Linux Virtualization - Sep 2019 - [PATCH 5/6] vringh: fix copy direction of vringh_iov_push_kern()

On Mon, 23 Sep 2019 21:03:30 +0800
Jason Wang <jasowang at redhat.com> wrote:
> We want to copy from iov to buf, so the direction was wrong.
> 
> Signed-off-by: Jason Wang <jasowang at redhat.com>
> ---
>  drivers/vhost/vringh.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)

Why is this included in the series?  Seems like an unrelated fix being
held up within a proposal for a new feature.  Thanks,

Alex
 
> diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> index 08ad0d1f0476..a0a2d74967ef 100644
> --- a/drivers/vhost/vringh.c
> +++ b/drivers/vhost/vringh.c
> @@ -852,6 +852,12 @@ static inline int xfer_kern(void *src, void *dst,
size_t len)
>  	return 0;
>  }
>  
> +static inline int kern_xfer(void *dst, void *src, size_t len)
> +{
> +	memcpy(dst, src, len);
> +	return 0;
> +}
> +
>  /**
>   * vringh_init_kern - initialize a vringh for a kernelspace vring.
>   * @vrh: the vringh to initialize.
> @@ -958,7 +964,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern);
>  ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
>  			     const void *src, size_t len)
>  {
> -	return vringh_iov_xfer(wiov, (void *)src, len, xfer_kern);
> +	return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer);
>  }
>  EXPORT_SYMBOL(vringh_iov_push_kern);
>

On Mon, Sep 23, 2019 at 09:45:59AM -0600, Alex Williamson
wrote:
> On Mon, 23 Sep 2019 21:03:30 +0800
> Jason Wang <jasowang at redhat.com> wrote:
> 
> > We want to copy from iov to buf, so the direction was wrong.
> > 
> > Signed-off-by: Jason Wang <jasowang at redhat.com>
> > ---
> >  drivers/vhost/vringh.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> 
> Why is this included in the series?  Seems like an unrelated fix being
> held up within a proposal for a new feature.  Thanks,
> 
> Alex
It's better to have it as patch 1/6, but it's a dependency of the
example driver in the series. I can reorder when I apply.

> > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> > index 08ad0d1f0476..a0a2d74967ef 100644
> > --- a/drivers/vhost/vringh.c
> > +++ b/drivers/vhost/vringh.c
> > @@ -852,6 +852,12 @@ static inline int xfer_kern(void *src, void *dst,
size_t len)
> >  	return 0;
> >  }
> >  
> > +static inline int kern_xfer(void *dst, void *src, size_t len)
> > +{
> > +	memcpy(dst, src, len);
> > +	return 0;
> > +}
> > +
> >  /**
> >   * vringh_init_kern - initialize a vringh for a kernelspace vring.
> >   * @vrh: the vringh to initialize.
> > @@ -958,7 +964,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern);
> >  ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
> >  			     const void *src, size_t len)
> >  {
> > -	return vringh_iov_xfer(wiov, (void *)src, len, xfer_kern);
> > +	return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer);
> >  }
> >  EXPORT_SYMBOL(vringh_iov_push_kern);
> >

On Mon, 23 Sep 2019 12:00:41 -0400
"Michael S. Tsirkin" <mst at redhat.com> wrote:
> On Mon, Sep 23, 2019 at 09:45:59AM -0600, Alex Williamson wrote:
> > On Mon, 23 Sep 2019 21:03:30 +0800
> > Jason Wang <jasowang at redhat.com> wrote:
> >   
> > > We want to copy from iov to buf, so the direction was wrong.
> > > 
> > > Signed-off-by: Jason Wang <jasowang at redhat.com>
> > > ---
> > >  drivers/vhost/vringh.c | 8 +++++++-
> > >  1 file changed, 7 insertions(+), 1 deletion(-)  
> > 
> > 
> > Why is this included in the series?  Seems like an unrelated fix being
> > held up within a proposal for a new feature.  Thanks,
> > 
> > Alex  
> 
> It's better to have it as patch 1/6, but it's a dependency of the
> example driver in the series. I can reorder when I apply.
It's a fix, please submit it separately through virtio/vhost channels,
then it will already be in the base kernel we use for the rest of the
series.  The remainder of the series certainly suggests a workflow
through the vfio tree rather than virtio/vhost.  Thanks,

Alex
> > > diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
> > > index 08ad0d1f0476..a0a2d74967ef 100644
> > > --- a/drivers/vhost/vringh.c
> > > +++ b/drivers/vhost/vringh.c
> > > @@ -852,6 +852,12 @@ static inline int xfer_kern(void *src, void
*dst, size_t len)
> > >  	return 0;
> > >  }
> > >  
> > > +static inline int kern_xfer(void *dst, void *src, size_t len)
> > > +{
> > > +	memcpy(dst, src, len);
> > > +	return 0;
> > > +}
> > > +
> > >  /**
> > >   * vringh_init_kern - initialize a vringh for a kernelspace
vring.
> > >   * @vrh: the vringh to initialize.
> > > @@ -958,7 +964,7 @@ EXPORT_SYMBOL(vringh_iov_pull_kern);
> > >  ssize_t vringh_iov_push_kern(struct vringh_kiov *wiov,
> > >  			     const void *src, size_t len)
> > >  {
> > > -	return vringh_iov_xfer(wiov, (void *)src, len, xfer_kern);
> > > +	return vringh_iov_xfer(wiov, (void *)src, len, kern_xfer);
> > >  }
> > >  EXPORT_SYMBOL(vringh_iov_push_kern);
> > >