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 e57f738f04f9..aa868090b9ab 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 11b0a68dc765..5350f6e580f0 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 81ddb4ae6c3f..9087b200e552 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 *,