Re: [Qemu-devel] [PATCH] virtio-scsi: clean up virtio_scsi_parse_cdb

[Laszlo Ersek <lersek@redhat.com>]

On 09/18/14 16:58, Paolo Bonzini wrote:
> The command direction according to the guest-passed buffers
> is already stored in the VirtIOSCSIReq.  We can use it instead
> of computing it again from req->elem.
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/scsi/virtio-scsi.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
> index f0d21a3..6953cbe 100644
> --- a/hw/scsi/virtio-scsi.c
> +++ b/hw/scsi/virtio-scsi.c
> @@ -430,13 +430,7 @@ static int virtio_scsi_parse_cdb(SCSIDevice *dev, SCSICommand *cmd,
>       * host device passthrough.
>       */
>      cmd->xfer = req->qsgl.size;
> -    if (cmd->xfer == 0) {
> -        cmd->mode = SCSI_XFER_NONE;
> -    } else if (iov_size(req->elem.in_sg, req->elem.in_num) > req->resp_size) {
> -        cmd->mode = SCSI_XFER_FROM_DEV;
> -    } else {
> -        cmd->mode = SCSI_XFER_TO_DEV;
> -    }
> +    cmd->mode = req->mode;
>      return 0;
>  }
>  
> 

virtio_scsi_handle_cmd()                              [hw/scsi/virtio-scsi.c]
  virtio_scsi_parse_req()                             [hw/scsi/virtio-scsi.c]
    /* sets req->mode */
  scsi_req_new()                                      [hw/scsi/scsi-bus.c]
    scsi_block_parse_cdb() | scsi_generic_parse_cdb() [hw/scsi/scsi-disk.c | hw/scsi/scsi-generic.c]
      scsi_bus_parse_cdb()                            [hw/scsi/scsi-bus.c]
        virtio_scsi_parse_cdb()                       [hw/scsi/virtio-scsi.c]
          /* uses req->mode */

Reviewed-by: Laszlo Ersek <lersek@redhat.com>