Writing Device Drivers

tran_destroy_pkt() Entry Point

The tran_destroy_pkt(9E) entry point is the HBA driver function that deallocates scsi_pkt(9S) structures. The tran_destroy_pkt() entry point is called when the target driver calls scsi_destroy_pkt(9F).

The tran_destroy_pkt() entry point must free any DMA resources that have been allocated for the packet. An implicit DMA synchronization occurs if the DMA resources are freed and any cached data remains after the completion of the transfer. The tran_destroy_pkt() entry point frees the SCSI packet by calling scsi_hba_pkt_free(9F).

Example 18–5 HBA Driver tran_destroy_pkt(9E) Entry Point

static void
    struct scsi_address    *ap,
    struct scsi_pkt    *pkt)
    struct isp_cmd *sp = (struct isp_cmd *)pkt->pkt_ha_private;
    * Free the DMA, if any
    if (sp->cmd_flags & CFLAG_DMAVALID) {
        sp->cmd_flags &= ~CFLAG_DMAVALID;
        (void) ddi_dma_unbind_handle(sp->cmd_dmahandle);
        sp->cmd_dmahandle = NULL;
    * Free the pkt
    scsi_hba_pkt_free(ap, pkt);