Re: [PATCH v2 54/58] qdev: Make qdev_realize() support bus-less devices

[Philippe Mathieu-Daudé]

On 5/29/20 3:45 PM, Markus Armbruster wrote:
> So far, qdev_realize() supports only devices that plug into a bus:
> argument @bus cannot be null.  Extend it to support bus-less devices,
> too.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  hw/core/qdev.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 78a06db76e..50336168f2 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -408,7 +408,7 @@ void qdev_init_nofail(DeviceState *dev)
>  /*
>   * Realize @dev.
>   * @dev must not be plugged into a bus.
> - * Plug @dev into @bus.  This takes a reference to @dev.
> + * If @bus, plug @dev into @bus.  This takes a reference to @dev.
>   * If @dev has no QOM parent, make one up, taking another reference.
>   * On success, return true.
>   * On failure, store an error through @errp and return false.
> @@ -418,9 +418,12 @@ bool qdev_realize(DeviceState *dev, BusState *bus, Error 
> **errp)
>      Error *err = NULL;
>  
>      assert(!dev->realized && !dev->parent_bus);
> -    assert(bus);

This simpler form is easier to review IMHO:

       if (!bus) {
            assert(!DEVICE_GET_CLASS(dev)->bus_type);
       }

Whichever you prefer (the simpler the better):
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

>  
> -    qdev_set_parent_bus(dev, bus);
> +    if (bus) {
> +        qdev_set_parent_bus(dev, bus);
> +    } else {
> +        assert(!DEVICE_GET_CLASS(dev)->bus_type);
> +    }
>  
>      object_property_set_bool(OBJECT(dev), true, "realized", &err);
>      if (err) {
>