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

[Philippe Mathieu-Daudé]

On 04/19/2018 06:27 PM, 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 <address@hidden>
> ---
>  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 */

The DeviceClass documentation (top of this file) is now out of date :(

If the maintainer taking this series prefer a respin, I plan to only
remove the 'init' references in the big comment.

>      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;
> +    /* 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,
>