Re: [Qemu-devel] [PATCH v3 3/4] qdev: Simplify the SysBusDeviceClass::init path

[Yoni Bettan <ybettan@redhat.com>]

On 04/20/2018 12:27 AM, Philippe Mathieu-Daudé wrote:
> The SysBusDevice is the last DeviceClass::init user.
>
> Instead of using
>    SysBusDeviceClass::realize
>     -> DeviceClass::realize
>         -> DeviceClass::init
>             -> sysbus_device_init
>                -> SysBusDeviceClass::init
>
> Simplify the path by directly calling SysBusDeviceClass::init
> in SysBusDeviceClass::realize:
>
>    SysBusDeviceClass::realize
>     -> SysBusDeviceClass::init
>
> Finally, remove the DeviceClass::init, there are no more users.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>   include/hw/qdev-core.h |  2 --
>   hw/core/qdev.c         | 14 --------------
>   hw/core/sysbus.c       | 15 ++++++++++-----
>   3 files changed, 10 insertions(+), 21 deletions(-)
>
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index 9453588160..6f60748043 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -29,7 +29,6 @@ typedef enum DeviceCategory {
>       DEVICE_CATEGORY_MAX
>   } DeviceCategory;
>   
> -typedef int (*qdev_initfn)(DeviceState *dev);
>   typedef int (*qdev_event)(DeviceState *dev);
>   typedef void (*DeviceRealize)(DeviceState *dev, Error **errp);
>   typedef void (*DeviceUnrealize)(DeviceState *dev, Error **errp);
> @@ -124,7 +123,6 @@ typedef struct DeviceClass {
>       const struct VMStateDescription *vmsd;
>   
>       /* Private to qdev / bus.  */
> -    qdev_initfn init; /* TODO remove, once users are converted to realize */
>       qdev_event exit; /* TODO remove, once users are converted to unrealize */
>       const char *bus_type;
>   } DeviceClass;
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index f6f92473b8..4153b733c8 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -208,19 +208,6 @@ void device_listener_unregister(DeviceListener *listener)
>       QTAILQ_REMOVE(&device_listeners, listener, link);
>   }
>   
> -static void device_realize(DeviceState *dev, Error **errp)
> -{
> -    DeviceClass *dc = DEVICE_GET_CLASS(dev);
> -
> -    if (dc->init) {
> -        int rc = dc->init(dev);
> -        if (rc < 0) {
> -            error_setg(errp, "Device initialization failed.");
> -            return;
> -        }
> -    }
> -}
> -
>   static void device_unrealize(DeviceState *dev, Error **errp)
>   {
>       DeviceClass *dc = DEVICE_GET_CLASS(dev);
> @@ -1065,7 +1052,6 @@ static void device_class_init(ObjectClass *class, void *data)
>       DeviceClass *dc = DEVICE_CLASS(class);
>   
>       class->unparent = device_unparent;
> -    dc->realize = device_realize;
>       dc->unrealize = device_unrealize;
>   
>       /* by default all devices were considered as hotpluggable,
> diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
> index 5d0887f499..11f6d14b84 100644
> --- a/hw/core/sysbus.c
> +++ b/hw/core/sysbus.c
> @@ -18,6 +18,7 @@
>    */
>   
>   #include "qemu/osdep.h"
> +#include "qapi/error.h"
>   #include "hw/sysbus.h"
>   #include "monitor/monitor.h"
>   #include "exec/address-spaces.h"
> @@ -200,15 +201,19 @@ void sysbus_init_ioports(SysBusDevice *dev, uint32_t ioport, uint32_t size)
>       }
>   }
>   
> -static int sysbus_device_init(DeviceState *dev)
> +static void sysbus_realize(DeviceState *dev, Error **errp)
>   {
>       SysBusDevice *sd = SYS_BUS_DEVICE(dev);
>       SysBusDeviceClass *sbc = SYS_BUS_DEVICE_GET_CLASS(sd);
>   
> -    if (!sbc->init) {
> -        return 0;

Hello Philippe, is the purpose of this part to enable incremental 
conversion init->realize
to SysBusDevices ?!

Thanks,
Yoni
> +    /* TODO remove, once users are converted to realize */
> +    if (sbc->init) {
> +        int rc = sbc->init(sd);
> +        if (rc < 0) {
> +            error_setg(errp, "Device initialization failed.");
> +            return;
> +        }
>       }
> -    return sbc->init(sd);
>   }
>   
>   DeviceState *sysbus_create_varargs(const char *name,
> @@ -324,7 +329,7 @@ MemoryRegion *sysbus_address_space(SysBusDevice *dev)
>   static void sysbus_device_class_init(ObjectClass *klass, void *data)
>   {
>       DeviceClass *k = DEVICE_CLASS(klass);
> -    k->init = sysbus_device_init;
> +    k->realize = sysbus_realize;
>       k->bus_type = TYPE_SYSTEM_BUS;
>       /*
>        * device_add plugs devices into a suitable bus.  For "real" buses,