Re: [PATCH 1/2] include/public: add possible status values to usbif.h

[Juergen Gross <jgross@xxxxxxxx>]

On 27.09.21 10:13, Jan Beulich wrote:
> On 24.09.2021 17:04, Juergen Gross wrote:
> > The interface definition of PV USB devices is lacking the specification
> > of possible values of the status filed in a response. Those are
> Nit: "field"?
Yes, of course.

> > negative errno values as used in Linux, so they might differ in other
> > OS's. Specify them via appropriate defines.
> What if new errno values got used by the driver? Would we alter the
> public header every time? Or is the likelihood of further values ever
> getting used vanishingly small? In how far would it be possible to tie
> these to Xen's public/errno.h instead?
Those are the current values returned by the backend. Other ones used
internally in the backend should IMO tried to be mapped to the values
defined in the interface specification.

> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > ---
> >   xen/include/public/io/usbif.h | 7 +++++++
> >   1 file changed, 7 insertions(+)
> >
> > diff --git a/xen/include/public/io/usbif.h b/xen/include/public/io/usbif.h
> > index c6a58639d6..fbd6f953f8 100644
> > --- a/xen/include/public/io/usbif.h
> > +++ b/xen/include/public/io/usbif.h
> > @@ -221,6 +221,13 @@ struct usbif_urb_response {
> >         uint16_t id; /* request id */
> >         uint16_t start_frame;  /* start frame (ISO) */
> >         int32_t status; /* status (non-ISO) */
> > +#define USBIF_STATUS_OK                0
> > +#define USBIF_STATUS_NODEV     -19
> > +#define USBIF_STATUS_INVAL     -22
> > +#define USBIF_STATUS_STALL     -32
> > +#define USBIF_STATUS_IOERROR   -71
> > +#define USBIF_STATUS_BABBLE    -75
> > +#define USBIF_STATUS_SHUTDOWN  -108
> Nit: While probably benign for all practical uses, these negative
> values nevertheless would better be parenthesized.
Okay, fine with me.


Juergen

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