migration: add comment for TYPE_MIGRATE

It'll be strange that the migration object inherits TYPE_DEVICE. Add
some explanations to it.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <1498634144-26508-1-git-send-email-peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Peter Xu 2017-06-28 15:15:44 +08:00 committed by Juan Quintela
parent 9d18af93b3
commit 01f6e14c78

View File

@ -2046,6 +2046,14 @@ static void migration_instance_init(Object *obj)
static const TypeInfo migration_type = {
.name = TYPE_MIGRATION,
/*
* NOTE: "migration" itself is not really a device. We used
* TYPE_DEVICE here only to leverage some existing QDev features
* like "-global" properties, and HW_COMPAT_* fields (which are
* finally applied as global properties as well). If one day the
* global property feature can be migrated from QDev to QObject in
* general, then we can switch to QObject as well.
*/
.parent = TYPE_DEVICE,
.class_init = migration_class_init,
.class_size = sizeof(MigrationClass),