vmxnet3_barrier
vmxnet3_barrier(sc, VMXNET3_BARRIER_WR);
vmxnet3_barrier(sc, VMXNET3_BARRIER_RD);
vmxnet3_barrier(sc, VMXNET3_BARRIER_RD);
static void vmxnet3_barrier(struct vmxnet3_softc *, vmxnet3_barrier_t);