[PATCH 002/117] Introduce enums for the SAM, message, host and driver status codes

Bart Van Assche
2021-04-20T00:09:00Z

Allow the compiler to verify whether SAM, message, host and driver status
codes are used correctly. Add the attribute "__packed" to these enum
definitions such that instances of the new enum types only occupy a single
byte.

Cc: Hannes Reinecke <hare@suse.com>
Cc: John Garry <john.garry@huawei.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/scsi/scsi_error.c | 2 +
include/scsi/scsi.h | 84 ++---------------------------------
include/scsi/scsi_cmnd.h | 11 +++--
include/scsi/scsi_proto.h | 53 ++++++++++++----------
include/scsi/scsi_status.h | 91 ++++++++++++++++++++++++++++++++++++++
5 files changed, 133 insertions(+), 108 deletions(-)
create mode 100644 include/scsi/scsi_status.h

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 9afd65eb2c8b..54213c37806b 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1775,6 +1775,8 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd)
fallthrough;
case DID_SOFT_ERROR:
return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
+ default:
+ break;
}

if (status_byte(scmd->result) != CHECK_CONDITION)
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 246ced401683..c9ccb6b45b76 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
#include <scsi/scsi_common.h>
#include <scsi/scsi_proto.h>
+#include <scsi/scsi_status.h>

struct scsi_cmnd;

@@ -90,92 +91,14 @@ static inline int scsi_is_wlun(u64 lun)

/*
- * MESSAGE CODES
+ * Extended message codes. See also chapter 16 in SPI-5.
*/
-
-#define COMMAND_COMPLETE 0x00
-#define EXTENDED_MESSAGE 0x01
#define EXTENDED_MODIFY_DATA_POINTER 0x00
#define EXTENDED_SDTR 0x01
#define EXTENDED_EXTENDED_IDENTIFY 0x02 /* SCSI-I only */
#define EXTENDED_WDTR 0x03
#define EXTENDED_PPR 0x04
#define EXTENDED_MODIFY_BIDI_DATA_PTR 0x05
-#define SAVE_POINTERS 0x02
-#define RESTORE_POINTERS 0x03
-#define DISCONNECT 0x04
-#define INITIATOR_ERROR 0x05
-#define ABORT_TASK_SET 0x06
-#define MESSAGE_REJECT 0x07
-#define NOP 0x08
-#define MSG_PARITY_ERROR 0x09
-#define LINKED_CMD_COMPLETE 0x0a
-#define LINKED_FLG_CMD_COMPLETE 0x0b
-#define TARGET_RESET 0x0c
-#define ABORT_TASK 0x0d
-#define CLEAR_TASK_SET 0x0e
-#define INITIATE_RECOVERY 0x0f /* SCSI-II only */
-#define RELEASE_RECOVERY 0x10 /* SCSI-II only */
-#define TERMINATE_IO_PROC 0x11 /* SCSI-II only */
-#define CLEAR_ACA 0x16
-#define LOGICAL_UNIT_RESET 0x17
-#define SIMPLE_QUEUE_TAG 0x20
-#define HEAD_OF_QUEUE_TAG 0x21
-#define ORDERED_QUEUE_TAG 0x22
-#define IGNORE_WIDE_RESIDUE 0x23
-#define ACA 0x24
-#define QAS_REQUEST 0x55
-
-/* Old SCSI2 names, don't use in new code */
-#define BUS_DEVICE_RESET TARGET_RESET
-#define ABORT ABORT_TASK_SET
-
-/*
- * Host byte codes
- */
-
-#define DID_OK 0x00 /* NO error */
-#define DID_NO_CONNECT 0x01 /* Couldn't connect before timeout period */
-#define DID_BUS_BUSY 0x02 /* BUS stayed busy through time out period */
-#define DID_TIME_OUT 0x03 /* TIMED OUT for other reason */
-#define DID_BAD_TARGET 0x04 /* BAD target. */
-#define DID_ABORT 0x05 /* Told to abort for some other reason */
-#define DID_PARITY 0x06 /* Parity error */
-#define DID_ERROR 0x07 /* Internal error */
-#define DID_RESET 0x08 /* Reset by somebody. */
-#define DID_BAD_INTR 0x09 /* Got an interrupt we weren't expecting. */
-#define DID_PASSTHROUGH 0x0a /* Force command past mid-layer */
-#define DID_SOFT_ERROR 0x0b /* The low level driver just wish a retry */
-#define DID_IMM_RETRY 0x0c /* Retry without decrementing retry count */
-#define DID_REQUEUE 0x0d /* Requeue command (no immediate retry) also
- * without decrementing the retry count */
-#define DID_TRANSPORT_DISRUPTED 0x0e /* Transport error disrupted execution
- * and the driver blocked the port to
- * recover the link. Transport class will
- * retry or fail IO */
-#define DID_TRANSPORT_FAILFAST 0x0f /* Transport class fastfailed the io */
-#define DID_TARGET_FAILURE 0x10 /* Permanent target failure, do not retry on
- * other paths */
-#define DID_NEXUS_FAILURE 0x11 /* Permanent nexus failure, retry on other
- * paths might yield different results */
-#define DID_ALLOC_FAILURE 0x12 /* Space allocation on the device failed */
-#define DID_MEDIUM_ERROR 0x13 /* Medium error */
-#define DID_TRANSPORT_MARGINAL 0x14 /* Transport marginal errors */
-#define DRIVER_OK 0x00 /* Driver status */
-
-/*
- * These indicate the error that occurred, and what is available.
- */
-
-#define DRIVER_BUSY 0x01
-#define DRIVER_SOFT 0x02
-#define DRIVER_MEDIA 0x03
-#define DRIVER_ERROR 0x04
-
-#define DRIVER_INVALID 0x05
-#define DRIVER_TIMEOUT 0x06
-#define DRIVER_HARD 0x07
-#define DRIVER_SENSE 0x08

/*
* Internal return values.
@@ -210,7 +133,8 @@ enum scsi_disposition {
* host_byte = set by low-level driver to indicate status.
* driver_byte = set by mid-level.
*/
-#define status_byte(result) (((result) >> 1) & 0x7f)
+#define status_byte(result) ((enum sam_status_divided_by_two) \
+ (((result) >> 1) & 0x7f))
#define msg_byte(result) (((result) >> 8) & 0xff)
#define host_byte(result) (((result) >> 16) & 0xff)
#define driver_byte(result) (((result) >> 24) & 0xff)
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index adb8df40b942..202106e7c814 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -12,6 +12,7 @@
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_request.h>
+#include <scsi/scsi_status.h>

struct Scsi_Host;
struct scsi_driver;
@@ -313,22 +314,24 @@ static inline struct scsi_data_buffer *scsi_prot(struct scsi_cmnd *cmd)
#define scsi_for_each_prot_sg(cmd, sg, nseg, __i) \
for_each_sg(scsi_prot_sglist(cmd), sg, nseg, __i)

-static inline void set_status_byte(struct scsi_cmnd *cmd, char status)
+static inline void set_status_byte(struct scsi_cmnd *cmd,
+ enum sam_status status)
{
cmd->result = (cmd->result & 0xffffff00) | status;
}

-static inline void set_msg_byte(struct scsi_cmnd *cmd, char status)
+static inline void set_msg_byte(struct scsi_cmnd *cmd, enum msg_byte status)
{
cmd->result = (cmd->result & 0xffff00ff) | (status << 8);
}

-static inline void set_host_byte(struct scsi_cmnd *cmd, char status)
+static inline void set_host_byte(struct scsi_cmnd *cmd, enum host_status status)
{
cmd->result = (cmd->result & 0xff00ffff) | (status << 16);
}

-static inline void set_driver_byte(struct scsi_cmnd *cmd, char status)
+static inline void set_driver_byte(struct scsi_cmnd *cmd,
+ enum driver_status status)
{
cmd->result = (cmd->result & 0x00ffffff) | (status << 24);
}
diff --git a/include/scsi/scsi_proto.h b/include/scsi/scsi_proto.h
index c36860111932..e970fecfeaa1 100644
--- a/include/scsi/scsi_proto.h
+++ b/include/scsi/scsi_proto.h
@@ -11,6 +11,7 @@
#define _SCSI_PROTO_H_

#include <linux/types.h>
+#include <linux/compiler_attributes.h>

/*
* SCSI opcodes
@@ -187,20 +188,22 @@ struct scsi_varlen_cdb_hdr {
};

/*
- * SCSI Architecture Model (SAM) Status codes. Taken from SAM-3 draft
- * T10/1561-D Revision 4 Draft dated 7th November 2002.
+ * SCSI Architecture Model (SAM) status codes. Taken from SAM-6 draft
+ * revision 7 dated 17 February 2021.
*/
-#define SAM_STAT_GOOD 0x00
-#define SAM_STAT_CHECK_CONDITION 0x02
-#define SAM_STAT_CONDITION_MET 0x04
-#define SAM_STAT_BUSY 0x08
-#define SAM_STAT_INTERMEDIATE 0x10
-#define SAM_STAT_INTERMEDIATE_CONDITION_MET 0x14
-#define SAM_STAT_RESERVATION_CONFLICT 0x18
-#define SAM_STAT_COMMAND_TERMINATED 0x22 /* obsolete in SAM-3 */
-#define SAM_STAT_TASK_SET_FULL 0x28
-#define SAM_STAT_ACA_ACTIVE 0x30
-#define SAM_STAT_TASK_ABORTED 0x40
+enum sam_status {
+ SAM_STAT_GOOD = 0x00,
+ SAM_STAT_CHECK_CONDITION = 0x02,
+ SAM_STAT_CONDITION_MET = 0x04,
+ SAM_STAT_BUSY = 0x08,
+ SAM_STAT_INTERMEDIATE = 0x10, /* obsolete in SAM-4 */
+ SAM_STAT_INTERMEDIATE_CONDITION_MET = 0x14, /* obsolete in SAM-4 */
+ SAM_STAT_RESERVATION_CONFLICT = 0x18,
+ SAM_STAT_COMMAND_TERMINATED = 0x22, /* obsolete in SAM-3 */
+ SAM_STAT_TASK_SET_FULL = 0x28,
+ SAM_STAT_ACA_ACTIVE = 0x30,
+ SAM_STAT_TASK_ABORTED = 0x40,
+} __packed;

/*
* Status codes. These are deprecated as they are shifted 1 bit right
@@ -209,17 +212,19 @@ struct scsi_varlen_cdb_hdr {
* above.
*/

-#define GOOD 0x00
-#define CHECK_CONDITION 0x01
-#define CONDITION_GOOD 0x02
-#define BUSY 0x04
-#define INTERMEDIATE_GOOD 0x08
-#define INTERMEDIATE_C_GOOD 0x0a
-#define RESERVATION_CONFLICT 0x0c
-#define COMMAND_TERMINATED 0x11
-#define QUEUE_FULL 0x14
-#define ACA_ACTIVE 0x18
-#define TASK_ABORTED 0x20
+enum sam_status_divided_by_two {
+ GOOD = 0x00,
+ CHECK_CONDITION = 0x01,
+ CONDITION_GOOD = 0x02,
+ BUSY = 0x04,
+ INTERMEDIATE_GOOD = 0x08,
+ INTERMEDIATE_C_GOOD = 0x0a,
+ RESERVATION_CONFLICT = 0x0c,
+ COMMAND_TERMINATED = 0x11,
+ QUEUE_FULL = 0x14,
+ ACA_ACTIVE = 0x18,
+ TASK_ABORTED = 0x20,
+} __packed;

#define STATUS_MASK 0xfe

diff --git a/include/scsi/scsi_status.h b/include/scsi/scsi_status.h
new file mode 100644
index 000000000000..da2ba825f981
--- /dev/null
+++ b/include/scsi/scsi_status.h
@@ -0,0 +1,91 @@
+#ifndef _SCSI_SCSI_STATUS_H
+#define _SCSI_SCSI_STATUS_H
+
+#include <linux/types.h>
+#include <linux/compiler_attributes.h>
+#include <scsi/scsi_proto.h>
+
+/*
+ * Message codes. See also table 60 "Link control message codes" in SPI-5.
+ * See also table 47 "Link control message codes" in SPI-2.
+ */
+enum msg_byte {
+ COMMAND_COMPLETE = 0x00,
+ EXTENDED_MESSAGE = 0x01,
+ SAVE_POINTERS = 0x02,
+ RESTORE_POINTERS = 0x03,
+ DISCONNECT = 0x04,
+ INITIATOR_ERROR = 0x05,
+ ABORT_TASK_SET = 0x06,
+ MESSAGE_REJECT = 0x07,
+ NOP = 0x08,
+ MSG_PARITY_ERROR = 0x09,
+ LINKED_CMD_COMPLETE = 0x0a,
+ LINKED_FLG_CMD_COMPLETE = 0x0b,
+ TARGET_RESET = 0x0c,
+ ABORT_TASK = 0x0d,
+ CLEAR_TASK_SET = 0x0e,
+ INITIATE_RECOVERY = 0x0f, /* SCSI-II only */
+ RELEASE_RECOVERY = 0x10, /* SCSI-II only */
+ TERMINATE_IO_PROC = 0x11, /* SCSI-II only */
+ CLEAR_ACA = 0x16,
+ LOGICAL_UNIT_RESET = 0x17,
+ SIMPLE_QUEUE_TAG = 0x20,
+ HEAD_OF_QUEUE_TAG = 0x21,
+ ORDERED_QUEUE_TAG = 0x22,
+ IGNORE_WIDE_RESIDUE = 0x23,
+ ACA = 0x24,
+ QAS_REQUEST = 0x55,
+
+ /* Old SCSI2 names, don't use in new code */
+ BUS_DEVICE_RESET = TARGET_RESET,
+ ABORT = ABORT_TASK_SET,
+} __packed;
+
+/* Host byte codes. */
+enum host_status {
+ DID_OK = 0x00, /* NO error */
+ DID_NO_CONNECT = 0x01, /* Couldn't connect before timeout period */
+ DID_BUS_BUSY = 0x02, /* BUS stayed busy through time out period */
+ DID_TIME_OUT = 0x03, /* TIMED OUT for other reason */
+ DID_BAD_TARGET = 0x04, /* BAD target. */
+ DID_ABORT = 0x05, /* Told to abort for some other reason */
+ DID_PARITY = 0x06, /* Parity error */
+ DID_ERROR = 0x07, /* Internal error */
+ DID_RESET = 0x08, /* Reset by somebody. */
+ DID_BAD_INTR = 0x09, /* Got an interrupt we weren't expecting. */
+ DID_PASSTHROUGH = 0x0a, /* Force command past mid-layer */
+ DID_SOFT_ERROR = 0x0b, /* The low level driver just wish a retry */
+ DID_IMM_RETRY = 0x0c, /* Retry without decrementing retry count */
+ DID_REQUEUE = 0x0d, /* Requeue command (no immediate retry) also
+ * without decrementing the retry count */
+ DID_TRANSPORT_DISRUPTED = 0x0e, /* Transport error disrupted execution
+ * and the driver blocked the port to
+ * recover the link. Transport class will
+ * retry or fail IO */
+ DID_TRANSPORT_FAILFAST = 0x0f, /* Transport class fastfailed the io */
+ DID_TARGET_FAILURE = 0x10, /* Permanent target failure, do not retry on
+ * other paths */
+ DID_NEXUS_FAILURE = 0x11, /* Permanent nexus failure, retry on other
+ * paths might yield different results */
+ DID_ALLOC_FAILURE = 0x12, /* Space allocation on the device failed */
+ DID_MEDIUM_ERROR = 0x13, /* Medium error */
+ DID_TRANSPORT_MARGINAL = 0x14, /* Transport marginal errors */
+} __packed;
+
+/* Driver byte codes. */
+enum driver_status {
+ DRIVER_OK = 0x00,
+
+ DRIVER_BUSY = 0x01,
+ DRIVER_SOFT = 0x02,
+ DRIVER_MEDIA = 0x03,
+ DRIVER_ERROR = 0x04,
+
+ DRIVER_INVALID = 0x05,
+ DRIVER_TIMEOUT = 0x06,
+ DRIVER_HARD = 0x07,
+ DRIVER_SENSE = 0x08,
+} __packed;
+
+#endif /* _SCSI_SCSI_STATUS_H */