Re: [Qemu-devel] [RFC][PATCH 11/45] msi: Factor out delivery hook

[Jan Kiszka]

On 2011-10-18 14:05, Michael S. Tsirkin wrote:
> On Mon, Oct 17, 2011 at 09:15:47PM +0200, Jan Kiszka wrote:
>> On 2011-10-17 15:43, Michael S. Tsirkin wrote:
>>> On Mon, Oct 17, 2011 at 11:27:45AM +0200, Jan Kiszka wrote:
>>>> diff --git a/hw/msi.c b/hw/msi.c
>>>> index 3c7ebc3..9055155 100644
>>>> --- a/hw/msi.c
>>>> +++ b/hw/msi.c
>>>> @@ -40,6 +40,14 @@
>>>>  /* Flag for interrupt controller to declare MSI/MSI-X support */
>>>>  bool msi_supported;
>>>>  
>>>> +static void msi_unsupported(MSIMessage *msg)
>>>> +{
>>>> +    /* If we get here, the board failed to register a delivery handler. */
>>>> +    abort();
>>>> +}
>>>> +
>>>> +void (*msi_deliver)(MSIMessage *msg) = msi_unsupported;
>>>> +
>>>
>>> How about we set this to NULL, and check it instead of the bool
>>> flag?
>>>
>>
>> Yeah. I will introduce
>>
>> bool msi_supported(void)
>> {
>>     return msi_deliver != msi_unsupported;
>> }
>>
>> OK?
>>
>> Jan
>>
> 
> Looks a bit weird ...
> NULL is a pretty standard value for an invalid pointer, isn't it?

Save us the runtime check and is equally expressive and readable IMHO.

Jan

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