isci: save the i/o tag outside the scic request structure.

The pointer to the core representation of a request is marked NULL at
completion, but we need to save the i/o tag for task management.

Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: Jacek Danecki <Jacek.Danecki@intel.com>
[revise changelog]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/scsi/isci/request.c

@@ -463,6 +463,12 @@ int isci_request_execute(
 				 */
 				status = SCI_SUCCESS;
 			}
+			else
+				/* Save the tag for possible task mgmt later. */
+				request->io_tag = scic_io_request_get_io_tag(
+						     request->sci_request_handle);
+
+
 		} else
 			dev_warn(&isci_host->pdev->dev,
 				 "%s: failed request start\n",