On Mon, 13 Nov 2023 17:11:04 +0100, Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx> wrote: > On Tue, Nov 07, 2023 at 11:12:24AM +0800, Xuan Zhuo wrote: > > The virtnet_xdp_handler() is re-used. But > > > > 1. We need to copy data to create skb for XDP_PASS. > > 2. We need to call xsk_buff_free() to release the buffer. > > 3. The handle for xdp_buff is difference. > > > > If we pushed this logic into existing receive handle(merge and small), > > we would have to maintain code scattered inside merge and small (and big). > > So I think it is a good choice for us to put the xsk code into an > > independent function. > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> > > --- > > drivers/net/virtio/main.c | 12 ++-- > > drivers/net/virtio/virtio_net.h | 4 ++ > > drivers/net/virtio/xsk.c | 120 ++++++++++++++++++++++++++++++++ > > drivers/net/virtio/xsk.h | 4 ++ > > 4 files changed, 135 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c > > index a318b2533b94..095f4acb0577 100644 > > --- a/drivers/net/virtio/main.c > > +++ b/drivers/net/virtio/main.c > > @@ -831,10 +831,10 @@ static void put_xdp_frags(struct xdp_buff *xdp) > > } > > } > > > > -static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp, > > - struct net_device *dev, > > - unsigned int *xdp_xmit, > > - struct virtnet_rq_stats *stats) > > +int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp, > > + struct net_device *dev, > > + unsigned int *xdp_xmit, > > + struct virtnet_rq_stats *stats) > > { > > struct xdp_frame *xdpf; > > int err; > > @@ -1598,7 +1598,9 @@ static void receive_buf(struct virtnet_info *vi, struct virtnet_rq *rq, > > return; > > } > > > > - if (vi->mergeable_rx_bufs) > > + if (rq->xsk.pool) > > + skb = virtnet_receive_xsk(dev, vi, rq, buf, len, xdp_xmit, stats); > > + else if (vi->mergeable_rx_bufs) > > skb = receive_mergeable(dev, vi, rq, buf, ctx, len, xdp_xmit, > > stats); > > else if (vi->big_packets) > > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h > > index 2005d0cd22e2..f520fec06662 100644 > > --- a/drivers/net/virtio/virtio_net.h > > +++ b/drivers/net/virtio/virtio_net.h > > @@ -339,4 +339,8 @@ void virtnet_tx_pause(struct virtnet_info *vi, struct virtnet_sq *sq); > > void virtnet_tx_resume(struct virtnet_info *vi, struct virtnet_sq *sq); > > void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); > > void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); > > +int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp, > > + struct net_device *dev, > > + unsigned int *xdp_xmit, > > + struct virtnet_rq_stats *stats); > > #endif > > diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c > > index b09c473c29fb..5c7eb19ab04b 100644 > > --- a/drivers/net/virtio/xsk.c > > +++ b/drivers/net/virtio/xsk.c > > @@ -14,6 +14,18 @@ static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len) > > sg->length = len; > > } > > > > +static unsigned int virtnet_receive_buf_num(struct virtnet_info *vi, char *buf) > > +{ > > + struct virtio_net_hdr_mrg_rxbuf *hdr; > > + > > + if (vi->mergeable_rx_bufs) { > > + hdr = (struct virtio_net_hdr_mrg_rxbuf *)buf; > > + return virtio16_to_cpu(vi->vdev, hdr->num_buffers); > > + } > > + > > + return 1; > > +} > > + > > static void virtnet_xsk_check_queue(struct virtnet_sq *sq) > > { > > struct virtnet_info *vi = sq->vq->vdev->priv; > > @@ -38,6 +50,114 @@ static void virtnet_xsk_check_queue(struct virtnet_sq *sq) > > netif_stop_subqueue(dev, qnum); > > } > > > > +static void merge_drop_follow_xdp(struct net_device *dev, > > + struct virtnet_rq *rq, > > + u32 num_buf, > > + struct virtnet_rq_stats *stats) > > +{ > > + struct xdp_buff *xdp; > > + u32 len; > > + > > + while (num_buf-- > 1) { > > + xdp = virtqueue_get_buf(rq->vq, &len); > > + if (unlikely(!xdp)) { > > + pr_debug("%s: rx error: %d buffers missing\n", > > + dev->name, num_buf); > > + dev->stats.rx_length_errors++; > > + break; > > + } > > + u64_stats_add(&stats->bytes, len); > > + xsk_buff_free(xdp); > > + } > > +} > > + > > +static struct sk_buff *construct_skb(struct virtnet_rq *rq, > > could you name this to virtnet_construct_skb_zc > > > + struct xdp_buff *xdp) > > +{ > > + unsigned int metasize = xdp->data - xdp->data_meta; > > + struct sk_buff *skb; > > + unsigned int size; > > + > > + size = xdp->data_end - xdp->data_hard_start; > > + skb = napi_alloc_skb(&rq->napi, size); > > + if (unlikely(!skb)) > > + return NULL; > > + > > + skb_reserve(skb, xdp->data_meta - xdp->data_hard_start); > > + > > + size = xdp->data_end - xdp->data_meta; > > + memcpy(__skb_put(skb, size), xdp->data_meta, size); > > + > > + if (metasize) { > > + __skb_pull(skb, metasize); > > + skb_metadata_set(skb, metasize); > > + } > > + > > + return skb; > > +} > > + > > +struct sk_buff *virtnet_receive_xsk(struct net_device *dev, struct virtnet_info *vi, > > + struct virtnet_rq *rq, void *buf, > > + unsigned int len, unsigned int *xdp_xmit, > > + struct virtnet_rq_stats *stats) > > +{ > > + struct virtio_net_hdr_mrg_rxbuf *hdr; > > + struct sk_buff *skb = NULL; > > + u32 ret, headroom, num_buf; > > + struct bpf_prog *prog; > > + struct xdp_buff *xdp; > > + > > + len -= vi->hdr_len; > > + > > + xdp = (struct xdp_buff *)buf; > > + > > + xsk_buff_set_size(xdp, len); > > + > > + hdr = xdp->data - vi->hdr_len; > > + > > + num_buf = virtnet_receive_buf_num(vi, (char *)hdr); > > + if (num_buf > 1) > > + goto drop; > > + > > + headroom = xdp->data - xdp->data_hard_start; > > + > > + xdp_prepare_buff(xdp, xdp->data_hard_start, headroom, len, true); > > Please don't. > > xsk_buff_pool has ::data_hard_start initialized and you already > initialized ::data and ::data_end within xsk_buff_set_size(). Yes, you are right. > > > + xsk_buff_dma_sync_for_cpu(xdp, rq->xsk.pool); > > + > > + ret = XDP_PASS; > > + rcu_read_lock(); > > We don't need RCU sections for running XDP progs anymore. > > > + prog = rcu_dereference(rq->xdp_prog); > > + if (prog) > > Prog is always !NULL for ZC case. Just dereference it at the beginning of > rx processing instead of doing it for each buf. That is a problem of virtio-net. I notice that, I will post patch to fix that. Thanks. > > > + ret = virtnet_xdp_handler(prog, xdp, dev, xdp_xmit, stats); > > + rcu_read_unlock(); > > + > > + switch (ret) { > > + case XDP_PASS: > > + skb = construct_skb(rq, xdp); > > + xsk_buff_free(xdp); > > + break; > > + > > + case XDP_TX: > > + case XDP_REDIRECT: > > + goto consumed; > > + > > + default: > > + goto drop; > > + } > > + > > + return skb; > > + > > +drop: > > + u64_stats_inc(&stats->drops); > > + > > + xsk_buff_free(xdp); > > + > > + if (num_buf > 1) > > + merge_drop_follow_xdp(dev, rq, num_buf, stats); > > +consumed: > > + return NULL; > > +} > > + > > int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct virtnet_rq *rq, > > struct xsk_buff_pool *pool, gfp_t gfp) > > { > > diff --git a/drivers/net/virtio/xsk.h b/drivers/net/virtio/xsk.h > > index bef41a3f954e..dbd2839a5f61 100644 > > --- a/drivers/net/virtio/xsk.h > > +++ b/drivers/net/virtio/xsk.h > > @@ -25,4 +25,8 @@ bool virtnet_xsk_xmit(struct virtnet_sq *sq, struct xsk_buff_pool *pool, > > int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag); > > int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct virtnet_rq *rq, > > struct xsk_buff_pool *pool, gfp_t gfp); > > +struct sk_buff *virtnet_receive_xsk(struct net_device *dev, struct virtnet_info *vi, > > + struct virtnet_rq *rq, void *buf, > > + unsigned int len, unsigned int *xdp_xmit, > > + struct virtnet_rq_stats *stats); > > #endif > > -- > > 2.32.0.3.g01195cf9f > > > >