scsi: core: Add a new error code DID_TRANSPORT_MARGINAL in scsi.h

Add code in scsi_result_to_blk_status to translate a new error
DID_TRANSPORT_MARGINAL to the corresponding blk_status_t i.e
BLK_STS_TRANSPORT.

Add DID_TRANSPORT_MARGINAL case to scsi_decide_disposition().

Link: https://lore.kernel.org/r/1609969748-17684-2-git-send-email-muneendra.kumar@broadcom.comReviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Muneendra Kumar <muneendra.kumar@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_error.c

@@ -1861,6 +1861,12 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
 		 * the fast io fail tmo fired), so send IO directly upwards.
 		 */
 		return SUCCESS;
+	case DID_TRANSPORT_MARGINAL:
+		/*
+		 * caller has decided not to do retries on
+		 * abort success, so send IO directly upwards
+		 */
+		return SUCCESS;
 	case DID_ERROR:
 		if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
 		    status_byte(scmd->result) == RESERVATION_CONFLICT)

drivers/scsi/scsi_lib.c

@@ -630,6 +630,7 @@ static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
 			return BLK_STS_OK;
 		return BLK_STS_IOERR;
 	case DID_TRANSPORT_FAILFAST:
+	case DID_TRANSPORT_MARGINAL:
 		return BLK_STS_TRANSPORT;
 	case DID_TARGET_FAILURE:
 		set_host_byte(cmd, DID_OK);

include/scsi/scsi.h

@@ -159,6 +159,7 @@ static inline int scsi_is_wlun(u64 lun)
 				 * 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                           */
 
 /*