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From: | Anthony Liguori |
Subject: | Re: [Qemu-devel] [PATCH 01/16] qdev: fix hot-unplug |
Date: | Fri, 03 Feb 2012 08:27:33 -0600 |
User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.23) Gecko/20110922 Lightning/1.0b2 Thunderbird/3.1.15 |
On 02/02/2012 10:45 AM, Paolo Bonzini wrote:
The reference that is returned by qdev_device_add is never given back, so that device_del does not cause the refcount to go to zero (and thus does nothing). Signed-off-by: Paolo Bonzini<address@hidden>
This isn't needed in qom-upstream.14. Here's why: object_init does not increase the reference count object_property_add_child increases the reference count object_new increases the reference count object_delete decrements the reference count object_property_del_child decreases the reference count object_delete calls object_property_del_child(obj->parent, obj) qdev_device_add calls object_new and object_property_add_child -> ref == 2 qdev_device_del calls object_delete -> ref -= 2In qom-upstream.13, object_delete wasn't calling object_property_del_child which is why you saw the behavior you did. This problem would still exist with a composed device so dropping the reference here isn't enough.
Regards, Anthony Liguori
--- vl.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/vl.c b/vl.c index d88a18c..c63af69 100644 --- a/vl.c +++ b/vl.c @@ -1746,6 +1746,7 @@ static int device_init_func(QemuOpts *opts, void *opaque) dev = qdev_device_add(opts); if (!dev) return -1; + object_unref(OBJECT(dev)); return 0; }
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