Re: [Qemu-devel] [PATCH 3/4] SCSI-Hotdel: Implement drive_hot_del

[Wolfgang Mauerer]

Gerd Hoffmann wrote:
> On 09/30/09 17:45, Wolfgang Mauerer wrote:
>> Gerd Hoffmann wrote:
>>>     Hi,
>>>
>>>> +     dinfo = drive_get(type, bus, unit);
>>>> +     if (!dinfo) {
>>>> +         monitor_printf(mon, "Trying to remove non-existent device\n");
>>>> +   return;
>>>> +     }
>>> No.  Just don't do this silly if/bus/unit parsing.  At very minimum use
>>> drive_get_by_id() here, then have something like 'drive_del $id'.
>>>
>>> IMHO much better would be to go qdev instead though.  We should have
>>> generic device_add + device_del monitor commands which work for any
>>> device, pretty much like the -device command line switch.
>> That makes sense, but I'd nevertheless prefer to stick with the
>> more traditional approach right now, replacing the
>> bus/unit parsing with an ID-based variant.
> 
> Have a look at the "qdev: bus management updates." patch series posted a 
> few days ago.  It adds device_add+device_del.

Thanks for the pointer. The reason why I'd (still :-)) like
to stick to the non-qdev variant is because I would want
the patch to be applicable to older qemu releases for various
reasons, and backporting all the required qdev  changes does
not seem to be a reasonable option (but please tell me if you
think this would make sense)

>> However, is there any
>> standard way to get from an instance of DriveInfo to
>> the corresponding instance of SCSIDevice respectively
>> SCSIDeviceInfo?
> 
> No.  It is linked the other way around: The device has a reference to 
> the DriveInfo.  Which is one of the reasons why I think drive_del isn't 
> that a great idea.

Cheers, Wolfgang