diff options
| author | Tony Krowiak <akrowiak@linux.ibm.com> | 2018-12-17 10:57:30 -0500 |
|---|---|---|
| committer | Eduardo Habkost <ehabkost@redhat.com> | 2019-03-06 11:51:08 -0300 |
| commit | 12b2e9f30f978f26f35f9df5c2ef96fbc019bab6 (patch) | |
| tree | 9fe1c09e733beecb3164acc6406e200a79fb17fa | |
| parent | 9b748c5e061b1202fba59afd857e16a693743d90 (diff) | |
| download | qemu-12b2e9f30f978f26f35f9df5c2ef96fbc019bab6.zip qemu-12b2e9f30f978f26f35f9df5c2ef96fbc019bab6.tar.gz qemu-12b2e9f30f978f26f35f9df5c2ef96fbc019bab6.tar.bz2 | |
qdev/core: fix qbus_is_full()
The qbus_is_full(BusState *bus) function (qdev_monitor.c) compares the max_index
value of the BusState structure with the max_dev value of the BusClass structure
to determine whether the maximum number of children has been reached for the
bus. The problem is, the max_index field of the BusState structure does not
necessarily reflect the number of devices that have been plugged into
the bus.
Whenever a child device is plugged into the bus, the bus's max_index value is
assigned to the child device and then incremented. If the child is subsequently
unplugged, the value of the max_index does not change and no longer reflects the
number of children.
When the bus's max_index value reaches the maximum number of devices
allowed for the bus (i.e., the max_dev field in the BusClass structure),
attempts to plug another device will be rejected claiming that the bus is
full -- even if the bus is actually empty.
To resolve the problem, a new 'num_children' field is being added to the
BusState structure to keep track of the number of children plugged into the
bus. It will be incremented when a child is plugged, and decremented when a
child is unplugged.
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Pierre Morel<pmorel@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Message-Id: <1545062250-7573-1-git-send-email-akrowiak@linux.ibm.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
| -rw-r--r-- | hw/core/qdev.c | 3 | ||||
| -rw-r--r-- | include/hw/qdev-core.h | 1 | ||||
| -rw-r--r-- | qdev-monitor.c | 2 |
3 files changed, 5 insertions, 1 deletions
diff --git a/hw/core/qdev.c b/hw/core/qdev.c index d59071b..00a5a39 100644 --- a/hw/core/qdev.c +++ b/hw/core/qdev.c @@ -59,6 +59,8 @@ static void bus_remove_child(BusState *bus, DeviceState *child) snprintf(name, sizeof(name), "child[%d]", kid->index); QTAILQ_REMOVE(&bus->children, kid, sibling); + bus->num_children--; + /* This gives back ownership of kid->child back to us. */ object_property_del(OBJECT(bus), name, NULL); object_unref(OBJECT(kid->child)); @@ -73,6 +75,7 @@ static void bus_add_child(BusState *bus, DeviceState *child) char name[32]; BusChild *kid = g_malloc0(sizeof(*kid)); + bus->num_children++; kid->index = bus->max_index++; kid->child = child; object_ref(OBJECT(kid->child)); diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index e70a4bf..35b8154 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -206,6 +206,7 @@ struct BusState { HotplugHandler *hotplug_handler; int max_index; bool realized; + int num_children; QTAILQ_HEAD(, BusChild) children; QLIST_ENTRY(BusState) sibling; }; diff --git a/qdev-monitor.c b/qdev-monitor.c index 07147c6..45a8ba4 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -414,7 +414,7 @@ static DeviceState *qbus_find_dev(BusState *bus, char *elem) static inline bool qbus_is_full(BusState *bus) { BusClass *bus_class = BUS_GET_CLASS(bus); - return bus_class->max_dev && bus->max_index >= bus_class->max_dev; + return bus_class->max_dev && bus->num_children >= bus_class->max_dev; } /* |