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[Qemu-devel] [PATCH v2] hw/core/bus.c: Only the main system bus can have
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH v2] hw/core/bus.c: Only the main system bus can have no parent |
Date: |
Thu, 23 May 2019 16:05:43 +0100 |
In commit 80376c3fc2c38fdd453 in 2010 we added a workaround for
some qbus buses not being connected to qdev devices -- if the
bus has no parent object then we register a reset function which
resets the bus on system reset (and unregister it when the
bus is unparented).
Nearly a decade later, we have now no buses in the tree which
are created with non-NULL parents, so we can remove the
workaround and instead just assert that if the bus has a NULL
parent then it is the main system bus.
(The absence of other parentless buses was confirmed by
code inspection of all the callsites of qbus_create() and
qbus_create_inplace() and cross-checked by 'make check'.)
Signed-off-by: Peter Maydell <address@hidden>
Reviewed-by: Markus Armbruster <address@hidden>
---
v1->v2: clean up also the bus_unparent() code
---
hw/core/bus.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/hw/core/bus.c b/hw/core/bus.c
index e09843f6abe..b8839c7268d 100644
--- a/hw/core/bus.c
+++ b/hw/core/bus.c
@@ -96,10 +96,9 @@ static void qbus_realize(BusState *bus, DeviceState *parent,
const char *name)
bus->parent->num_child_bus++;
object_property_add_child(OBJECT(bus->parent), bus->name, OBJECT(bus),
NULL);
object_unref(OBJECT(bus));
- } else if (bus != sysbus_get_default()) {
- /* TODO: once all bus devices are qdevified,
- only reset handler for main_system_bus should be registered here. */
- qemu_register_reset(qbus_reset_all_fn, bus);
+ } else {
+ /* The only bus without a parent is the main system bus */
+ assert(bus == sysbus_get_default());
}
}
@@ -108,18 +107,16 @@ static void bus_unparent(Object *obj)
BusState *bus = BUS(obj);
BusChild *kid;
+ /* Only the main system bus has no parent, and that bus is never freed */
+ assert(bus->parent);
+
while ((kid = QTAILQ_FIRST(&bus->children)) != NULL) {
DeviceState *dev = kid->child;
object_unparent(OBJECT(dev));
}
- if (bus->parent) {
- QLIST_REMOVE(bus, sibling);
- bus->parent->num_child_bus--;
- bus->parent = NULL;
- } else {
- assert(bus != sysbus_get_default()); /* main_system_bus is never freed
*/
- qemu_unregister_reset(qbus_reset_all_fn, bus);
- }
+ QLIST_REMOVE(bus, sibling);
+ bus->parent->num_child_bus--;
+ bus->parent = NULL;
}
void qbus_create_inplace(void *bus, size_t size, const char *typename,
--
2.20.1
- [Qemu-devel] [PATCH v2] hw/core/bus.c: Only the main system bus can have no parent,
Peter Maydell <=