Re: [Qemu-devel] [PATCH] qdev: Keep global allocation counter per bus

[Paolo Bonzini <pbonzini@redhat.com>]

Il 04/12/2013 21:24, Alexander Graf ha scritto:
> When we have 2 separate qdev devices that both create a qbus of the
> same type without specifying a bus name or device name, we end up
> with two buses of the same name, such as ide.0 on the Mac machines:
> 
>   dev: macio-ide, id ""
>     bus: ide.0
>       type IDE
>   dev: macio-ide, id ""
>     bus: ide.0
>       type IDE
> 
> If we now spawn a device that connects to a ide.0 the last created
> bus gets the device, with the first created bus inaccessible to the
> command line.
> 
> After some discussion on IRC we concluded that the best quick fix way
> forward for this is to make automated bus-class type based allocation
> count a global counter. That's what this patch implements. With this
> we instead get
> 
>   dev: macio-ide, id ""
>     bus: ide.1
>       type IDE
>   dev: macio-ide, id ""
>     bus: ide.0
>       type IDE
> 
> on the example mentioned above.
> 
> CC: Paolo Bonzini <pbonzini@redhat.com>
> CC: Markus Armbruster <armbru@redhat.com>
> CC: Anthony Liguori <aliguori@amazon.com>
> Signed-off-by: Alexander Graf <agraf@suse.de>
> ---
>  hw/core/qdev.c         | 20 +++++++++++++-------
>  include/hw/qdev-core.h |  2 ++
>  2 files changed, 15 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index e374a93..959130c 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -409,27 +409,33 @@ DeviceState *qdev_find_recursive(BusState *bus, const char *id)
>  static void qbus_realize(BusState *bus, DeviceState *parent, const char *name)
>  {
>      const char *typename = object_get_typename(OBJECT(bus));
> +    BusClass *bc;
>      char *buf;
> -    int i,len;
> +    int i, len, bus_id;
>  
>      bus->parent = parent;
>  
>      if (name) {
>          bus->name = g_strdup(name);
>      } else if (bus->parent && bus->parent->id) {
> -        /* parent device has id -> use it for bus name */
> +        /* parent device has id -> use it plus parent-bus-id for bus name */
> +        bus_id = bus->parent->num_child_bus;
> +
>          len = strlen(bus->parent->id) + 16;
>          buf = g_malloc(len);
> -        snprintf(buf, len, "%s.%d", bus->parent->id, bus->parent->num_child_bus);
> +        snprintf(buf, len, "%s.%d", bus->parent->id, bus_id);
>          bus->name = buf;
>      } else {
> -        /* no id -> use lowercase bus type for bus name */
> +        /* no id -> use lowercase bus type plus global bus-id for bus name */
> +        bc = BUS_GET_CLASS(bus);
> +        bus_id = bc->automatic_ids++;
> +
>          len = strlen(typename) + 16;
>          buf = g_malloc(len);
> -        len = snprintf(buf, len, "%s.%d", typename,
> -                       bus->parent ? bus->parent->num_child_bus : 0);
> -        for (i = 0; i < len; i++)
> +        len = snprintf(buf, len, "%s.%d", typename, bus_id);
> +        for (i = 0; i < len; i++) {
>              buf[i] = qemu_tolower(buf[i]);
> +        }
>          bus->name = buf;
>      }
>  
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index f2043a6..09f8527 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -161,6 +161,8 @@ struct BusClass {
>      int (*reset)(BusState *bus);
>      /* maximum devices allowed on the bus, 0: no limit. */
>      int max_dev;
> +    /* number of automatically allocated bus ids (e.g. ide.0) */
> +    int automatic_ids;
>  };
>  
>  typedef struct BusChild {
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>