QOM patches for 2020-05-15

[PULL 01/21] qom: Clearer reference counting in object_initialize_childv()

Markus Armbruster posted 21 patches 5 years, 8 months ago

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Maintainers: Peter Maydell <peter.maydell@linaro.org>, Igor Mammedov <imammedo@redhat.com>, Keith Busch <kbusch@kernel.org>, Fam Zheng <fam@euphon.net>, "Gonglei (Arei)" <arei.gonglei@huawei.com>, Subbaraya Sundeep <sundeep.lkml@gmail.com>, Leif Lindholm <leif@nuviainc.com>, Sergio Lopez <slp@redhat.com>, Alistair Francis <alistair@alistair23.me>, Cornelia Huck <cohuck@redhat.com>, Niek Linnenbank <nieklinnenbank@gmail.com>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, "Cédric Le Goater" <clg@kaod.org>, Jean-Christophe Dubois <jcd@tribudubois.net>, Li Zhijian <lizhijian@cn.fujitsu.com>, Marek Vasut <marex@denx.de>, Corey Minyard <minyard@acm.org>, Sven Schnelle <svens@stackframe.org>, "Philippe Mathieu-Daudé" <philmd@redhat.com>, Halil Pasic <pasic@linux.ibm.com>, Paul Durrant <paul@xen.org>, Andrew Baumann <Andrew.Baumann@microsoft.com>, Sagar Karandikar <sagark@eecs.berkeley.edu>, Xiao Guangrong <xiaoguangrong.eric@gmail.com>, Andrew Jeffery <andrew@aj.id.au>, Pierre Morel <pmorel@linux.ibm.com>, BALATON Zoltan <balaton@eik.bme.hu>, Andrzej Zaborowski <balrogg@gmail.com>, Beniamino Galvani <b.galvani@gmail.com>, "Hervé Poussineau" <hpoussin@reactos.org>, Alex Williamson <alex.williamson@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Max Reitz <mreitz@redhat.com>, Kevin Wolf <kwolf@redhat.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Jason Wang <jasowang@redhat.com>, Eric Farman <farman@linux.ibm.com>, Gerd Hoffmann <kraxel@redhat.com>, David Hildenbrand <david@redhat.com>, Palmer Dabbelt <palmer@dabbelt.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Dmitry Fleytman <dmitry.fleytman@gmail.com>, Anthony Perard <anthony.perard@citrix.com>, Chris Wulff <crwulff@gmail.com>, Andrey Smirnov <andrew.smirnov@gmail.com>, Stefano Stabellini <sstabellini@kernel.org>, John Snow <jsnow@redhat.com>, Jiri Slaby <jslaby@suse.cz>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Markus Armbruster <armbru@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Radoslaw Biernacki <radoslaw.biernacki@linaro.org>, Raphael Norwitz <raphael.norwitz@nutanix.com>, Artyom Tarasenko <atar4qemu@gmail.com>, Laszlo Ersek <lersek@redhat.com>, Zhang Chen <chen.zhang@intel.com>, Amit Shah <amit@kernel.org>, Alberto Garcia <berto@igalia.com>, "Daniel P. Berrangé" <berrange@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Laurent Vivier <lvivier@redhat.com>, David Gibson <david@gibson.dropbear.id.au>, Aurelien Jarno <aurelien@aurel32.net>, Richard Henderson <rth@twiddle.net>, Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>, Stefan Weil <sw@weilnetz.de>, Joel Stanley <joel@jms.id.au>, Christian Borntraeger <borntraeger@de.ibm.com>, Eduardo Habkost <ehabkost@redhat.com>, Tony Krowiak <akrowiak@linux.ibm.com>

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[PULL 01/21] qom: Clearer reference counting in object_initialize_childv()

Posted by Markus Armbruster 5 years, 8 months ago

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-2-armbru@redhat.com>
---
 qom/object.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/qom/object.c b/qom/object.c
index be700e831f..5511649502 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -571,18 +571,18 @@ void object_initialize_childv(Object *parentobj, const char *propname,
         }
     }
 
+out:
     /*
-     * Since object_property_add_child added a reference to the child object,
-     * we can drop the reference added by object_initialize(), so the child
-     * property will own the only reference to the object.
+     * We want @obj's reference to be 1 on success, 0 on failure.
+     * On success, it's 2: one taken by object_initialize(), and one
+     * by object_property_add_child().
+     * On failure in object_initialize() or earlier, it's 1.
+     * On failure afterwards, it's also 1: object_unparent() releases
+     * the reference taken by object_property_add_child().
      */
     object_unref(obj);
 
-out:
-    if (local_err) {
-        error_propagate(errp, local_err);
-        object_unref(obj);
-    }
+    error_propagate(errp, local_err);
 }
 
 static inline bool object_property_is_child(ObjectProperty *prop)
-- 
2.21.1