Re: [PATCH v2 16/19] hw/vfio/ccw: Replace DO_UPCAST(VFIOCCWDevice) by VFIO_CCW()

[Eric Farman <farman@linux.ibm.com>]

On Mon, 2023-02-13 at 08:08 +0100, Philippe Mathieu-Daudé wrote:
> Use the VFIO_CCW() QOM type-checking macro to avoid DO_UPCAST().
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  hw/vfio/ccw.c | 35 ++++++++++++++++-------------------
>  1 file changed, 16 insertions(+), 19 deletions(-)
> 
> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
> index 0354737666..a8aa5b48c4 100644
> --- a/hw/vfio/ccw.c
> +++ b/hw/vfio/ccw.c

...snip...

> @@ -252,8 +248,8 @@ again:
>  static void vfio_ccw_reset(DeviceState *dev)
>  {
>      CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);

If I'm not mistaken, I believe that this (and (un)realize below) could
be changed to:

   CcwDevice *ccw_dev = CCW_DEVICE(dev);

> -    S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj,
> ccw_dev);
> -    VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
> +    S390CCWDevice *cdev = S390_CCW_DEVICE(ccw_dev);
> +    VFIOCCWDevice *vcdev = VFIO_CCW(cdev);
>  
>      ioctl(vcdev->vdev.fd, VFIO_DEVICE_RESET);
>  }

...snip...

> @@ -657,9 +654,9 @@ static void vfio_ccw_realize(DeviceState *dev,
> Error **errp)
>  {
>      VFIOGroup *group;
>      CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
> -    S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj,
> ccw_dev);
> -    VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
> +    S390CCWDevice *cdev = S390_CCW_DEVICE(ccw_dev);
>      S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
> +    VFIOCCWDevice *vcdev = VFIO_CCW(cdev);
>      Error *err = NULL;
>  
>      /* Call the class init function for subchannel. */
> @@ -729,9 +726,9 @@ out_err_propagate:
>  static void vfio_ccw_unrealize(DeviceState *dev)
>  {
>      CcwDevice *ccw_dev = DO_UPCAST(CcwDevice, parent_obj, dev);
> -    S390CCWDevice *cdev = DO_UPCAST(S390CCWDevice, parent_obj,
> ccw_dev);
> -    VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
> +    S390CCWDevice *cdev = S390_CCW_DEVICE(ccw_dev);
>      S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
> +    VFIOCCWDevice *vcdev = VFIO_CCW(cdev);
>      VFIOGroup *group = vcdev->vdev.group;
>  
>      vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_REQ_IRQ_INDEX);