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

[Yoni Bettan]

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 <f4...@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,