITE_PROTECTED			= 0x0c,
-	TCM_CHECK_CONDITION_ABORT_CMD		= 0x0d,
-	TCM_CHECK_CONDITION_UNIT_ATTENTION	= 0x0e,
-	TCM_CHECK_CONDITION_NOT_READY		= 0x0f,
-	TCM_RESERVATION_CONFLICT		= 0x10,
-	TCM_ADDRESS_OUT_OF_RANGE		= 0x11,
+#define R(x)	(__force sense_reason_t )(x)
+	TCM_NON_EXISTENT_LUN			= R(0x01),
+	TCM_UNSUPPORTED_SCSI_OPCODE		= R(0x02),
+	TCM_INCORRECT_AMOUNT_OF_DATA		= R(0x03),
+	TCM_UNEXPECTED_UNSOLICITED_DATA		= R(0x04),
+	TCM_SERVICE_CRC_ERROR			= R(0x05),
+	TCM_SNACK_REJECTED			= R(0x06),
+	TCM_SECTOR_COUNT_TOO_MANY		= R(0x07),
+	TCM_INVALID_CDB_FIELD			= R(0x08),
+	TCM_INVALID_PARAMETER_LIST		= R(0x09),
+	TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE	= R(0x0a),
+	TCM_UNKNOWN_MODE_PAGE			= R(0x0b),
+	TCM_WRITE_PROTECTED			= R(0x0c),
+	TCM_CHECK_CONDITION_ABORT_CMD		= R(0x0d),
+	TCM_CHECK_CONDITION_UNIT_ATTENTION	= R(0x0e),
+	TCM_CHECK_CONDITION_NOT_READY		= R(0x0f),
+	TCM_RESERVATION_CONFLICT		= R(0x10),
+	TCM_ADDRESS_OUT_OF_RANGE		= R(0x11),
+	TCM_OUT_OF_RESOURCES			= R(0x12),
+#undef R
 };
 
 enum target_sc_flags_table {
@@ -407,7 +410,6 @@ struct se_cmd {
 	u8			scsi_status;
 	u8			scsi_asc;
 	u8			scsi_ascq;
-	u8			scsi_sense_reason;
 	u16			scsi_sense_length;
 	/* Delay for ALUA Active/NonOptimized state access in milliseconds */
 	int			alua_nonop_delay;
@@ -445,7 +447,7 @@ struct se_cmd {
 	struct completion	cmd_wait_comp;
 	struct kref		cmd_kref;
 	struct target_core_fabric_ops *se_tfo;
-	int (*execute_cmd)(struct se_cmd *);
+	sense_reason_t		(*execute_cmd)(struct se_cmd *);
 	void (*transport_complete_callback)(struct se_cmd *);
 
 	unsigned char		*t_task_cdb;
diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 81ddb4a..9087b20 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -98,8 +98,8 @@ void	transport_deregister_session(struct se_session *);
 
 void	transport_init_se_cmd(struct se_cmd *, struct target_core_fabric_ops *,
 		struct se_session *, u32, int, int, unsigned char *);
-int	transport_lookup_cmd_lun(struct se_cmd *, u32);
-int	target_setup_cmd_from_cdb(struct se_cmd *, unsigned char *);
+sense_reason_t transport_lookup_cmd_lun(struct se_cmd *, u32);
+sense_reason_t target_setup_cmd_from_cdb(struct se_cmd *, unsigned char *);
 int	target_submit_cmd_map_sgls(struct se_cmd *, struct se_session *,
 		unsigned char *, unsigned char *, u32, u32, int, int, int,
 		struct scatterlist *, u32, struct scatterlist *, u32);
@@ -110,9 +110,7 @@ int	target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
 		void *fabric_tmr_ptr, unsigned char tm_type,
 		gfp_t, unsigned int, int);
 int	transport_handle_cdb_direct(struct se_cmd *);
-int	transport_generic_map_mem_to_cmd(struct se_cmd *cmd,
-		struct scatterlist *, u32, struct scatterlist *, u32);
-int	transport_generic_new_cmd(struct se_cmd *);
+sense_reason_t	transport_generic_new_cmd(struct se_cmd *);
 
 void	target_execute_cmd(struct se_cmd *cmd);
 
@@ -120,7 +118,8 @@ void	transport_generic_free_cmd(struct se_cmd *, int);
 
 bool	transport_wait_for_tasks(struct se_cmd *);
 int	transport_check_aborted_status(struct se_cmd *, int);
-int	transport_send_check_condition_and_sense(struct se_cmd *, u8, int);
+int	transport_send_check_condition_and_sense(struct se_cmd *,
+		sense_reason_t, int);
 
 int	target_put_sess_cmd(struct se_session *, struct se_cmd *);
 void	target_sess_cmd_list_set_waiting(struct se_session *);
@@ -131,7 +130,7 @@ int	core_alua_check_nonop_delay(struct se_cmd *);
 int	core_tmr_alloc_req(struct se_cmd *, void *, u8, gfp_t);
 void	core_tmr_release_req(struct se_tmr_req *);
 int	transport_generic_handle_tmr(struct se_cmd *);
-void	transport_generic_request_failure(struct se_cmd *);
+void	transport_generic_request_failure(struct se_cmd *, sense_reason_t);
 int	transport_lookup_tmr_lun(struct se_cmd *, u32);
 
 struct se_node_acl *core_tpg_check_initiator_node_acl(struct se_portal_group *,