Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH net-next v2 2/3] vhost_net: Call peek_len when using xdp | From | Paolo Abeni <> | Date | Thu, 29 Feb 2024 11:48:43 +0100 |
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On Wed, 2024-02-28 at 19:05 +0800, Yunjian Wang wrote: > If TUN supports AF_XDP TX zero-copy, the XDP program will enqueue > packets to the XDP ring and wake up the vhost worker. This requires > the vhost worker to call peek_len(), which can be used to consume > XDP descriptors. > > Signed-off-by: Yunjian Wang <wangyunjian@huawei.com> > --- > drivers/vhost/net.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index f2ed7167c848..077e74421558 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -207,6 +207,11 @@ static int vhost_net_buf_peek_len(void *ptr) > return __skb_array_len_with_tag(ptr); > } > > +static bool vhost_sock_xdp(struct socket *sock) > +{ > + return sock_flag(sock->sk, SOCK_XDP); > +} > + > static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) > { > struct vhost_net_buf *rxq = &nvq->rxq; > @@ -214,6 +219,13 @@ static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) > if (!vhost_net_buf_is_empty(rxq)) > goto out; > > + if (ptr_ring_empty(nvq->rx_ring)) { > + struct socket *sock = vhost_vq_get_backend(&nvq->vq); > + /* Call peek_len to consume XSK descriptors, when using xdp */ > + if (vhost_sock_xdp(sock) && sock->ops->peek_len) > + sock->ops->peek_len(sock);
This really looks like a socket API misuse. Why can't you use ptr-ring primitives to consume XSK descriptors? peek_len could be constified some day, this code will prevent such (good) thing.
Cheers,
Paolo
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