Jason Wang
2021-Jan-18 06:45 UTC
[PATCH net-next v2 2/7] virtio-net, xsk: distinguish XDP_TX and XSK XMIT ctx
On 2021/1/16 ??10:59, Xuan Zhuo wrote:> If support xsk, a new ptr will be recovered during the > process of freeing the old ptr. In order to distinguish between ctx sent > by XDP_TX and ctx sent by xsk, a struct is added here to distinguish > between these two situations. virtnet_xdp_type.type It is used to > distinguish different ctx, and virtnet_xdp_type.offset is used to record > the offset between "true ctx" and virtnet_xdp_type. > > The newly added virtnet_xsk_hdr will be used for xsk. > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>Any reason that you can't simply encode the type in the pointer itself as we used to do? #define VIRTIO_XSK_FLAG??? BIT(1) ?> --- > drivers/net/virtio_net.c | 75 ++++++++++++++++++++++++++++++++++++++---------- > 1 file changed, 60 insertions(+), 15 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index ba8e637..e707c31 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -94,6 +94,22 @@ struct virtnet_rq_stats { > u64 kicks; > }; > > +enum { > + XDP_TYPE_XSK, > + XDP_TYPE_TX, > +}; > + > +struct virtnet_xdp_type { > + int offset:24; > + unsigned type:8; > +}; > + > +struct virtnet_xsk_hdr { > + struct virtnet_xdp_type type; > + struct virtio_net_hdr_mrg_rxbuf hdr; > + u32 len; > +}; > + > #define VIRTNET_SQ_STAT(m) offsetof(struct virtnet_sq_stats, m) > #define VIRTNET_RQ_STAT(m) offsetof(struct virtnet_rq_stats, m) > > @@ -251,14 +267,19 @@ static bool is_xdp_frame(void *ptr) > return (unsigned long)ptr & VIRTIO_XDP_FLAG; > } > > -static void *xdp_to_ptr(struct xdp_frame *ptr) > +static void *xdp_to_ptr(struct virtnet_xdp_type *ptr) > { > return (void *)((unsigned long)ptr | VIRTIO_XDP_FLAG); > } > > -static struct xdp_frame *ptr_to_xdp(void *ptr) > +static struct virtnet_xdp_type *ptr_to_xtype(void *ptr) > +{ > + return (struct virtnet_xdp_type *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG); > +} > + > +static void *xtype_get_ptr(struct virtnet_xdp_type *xdptype) > { > - return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG); > + return (char *)xdptype + xdptype->offset; > } > > /* Converting between virtqueue no. and kernel tx/rx queue no. > @@ -459,11 +480,16 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, > struct xdp_frame *xdpf) > { > struct virtio_net_hdr_mrg_rxbuf *hdr; > + struct virtnet_xdp_type *xdptype; > int err; > > - if (unlikely(xdpf->headroom < vi->hdr_len)) > + if (unlikely(xdpf->headroom < vi->hdr_len + sizeof(*xdptype))) > return -EOVERFLOW; > > + xdptype = (struct virtnet_xdp_type *)(xdpf + 1); > + xdptype->offset = (char *)xdpf - (char *)xdptype; > + xdptype->type = XDP_TYPE_TX; > + > /* Make room for virtqueue hdr (also change xdpf->headroom?) */ > xdpf->data -= vi->hdr_len; > /* Zero header and leave csum up to XDP layers */ > @@ -473,7 +499,7 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, > > sg_init_one(sq->sg, xdpf->data, xdpf->len); > > - err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdpf), > + err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdptype), > GFP_ATOMIC); > if (unlikely(err)) > return -ENOSPC; /* Caller handle free/refcnt */ > @@ -523,8 +549,11 @@ static int virtnet_xdp_xmit(struct net_device *dev, > /* Free up any pending old buffers before queueing new ones. */ > while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) { > if (likely(is_xdp_frame(ptr))) { > - struct xdp_frame *frame = ptr_to_xdp(ptr); > + struct virtnet_xdp_type *xtype; > + struct xdp_frame *frame; > > + xtype = ptr_to_xtype(ptr); > + frame = xtype_get_ptr(xtype); > bytes += frame->len; > xdp_return_frame(frame); > } else { > @@ -1373,24 +1402,34 @@ static int virtnet_receive(struct receive_queue *rq, int budget, > > static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi) > { > - unsigned int len; > unsigned int packets = 0; > unsigned int bytes = 0; > - void *ptr; > + unsigned int len; > + struct virtnet_xdp_type *xtype; > + struct xdp_frame *frame; > + struct virtnet_xsk_hdr *xskhdr; > + struct sk_buff *skb; > + void *ptr; > > while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) { > if (likely(!is_xdp_frame(ptr))) { > - struct sk_buff *skb = ptr; > + skb = ptr; > > pr_debug("Sent skb %p\n", skb); > > bytes += skb->len; > napi_consume_skb(skb, in_napi); > } else { > - struct xdp_frame *frame = ptr_to_xdp(ptr); > + xtype = ptr_to_xtype(ptr); > > - bytes += frame->len; > - xdp_return_frame(frame); > + if (xtype->type == XDP_TYPE_XSK) { > + xskhdr = (struct virtnet_xsk_hdr *)xtype; > + bytes += xskhdr->len; > + } else { > + frame = xtype_get_ptr(xtype); > + xdp_return_frame(frame); > + bytes += frame->len; > + } > } > packets++; > } > @@ -2659,10 +2698,16 @@ static void free_unused_bufs(struct virtnet_info *vi) > for (i = 0; i < vi->max_queue_pairs; i++) { > struct virtqueue *vq = vi->sq[i].vq; > while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) { > - if (!is_xdp_frame(buf)) > + if (!is_xdp_frame(buf)) { > dev_kfree_skb(buf); > - else > - xdp_return_frame(ptr_to_xdp(buf)); > + } else { > + struct virtnet_xdp_type *xtype; > + > + xtype = ptr_to_xtype(buf); > + > + if (xtype->type != XDP_TYPE_XSK) > + xdp_return_frame(xtype_get_ptr(xtype)); > + } > } > } >