Re: [Qemu-devel] [QEMU PATCH v3] qdev: fix get_fw_dev_path to support to add nothing to fw_dev_path

[Laszlo Ersek <lersek@redhat.com>]

On 05/29/13 09:56, Amos Kong wrote:
> Recent virtio refactoring in QEMU made virtio-bus become the parent bus
> of scsi-bus, and virtio-bus doesn't have get_fw_dev_path implementation,
> typename will be added to fw_dev_path by default, the new fw_dev_path
> could not be identified by seabios. It causes that bootindex parameter
> of scsi device doesn't work.
> 
> This patch implements get_fw_dev_path() in BusClass, it will be called
> if bus doesn't implement the method, tyename will be added to
> fw_dev_path. If the implemented method returns NULL, nothing will be
> added to fw_dev_path.
> 
> It also implements virtio_bus_get_fw_dev_path() to return NULL. Then
> QEMU will still pass original style of fw_dev_path to seabios.
> 
> Signed-off-by: Amos Kong <akong@redhat.com>
> --
> v2: only add nothing to fw_dev_path when get_fw_dev_path() is
>     implemented and returns NULL. then it will not effect other devices
>     don't have get_fw_dev_path() implementation.
> v3: implement default get_fw_dev_path() in BusClass
> ---
>  hw/core/qdev.c         | 10 +++++++++-
>  hw/virtio/virtio-bus.c |  6 ++++++
>  2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 6985ad8..9190a7e 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -515,7 +515,7 @@ static int qdev_get_fw_dev_path_helper(DeviceState *dev, char *p, int size)
>              l += snprintf(p + l, size - l, "%s", d);
>              g_free(d);
>          } else {
> -            l += snprintf(p + l, size - l, "%s", object_get_typename(OBJECT(dev)));
> +            return l;
>          }
>      }
>      l += snprintf(p + l , size - l, "/");
> @@ -867,9 +867,17 @@ static void qbus_initfn(Object *obj)
>      QTAILQ_INIT(&bus->children);
>  }
>  
> +static char *default_bus_get_fw_dev_path(DeviceState *dev)
> +{
> +    return g_strdup(object_get_typename(OBJECT(dev)));
> +}
> +
>  static void bus_class_init(ObjectClass *class, void *data)
>  {
> +    BusClass *bc = BUS_CLASS(class);
> +
>      class->unparent = bus_unparent;
> +    bc->get_fw_dev_path = default_bus_get_fw_dev_path;
>  }
>  
>  static void qbus_finalize(Object *obj)
> diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
> index ea2e11a..6849a01 100644
> --- a/hw/virtio/virtio-bus.c
> +++ b/hw/virtio/virtio-bus.c
> @@ -161,10 +161,16 @@ static char *virtio_bus_get_dev_path(DeviceState *dev)
>      return qdev_get_dev_path(proxy);
>  }
>  
> +static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
> +{
> +    return NULL;
> +}
> +
>  static void virtio_bus_class_init(ObjectClass *klass, void *data)
>  {
>      BusClass *bus_class = BUS_CLASS(klass);
>      bus_class->get_dev_path = virtio_bus_get_dev_path;
> +    bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
>  }
>  
>  static const TypeInfo virtio_bus_info = {
> 

Ah, the happiness of finally understanding what Paolo suggested. (Or at
least believing so.)

My R-b is superfluous after Paolo's, but I can't resist.

Reviewed-by: Laszlo Ersek <lersek@redhat.com>