[PATCH 51/55] qdev: Make qdev_realize() support bus-less devices

[Markus Armbruster]

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.

qdev_realize_and_unref() remains restricted, because its reference
counting would become rather confusing for bus-less devices.

Signed-off-by: Markus Armbruster <address@hidden>
---
 hw/core/qdev.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 323b6328c8..0662bbc812 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);
 
-    qdev_set_parent_bus(dev, bus);
+    if (bus) {
+        qdev_set_parent_bus(dev, bus);
+    } else {
+        assert(!DEVICE_GET_CLASS(dev)->bus_type);
+    }
 
     object_ref(OBJECT(dev));
     object_property_set_bool(OBJECT(dev), true, "realized", &err);
@@ -442,7 +445,7 @@ void qdev_unrealize(DeviceState *dev)
  * Realize @dev and drop a reference.
  * This is like qdev_realize(), except it steals a reference rather
  * than take one to plug @dev into @bus.  On failure, it drops that
- * reference instead.  Intended use:
+ * reference instead.  @bus must not be null.  Intended use:
  *     dev = qdev_new();
  *     [...]
  *     qdev_realize_and_unref(dev, bus, errp);
@@ -452,6 +455,8 @@ bool qdev_realize_and_unref(DeviceState *dev, BusState 
*bus, Error **errp)
 {
     bool ret;
 
+    assert(bus);
+
     ret = qdev_realize(dev, bus, errp);
     object_unref(OBJECT(dev));
     return ret;
-- 
2.21.1