Re: [Xen-devel] [PATCH for 4.7] pvusb: add missing definition to usbif.h

[Juergen Gross <jgross@xxxxxxxx>]

On 05/05/16 11:22, Wei Liu wrote:
> On Thu, May 05, 2016 at 11:10:33AM +0200, Juergen Gross wrote:
>> On 05/05/16 11:02, Wei Liu wrote:
>>> On Thu, May 05, 2016 at 08:36:45AM +0200, Juergen Gross wrote:
>>>> The pvusb request structure contains the transfer_flags member which
>>>> is missing definitions of it's semantics.
>>>>
>>>> Add the definition of the USBIF_SHORT_NOT_OK flag.
>>>>
>>>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>>>> ---
>>>> Please consider taking this patch for 4.7 release. I believe this is the
>>>> last bit missing for support of qemu based pvusb backend. The risk of the
>>>> patch should be zero, as no Xen component is using this header.
>>>> ---
>>>>  xen/include/public/io/usbif.h | 1 +
>>>>  1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/xen/include/public/io/usbif.h b/xen/include/public/io/usbif.h
>>>> index 9ef0cdc..4053c24 100644
>>>> --- a/xen/include/public/io/usbif.h
>>>> +++ b/xen/include/public/io/usbif.h
>>>> @@ -187,6 +187,7 @@ struct usbif_urb_request {
>>>>    /* basic urb parameter */
>>>>    uint32_t pipe;
>>>>    uint16_t transfer_flags;
>>>> +#define USBIF_SHORT_NOT_OK        0x0001
>>>
>>> Where does this come from? Should it be surrounded by define guard?
>>
>> I just wasn't defined up to now (to be precise: transfer_flags was just
>> copied from the related URB struct member in the frontend, so the
>> interface was based on some Linux kernel internals, and the qemu backend
>> used a literal "1" for testing the flag).
>>
>>> #ifndef USBIF_SHORT_NOT_OK
>>> #define USBIF_SHORT_NOT_OK 0x0001
>>> #endif
>>>
>>> Why does it need to be in our public header? If we end up taking this
>>> I think it should at least start with XEN_ prefix.
>>
>> This is just a part of the pvusb interface. So it should be defined in
>> the appropriate header file.
>>
> 
> OK. I get it now.
> 
>> Regarding prefix: I can do this, but in this case I'd prefer to add the
>> prefix to all definitions in the header. As there are currently no
>> in-tree users of this header, the risk would still be zero. :-)
>>
>> Thoughts?
>>
> 
> Actually not all public #define are prefixed by XEN_ (netif.h does,
> blkif.h doesn't) so I won't insists on this. But I still using XEN_
> prefix is better.

Sure. But I think it should be consistent at header file level. So in
my opinion the question is: should I change all definitions in usbif.h
to use the XEN_ prefix or should I add the new definition without
prefix?


Juergen

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