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Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical p
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del |
Date: |
Tue, 21 Aug 2012 09:06:39 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120717 Thunderbird/14.0 |
Il 20/08/2012 19:58, Anthony Liguori ha scritto:
> Michael Tokarev <address@hidden> writes:
>
>> On 08.08.2012 17:09, Michael Tokarev wrote:
>> []
>>> Something similar should be applied to 1.1-stable. FWIW, some
>>> changes are not needed there.
>>
>> Cherry-pick to stable-1.1 removes the two unneeded hunks.
>> This is what I plan to include into debian package. It
>> fixes the original usb_del issue, and I didn't find new
>> regressions so far - tried a few device_del and similar.
>>
>> Should it go to qemu/stable-1.1 as well?
>>
>> Thank you!
>>
>> /mjtAuthor: Paolo Bonzini <address@hidden>
>> Date: Wed Aug 8 14:39:11 2012 +0200
>> Bug-Debian: http://bugs.debian.org/684282
>> Comment: cherry-picked from qemu/master to stable-1.1 (mjt)
>>
>> qom: object_delete should unparent the object first
>>
>> object_deinit is only called when the reference count goes to zero,
>> and yet tries to do an object_unparent. Now, object_unparent
>> either does nothing or it will decrease the reference count.
>> Because we know the reference count is zero, the object_unparent
>> call in object_deinit is useless.
>>
>> Instead, we need to disconnect the object from its parent just
>> before we remove the last reference apart from the parent's. This
>> happens in object_delete. Once we do this, all calls to
>> object_unparent peppered through QEMU can go away.
>>
>> Signed-off-by: Paolo Bonzini <address@hidden>
>> Signed-off-by: Michael Tokarev <address@hidden>
>>
>> diff --git a/hw/acpi_piix4.c b/hw/acpi_piix4.c
>> index 0345490..585da4e 100644
>> --- a/hw/acpi_piix4.c
>> +++ b/hw/acpi_piix4.c
>> @@ -299,7 +299,6 @@ static void acpi_piix_eject_slot(PIIX4PMState *s,
>> unsigned slots)
>> if (pc->no_hotplug) {
>> slot_free = false;
>> } else {
>> - object_unparent(OBJECT(dev));
>> qdev_free(qdev);
>> }
>> }
>> diff --git a/hw/qdev.c b/hw/qdev.c
>> index 6a8f6bd..9bb1c6b 100644
>> --- a/hw/qdev.c
>> +++ b/hw/qdev.c
>> @@ -240,7 +240,6 @@ void qbus_reset_all_fn(void *opaque)
>> int qdev_simple_unplug_cb(DeviceState *dev)
>> {
>> /* just zap it */
>> - object_unparent(OBJECT(dev));
>> qdev_free(dev);
>> return 0;
>> }
>> diff --git a/hw/xen_platform.c b/hw/xen_platform.c
>> index 0214f37..84221df 100644
>> --- a/hw/xen_platform.c
>> +++ b/hw/xen_platform.c
>> @@ -87,9 +87,6 @@ static void unplug_nic(PCIBus *b, PCIDevice *d)
>> {
>> if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
>> PCI_CLASS_NETWORK_ETHERNET) {
>> - /* Until qdev_free includes a call to object_unparent, we call it
>> here
>> - */
>> - object_unparent(&d->qdev.parent_obj);
>> qdev_free(&d->qdev);
>> }
>> }
>> diff --git a/qom/object.c b/qom/object.c
>> index 6f839ad..58dd886 100644
>> --- a/qom/object.c
>> +++ b/qom/object.c
>> @@ -347,8 +347,6 @@ static void object_deinit(Object *obj, TypeImpl *type)
>> if (type_has_parent(type)) {
>> object_deinit(obj, type_get_parent(type));
>> }
>> -
>> - object_unparent(obj);
>> }
>>
>> void object_finalize(void *data)
>> @@ -385,8 +383,9 @@ Object *object_new(const char *typename)
>>
>> void object_delete(Object *obj)
>> {
>> + object_unparent(obj);
>> + g_assert(obj->ref == 1);
>> object_unref(obj);
>> - g_assert(obj->ref == 0);
>> g_free(obj);
>> }
>
> This won't work with composition. object_delete() is never called for
> child<> objects.
For non-heap-allocated children, their last ref will go away when the
parent's child<> property is eliminated. This will remove the last
reference and call object_finalize (which will take care of multiple
levels of compositions).
The same holds for heap-allocated children, but indeed you will leak the
memory for the object because object_delete is not called. However this
is already the case, the patch is not introducing a regression.
Paolo
- [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Michael Tokarev, 2012/08/08
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Michael Tokarev, 2012/08/08
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Paolo Bonzini, 2012/08/08
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Michael Tokarev, 2012/08/08
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Michael Tokarev, 2012/08/08
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Michael Tokarev, 2012/08/08
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Anthony Liguori, 2012/08/20
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del,
Paolo Bonzini <=
- Re: [Qemu-devel] commit da57febfed "qdev: give all devices a canonical path" broke usb_del, Anthony Liguori, 2012/08/21