qom: Drop parameter @errp of object_property_add() & friends

The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]

9 files changed, 11 insertions, 12 deletions

diff --git a/hw/virtio/vhost-scsi-pci.c b/hw/virtio/vhost-scsi-pci.c
index 5dce640..5da6bb6 100644
--- a/hw/virtio/vhost-scsi-pci.c
+++ b/hw/virtio/vhost-scsi-pci.c
@@ -78,7 +78,7 @@ static void vhost_scsi_pci_instance_init(Object *obj)
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VHOST_SCSI);
     object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
-                              "bootindex", &error_abort);
+                              "bootindex");
 }
 
 static const VirtioPCIDeviceTypeInfo vhost_scsi_pci_info = {
diff --git a/hw/virtio/vhost-user-blk-pci.c b/hw/virtio/vhost-user-blk-pci.c
index 8d3d766..58d7c31 100644
--- a/hw/virtio/vhost-user-blk-pci.c
+++ b/hw/virtio/vhost-user-blk-pci.c
@@ -84,7 +84,7 @@ static void vhost_user_blk_pci_instance_init(Object *obj)
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VHOST_USER_BLK);
     object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
-                              "bootindex", &error_abort);
+                              "bootindex");
 }
 
 static const VirtioPCIDeviceTypeInfo vhost_user_blk_pci_info = {
diff --git a/hw/virtio/vhost-user-input-pci.c b/hw/virtio/vhost-user-input-pci.c
index ae9cff9..0a50015 100644
--- a/hw/virtio/vhost-user-input-pci.c
+++ b/hw/virtio/vhost-user-input-pci.c
@@ -31,8 +31,7 @@ static void vhost_user_input_pci_instance_init(Object *obj)
                                 TYPE_VHOST_USER_INPUT);
 
     object_property_add_alias(obj, "chardev",
-                              OBJECT(&dev->vhi), "chardev",
-                              &error_abort);
+                              OBJECT(&dev->vhi), "chardev");
 }
 
 static const VirtioPCIDeviceTypeInfo vhost_user_input_pci_info = {
diff --git a/hw/virtio/vhost-user-scsi-pci.c b/hw/virtio/vhost-user-scsi-pci.c
index 32febb2..6f3375f 100644
--- a/hw/virtio/vhost-user-scsi-pci.c
+++ b/hw/virtio/vhost-user-scsi-pci.c
@@ -84,7 +84,7 @@ static void vhost_user_scsi_pci_instance_init(Object *obj)
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VHOST_USER_SCSI);
     object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
-                              "bootindex", &error_abort);
+                              "bootindex");
 }
 
 static const VirtioPCIDeviceTypeInfo vhost_user_scsi_pci_info = {
diff --git a/hw/virtio/virtio-balloon-pci.c b/hw/virtio/virtio-balloon-pci.c
index 56962ae..cc25df0 100644
--- a/hw/virtio/virtio-balloon-pci.c
+++ b/hw/virtio/virtio-balloon-pci.c
@@ -73,10 +73,10 @@ static void virtio_balloon_pci_instance_init(Object *obj)
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VIRTIO_BALLOON);
     object_property_add_alias(obj, "guest-stats", OBJECT(&dev->vdev),
-                                  "guest-stats", &error_abort);
+                                  "guest-stats");
     object_property_add_alias(obj, "guest-stats-polling-interval",
                               OBJECT(&dev->vdev),
-                              "guest-stats-polling-interval", &error_abort);
+                              "guest-stats-polling-interval");
 }
 
 static const VirtioPCIDeviceTypeInfo virtio_balloon_pci_info = {
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index a4729f7..6d3ddf6 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -893,12 +893,12 @@ static void virtio_balloon_instance_init(Object *obj)
     VirtIOBalloon *s = VIRTIO_BALLOON(obj);
 
     object_property_add(obj, "guest-stats", "guest statistics",
-                        balloon_stats_get_all, NULL, NULL, s, NULL);
+                        balloon_stats_get_all, NULL, NULL, s);
 
     object_property_add(obj, "guest-stats-polling-interval", "int",
                         balloon_stats_get_poll_interval,
                         balloon_stats_set_poll_interval,
-                        NULL, s, NULL);
+                        NULL, s);
 }
 
 static const VMStateDescription vmstate_virtio_balloon = {
diff --git a/hw/virtio/virtio-blk-pci.c b/hw/virtio/virtio-blk-pci.c
index efb2c22..28838fa 100644
--- a/hw/virtio/virtio-blk-pci.c
+++ b/hw/virtio/virtio-blk-pci.c
@@ -81,7 +81,7 @@ static void virtio_blk_pci_instance_init(Object *obj)
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VIRTIO_BLK);
     object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
-                              "bootindex", &error_abort);
+                              "bootindex");
 }
 
 static const VirtioPCIDeviceTypeInfo virtio_blk_pci_info = {
diff --git a/hw/virtio/virtio-net-pci.c b/hw/virtio/virtio-net-pci.c
index 5ca71d4..ea43040 100644
--- a/hw/virtio/virtio-net-pci.c
+++ b/hw/virtio/virtio-net-pci.c
@@ -79,7 +79,7 @@ static void virtio_net_pci_instance_init(Object *obj)
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VIRTIO_NET);
     object_property_add_alias(obj, "bootindex", OBJECT(&dev->vdev),
-                              "bootindex", &error_abort);
+                              "bootindex");
 }
 
 static const VirtioPCIDeviceTypeInfo virtio_net_pci_info = {
diff --git a/hw/virtio/virtio-rng.c b/hw/virtio/virtio-rng.c
index 1e363ad..672619c 100644
--- a/hw/virtio/virtio-rng.c
+++ b/hw/virtio/virtio-rng.c
@@ -203,7 +203,7 @@ static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
         }
 
         object_property_add_child(OBJECT(dev), "default-backend",
-                                  default_backend, &error_abort);
+                                  default_backend);
 
         /* The child property took a reference, we can safely drop ours now */
         object_unref(default_backend);