> -----Original Message----- > From: Paolo Abeni [mailto:pabeni@xxxxxxxxxx] > Sent: Thursday, February 29, 2024 6:49 PM > To: wangyunjian <wangyunjian@xxxxxxxxxx>; mst@xxxxxxxxxx; > willemdebruijn.kernel@xxxxxxxxx; jasowang@xxxxxxxxxx; kuba@xxxxxxxxxx; > bjorn@xxxxxxxxxx; magnus.karlsson@xxxxxxxxx; maciej.fijalkowski@xxxxxxxxx; > jonathan.lemon@xxxxxxxxx; davem@xxxxxxxxxxxxx > Cc: bpf@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; > virtualization@xxxxxxxxxxxxxxx; xudingke <xudingke@xxxxxxxxxx>; liwei (DT) > <liwei395@xxxxxxxxxx> > Subject: Re: [PATCH net-next v2 2/3] vhost_net: Call peek_len when using xdp > > 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@xxxxxxxxxx> > > --- > > 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. Thank you for your suggestion. I will consider that with Patch 3/3. > > Cheers, > > Paolo
