[Qemu-devel] Re: [PATCH] qdev: Reset hotplugged devices

[Paolo Bonzini <pbonzini@redhat.com>]

On 08/20/2010 08:12 PM, Anthony Liguori wrote:
> +/* Returns false to terminate walk; true to continue */
> +typedef int (qdev_walkerfn)(DeviceState *dev, void *opaque);
> +

Since you're introducing qbus_walk_children, I suggest a different 
interface: qdev_walkerfn should return 0 to walk children, -1 to skip 
walking children, and anything else to terminate walk.  If anything ever 
returns x > 0, qbus_walk_children returns that x, else 
qbus_walk_children returns 0.  This interface is inspired by a similar 
one in GCC and it works well.

If you don't want to introduce the full complication, removing the "-1 
to skip walking children" part would still give the same flexibility WRT 
to the return values, which is the important part.

Paolo