[Qemu-devel] [PATCH 20/21] qbus: make child devices links

[Paolo Bonzini <pbonzini@redhat.com>]

From: Anthony Liguori <aliguori@us.ibm.com>

Make qbus children show up as link<> properties.  There is no stable addressing
for qbus children so we use an unstable naming convention.

This is okay in QOM though because the composition name is expected to be what's
stable.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/acpi_piix4.c      |   10 ++++----
 hw/i2c.c             |    5 ++--
 hw/intel-hda.c       |   15 +++++++-----
 hw/lsi53c895a.c      |    5 ++--
 hw/qdev-monitor.c    |   26 ++++++++++++--------
 hw/qdev.c            |   64 +++++++++++++++++++++++++++++++++++++++++---------
 hw/qdev.h            |   11 +++++++--
 hw/s390-virtio-bus.c |   25 ++++++++++----------
 hw/scsi-bus.c        |   13 ++++++----
 hw/spapr_pci.c       |    7 +++---
 hw/spapr_vio.c       |   27 +++++++++++----------
 hw/spapr_vty.c       |    6 +++--
 hw/ssi.c             |   14 ++++++-----
 hw/virtio-scsi.c     |    6 ++---
 qom/object.c         |   11 +++++++--
 15 files changed, 161 insertions(+), 84 deletions(-)

diff --git a/hw/acpi_piix4.c b/hw/acpi_piix4.c
index 585da4e..03daf9a 100644
--- a/hw/acpi_piix4.c
+++ b/hw/acpi_piix4.c
@@ -284,7 +284,7 @@ static const VMStateDescription vmstate_acpi = {
 
 static void acpi_piix_eject_slot(PIIX4PMState *s, unsigned slots)
 {
-    DeviceState *qdev, *next;
+    BusChild *kid, *next;
     BusState *bus = qdev_get_parent_bus(&s->dev.qdev);
     int slot = ffs(slots) - 1;
     bool slot_free = true;
@@ -292,7 +292,8 @@ static void acpi_piix_eject_slot(PIIX4PMState *s, unsigned slots)
     /* Mark request as complete */
     s->pci0_status.down &= ~(1U << slot);
 
-    QTAILQ_FOREACH_SAFE(qdev, &bus->children, sibling, next) {
+    QTAILQ_FOREACH_SAFE(kid, &bus->children, sibling, next) {
+        DeviceState *qdev = kid->child;
         PCIDevice *dev = PCI_DEVICE(qdev);
         PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
         if (PCI_SLOT(dev->devfn) == slot) {
@@ -312,7 +313,7 @@ static void piix4_update_hotplug(PIIX4PMState *s)
 {
     PCIDevice *dev = &s->dev;
     BusState *bus = qdev_get_parent_bus(&dev->qdev);
-    DeviceState *qdev, *next;
+    BusChild *kid, *next;
 
     /* Execute any pending removes during reset */
     while (s->pci0_status.down) {
@@ -322,7 +323,8 @@ static void piix4_update_hotplug(PIIX4PMState *s)
     s->pci0_hotplug_enable = ~0;
     s->pci0_slot_device_present = 0;
 
-    QTAILQ_FOREACH_SAFE(qdev, &bus->children, sibling, next) {
+    QTAILQ_FOREACH_SAFE(kid, &bus->children, sibling, next) {
+        DeviceState *qdev = kid->child;
         PCIDevice *pdev = PCI_DEVICE(qdev);
         PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(pdev);
         int slot = PCI_SLOT(pdev->devfn);
diff --git a/hw/i2c.c b/hw/i2c.c
index cd8fa31..47219f5 100644
--- a/hw/i2c.c
+++ b/hw/i2c.c
@@ -86,11 +86,12 @@ int i2c_bus_busy(i2c_bus *bus)
 /* TODO: Make this handle multiple masters.  */
 int i2c_start_transfer(i2c_bus *bus, uint8_t address, int recv)
 {
-    DeviceState *qdev;
+    BusChild *kid;
     I2CSlave *slave = NULL;
     I2CSlaveClass *sc;
 
-    QTAILQ_FOREACH(qdev, &bus->qbus.children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
+        DeviceState *qdev = kid->child;
         I2CSlave *candidate = I2C_SLAVE_FROM_QDEV(qdev);
         if (candidate->address == address) {
             slave = candidate;
diff --git a/hw/intel-hda.c b/hw/intel-hda.c
index 63bdb27..fb585b5 100644
--- a/hw/intel-hda.c
+++ b/hw/intel-hda.c
@@ -78,10 +78,11 @@ static int hda_codec_dev_exit(DeviceState *qdev)
 
 HDACodecDevice *hda_codec_find(HDACodecBus *bus, uint32_t cad)
 {
-    DeviceState *qdev;
+    BusChild *kid;
     HDACodecDevice *cdev;
 
-    QTAILQ_FOREACH(qdev, &bus->qbus.children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
+        DeviceState *qdev = kid->child;
         cdev = DO_UPCAST(HDACodecDevice, qdev, qdev);
         if (cdev->cad == cad) {
             return cdev;
@@ -483,10 +484,11 @@ static void intel_hda_parse_bdl(IntelHDAState *d, IntelHDAStream *st)
 
 static void intel_hda_notify_codecs(IntelHDAState *d, uint32_t stream, bool running, bool output)
 {
-    DeviceState *qdev;
+    BusChild *kid;
     HDACodecDevice *cdev;
 
-    QTAILQ_FOREACH(qdev, &d->codecs.qbus.children, sibling) {
+    QTAILQ_FOREACH(kid, &d->codecs.qbus.children, sibling) {
+        DeviceState *qdev = kid->child;
         HDACodecDeviceClass *cdc;
 
         cdev = DO_UPCAST(HDACodecDevice, qdev, qdev);
@@ -1105,15 +1107,16 @@ static const MemoryRegionOps intel_hda_mmio_ops = {
 
 static void intel_hda_reset(DeviceState *dev)
 {
+    BusChild *kid;
     IntelHDAState *d = DO_UPCAST(IntelHDAState, pci.qdev, dev);
-    DeviceState *qdev;
     HDACodecDevice *cdev;
 
     intel_hda_regs_reset(d);
     d->wall_base_ns = qemu_get_clock_ns(vm_clock);
 
     /* reset codecs */
-    QTAILQ_FOREACH(qdev, &d->codecs.qbus.children, sibling) {
+    QTAILQ_FOREACH(kid, &d->codecs.qbus.children, sibling) {
+        DeviceState *qdev = kid->child;
         cdev = DO_UPCAST(HDACodecDevice, qdev, qdev);
         device_reset(DEVICE(cdev));
         d->state_sts |= (1 << cdev->cad);
diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
index f022a02..2fe141d 100644
--- a/hw/lsi53c895a.c
+++ b/hw/lsi53c895a.c
@@ -1677,9 +1677,10 @@ static void lsi_reg_writeb(LSIState *s, int offset, uint8_t val)
         }
         if (val & LSI_SCNTL1_RST) {
             if (!(s->sstat0 & LSI_SSTAT0_RST)) {
-                DeviceState *dev;
+                BusChild *kid;
 
-                QTAILQ_FOREACH(dev, &s->bus.qbus.children, sibling) {
+                QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) {
+                    DeviceState *dev = kid->child;
                     device_reset(dev);
                 }
                 s->sstat0 |= LSI_SSTAT0_RST;
diff --git a/hw/qdev-monitor.c b/hw/qdev-monitor.c
index 703d895..e57220e 100644
--- a/hw/qdev-monitor.c
+++ b/hw/qdev-monitor.c
@@ -205,11 +205,12 @@ static void qbus_list_bus(DeviceState *dev)
 
 static void qbus_list_dev(BusState *bus)
 {
-    DeviceState *dev;
+    BusChild *kid;
     const char *sep = " ";
 
     error_printf("devices at \"%s\":", bus->name);
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
         error_printf("%s\"%s\"", sep, object_get_typename(OBJECT(dev)));
         if (dev->id)
             error_printf("/\"%s\"", dev->id);
@@ -232,7 +233,7 @@ static BusState *qbus_find_bus(DeviceState *dev, char *elem)
 
 static DeviceState *qbus_find_dev(BusState *bus, char *elem)
 {
-    DeviceState *dev;
+    BusChild *kid;
 
     /*
      * try to match in order:
@@ -240,17 +241,20 @@ static DeviceState *qbus_find_dev(BusState *bus, char *elem)
      *   (2) driver name
      *   (3) driver alias, if present
      */
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
         if (dev->id  &&  strcmp(dev->id, elem) == 0) {
             return dev;
         }
     }
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
         if (strcmp(object_get_typename(OBJECT(dev)), elem) == 0) {
             return dev;
         }
     }
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
         DeviceClass *dc = DEVICE_GET_CLASS(dev);
 
         if (qdev_class_has_alias(dc) &&
@@ -264,7 +268,7 @@ static DeviceState *qbus_find_dev(BusState *bus, char *elem)
 static BusState *qbus_find_recursive(BusState *bus, const char *name,
                                      const char *bus_typename)
 {
-    DeviceState *dev;
+    BusChild *kid;
     BusState *child, *ret;
     int match = 1;
 
@@ -279,7 +283,8 @@ static BusState *qbus_find_recursive(BusState *bus, const char *name,
         return bus;
     }
 
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
         QLIST_FOREACH(child, &dev->child_bus, sibling) {
             ret = qbus_find_recursive(child, name, bus_typename);
             if (ret) {
@@ -533,12 +538,13 @@ static void qdev_print(Monitor *mon, DeviceState *dev, int indent)
 
 static void qbus_print(Monitor *mon, BusState *bus, int indent)
 {
-    struct DeviceState *dev;
+    BusChild *kid;
 
     qdev_printf("bus: %s\n", bus->name);
     indent += 2;
     qdev_printf("type %s\n", object_get_typename(OBJECT(bus)));
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
         qdev_print(mon, dev, indent);
     }
 }
diff --git a/hw/qdev.c b/hw/qdev.c
index decbcb1..6965da0 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -60,14 +60,48 @@ bool qdev_exists(const char *name)
 static void qdev_property_add_legacy(DeviceState *dev, Property *prop,
                                      Error **errp);
 
-void qdev_set_parent_bus(DeviceState *dev, BusState *bus)
+static void bus_remove_child(BusState *bus, DeviceState *child)
 {
+    BusChild *kid;
+
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        if (kid->child == child) {
+            char name[32];
+
+            snprintf(name, sizeof(name), "child[%d]", kid->index);
+            QTAILQ_REMOVE(&bus->children, kid, sibling);
+            object_property_del(OBJECT(bus), name, NULL);
+            g_free(kid);
+            return;
+        }
+    }
+}
+
+static void bus_add_child(BusState *bus, DeviceState *child)
+{
+    char name[32];
+    BusChild *kid = g_malloc0(sizeof(*kid));
+
     if (qdev_hotplug) {
         assert(bus->allow_hotplug);
     }
 
+    kid->index = bus->max_index++;
+    kid->child = child;
+
+    QTAILQ_INSERT_HEAD(&bus->children, kid, sibling);
+
+    snprintf(name, sizeof(name), "child[%d]", kid->index);
+    object_property_add_link(OBJECT(bus), name,
+                             object_get_typename(OBJECT(child)),
+                             (Object **)&kid->child,
+                             NULL);
+}
+
+void qdev_set_parent_bus(DeviceState *dev, BusState *bus)
+{
     dev->parent_bus = bus;
-    QTAILQ_INSERT_HEAD(&bus->children, dev, sibling);
+    bus_add_child(bus, dev);
 }
 
 /* Create a new device.  This only initializes the device state structure
@@ -310,7 +344,7 @@ BusState *qdev_get_child_bus(DeviceState *dev, const char *name)
 int qbus_walk_children(BusState *bus, qdev_walkerfn *devfn,
                        qbus_walkerfn *busfn, void *opaque)
 {
-    DeviceState *dev;
+    BusChild *kid;
     int err;
 
     if (busfn) {
@@ -320,8 +354,8 @@ int qbus_walk_children(BusState *bus, qdev_walkerfn *devfn,
         }
     }
 
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
-        err = qdev_walk_children(dev, devfn, busfn, opaque);
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        err = qdev_walk_children(kid->child, devfn, busfn, opaque);
         if (err < 0) {
             return err;
         }
@@ -355,12 +389,17 @@ int qdev_walk_children(DeviceState *dev, qdev_walkerfn *devfn,
 
 DeviceState *qdev_find_recursive(BusState *bus, const char *id)
 {
-    DeviceState *dev, *ret;
+    BusChild *kid;
+    DeviceState *ret;
     BusState *child;
 
-    QTAILQ_FOREACH(dev, &bus->children, sibling) {
-        if (dev->id && strcmp(dev->id, id) == 0)
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
+
+        if (dev->id && strcmp(dev->id, id) == 0) {
             return dev;
+        }
+
         QLIST_FOREACH(child, &dev->child_bus, sibling) {
             ret = qdev_find_recursive(child, id);
             if (ret) {
@@ -431,9 +470,10 @@ BusState *qbus_create(const char *typename, DeviceState *parent, const char *nam
 
 void qbus_free(BusState *bus)
 {
-    DeviceState *dev;
+    BusChild *kid;
 
-    while ((dev = QTAILQ_FIRST(&bus->children)) != NULL) {
+    while ((kid = QTAILQ_FIRST(&bus->children)) != NULL) {
+        DeviceState *dev = kid->child;
         qdev_free(dev);
     }
     if (bus->parent) {
@@ -679,7 +719,9 @@ static void device_finalize(Object *obj)
             qemu_opts_del(dev->opts);
         }
     }
-    QTAILQ_REMOVE(&dev->parent_bus->children, dev, sibling);
+    if (dev->parent_bus) {
+        bus_remove_child(dev->parent_bus, dev);
+    }
 }
 
 static void device_class_base_init(ObjectClass *class, void *data)
diff --git a/hw/qdev.h b/hw/qdev.h
index 3c54a6f..7deb2cb 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -74,7 +74,6 @@ struct DeviceState {
     qemu_irq *gpio_in;
     QLIST_HEAD(, BusState) child_bus;
     int num_child_bus;
-    QTAILQ_ENTRY(DeviceState) sibling;
     int instance_id_alias;
     int alias_required_for_version;
 };
@@ -100,13 +99,20 @@ struct BusClass {
     int (*reset)(BusState *bus);
 };
 
+typedef struct BusChild {
+    DeviceState *child;
+    int index;
+    QTAILQ_ENTRY(BusChild) sibling;
+} BusChild;
+
 struct BusState {
     Object obj;
     DeviceState *parent;
     const char *name;
     int allow_hotplug;
     int qdev_allocated;
-    QTAILQ_HEAD(ChildrenHead, DeviceState) children;
+    int max_index;
+    QTAILQ_HEAD(ChildrenHead, BusChild) children;
     QLIST_ENTRY(BusState) sibling;
 };
 
diff --git a/hw/s390-virtio-bus.c b/hw/s390-virtio-bus.c
index d259050..6831b12 100644
--- a/hw/s390-virtio-bus.c
+++ b/hw/s390-virtio-bus.c
@@ -291,20 +291,20 @@ VirtIOS390Device *s390_virtio_bus_find_vring(VirtIOS390Bus *bus,
                                              ram_addr_t mem,
                                              int *vq_num)
 {
-    VirtIOS390Device *_dev;
-    DeviceState *dev;
+    BusChild *kid;
     int i;
 
-    QTAILQ_FOREACH(dev, &bus->bus.children, sibling) {
-        _dev = (VirtIOS390Device *)dev;
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
+        VirtIOS390Device *dev = (VirtIOS390Device *)kid->child;
+
         for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) {
-            if (!virtio_queue_get_addr(_dev->vdev, i))
+            if (!virtio_queue_get_addr(dev->vdev, i))
                 break;
-            if (virtio_queue_get_addr(_dev->vdev, i) == mem) {
+            if (virtio_queue_get_addr(dev->vdev, i) == mem) {
                 if (vq_num) {
                     *vq_num = i;
                 }
-                return _dev;
+                return dev;
             }
         }
     }
@@ -315,13 +315,12 @@ VirtIOS390Device *s390_virtio_bus_find_vring(VirtIOS390Bus *bus,
 /* Find a device by device descriptor location */
 VirtIOS390Device *s390_virtio_bus_find_mem(VirtIOS390Bus *bus, ram_addr_t mem)
 {
-    VirtIOS390Device *_dev;
-    DeviceState *dev;
+    BusChild *kid;
 
-    QTAILQ_FOREACH(dev, &bus->bus.children, sibling) {
-        _dev = (VirtIOS390Device *)dev;
-        if (_dev->dev_offs == mem) {
-            return _dev;
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
+        VirtIOS390Device *dev = (VirtIOS390Device *)kid->child;
+        if (dev->dev_offs == mem) {
+            return dev;
         }
     }
 
diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index 004f852..3dbe335 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -303,7 +303,7 @@ static void store_lun(uint8_t *outbuf, int lun)
 
 static bool scsi_target_emulate_report_luns(SCSITargetReq *r)
 {
-    DeviceState *qdev;
+    BusChild *kid;
     int i, len, n;
     int channel, id;
     bool found_lun0;
@@ -318,7 +318,8 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r)
     id = r->req.dev->id;
     found_lun0 = false;
     n = 0;
-    QTAILQ_FOREACH(qdev, &r->req.bus->qbus.children, sibling) {
+    QTAILQ_FOREACH(kid, &r->req.bus->qbus.children, sibling) {
+        DeviceState *qdev = kid->child;
         SCSIDevice *dev = SCSI_DEVICE(qdev);
 
         if (dev->channel == channel && dev->id == id) {
@@ -340,7 +341,8 @@ static bool scsi_target_emulate_report_luns(SCSITargetReq *r)
     memset(r->buf, 0, len);
     stl_be_p(&r->buf, n);
     i = found_lun0 ? 8 : 16;
-    QTAILQ_FOREACH(qdev, &r->req.bus->qbus.children, sibling) {
+    QTAILQ_FOREACH(kid, &r->req.bus->qbus.children, sibling) {
+        DeviceState *qdev = kid->child;
         SCSIDevice *dev = SCSI_DEVICE(qdev);
 
         if (dev->channel == channel && dev->id == id) {
@@ -1465,10 +1467,11 @@ static char *scsibus_get_fw_dev_path(DeviceState *dev)
 
 SCSIDevice *scsi_device_find(SCSIBus *bus, int channel, int id, int lun)
 {
-    DeviceState *qdev;
+    BusChild *kid;
     SCSIDevice *target_dev = NULL;
 
-    QTAILQ_FOREACH_REVERSE(qdev, &bus->qbus.children, ChildrenHead, sibling) {
+    QTAILQ_FOREACH_REVERSE(kid, &bus->qbus.children, ChildrenHead, sibling) {
+        DeviceState *qdev = kid->child;
         SCSIDevice *dev = SCSI_DEVICE(qdev);
 
         if (dev->channel == channel && dev->id == id) {
diff --git a/hw/spapr_pci.c b/hw/spapr_pci.c
index a564c00..fcc6d58 100644
--- a/hw/spapr_pci.c
+++ b/hw/spapr_pci.c
@@ -35,17 +35,18 @@
 static PCIDevice *find_dev(sPAPREnvironment *spapr,
                            uint64_t buid, uint32_t config_addr)
 {
-    DeviceState *qdev;
     int devfn = (config_addr >> 8) & 0xFF;
     sPAPRPHBState *phb;
 
     QLIST_FOREACH(phb, &spapr->phbs, list) {
+        BusChild *kid;
+
         if (phb->buid != buid) {
             continue;
         }
 
-        QTAILQ_FOREACH(qdev, &phb->host_state.bus->qbus.children, sibling) {
-            PCIDevice *dev = (PCIDevice *)qdev;
+        QTAILQ_FOREACH(kid, &phb->host_state.bus->qbus.children, sibling) {
+            PCIDevice *dev = (PCIDevice *)kid->child;
             if (dev->devfn == devfn) {
                 return dev;
             }
diff --git a/hw/spapr_vio.c b/hw/spapr_vio.c
index 7c5493e..2c9256e 100644
--- a/hw/spapr_vio.c
+++ b/hw/spapr_vio.c
@@ -62,11 +62,11 @@ static TypeInfo spapr_vio_bus_info = {
 
 VIOsPAPRDevice *spapr_vio_find_by_reg(VIOsPAPRBus *bus, uint32_t reg)
 {
-    DeviceState *qdev;
+    BusChild *kid;
     VIOsPAPRDevice *dev = NULL;
 
-    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
-        dev = (VIOsPAPRDevice *)qdev;
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
+        dev = (VIOsPAPRDevice *)kid->child;
         if (dev->reg == reg) {
             return dev;
         }
@@ -606,7 +606,7 @@ static void rtas_quiesce(sPAPREnvironment *spapr, uint32_t token,
                          uint32_t nret, target_ulong rets)
 {
     VIOsPAPRBus *bus = spapr->vio_bus;
-    DeviceState *qdev;
+    BusChild *kid;
     VIOsPAPRDevice *dev = NULL;
 
     if (nargs != 0) {
@@ -614,8 +614,8 @@ static void rtas_quiesce(sPAPREnvironment *spapr, uint32_t token,
         return;
     }
 
-    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
-        dev = (VIOsPAPRDevice *)qdev;
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
+        dev = (VIOsPAPRDevice *)kid->child;
         spapr_vio_quiesce_one(dev);
     }
 
@@ -625,7 +625,7 @@ static void rtas_quiesce(sPAPREnvironment *spapr, uint32_t token,
 static int spapr_vio_check_reg(VIOsPAPRDevice *sdev)
 {
     VIOsPAPRDevice *other_sdev;
-    DeviceState *qdev;
+    BusChild *kid;
     VIOsPAPRBus *sbus;
 
     sbus = DO_UPCAST(VIOsPAPRBus, bus, sdev->qdev.parent_bus);
@@ -635,13 +635,13 @@ static int spapr_vio_check_reg(VIOsPAPRDevice *sdev)
      * other mechanism). We have to open code this because we have to check
      * for matches with devices other than us.
      */
-    QTAILQ_FOREACH(qdev, &sbus->bus.children, sibling) {
-        other_sdev = DO_UPCAST(VIOsPAPRDevice, qdev, qdev);
+    QTAILQ_FOREACH(kid, &sbus->bus.children, sibling) {
+        other_sdev = DO_UPCAST(VIOsPAPRDevice, qdev, kid->child);
 
         if (other_sdev != sdev && other_sdev->reg == sdev->reg) {
             fprintf(stderr, "vio: %s and %s devices conflict at address %#x\n",
                     object_get_typename(OBJECT(sdev)),
-                    object_get_typename(OBJECT(qdev)),
+                    object_get_typename(OBJECT(other_sdev)),
                     sdev->reg);
             return -EEXIST;
         }
@@ -826,19 +826,20 @@ static int compare_reg(const void *p1, const void *p2)
 int spapr_populate_vdevice(VIOsPAPRBus *bus, void *fdt)
 {
     DeviceState *qdev, **qdevs;
+    BusChild *kid;
     int i, num, ret = 0;
 
     /* Count qdevs on the bus list */
     num = 0;
-    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
         num++;
     }
 
     /* Copy out into an array of pointers */
     qdevs = g_malloc(sizeof(qdev) * num);
     num = 0;
-    QTAILQ_FOREACH(qdev, &bus->bus.children, sibling) {
-        qdevs[num++] = qdev;
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
+        qdevs[num++] = kid->child;
     }
 
     /* Sort the array */
diff --git a/hw/spapr_vty.c b/hw/spapr_vty.c
index a30c040..cfdc500 100644
--- a/hw/spapr_vty.c
+++ b/hw/spapr_vty.c
@@ -161,7 +161,7 @@ static TypeInfo spapr_vty_info = {
 VIOsPAPRDevice *spapr_vty_get_default(VIOsPAPRBus *bus)
 {
     VIOsPAPRDevice *sdev, *selected;
-    DeviceState *iter;
+    BusChild *kid;
 
     /*
      * To avoid the console bouncing around we want one VTY to be
@@ -170,7 +170,9 @@ VIOsPAPRDevice *spapr_vty_get_default(VIOsPAPRBus *bus)
      */
 
     selected = NULL;
-    QTAILQ_FOREACH(iter, &bus->bus.children, sibling) {
+    QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
+        DeviceState *iter = kid->child;
+
         /* Only look at VTY devices */
         if (!object_dynamic_cast(OBJECT(iter), "spapr-vty")) {
             continue;
diff --git a/hw/ssi.c b/hw/ssi.c
index d645691..19e5ae1 100644
--- a/hw/ssi.c
+++ b/hw/ssi.c
@@ -30,10 +30,11 @@ static int ssi_slave_init(DeviceState *dev)
     SSISlave *s = SSI_SLAVE(dev);
     SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
     SSIBus *bus;
+    BusChild *kid;
 
     bus = FROM_QBUS(SSIBus, qdev_get_parent_bus(dev));
-    if (QTAILQ_FIRST(&bus->qbus.children) != dev
-        || QTAILQ_NEXT(dev, sibling) != NULL) {
+    kid = QTAILQ_FIRST(&bus->qbus.children);
+    if (kid->child != dev || QTAILQ_NEXT(kid, sibling) != NULL) {
         hw_error("Too many devices on SSI bus");
     }
 
@@ -72,14 +73,15 @@ SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
 
 uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
 {
-    DeviceState *dev;
+    BusChild *kid;
     SSISlave *slave;
     SSISlaveClass *ssc;
-    dev = QTAILQ_FIRST(&bus->qbus.children);
-    if (!dev) {
+
+    kid = QTAILQ_FIRST(&bus->qbus.children);
+    if (!kid) {
         return 0;
     }
-    slave = SSI_SLAVE(dev);
+    slave = SSI_SLAVE(kid->child);
     ssc = SSI_SLAVE_GET_CLASS(slave);
     return ssc->transfer(slave, val);
 }
diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c
index e8328f4..970b691 100644
--- a/hw/virtio-scsi.c
+++ b/hw/virtio-scsi.c
@@ -275,7 +275,7 @@ static void virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
 {
     SCSIDevice *d = virtio_scsi_device_find(s, req->req.tmf->lun);
     SCSIRequest *r, *next;
-    DeviceState *qdev;
+    BusChild *kid;
     int target;
 
     /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */
@@ -346,8 +346,8 @@ static void virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
     case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET:
         target = req->req.tmf->lun[1];
         s->resetting++;
-        QTAILQ_FOREACH(qdev, &s->bus.qbus.children, sibling) {
-             d = DO_UPCAST(SCSIDevice, qdev, qdev);
+        QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) {
+             d = DO_UPCAST(SCSIDevice, qdev, kid->child);
              if (d->channel == 0 && d->id == target) {
                 qdev_reset_all(&d->qdev);
              }
diff --git a/qom/object.c b/qom/object.c
index b4f6c1d..6359486 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -662,9 +662,16 @@ void object_property_del(Object *obj, const char *name, Error **errp)
 {
     ObjectProperty *prop = object_property_find(obj, name);
 
-    QTAILQ_REMOVE(&obj->properties, prop, node);
+    if (prop == NULL) {
+        error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
+        return;
+    }
+
+    if (prop->release) {
+        prop->release(obj, name, prop->opaque);
+    }
 
-    prop->release(obj, prop->name, prop->opaque);
+    QTAILQ_REMOVE(&obj->properties, prop, node);
 
     g_free(prop->name);
     g_free(prop->type);
-- 
1.7.9.3