pvscsi_free_dma_buffer
pvscsi_free_dma_buffer(&db);
pvscsi_free_dma_buffer(&pvs->msg_ring_buf);
pvscsi_free_dma_buffer(&pvs->cmp_ring_buf);
pvscsi_free_dma_buffer(&pvs->req_ring_buf);
pvscsi_free_dma_buffer(&pvs->state_buf);