Re: [Xen-devel] [PATCH] libvchan: Make raw_get_{data_ready, buffer_space} match

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

On 05/19/2014 07:31 AM, Ian Jackson wrote:
> Jason Andryuk writes ("[PATCH] libvchan: Make raw_get_{data_ready,buffer_space} 
> match"):
> > For writing into a vchan, raw_get_buffer_space used >, allowing the full
> > ring size to be written.  On the read side, raw_get_data_ready compared
> > the ring size with >=.  This mismatch means a completely filled buffer
> > cannot be read.  Fix this by making the size checks identical.
> This seems right to me, but I have CC'd the authors of this area of
> code to give them a chance to comment.
>
> Thanks,
> Ian.
This also looks correct to me.

> > Signed-off-by: Jason Andryuk <andryuk@xxxxxxxx>
> > ---
> >   tools/libvchan/io.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/libvchan/io.c b/tools/libvchan/io.c
> > index 804c63c..6e6e239 100644
> > --- a/tools/libvchan/io.c
> > +++ b/tools/libvchan/io.c
> > @@ -118,7 +118,7 @@ static inline int send_notify(struct libxenvchan *ctrl, 
> > uint8_t bit)
> >   static inline int raw_get_data_ready(struct libxenvchan *ctrl)
> >   {
> >         uint32_t ready = rd_prod(ctrl) - rd_cons(ctrl);
> > -       if (ready >= rd_ring_size(ctrl))
> > +       if (ready > rd_ring_size(ctrl))
> >                 /* We have no way to return errors.  Locking up the ring is
> >                  * better than the alternatives. */
> >                 return 0;
> > --
> > 1.8.3.1

--
Daniel De Graaf
National Security Agency

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel