Re: [Qemu-ppc] [PATCH v2 02/16] hw/misc/macio: Use object_initialize_child for correct ref. counting

[David Gibson]

On Tue, May 07, 2019 at 06:34:02PM +0200, Philippe Mathieu-Daudé wrote:
> 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));
>  )
> 
> 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.
> 
> Suggested-by: Eduardo Habkost <address@hidden>
> Inspired-by: Thomas Huth <address@hidden>
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>

Acked-by: David Gibson <address@hidden>

> ---
>  hw/misc/macio/macio.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/misc/macio/macio.c b/hw/misc/macio/macio.c
> index 94da85c8d7d..b726c73022c 100644
> --- a/hw/misc/macio/macio.c
> +++ b/hw/misc/macio/macio.c
> @@ -346,12 +346,12 @@ static void macio_newworld_realize(PCIDevice *d, Error 
> **errp)
>          object_property_set_bool(OBJECT(&ns->gpio), true, "realized", &err);
>  
>          /* PMU */
> -        object_initialize(&s->pmu, sizeof(s->pmu), TYPE_VIA_PMU);
> +        object_initialize_child(OBJECT(s), "pmu", &s->pmu, sizeof(s->pmu),
> +                                TYPE_VIA_PMU, &error_abort, NULL);
>          object_property_set_link(OBJECT(&s->pmu), OBJECT(sysbus_dev), "gpio",
>                                   &error_abort);
>          qdev_prop_set_bit(DEVICE(&s->pmu), "has-adb", ns->has_adb);
>          qdev_set_parent_bus(DEVICE(&s->pmu), BUS(&s->macio_bus));
> -        object_property_add_child(OBJECT(s), "pmu", OBJECT(&s->pmu), NULL);
>  
>          object_property_set_bool(OBJECT(&s->pmu), true, "realized", &err);
>          if (err) {
> @@ -365,9 +365,9 @@ static void macio_newworld_realize(PCIDevice *d, Error 
> **errp)
>                                      sysbus_mmio_get_region(sysbus_dev, 0));
>      } else {
>          /* CUDA */
> -        object_initialize(&s->cuda, sizeof(s->cuda), TYPE_CUDA);
> +        object_initialize_child(OBJECT(s), "cuda", &s->cuda, sizeof(s->cuda),
> +                                TYPE_CUDA, &error_abort, NULL);
>          qdev_set_parent_bus(DEVICE(&s->cuda), BUS(&s->macio_bus));
> -        object_property_add_child(OBJECT(s), "cuda", OBJECT(&s->cuda), NULL);
>          qdev_prop_set_uint64(DEVICE(&s->cuda), "timebase-frequency",
>                               s->frequency);
>  

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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