Re: [dpdk-dev] [PATCH v7 09/15] vhost: add shadow used ring support for packed rings

[Tiwei Bie <tiwei.bie@intel.com>]

On Thu, Jul 05, 2018 at 02:49:34PM +0200, Maxime Coquelin wrote:
> On 07/05/2018 09:15 AM, Tiwei Bie wrote:
> > On Wed, Jul 04, 2018 at 11:54:32PM +0200, Maxime Coquelin wrote:
> > [...]
> > > +
> > > +static __rte_always_inline void
> > > +flush_shadow_used_ring_packed(struct virtio_net *dev,
> > > +			struct vhost_virtqueue *vq)
> > > +{
> > [...]
> > > +}
> > > +
> > > +static __rte_always_inline void
> > > +update_shadow_used_ring_packed(struct vhost_virtqueue *vq,
> > > +			 uint16_t desc_idx, uint16_t len, uint16_t count)
> > > +{
> > > +	uint16_t i = vq->shadow_used_idx++;
> > > +
> > > +	vq->shadow_used_packed[i].id  = desc_idx;
> > > +	vq->shadow_used_packed[i].len = len;
> > > +	vq->shadow_used_packed[i].count = count;
> > >   }
> > 
> > I met below build errors in this patch when doing
> > per-patch build test with clang:
> > 
> > lib/librte_vhost/virtio_net.c:134:1: error: unused function 'flush_shadow_used_ring_packed'
> >        [-Werror,-Wunused-function]
> > flush_shadow_used_ring_packed(struct virtio_net *dev,
> > ^
> > lib/librte_vhost/virtio_net.c:188:1: error: unused function 'update_shadow_used_ring_packed'
> >        [-Werror,-Wunused-function]
> > update_shadow_used_ring_packed(struct vhost_virtqueue *vq,
> > ^
> > 
> > It's better to add __rte_unused in this patch,
> > and remove it when functions are used.
> > 
> > PS. I also saw similar errors with fill_vec_buf_packed()
> >      in patch 11/15.
> > 
> 
> Thanks for the report, I missed these build issues...
> This is not fixed using __rte_unused as you suggested.
> 

Why not? This can be fixed by something like this
on my machine:

-static __rte_always_inline void
+static __rte_always_inline __rte_unused void
 flush_shadow_used_ring_packed(struct virtio_net *dev,
 			struct vhost_virtqueue *vq)
 {

And __rte_unused can be removed in the patch that
above function is called.

Best regards,
Tiwei Bie