Re: [Qemu-devel] [PATCH for-1.5 4/4] virtio-scsi: fix the command line compatibility.

[Andreas Färber]

Am 29.04.2013 19:39, schrieb KONRAD Frédéric:
> On 29/04/2013 18:32, Paolo Bonzini wrote:
>> Il 29/04/2013 18:28, KONRAD Frédéric ha scritto:
>>>> Could this be simply a qdev property?
>>> Yes, that can be a good idea.
>>>
>>> What about adding a qdev property bus_name and using it in qbus_realize?
>>>
>>> Like this:
>>>
>>> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
>>> index 4eb0134..c5d5407 100644
>>> --- a/hw/core/qdev.c
>>> +++ b/hw/core/qdev.c
>>> @@ -421,6 +421,13 @@ static void qbus_realize(BusState *bus, DeviceState
>>> *parent, const char *name)
>>>
>>>       if (name) {
>>>           bus->name = g_strdup(name);
>>> +    } else if (bus->parent && bus->parent->bus_name) {
>>> +        /* parent device has bus_name -> use it for bus name */
>>> +        len = strlen(bus->parent->bus_name) + 16;
>>> +        buf = g_malloc(len);
>>> +        snprintf(buf, len, "%s.%d", bus->parent->bus_name,
>>> +                 bus->parent->num_child_bus);
>>> +        bus->name = buf;
>>>       } else if (bus->parent && bus->parent->id) {
>>>           /* parent device has id -> use it for bus name */
>>>           len = strlen(bus->parent->id) + 16;
>>>
>>> If so, change to scsi_bus_new is not needed and the two new functions
>>> are
>>> not needed.
>>>
>>> Is that making sense?
>> Ah, that's a bit more extreme. :)
>>
>> I think I like it, but I need more input.
>>
>> Paolo
> Well, just for virtio-scsi-pci, something like that:
> 
> ---
>  hw/core/qdev.c         | 14 ++++++++++++++
>  hw/virtio/virtio-pci.c |  9 +++++++++
>  include/hw/qdev-core.h |  4 ++++
>  3 files changed, 27 insertions(+)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 4eb0134..3aa0082 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -342,6 +342,13 @@ BusState *qdev_get_child_bus(DeviceState *dev,
> const char *name)
>      return NULL;
>  }
> 
> +void qdev_set_bus_name(DeviceState *dev, const char *bus_name)

device_... for new functions please. :)

> +{


Might be called multiple times, so better insert:

if (dev->bus_name) {
    g_free(dev->bus_name);
    dev->bus_name = NULL;
}

> +    if (bus_name) {
> +        dev->bus_name = g_strdup(bus_name);
> +    }
> +}
> +
>  int qbus_walk_children(BusState *bus, qdev_walkerfn *devfn,
>                         qbus_walkerfn *busfn, void *opaque)
>  {
> @@ -421,6 +428,13 @@ static void qbus_realize(BusState *bus, DeviceState
> *parent, const char *name)
> 
>      if (name) {
>          bus->name = g_strdup(name);
> +    } else if (bus->parent && bus->parent->bus_name) {
> +        /* parent device has bus_name -> use it for bus name */

This seems backwards to me. qdev had made sure to have a 1:n
relationship between device and bus, whereas you are making the name
template 1:1 here. Don't you rather want a qbus_set_name() mechanism
operating on the bus?

> +        len = strlen(bus->parent->bus_name) + 16;

Why 15 decimal digits? Is there any constant we could reuse?

> +        buf = g_malloc(len);
> +        snprintf(buf, len, "%s.%d", bus->parent->bus_name,
> +                 bus->parent->num_child_bus);
> +        bus->name = buf;
>      } else if (bus->parent && bus->parent->id) {
>          /* parent device has id -> use it for bus name */
>          len = strlen(bus->parent->id) + 16;
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 070df44..8d5d146 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1106,11 +1106,20 @@ static int
> virtio_scsi_pci_init_pci(VirtIOPCIProxy *vpci_dev)
>      VirtIOSCSIPCI *dev = VIRTIO_SCSI_PCI(vpci_dev);
>      DeviceState *vdev = DEVICE(&dev->vdev);
>      VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(vdev);
> +    DeviceState *proxy = DEVICE(dev);
> 
>      if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
>          vpci_dev->nvectors = vs->conf.num_queues + 3;
>      }
> 
> +    /*
> +     * For command line compatibility, this set the virtio-scsi-device bus

"sets"

> +     * name as before.
> +     */
> +    if (proxy->id) {
> +        qdev_set_bus_name(vdev, proxy->id);
> +    }
> +
>      qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));
>      if (qdev_init(vdev) < 0) {
>          return -1;
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index cf83d54..332e11f 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -125,6 +125,7 @@ struct DeviceState {
>      int num_child_bus;
>      int instance_id_alias;
>      int alias_required_for_version;
> +    const char *bus_name;
>  };
> 
>  #define TYPE_BUS "bus"
> @@ -224,6 +225,9 @@ BusState *qdev_get_child_bus(DeviceState *dev, const
> char *name);
>  void qdev_init_gpio_in(DeviceState *dev, qemu_irq_handler handler, int n);
>  void qdev_init_gpio_out(DeviceState *dev, qemu_irq *pins, int n);
> 
> +/* Set the bus_name property. */
> +void qdev_set_bus_name(DeviceState *dev, const char *bus_name);
> +
>  BusState *qdev_get_parent_bus(DeviceState *dev);
> 
>  /*** BUS API. ***/

Andreas

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