Blame SOURCES/kvm-object-fix-OBJ_PROP_LINK_UNREF_ON_RELEASE-ambivalenc.patch

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From 206abaa45b1c845ef665f2639a8008b04a218165 Mon Sep 17 00:00:00 2001
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From: Serhii Popovych <spopovyc@redhat.com>
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Date: Mon, 9 Jul 2018 11:31:16 +0200
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Subject: [PATCH 200/268] object: fix OBJ_PROP_LINK_UNREF_ON_RELEASE
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 ambivalence
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Serhii Popovych <spopovyc@redhat.com>
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Message-id: <1531135878-18813-2-git-send-email-spopovyc@redhat.com>
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Patchwork-id: 81265
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O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH v2 1/3] object: fix OBJ_PROP_LINK_UNREF_ON_RELEASE ambivalence
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Bugzilla: 1556678
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RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
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RH-Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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RH-Acked-by: David Gibson <dgibson@redhat.com>
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From: Marc-André Lureau <marcandre.lureau@redhat.com>
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A link property can be set during creation, with
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object_property_add_link() and later with object_property_set_link().
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add_link() doesn't add a reference to the target object, while
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set_link() does.
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Furthemore, OBJ_PROP_LINK_UNREF_ON_RELEASE flags, set during add_link,
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says whether a reference must be released when the property is destroyed.
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This can lead to leaks if the property was later set_link(), as the
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added reference is never released.
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Instead, rename OBJ_PROP_LINK_UNREF_ON_RELEASE to OBJ_PROP_LINK_STRONG
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and use that has an indication on how the link handle reference
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management in set_link().
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Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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Message-id: 20180531195119.22021-3-marcandre.lureau@redhat.com
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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(cherry picked from commit 265b578c584b1a86c7028790deaa2f4392dd0a65)
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Signed-off-by: Serhii Popovych <spopovyc@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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Conflicts:
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	hw/dma/xlnx-zdma.c
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This file is missing in 2.12.0.
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---
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 hw/core/qdev-properties.c |  2 +-
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 hw/core/qdev.c            |  2 +-
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 hw/display/xlnx_dp.c      |  2 +-
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 hw/dma/xilinx_axidma.c    |  4 ++--
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 hw/i386/pc.c              |  2 +-
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 hw/i386/pc_piix.c         |  2 +-
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 hw/i386/pc_q35.c          |  2 +-
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 hw/ipmi/ipmi.c            |  2 +-
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 hw/net/xilinx_axienet.c   |  4 ++--
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 hw/ssi/xilinx_spips.c     |  2 +-
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 include/qom/object.h      | 12 +++++++++---
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 net/can/can_host.c        |  2 +-
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 net/colo-compare.c        |  2 +-
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 qom/object.c              |  8 +++++---
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 target/arm/cpu.c          |  4 ++--
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 ui/console.c              |  2 +-
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 16 files changed, 31 insertions(+), 23 deletions(-)
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diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
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index 5bbc2d9..f3a83a3 100644
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--- a/hw/core/qdev-properties.c
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+++ b/hw/core/qdev-properties.c
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@@ -1309,7 +1309,7 @@ static void create_link_property(Object *obj, Property *prop, Error **errp)
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     object_property_add_link(obj, prop->name, prop->link_type,
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                              child,
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                              qdev_prop_allow_set_link_before_realize,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              errp);
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 }
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diff --git a/hw/core/qdev.c b/hw/core/qdev.c
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index f6f9247..ce7c316 100644
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--- a/hw/core/qdev.c
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+++ b/hw/core/qdev.c
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@@ -435,7 +435,7 @@ void qdev_init_gpio_out_named(DeviceState *dev, qemu_irq *pins,
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         object_property_add_link(OBJECT(dev), propname, TYPE_IRQ,
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                                  (Object **)&pins[i],
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                                  object_property_allow_set_link,
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-                                 OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                                 OBJ_PROP_LINK_STRONG,
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                                  &error_abort);
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         g_free(propname);
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     }
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diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
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index 6715b9c..b737e1d 100644
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--- a/hw/display/xlnx_dp.c
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+++ b/hw/display/xlnx_dp.c
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@@ -1221,7 +1221,7 @@ static void xlnx_dp_init(Object *obj)
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     object_property_add_link(obj, "dpdma", TYPE_XLNX_DPDMA,
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                              (Object **) &s->dpdma,
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                              xlnx_dp_set_dpdma,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &error_abort);
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     /*
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diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
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index 9b48103..401a328 100644
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--- a/hw/dma/xilinx_axidma.c
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+++ b/hw/dma/xilinx_axidma.c
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@@ -525,12 +525,12 @@ static void xilinx_axidma_realize(DeviceState *dev, Error **errp)
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     object_property_add_link(OBJECT(ds), "dma", TYPE_XILINX_AXI_DMA,
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                              (Object **)&ds->dma,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &local_err);
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     object_property_add_link(OBJECT(cs), "dma", TYPE_XILINX_AXI_DMA,
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                              (Object **)&cs->dma,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &local_err);
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     if (local_err) {
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         goto xilinx_axidma_realize_fail;
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diff --git a/hw/i386/pc.c b/hw/i386/pc.c
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index 6f686c7..9034f02 100644
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--- a/hw/i386/pc.c
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+++ b/hw/i386/pc.c
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@@ -484,7 +484,7 @@ void pc_cmos_init(PCMachineState *pcms,
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                              TYPE_ISA_DEVICE,
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                              (Object **)&pcms->rtc,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
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+                             OBJ_PROP_LINK_STRONG, &error_abort);
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     object_property_set_link(OBJECT(pcms), OBJECT(s),
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                              "rtc_state", &error_abort);
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diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
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index 229d551..60441c1 100644
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--- a/hw/i386/pc_piix.c
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+++ b/hw/i386/pc_piix.c
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@@ -290,7 +290,7 @@ static void pc_init1(MachineState *machine,
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                                  TYPE_HOTPLUG_HANDLER,
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                                  (Object **)&pcms->acpi_dev,
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                                  object_property_allow_set_link,
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-                                 OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
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+                                 OBJ_PROP_LINK_STRONG, &error_abort);
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         object_property_set_link(OBJECT(machine), OBJECT(piix4_pm),
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                                  PC_MACHINE_ACPI_DEVICE_PROP, &error_abort);
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     }
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diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
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index e1fd23e..ccdeb11 100644
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--- a/hw/i386/pc_q35.c
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+++ b/hw/i386/pc_q35.c
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@@ -194,7 +194,7 @@ static void pc_q35_init(MachineState *machine)
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                              TYPE_HOTPLUG_HANDLER,
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                              (Object **)&pcms->acpi_dev,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
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+                             OBJ_PROP_LINK_STRONG, &error_abort);
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     object_property_set_link(OBJECT(machine), OBJECT(lpc),
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                              PC_MACHINE_ACPI_DEVICE_PROP, &error_abort);
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diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
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index 9be281f..63c0317 100644
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--- a/hw/ipmi/ipmi.c
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+++ b/hw/ipmi/ipmi.c
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@@ -104,7 +104,7 @@ void ipmi_bmc_find_and_link(Object *obj, Object **bmc)
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 {
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     object_property_add_link(obj, "bmc", TYPE_IPMI_BMC, bmc,
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                              isa_ipmi_bmc_check,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &error_abort);
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 }
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diff --git a/hw/net/xilinx_axienet.c b/hw/net/xilinx_axienet.c
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index d4c2c89..cc880a3 100644
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--- a/hw/net/xilinx_axienet.c
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+++ b/hw/net/xilinx_axienet.c
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@@ -951,12 +951,12 @@ static void xilinx_enet_realize(DeviceState *dev, Error **errp)
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     object_property_add_link(OBJECT(ds), "enet", "xlnx.axi-ethernet",
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                              (Object **) &ds->enet,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &local_err);
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     object_property_add_link(OBJECT(cs), "enet", "xlnx.axi-ethernet",
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                              (Object **) &cs->enet,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &local_err);
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     if (local_err) {
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         goto xilinx_enet_realize_fail;
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diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
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index 426f971..068878c 100644
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--- a/hw/ssi/xilinx_spips.c
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+++ b/hw/ssi/xilinx_spips.c
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@@ -1345,7 +1345,7 @@ static void xlnx_zynqmp_qspips_init(Object *obj)
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     object_property_add_link(obj, "stream-connected-dma", TYPE_STREAM_SLAVE,
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                              (Object **)&rq->dma,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              NULL);
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 }
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diff --git a/include/qom/object.h b/include/qom/object.h
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index 96ce81b..fc4555d 100644
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--- a/include/qom/object.h
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+++ b/include/qom/object.h
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@@ -1103,6 +1103,11 @@ char *object_property_get_str(Object *obj, const char *name,
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  * @errp: returns an error if this function fails
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  *
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  * Writes an object's canonical path to a property.
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+ *
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+ * If the link property was created with
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+ * OBJ_PROP_LINK_STRONG bit, the old target object is
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+ * unreferenced, and a reference is added to the new target object.
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+ *
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  */
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 void object_property_set_link(Object *obj, Object *value,
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                               const char *name, Error **errp);
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@@ -1393,7 +1398,7 @@ void object_property_add_child(Object *obj, const char *name,
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 typedef enum {
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     /* Unref the link pointer when the property is deleted */
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-    OBJ_PROP_LINK_UNREF_ON_RELEASE = 0x1,
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+    OBJ_PROP_LINK_STRONG = 0x1,
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 } ObjectPropertyLinkFlags;
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 /**
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@@ -1431,8 +1436,9 @@ void object_property_allow_set_link(const Object *, const char *,
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  * link property.  The reference count for *@child is
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  * managed by the property from after the function returns till the
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  * property is deleted with object_property_del().  If the
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- * @flags OBJ_PROP_LINK_UNREF_ON_RELEASE bit is set,
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- * the reference count is decremented when the property is deleted.
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+ * @flags OBJ_PROP_LINK_STRONG bit is set,
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+ * the reference count is decremented when the property is deleted or
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+ * modified.
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  */
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 void object_property_add_link(Object *obj, const char *name,
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                               const char *type, Object **child,
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diff --git a/net/can/can_host.c b/net/can/can_host.c
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index c3d2652..c79347a 100644
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--- a/net/can/can_host.c
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+++ b/net/can/can_host.c
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@@ -77,7 +77,7 @@ static void can_host_instance_init(Object *obj)
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     object_property_add_link(obj, "canbus", TYPE_CAN_BUS,
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                              (Object **)&ch->bus,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &error_abort);
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 }
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diff --git a/net/colo-compare.c b/net/colo-compare.c
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index 23b2d2c..63469b1 100644
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--- a/net/colo-compare.c
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+++ b/net/colo-compare.c
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@@ -980,7 +980,7 @@ static void colo_compare_init(Object *obj)
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     object_property_add_link(obj, "iothread", TYPE_IOTHREAD,
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                             (Object **)&s->iothread,
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                             object_property_allow_set_link,
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-                            OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
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+                            OBJ_PROP_LINK_STRONG, NULL);
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     s->vnet_hdr = false;
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     object_property_add_bool(obj, "vnet_hdr_support", compare_get_vnet_hdr,
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diff --git a/qom/object.c b/qom/object.c
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index 76a89af..c4f1d36 100644
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--- a/qom/object.c
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+++ b/qom/object.c
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@@ -1564,9 +1564,11 @@ static void object_set_link_property(Object *obj, Visitor *v,
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         return;
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     }
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-    object_ref(new_target);
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     *child = new_target;
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-    object_unref(old_target);
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+    if (prop->flags == OBJ_PROP_LINK_STRONG) {
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+        object_ref(new_target);
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+        object_unref(old_target);
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+    }
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 }
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 static Object *object_resolve_link_property(Object *parent, void *opaque, const gchar *part)
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@@ -1581,7 +1583,7 @@ static void object_release_link_property(Object *obj, const char *name,
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 {
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     LinkProperty *prop = opaque;
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-    if ((prop->flags & OBJ_PROP_LINK_UNREF_ON_RELEASE) && *prop->child) {
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+    if ((prop->flags & OBJ_PROP_LINK_STRONG) && *prop->child) {
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         object_unref(*prop->child);
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     }
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     g_free(prop);
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diff --git a/target/arm/cpu.c b/target/arm/cpu.c
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index 4255e9c..9d030e0 100644
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--- a/target/arm/cpu.c
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+++ b/target/arm/cpu.c
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@@ -672,7 +672,7 @@ static void arm_cpu_post_init(Object *obj)
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                                  TYPE_MEMORY_REGION,
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                                  (Object **)&cpu->secure_memory,
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                                  qdev_prop_allow_set_link_before_realize,
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-                                 OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                                 OBJ_PROP_LINK_STRONG,
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                                  &error_abort);
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 #endif
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     }
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@@ -700,7 +700,7 @@ static void arm_cpu_post_init(Object *obj)
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     if (arm_feature(&cpu->env, ARM_FEATURE_M_SECURITY)) {
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         object_property_add_link(obj, "idau", TYPE_IDAU_INTERFACE, &cpu->idau,
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                                  qdev_prop_allow_set_link_before_realize,
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-                                 OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                                 OBJ_PROP_LINK_STRONG,
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                                  &error_abort);
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         qdev_property_add_static(DEVICE(obj), &arm_cpu_initsvtor_property,
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                                  &error_abort);
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diff --git a/ui/console.c b/ui/console.c
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index 3fb2f4e..594ec63 100644
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--- a/ui/console.c
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+++ b/ui/console.c
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@@ -1280,7 +1280,7 @@ static QemuConsole *new_console(DisplayState *ds, console_type_t console_type,
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     object_property_add_link(obj, "device", TYPE_DEVICE,
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                              (Object **)&s->device,
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                              object_property_allow_set_link,
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-                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
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+                             OBJ_PROP_LINK_STRONG,
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                              &error_abort);
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     object_property_add_uint32_ptr(obj, "head",
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                                    &s->head, &error_abort);
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-- 
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1.8.3.1
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