qom: add a reference count to qdev objects

To ensure that a device isn't removed from the graph until all of its links are
broken.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Anthony Liguori 2011-12-12 14:29:25 -06:00
parent 222f23f508
commit 85ed303bfe
2 changed files with 42 additions and 0 deletions

View File

@ -323,6 +323,11 @@ int qdev_unplug(DeviceState *dev)
}
assert(dev->info->unplug != NULL);
if (dev->ref != 0) {
qerror_report(QERR_DEVICE_IN_USE, dev->id?:"");
return -1;
}
qdev_hot_removed = true;
return dev->info->unplug(dev);
@ -962,3 +967,14 @@ char* qdev_get_fw_dev_path(DeviceState *dev)
return strdup(path);
}
void qdev_ref(DeviceState *dev)
{
dev->ref++;
}
void qdev_unref(DeviceState *dev)
{
g_assert(dev->ref > 0);
dev->ref--;
}

View File

@ -45,6 +45,12 @@ struct DeviceState {
QTAILQ_ENTRY(DeviceState) sibling;
int instance_id_alias;
int alias_required_for_version;
/**
* This tracks the number of references between devices. See @qdev_ref for
* more information.
*/
uint32_t ref;
};
typedef void (*bus_dev_printfn)(Monitor *mon, DeviceState *dev, int indent);
@ -329,4 +335,24 @@ char *qdev_get_fw_dev_path(DeviceState *dev);
/* This is a nasty hack to allow passing a NULL bus to qdev_create. */
extern struct BusInfo system_bus_info;
/**
* @qdev_ref
*
* Increase the reference count of a device. A device cannot be freed as long
* as its reference count is greater than zero.
*
* @dev - the device
*/
void qdev_ref(DeviceState *dev);
/**
* @qdef_unref
*
* Decrease the reference count of a device. A device cannot be freed as long
* as its reference count is greater than zero.
*
* @dev - the device
*/
void qdev_unref(DeviceState *dev);
#endif