[SCSI] fix the new host byte settings (DID_TARGET_FAILURE and DID_NEXUS_FAILURE)

This patch fixes the host byte settings DID_TARGET_FAILURE and
DID_NEXUS_FAILURE.  The function __scsi_error_from_host_byte, tries to reset
the host byte to DID_OK. But that does not happen because of the OR operation.

Here is the flow.

scsi_softirq_done-> scsi_decide_disposition -> __scsi_error_from_host_byte

Let's take an example with DID_NEXUS_FAILURE. In scsi_decide_disposition,
result will be set as DID_NEXUS_FAILURE (=0x11). Then in
__scsi_error_from_host_byte, when we do OR with DID_OK.  Purpose is to reset
it back to DID_OK. But that does not happen.  This patch fixes this issue.
Signed-off-by: Babu Moger <babu.moger@netapp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/scsi_error.c

@@ -1540,7 +1540,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
 			 * Need to modify host byte to signal a
 			 * permanent target failure
 			 */
-			scmd->result |= (DID_TARGET_FAILURE << 16);
+			set_host_byte(scmd, DID_TARGET_FAILURE);
 			rtn = SUCCESS;
 		}
 		/* if rtn == FAILED, we have no sense information;
@@ -1560,7 +1560,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
 	case RESERVATION_CONFLICT:
 		sdev_printk(KERN_INFO, scmd->device,
 			    "reservation conflict\n");
-		scmd->result |= (DID_NEXUS_FAILURE << 16);
+		set_host_byte(scmd, DID_NEXUS_FAILURE);
 		return SUCCESS; /* causes immediate i/o error */
 	default:
 		return FAILED;

drivers/scsi/scsi_lib.c

@@ -682,11 +682,11 @@ static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
 		error = -ENOLINK;
 		break;
 	case DID_TARGET_FAILURE:
-		cmd->result |= (DID_OK << 16);
+		set_host_byte(cmd, DID_OK);
 		error = -EREMOTEIO;
 		break;
 	case DID_NEXUS_FAILURE:
-		cmd->result |= (DID_OK << 16);
+		set_host_byte(cmd, DID_OK);
 		error = -EBADE;
 		break;
 	default: