Re: [Qemu-devel] [PATCH v2 07/16] hw/arm/aspeed: Use object_initialize_child for correct ref. counting

[Paolo Bonzini]

On 07/05/19 11:34, 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));
>  )
> 
>  @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 <address@hidden>
> Inspired-by: Thomas Huth <address@hidden>
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> Signed-off-by: Cédric Le Goater <address@hidden>
> Reviewed-by: Joel Stanley <address@hidden>
> ---
> v2:
>  - Described new use of &error_abort (Markus)
>  - Added Cédric S-o-b (he sent the same 'hw/arm/aspeed_soc.c' patch)
>  - Added Joel R-b of Cédric patch
> ---
>  hw/arm/aspeed.c     |  6 +++---
>  hw/arm/aspeed_soc.c | 50 ++++++++++++++++++---------------------------
>  2 files changed, 23 insertions(+), 33 deletions(-)
> 
> diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c
> index 1c23ebd9925..f700b7e4fe0 100644
> --- a/hw/arm/aspeed.c
> +++ b/hw/arm/aspeed.c
> @@ -159,9 +159,9 @@ static void aspeed_board_init(MachineState *machine,
>      ram_addr_t max_ram_size;
>  
>      bmc = g_new0(AspeedBoardState, 1);
> -    object_initialize(&bmc->soc, (sizeof(bmc->soc)), cfg->soc_name);
> -    object_property_add_child(OBJECT(machine), "soc", OBJECT(&bmc->soc),
> -                              &error_abort);
> +    object_initialize_child(OBJECT(machine), "soc", &bmc->soc,
> +                            (sizeof(bmc->soc)), cfg->soc_name, &error_abort,
> +                            NULL);
>  
>      sc = ASPEED_SOC_GET_CLASS(&bmc->soc);
>  
> diff --git a/hw/arm/aspeed_soc.c b/hw/arm/aspeed_soc.c
> index a27233d4876..faff42b84ad 100644
> --- a/hw/arm/aspeed_soc.c
> +++ b/hw/arm/aspeed_soc.c
> @@ -106,12 +106,11 @@ static void aspeed_soc_init(Object *obj)
>      AspeedSoCClass *sc = ASPEED_SOC_GET_CLASS(s);
>      int i;
>  
> -    object_initialize(&s->cpu, sizeof(s->cpu), sc->info->cpu_type);
> -    object_property_add_child(obj, "cpu", OBJECT(&s->cpu), NULL);
> +    object_initialize_child(obj, "cpu", OBJECT(&s->cpu), sizeof(s->cpu),
> +                            sc->info->cpu_type, &error_abort, NULL);
>  
> -    object_initialize(&s->scu, sizeof(s->scu), TYPE_ASPEED_SCU);
> -    object_property_add_child(obj, "scu", OBJECT(&s->scu), NULL);
> -    qdev_set_parent_bus(DEVICE(&s->scu), sysbus_get_default());
> +    sysbus_init_child_obj(obj, "scu", OBJECT(&s->scu), sizeof(s->scu),
> +                          TYPE_ASPEED_SCU);
>      qdev_prop_set_uint32(DEVICE(&s->scu), "silicon-rev",
>                           sc->info->silicon_rev);
>      object_property_add_alias(obj, "hw-strap1", OBJECT(&s->scu),
> @@ -121,36 +120,29 @@ static void aspeed_soc_init(Object *obj)
>      object_property_add_alias(obj, "hw-prot-key", OBJECT(&s->scu),
>                                "hw-prot-key", &error_abort);
>  
> -    object_initialize(&s->vic, sizeof(s->vic), TYPE_ASPEED_VIC);
> -    object_property_add_child(obj, "vic", OBJECT(&s->vic), NULL);
> -    qdev_set_parent_bus(DEVICE(&s->vic), sysbus_get_default());
> +    sysbus_init_child_obj(obj, "vic", OBJECT(&s->vic), sizeof(s->vic),
> +                          TYPE_ASPEED_VIC);
>  
> -    object_initialize(&s->timerctrl, sizeof(s->timerctrl), 
> TYPE_ASPEED_TIMER);
> -    object_property_add_child(obj, "timerctrl", OBJECT(&s->timerctrl), NULL);
> +    sysbus_init_child_obj(obj, "timerctrl", OBJECT(&s->timerctrl),
> +                          sizeof(s->timerctrl), TYPE_ASPEED_TIMER);
>      object_property_add_const_link(OBJECT(&s->timerctrl), "scu",
>                                     OBJECT(&s->scu), &error_abort);
> -    qdev_set_parent_bus(DEVICE(&s->timerctrl), sysbus_get_default());
>  
> -    object_initialize(&s->i2c, sizeof(s->i2c), TYPE_ASPEED_I2C);
> -    object_property_add_child(obj, "i2c", OBJECT(&s->i2c), NULL);
> -    qdev_set_parent_bus(DEVICE(&s->i2c), sysbus_get_default());
> +    sysbus_init_child_obj(obj, "i2c", OBJECT(&s->i2c), sizeof(s->i2c),
> +                          TYPE_ASPEED_I2C);
>  
> -    object_initialize(&s->fmc, sizeof(s->fmc), sc->info->fmc_typename);
> -    object_property_add_child(obj, "fmc", OBJECT(&s->fmc), NULL);
> -    qdev_set_parent_bus(DEVICE(&s->fmc), sysbus_get_default());
> +    sysbus_init_child_obj(obj, "fmc", OBJECT(&s->fmc), sizeof(s->fmc),
> +                          sc->info->fmc_typename);
>      object_property_add_alias(obj, "num-cs", OBJECT(&s->fmc), "num-cs",
>                                &error_abort);
>  
>      for (i = 0; i < sc->info->spis_num; i++) {
> -        object_initialize(&s->spi[i], sizeof(s->spi[i]),
> -                          sc->info->spi_typename[i]);
> -        object_property_add_child(obj, "spi[*]", OBJECT(&s->spi[i]), NULL);
> -        qdev_set_parent_bus(DEVICE(&s->spi[i]), sysbus_get_default());
> +        sysbus_init_child_obj(obj, "spi[*]", OBJECT(&s->spi[i]),
> +                              sizeof(s->spi[i]), sc->info->spi_typename[i]);
>      }
>  
> -    object_initialize(&s->sdmc, sizeof(s->sdmc), TYPE_ASPEED_SDMC);
> -    object_property_add_child(obj, "sdmc", OBJECT(&s->sdmc), NULL);
> -    qdev_set_parent_bus(DEVICE(&s->sdmc), sysbus_get_default());
> +    sysbus_init_child_obj(obj, "sdmc", OBJECT(&s->sdmc), sizeof(s->sdmc),
> +                          TYPE_ASPEED_SDMC);
>      qdev_prop_set_uint32(DEVICE(&s->sdmc), "silicon-rev",
>                           sc->info->silicon_rev);
>      object_property_add_alias(obj, "ram-size", OBJECT(&s->sdmc),
> @@ -159,16 +151,14 @@ static void aspeed_soc_init(Object *obj)
>                                "max-ram-size", &error_abort);
>  
>      for (i = 0; i < sc->info->wdts_num; i++) {
> -        object_initialize(&s->wdt[i], sizeof(s->wdt[i]), TYPE_ASPEED_WDT);
> -        object_property_add_child(obj, "wdt[*]", OBJECT(&s->wdt[i]), NULL);
> -        qdev_set_parent_bus(DEVICE(&s->wdt[i]), sysbus_get_default());
> +        sysbus_init_child_obj(obj, "wdt[*]", OBJECT(&s->wdt[i]),
> +                              sizeof(s->wdt[i]), TYPE_ASPEED_WDT);
>          qdev_prop_set_uint32(DEVICE(&s->wdt[i]), "silicon-rev",
>                                      sc->info->silicon_rev);
>      }
>  
> -    object_initialize(&s->ftgmac100, sizeof(s->ftgmac100), TYPE_FTGMAC100);
> -    object_property_add_child(obj, "ftgmac100", OBJECT(&s->ftgmac100), NULL);
> -    qdev_set_parent_bus(DEVICE(&s->ftgmac100), sysbus_get_default());
> +    sysbus_init_child_obj(obj, "ftgmac100", OBJECT(&s->ftgmac100),
> +                          sizeof(s->ftgmac100), TYPE_FTGMAC100);
>  }
>  
>  static void aspeed_soc_realize(DeviceState *dev, Error **errp)
> 

Reviewed-by: Paolo Bonzini <address@hidden>