net: orphan frags on stand-alone ptype in dev_queue_xmit_nit

Zerocopy skbs frags are copied when the skb is looped to a local sock.
Commit 1080e512 ("net: orphan frags on receive") introduced calls
to skb_orphan_frags to deliver_skb and __netif_receive_skb for this.

With msg_zerocopy, these skbs can also exist in the tx path and thus
loop from dev_queue_xmit_nit. This already calls deliver_skb in its
loop. But it does not orphan before a separate pt_prev->func().

Add the missing skb_orphan_frags_rx.

Changes
  v1->v2: handle skb_orphan_frags_rx failure

Fixes: 1f8b977a ("sock: enable MSG_ZEROCOPY")
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -1948,8 +1948,12 @@ void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
 		goto again;
 	}
 out_unlock:
-	if (pt_prev)
-		pt_prev->func(skb2, skb->dev, pt_prev, skb->dev);
+	if (pt_prev) {
+		if (!skb_orphan_frags_rx(skb2, GFP_ATOMIC))
+			pt_prev->func(skb2, skb->dev, pt_prev, skb->dev);
+		else
+			kfree_skb(skb2);
+	}
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(dev_queue_xmit_nit);