Hi Maxime,
I have noticed you changed the state this patch to Superseded.
So are you going to submit a new version of this patch?
Thanks,
Cheng
> -----Original Message-----
> From: Jiang, Cheng1
> Sent: Wednesday, July 7, 2021 7:11 PM
> To: Maxime Coquelin <maxime.coque...@redhat.com>; dev@dpdk.org; Xia,
> Chenbo <chenbo....@intel.com>
> Cc: sta...@dpdk.org
> Subject: RE: [PATCH v2] vhost: fix assuming packed ring size is a power of 2
>
> Hi Maxime,
>
> I have also noticed the wrong calculation here, thanks for the timely help.
>
> Thanks,
> Cheng
>
> > -----Original Message-----
> > From: Maxime Coquelin <maxime.coque...@redhat.com>
> > Sent: Wednesday, July 7, 2021 6:30 PM
> > To: dev@dpdk.org; Jiang, Cheng1 <cheng1.ji...@intel.com>; Xia, Chenbo
> > <chenbo....@intel.com>
> > Cc: Maxime Coquelin <maxime.coque...@redhat.com>; sta...@dpdk.org
> > Subject: [PATCH v2] vhost: fix assuming packed ring size is a power of
> > 2
> >
> > Unlike split ring, packed ring does not mandate the ring size to be a
> > power of 2. So we have to use a modulo operation when wrapping ring
> index.
> >
> > Fixes: 873e8dad6f49 ("vhost: support packed ring in async datapath")
> > Cc: sta...@dpdk.org
> >
> > Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
> > ---
> >
> > V2: Also fix wrapping in virtio_dev_rx_async_get_info_idx which is
> > used in the packed ring data path.
> >
> > lib/vhost/virtio_net.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c index
> > b93482587c..0de5231db7 100644
> > --- a/lib/vhost/virtio_net.c
> > +++ b/lib/vhost/virtio_net.c
> > @@ -1470,7 +1470,7 @@ virtio_dev_rx_async_get_info_idx(uint16_t
> > pkts_idx,
> > uint16_t vq_size, uint16_t n_inflight) {
> > return pkts_idx > n_inflight ? (pkts_idx - n_inflight) :
> > - (vq_size - n_inflight + pkts_idx) & (vq_size - 1);
> > + (vq_size - n_inflight + pkts_idx) % vq_size;
> > }
> >
> > static __rte_always_inline void
> > @@ -2131,7 +2131,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int
> > vid, uint16_t queue_id,
> >
> > if (vq_is_packed(dev)) {
> > for (i = 0; i < n_pkts_put; i++) {
> > - from = (start_idx + i) & (vq_size - 1);
> > + from = (start_idx + i) % vq_size;
> > n_buffers += pkts_info[from].nr_buffers;
> > pkts[i] = pkts_info[from].mbuf;
> > }
> > --
> > 2.31.1
>
>
> Acked-by: Cheng Jiang <cheng1.ji...@intel.com>
