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

[Wei Liu <wei.liu2@citrix.com>]

On Fri, May 06, 2016 at 07:01:12AM +0200, Juergen Gross wrote:
> 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@suse.com>
> >>>> ---
> >>>> 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?
> 

Yes we need to be consistent in usbif.h

> 
> Juergen

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