[SCSI] libiscsi: fix null ptr regression when aborting a command with data to transfer

We do not want to send data if we are aborting a task. There is
a check in iscsi_xmit_ctask, but right before calling this we overwrite
the state so we always go right past the test. Sending data causes problems
because when we clean up from a successful abort the LLD assumes that
the task is not running.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/libiscsi.c

@@ -737,12 +737,19 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
 		 */
 		conn->ctask = list_entry(conn->xmitqueue.next,
 					 struct iscsi_cmd_task, running);
-		if (conn->ctask->state == ISCSI_TASK_PENDING) {
+		switch (conn->ctask->state) {
+		case ISCSI_TASK_ABORTING:
+			break;
+		case ISCSI_TASK_PENDING:
 			iscsi_prep_scsi_cmd_pdu(conn->ctask);
 			conn->session->tt->init_cmd_task(conn->ctask);
+			/* fall through */
+		default:
+			conn->ctask->state = ISCSI_TASK_RUNNING;
+			break;
 		}
-		conn->ctask->state = ISCSI_TASK_RUNNING;
 		list_move_tail(conn->xmitqueue.next, &conn->run_list);
+
 		rc = iscsi_xmit_ctask(conn);
 		if (rc)
 			goto again;