virtio_net: introduce receive_mergeable_xdp()

The purpose of this patch is to simplify the receive_mergeable().
Separate all the logic of XDP into a function.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 2d1329c..2bb759d 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1308,6 +1308,66 @@ static void *mergeable_xdp_get_buf(struct virtnet_info *vi,
        return page_address(*page) + VIRTIO_XDP_HEADROOM;
 }
 
+static struct sk_buff *receive_mergeable_xdp(struct net_device *dev,
+                                            struct virtnet_info *vi,
+                                            struct receive_queue *rq,
+                                            struct bpf_prog *xdp_prog,
+                                            void *buf,
+                                            void *ctx,
+                                            unsigned int len,
+                                            unsigned int *xdp_xmit,
+                                            struct virtnet_rq_stats *stats)
+{
+       struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
+       int num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
+       struct page *page = virt_to_head_page(buf);
+       int offset = buf - page_address(page);
+       unsigned int xdp_frags_truesz = 0;
+       struct sk_buff *head_skb;
+       unsigned int frame_sz;
+       struct xdp_buff xdp;
+       void *data;
+       u32 act;
+       int err;
+
+       data = mergeable_xdp_get_buf(vi, rq, xdp_prog, ctx, &frame_sz, &num_buf, &page,
+                                    offset, &len, hdr);
+       if (unlikely(!data))
+               goto err_xdp;
+
+       err = virtnet_build_xdp_buff_mrg(dev, vi, rq, &xdp, data, len, frame_sz,
+                                        &num_buf, &xdp_frags_truesz, stats);
+       if (unlikely(err))
+               goto err_xdp;
+
+       act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
+
+       switch (act) {
+       case XDP_PASS:
+               head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
+               if (unlikely(!head_skb))
+                       break;
+               return head_skb;
+
+       case XDP_TX:
+       case XDP_REDIRECT:
+               return NULL;
+
+       default:
+               break;
+       }
+
+       put_xdp_frags(&xdp);
+
+err_xdp:
+       put_page(page);
+       mergeable_buf_free(rq, num_buf, dev, stats);
+
+       stats->xdp_drops++;
+       stats->drops++;
+       return NULL;
+}
+
 static struct sk_buff *receive_mergeable(struct net_device *dev,
                                         struct virtnet_info *vi,
                                         struct receive_queue *rq,
@@ -1327,8 +1387,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
        unsigned int headroom = mergeable_ctx_to_headroom(ctx);
        unsigned int tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
        unsigned int room = SKB_DATA_ALIGN(headroom + tailroom);
-       unsigned int frame_sz;
-       int err;
 
        head_skb = NULL;
        stats->bytes += len - vi->hdr_len;
@@ -1348,41 +1406,10 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
        rcu_read_lock();
        xdp_prog = rcu_dereference(rq->xdp_prog);
        if (xdp_prog) {
-               unsigned int xdp_frags_truesz = 0;
-               struct xdp_buff xdp;
-               void *data;
-               u32 act;
-
-               data = mergeable_xdp_get_buf(vi, rq, xdp_prog, ctx, &frame_sz,
-                                            &num_buf, &page, offset, &len, hdr);
-               if (unlikely(!data))
-                       goto err_xdp;
-
-               err = virtnet_build_xdp_buff_mrg(dev, vi, rq, &xdp, data, len, frame_sz,
-                                                &num_buf, &xdp_frags_truesz, stats);
-               if (unlikely(err))
-                       goto err_xdp;
-
-               act = virtnet_xdp_handler(xdp_prog, &xdp, dev, xdp_xmit, stats);
-
-               switch (act) {
-               case XDP_PASS:
-                       head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
-                       if (unlikely(!head_skb))
-                               goto err_xdp_frags;
-
-                       rcu_read_unlock();
-                       return head_skb;
-               case XDP_TX:
-               case XDP_REDIRECT:
-                       rcu_read_unlock();
-                       goto xdp_xmit;
-               default:
-                       break;
-               }
-err_xdp_frags:
-               put_xdp_frags(&xdp);
-               goto err_xdp;
+               head_skb = receive_mergeable_xdp(dev, vi, rq, xdp_prog, buf, ctx,
+                                                len, xdp_xmit, stats);
+               rcu_read_unlock();
+               return head_skb;
        }
        rcu_read_unlock();
 
@@ -1452,9 +1479,6 @@ skip_xdp:
        ewma_pkt_len_add(&rq->mrg_avg_pkt_len, head_skb->len);
        return head_skb;
 
-err_xdp:
-       rcu_read_unlock();
-       stats->xdp_drops++;
 err_skb:
        put_page(page);
        mergeable_buf_free(rq, num_buf, dev, stats);
@@ -1462,7 +1486,6 @@ err_skb:
 err_buf:
        stats->drops++;
        dev_kfree_skb(head_skb);
-xdp_xmit:
        return NULL;
 }