[Qemu-devel] [PATCH v2 08/16] hw/arm: Use object_initialize_child for correct reference counting

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

As explained in commit aff39be0ed97:

  Both functions, object_initialize() and object_property_add_child()
  increase the reference counter of the new object, so one of the
  references has to be dropped afterwards to get the reference
  counting right. Otherwise the child object will not be properly
  cleaned up when the parent gets destroyed.
  Thus let's use now object_initialize_child() instead to get the
  reference counting here right.

This patch was generated using the following Coccinelle script
(with a bit of manual fix-up for overly long lines):

 @use_object_initialize_child@
 expression parent_obj;
 expression child_ptr;
 expression child_name;
 expression child_type;
 expression child_size;
 expression errp;
 @@
 (
 -   object_initialize(child_ptr, child_size, child_type);
 +   object_initialize_child(parent_obj, child_name,  child_ptr, child_size,
 +                           child_type, &error_abort, NULL);
     ... when != parent_obj
 -   object_property_add_child(parent_obj, child_name, OBJECT(child_ptr), NULL);
     ...
 ?-  object_unref(OBJECT(child_ptr));
 |
 -   object_initialize(child_ptr, child_size, child_type);
 +   object_initialize_child(parent_obj, child_name,  child_ptr, child_size,
 +                            child_type, errp, NULL);
     ... when != parent_obj
 -   object_property_add_child(parent_obj, child_name, OBJECT(child_ptr), errp);
     ...
 ?-  object_unref(OBJECT(child_ptr));
 )

 @use_sysbus_init_child_obj@
 expression parent_obj;
 expression dev;
 expression child_ptr;
 expression child_name;
 expression child_type;
 expression child_size;
 expression errp;
 @@
 (
 -   object_initialize_child(parent_obj, child_name, child_ptr, child_size,
 -                           child_type, errp, NULL);
 +   sysbus_init_child_obj(parent_obj, child_name, child_ptr, child_size,
 +                         child_type);
     ...
 -   qdev_set_parent_bus(DEVICE(child_ptr), sysbus_get_default());
 |
 -   object_initialize_child(parent_obj, child_name, child_ptr, child_size,
 -                           child_type, errp, NULL);
 +   sysbus_init_child_obj(parent_obj, child_name, child_ptr, child_size,
 +                         child_type);
 -   dev = DEVICE(child_ptr);
 -   qdev_set_parent_bus(dev, sysbus_get_default());
 )

While the object_initialize() function doesn't take an
'Error *errp' argument, the object_initialize_child() does.
Since this code is used when a machine is created (and is not
yet running), we deliberately choose to use the &error_abort
argument instead of ignoring errors if an object creation failed.
This choice also matches when using sysbus_init_child_obj(),
since its code is:

  void sysbus_init_child_obj(Object *parent,
                             const char *childname, void *child,
                             size_t childsize, const char *childtype)
  {
      object_initialize_child(parent, childname, child, childsize,
                              childtype, &error_abort, NULL);

      qdev_set_parent_bus(DEVICE(child), sysbus_get_default());
  }

Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Inspired-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
v2:
 - Tweaked cocci to improve digic_init (Thomas)
 - Described new use of &error_abort (Markus)
---
 hw/arm/digic.c       | 17 ++++++-----------
 hw/arm/imx25_pdk.c   |  5 ++---
 hw/arm/kzm.c         |  5 ++---
 hw/arm/raspi.c       |  7 +++----
 hw/arm/sabrelite.c   |  5 ++---
 hw/arm/xlnx-zcu102.c |  5 ++---
 hw/arm/xlnx-zynqmp.c |  8 ++++----
 7 files changed, 21 insertions(+), 31 deletions(-)

diff --git a/hw/arm/digic.c b/hw/arm/digic.c
index 726abb9b485..6ef26c6bac3 100644
--- a/hw/arm/digic.c
+++ b/hw/arm/digic.c
@@ -32,27 +32,22 @@
 static void digic_init(Object *obj)
 {
     DigicState *s = DIGIC(obj);
-    DeviceState *dev;
     int i;
 
-    object_initialize(&s->cpu, sizeof(s->cpu), "arm946-" TYPE_ARM_CPU);
-    object_property_add_child(obj, "cpu", OBJECT(&s->cpu), NULL);
+    object_initialize_child(obj, "cpu", &s->cpu, sizeof(s->cpu),
+                            "arm946-" TYPE_ARM_CPU, &error_abort, NULL);
 
     for (i = 0; i < DIGIC4_NB_TIMERS; i++) {
 #define DIGIC_TIMER_NAME_MLEN    11
         char name[DIGIC_TIMER_NAME_MLEN];
 
-        object_initialize(&s->timer[i], sizeof(s->timer[i]), TYPE_DIGIC_TIMER);
-        dev = DEVICE(&s->timer[i]);
-        qdev_set_parent_bus(dev, sysbus_get_default());
         snprintf(name, DIGIC_TIMER_NAME_MLEN, "timer[%d]", i);
-        object_property_add_child(obj, name, OBJECT(&s->timer[i]), NULL);
+        sysbus_init_child_obj(obj, name, &s->timer[i], sizeof(s->timer[i]),
+                              TYPE_DIGIC_TIMER);
     }
 
-    object_initialize(&s->uart, sizeof(s->uart), TYPE_DIGIC_UART);
-    dev = DEVICE(&s->uart);
-    qdev_set_parent_bus(dev, sysbus_get_default());
-    object_property_add_child(obj, "uart", OBJECT(&s->uart), NULL);
+    sysbus_init_child_obj(obj, "uart", &s->uart, sizeof(s->uart),
+                          TYPE_DIGIC_UART);
 }
 
 static void digic_realize(DeviceState *dev, Error **errp)
diff --git a/hw/arm/imx25_pdk.c b/hw/arm/imx25_pdk.c
index 9f3ee147390..eef1b184b0d 100644
--- a/hw/arm/imx25_pdk.c
+++ b/hw/arm/imx25_pdk.c
@@ -72,9 +72,8 @@ static void imx25_pdk_init(MachineState *machine)
     unsigned int alias_offset;
     int i;
 
-    object_initialize(&s->soc, sizeof(s->soc), TYPE_FSL_IMX25);
-    object_property_add_child(OBJECT(machine), "soc", OBJECT(&s->soc),
-                              &error_abort);
+    object_initialize_child(OBJECT(machine), "soc", &s->soc, sizeof(s->soc),
+                            TYPE_FSL_IMX25, &error_abort, NULL);
 
     object_property_set_bool(OBJECT(&s->soc), true, "realized", &error_fatal);
 
diff --git a/hw/arm/kzm.c b/hw/arm/kzm.c
index 139934c4ecf..44cba8782bf 100644
--- a/hw/arm/kzm.c
+++ b/hw/arm/kzm.c
@@ -71,9 +71,8 @@ static void kzm_init(MachineState *machine)
     unsigned int alias_offset;
     unsigned int i;
 
-    object_initialize(&s->soc, sizeof(s->soc), TYPE_FSL_IMX31);
-    object_property_add_child(OBJECT(machine), "soc", OBJECT(&s->soc),
-                              &error_abort);
+    object_initialize_child(OBJECT(machine), "soc", &s->soc, sizeof(s->soc),
+                            TYPE_FSL_IMX31, &error_abort, NULL);
 
     object_property_set_bool(OBJECT(&s->soc), true, "realized", &error_fatal);
 
diff --git a/hw/arm/raspi.c b/hw/arm/raspi.c
index 66899c28dc1..0a6244096cc 100644
--- a/hw/arm/raspi.c
+++ b/hw/arm/raspi.c
@@ -175,10 +175,9 @@ static void raspi_init(MachineState *machine, int version)
     BusState *bus;
     DeviceState *carddev;
 
-    object_initialize(&s->soc, sizeof(s->soc),
-                      version == 3 ? TYPE_BCM2837 : TYPE_BCM2836);
-    object_property_add_child(OBJECT(machine), "soc", OBJECT(&s->soc),
-                              &error_abort);
+    object_initialize_child(OBJECT(machine), "soc", &s->soc, sizeof(s->soc),
+                            version == 3 ? TYPE_BCM2837 : TYPE_BCM2836,
+                            &error_abort, NULL);
 
     /* Allocate and map RAM */
     memory_region_allocate_system_memory(&s->ram, OBJECT(machine), "ram",
diff --git a/hw/arm/sabrelite.c b/hw/arm/sabrelite.c
index ee140e5d9eb..f1b00de2294 100644
--- a/hw/arm/sabrelite.c
+++ b/hw/arm/sabrelite.c
@@ -55,9 +55,8 @@ static void sabrelite_init(MachineState *machine)
         exit(1);
     }
 
-    object_initialize(&s->soc, sizeof(s->soc), TYPE_FSL_IMX6);
-    object_property_add_child(OBJECT(machine), "soc", OBJECT(&s->soc),
-                              &error_abort);
+    object_initialize_child(OBJECT(machine), "soc", &s->soc, sizeof(s->soc),
+                            TYPE_FSL_IMX6, &error_abort, NULL);
 
     object_property_set_bool(OBJECT(&s->soc), true, "realized", &err);
     if (err != NULL) {
diff --git a/hw/arm/xlnx-zcu102.c b/hw/arm/xlnx-zcu102.c
index b6bc6a93b89..c802f26fbdf 100644
--- a/hw/arm/xlnx-zcu102.c
+++ b/hw/arm/xlnx-zcu102.c
@@ -91,9 +91,8 @@ static void xlnx_zcu102_init(MachineState *machine)
     memory_region_allocate_system_memory(&s->ddr_ram, NULL, "ddr-ram",
                                          ram_size);
 
-    object_initialize(&s->soc, sizeof(s->soc), TYPE_XLNX_ZYNQMP);
-    object_property_add_child(OBJECT(machine), "soc", OBJECT(&s->soc),
-                              &error_abort);
+    object_initialize_child(OBJECT(machine), "soc", &s->soc, sizeof(s->soc),
+                            TYPE_XLNX_ZYNQMP, &error_abort, NULL);
 
     object_property_set_link(OBJECT(&s->soc), OBJECT(&s->ddr_ram),
                          "ddr-ram", &error_abort);
diff --git a/hw/arm/xlnx-zynqmp.c b/hw/arm/xlnx-zynqmp.c
index 4f8bc41d9d4..6e991903022 100644
--- a/hw/arm/xlnx-zynqmp.c
+++ b/hw/arm/xlnx-zynqmp.c
@@ -191,10 +191,10 @@ static void xlnx_zynqmp_create_rpu(XlnxZynqMPState *s, const char *boot_cpu,
     for (i = 0; i < num_rpus; i++) {
         char *name;
 
-        object_initialize(&s->rpu_cpu[i], sizeof(s->rpu_cpu[i]),
-                          "cortex-r5f-" TYPE_ARM_CPU);
-        object_property_add_child(OBJECT(&s->rpu_cluster), "rpu-cpu[*]",
-                                  OBJECT(&s->rpu_cpu[i]), &error_abort);
+        object_initialize_child(OBJECT(&s->rpu_cluster), "rpu-cpu[*]",
+                                &s->rpu_cpu[i], sizeof(s->rpu_cpu[i]),
+                                "cortex-r5f-" TYPE_ARM_CPU, &error_abort,
+                                NULL);
 
         name = object_get_canonical_path_component(OBJECT(&s->rpu_cpu[i]));
         if (strcmp(name, boot_cpu)) {
-- 
2.20.1