[SeaBIOS] [PATCH v2] qdev: don't add typename to fw_dev_path when get_fw_dev_path isn't implemented
pbonzini at redhat.com
Wed May 29 08:27:48 CEST 2013
Il 29/05/2013 06:41, Amos Kong ha scritto:
> On Tue, May 28, 2013 at 01:15:57PM +0200, Paolo Bonzini wrote:
>> Il 28/05/2013 13:00, Amos Kong ha scritto:
>>> 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,
>>> so redundant typename will be added to fw_dev_path. It causes that
>>> bootindex parameter of scsi device doesn't work.
>>> This patch changes qdev_get_fw_dev_path_helper() to add nothing if
>>> implemented get_fw_dev_path() returns NULL.
>>> Signed-off-by: Amos Kong <akong at redhat.com>
>>> v2: only add nothing to fw_dev_path when get_fw_dev_path() is
>>> implemented and return NULL. then it will not effect other devices
>>> don't have get_fw_dev_path() implementation.
> Hi Paolo,
>> To achieve the same result, you can simply ensure that all classes
>> implement the method.
> Do you mean if some classes didn't have an implement, I need to add
> a implement (just returns NULL) for all of them, then nothing will be
> added to fw_dev_path for those classes?
No, you can have an implementation in BusClass. See how
device_class_init provides a default implementation for
realize/unrealize, and do the same in bus_class_init.
> Currently I'm sure 'typename' is redundant for virio-bus. 'typename'
> might be needed for other class (have no get_fw_dev_path implementation)
> Applied patch v2, there are three conditions:
> 1) implement get_fw_dev_path, return specific string, add to
> fw_dev_path (same as original)
> 2) don't implement get_fw_dev_path, add typename to fw_dev_path.
> (same as original)
> 3) implement get_fw_dev_path and return NULL, nothing is added
> to fw_dev_path (new behavior)
> If some other class wants to add nothing to path, just define a method
> to return NULL.
>> The default implementation is just
> If we implement the method for all classes, the default implementation
> in qdev_get_fw_dev_path_helper() will not be called.
Yes, but we shouldn't implement the method for all classes. We should
implement it just once in BusClass. Then the default implementation in
qdev_get_fw_dev_path_helper() can be removed. It will live in BusClass
>> Remember that if you do not specify a method in a BusClass's class_init
>> function, it is inherited from the superclass.
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