Merge branch 'virtio_net-xdp-bugs'

Xuan Zhuo says:

====================
virtio_net: fix two bugs related to XDP

This patch set fixes two bugs related to XDP.
These two patch is not associated.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/virtio_net.c

@@ -446,7 +446,8 @@ static unsigned int mergeable_ctx_to_truesize(void *mrg_ctx)
 static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 				   struct receive_queue *rq,
 				   struct page *page, unsigned int offset,
-				   unsigned int len, unsigned int truesize)
+				   unsigned int len, unsigned int truesize,
+				   unsigned int headroom)
 {
 	struct sk_buff *skb;
 	struct virtio_net_hdr_mrg_rxbuf *hdr;
@@ -464,11 +465,11 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
 	else
 		hdr_padded_len = sizeof(struct padded_vnet_hdr);
 
-	buf = p;
+	buf = p - headroom;
 	len -= hdr_len;
 	offset += hdr_padded_len;
 	p += hdr_padded_len;
-	tailroom = truesize - hdr_padded_len - len;
+	tailroom = truesize - headroom  - hdr_padded_len - len;
 
 	shinfo_size = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
@@ -1009,7 +1010,7 @@ static struct sk_buff *receive_big(struct net_device *dev,
 {
 	struct page *page = buf;
 	struct sk_buff *skb =
-		page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
+		page_to_skb(vi, rq, page, 0, len, PAGE_SIZE, 0);
 
 	stats->bytes += len - vi->hdr_len;
 	if (unlikely(!skb))
@@ -1272,9 +1273,12 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 
 		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;
+
 			if (unlikely(xdp_page != page))
 				put_page(page);
-			head_skb = build_skb_from_xdp_buff(dev, vi, &xdp, xdp_frags_truesz);
 			rcu_read_unlock();
 			return head_skb;
 		case XDP_TX:
@@ -1332,7 +1336,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 	rcu_read_unlock();
 
 skip_xdp:
-	head_skb = page_to_skb(vi, rq, page, offset, len, truesize);
+	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, headroom);
 	curr_skb = head_skb;
 
 	if (unlikely(!curr_skb))