Re: [Qemu-devel] [PATCH v5 2/4] qdev: using NULL instead of local_err for qbus_child unrealize

[Peter Crosthwaite]

On Tue, Sep 2, 2014 at 10:03 PM,  <address@hidden> wrote:
> From: Gonglei <address@hidden>
>
> Forcefully unrealize all children regardless of early-iteration
> errors(if happened). We should keep going with cleanup operation
> rather than report a error immediately, meanwhile store the first
> child unrealize failure and propagate it at the end.
>
> We also forcefully un-vmsding and unrealizing actual object too.
> Because we can not guarantee that a botched recursive has no
> side-effects.
>

This last sentance doesn't make too much sense to me, but the rest of
the commit message covers it nicely so I think you can drop it.

> Signed-off-by: Gonglei <address@hidden>
> ---
>  hw/core/qdev.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 4a1ac5b..c869520 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -813,6 +813,7 @@ static void device_set_realized(Object *obj, bool value, 
> Error **errp)
>      DeviceClass *dc = DEVICE_GET_CLASS(dev);
>      BusState *bus;
>      Error *local_err = NULL;
> +    Error *child_unrealized_err = NULL;
>
>      if (dev->hotplugged && !dc->hotpluggable) {
>          error_set(errp, QERR_DEVICE_NO_HOTPLUG, object_get_typename(obj));
> @@ -875,13 +876,17 @@ static void device_set_realized(Object *obj, bool 
> value, Error **errp)
>              object_property_set_bool(OBJECT(bus), false, "realized",
>                                       &local_err);

I think you can make the concept of "pass in a errp only if I don't
have one already" simpler with this pattern:

Error **local_errp = local_err ? NULL : &local_err;
object_property_set_bool(... , local_errp)

Or if your into one-line killers you could do the ?: inline (although
some reviewers don't like that).

>              if (local_err != NULL) {
> -                break;
> +                if (child_unrealized_err == NULL) {
> +                    child_unrealized_err = error_copy(local_err);
> +                }
> +                error_free(local_err);
> +                local_err = NULL;
>              }

Then this whole if can go ...

>          }
> -        if (qdev_get_vmsd(dev) && local_err == NULL) {
> +        if (qdev_get_vmsd(dev)) {
>              vmstate_unregister(dev, qdev_get_vmsd(dev), dev);
>          }
> -        if (dc->unrealize && local_err == NULL) {
> +        if (dc->unrealize) {

local_errp = local_err ? NULL : &local_err;

>              dc->unrealize(dev, &local_err);
>          }
>          dev->pending_deleted_event = true;
> @@ -889,6 +894,10 @@ static void device_set_realized(Object *obj, bool value, 
> Error **errp)
>
>      if (local_err != NULL) {
>          error_propagate(errp, local_err);
> +        error_free(child_unrealized_err);
> +        return;
> +    } else if (child_unrealized_err != NULL) {
> +        error_propagate(errp, child_unrealized_err);

Then this if-else is not needed either.

Otherwise,

Reviewed-by: Peter Crosthwaite <address@hidden>

Regards,
Peter

>          return;
>      }
>
> --
> 1.7.12.4
>
>
>