To configure the driver as being MT SAFE, the cb_ops(9S) and dev_ops(9S) data structures must be initialized. This code must be in the header section of your module. For more information, see Example 12-1, and dev_ops(9S).
The driver is configured to be MT SAFE by setting the cb_flag field to D_MP. It also configures any MT STREAMS perimeters by setting flags in the cb_flag field. (See mt-streams(9F). The corresponding configuration for a module is done using the f_flag field in fmodsw(9S).