virtio_net: separate the logic of freeing xdp shinfo

This patch introduce a new function that releases the
xdp shinfo. The subsequent patch will reuse this 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>

drivers/net/virtio_net.c

@@ -789,6 +789,21 @@ static int virtnet_xdp_xmit(struct net_device *dev,
 	return ret;
 }
 
+static void put_xdp_frags(struct xdp_buff *xdp)
+{
+	struct skb_shared_info *shinfo;
+	struct page *xdp_page;
+	int i;
+
+	if (xdp_buff_has_frags(xdp)) {
+		shinfo = xdp_get_shared_info_from_buff(xdp);
+		for (i = 0; i < shinfo->nr_frags; i++) {
+			xdp_page = skb_frag_page(&shinfo->frags[i]);
+			put_page(xdp_page);
+		}
+	}
+}
+
 static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct xdp_buff *xdp,
 			       struct net_device *dev,
 			       unsigned int *xdp_xmit,
@@ -1308,12 +1323,9 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 	xdp_prog = rcu_dereference(rq->xdp_prog);
 	if (xdp_prog) {
 		unsigned int xdp_frags_truesz = 0;
-		struct skb_shared_info *shinfo;
-		struct page *xdp_page;
 		struct xdp_buff xdp;
 		void *data;
 		u32 act;
-		int i;
 
 		data = mergeable_xdp_get_buf(vi, rq, xdp_prog, ctx, &frame_sz,
 					     &num_buf, &page, offset, &len, hdr);
@@ -1343,14 +1355,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 			break;
 		}
 err_xdp_frags:
-		if (xdp_buff_has_frags(&xdp)) {
-			shinfo = xdp_get_shared_info_from_buff(&xdp);
-			for (i = 0; i < shinfo->nr_frags; i++) {
-				xdp_page = skb_frag_page(&shinfo->frags[i]);
-				put_page(xdp_page);
-			}
-		}
-
+		put_xdp_frags(&xdp);
 		goto err_xdp;
 	}
 	rcu_read_unlock();