From be1ba4d56eba5666ee03b40e286d7315862ab188 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Thu, 23 May 2019 16:05:43 +0100 Subject: [PATCH] hw/core/bus.c: Only the main system bus can have no parent MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Markus Armbruster Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Damien Hedde Tested-by: Philippe Mathieu-Daudé Message-id: 20190523150543.22676-1-peter.maydell@linaro.org --- 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 e6baa04e52..17bc1edcde 100644 --- a/hw/core/bus.c +++ b/hw/core/bus.c @@ -97,10 +97,9 @@ 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()); } } @@ -109,18 +108,16 @@ 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,