Re: [Qemu-arm] [Qemu-devel] [PATCH v2 14/16] hw/microblaze/zynqmp: Use object_initialize_child for correct ref. counting

[Alistair Francis]

On Tue, May 7, 2019 at 9:52 AM Philippe Mathieu-Daudé <address@hidden> 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>

Reviewed-by: Alistair Francis <address@hidden>

Alistair

> ---
>  hw/microblaze/xlnx-zynqmp-pmu.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/hw/microblaze/xlnx-zynqmp-pmu.c b/hw/microblaze/xlnx-zynqmp-pmu.c
> index 0948b1fd5f2..df6c0048aa6 100644
> --- a/hw/microblaze/xlnx-zynqmp-pmu.c
> +++ b/hw/microblaze/xlnx-zynqmp-pmu.c
> @@ -176,9 +176,9 @@ static void xlnx_zynqmp_pmu_init(MachineState *machine)
>                                  pmu_ram);
>
>      /* Create the PMU device */
> -    object_initialize(pmu, sizeof(XlnxZynqMPPMUSoCState), 
> TYPE_XLNX_ZYNQMP_PMU_SOC);
> -    object_property_add_child(OBJECT(machine), "pmu", OBJECT(pmu),
> -                              &error_abort);
> +    object_initialize_child(OBJECT(machine), "pmu", pmu,
> +                            sizeof(XlnxZynqMPPMUSoCState),
> +                            TYPE_XLNX_ZYNQMP_PMU_SOC, &error_abort, NULL);
>      object_property_set_bool(OBJECT(pmu), true, "realized", &error_fatal);
>
>      /* Load the kernel */
> --
> 2.20.1
>
>