Re: [PATCH net-next v3 4/4] net: tun: track dropped skb via kfree_skb_reason()

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index aa27268..bf7d8cd 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -1062,13 +1062,16 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct netdev_queue *queue;
 	struct tun_file *tfile;
 	int len = skb->len;
+	enum skb_drop_reason drop_reason;

 
 	rcu_read_lock();
 	tfile = rcu_dereference(tun->tfiles[txq]);
 
 	/* Drop packet if interface is not attached */
-	if (!tfile)
+	if (!tfile) {
+		drop_reason = SKB_DROP_REASON_DEV_READY;
 		goto drop;
+	}
 
 	if (!rcu_dereference(tun->steering_prog))
 		tun_automq_xmit(tun, skb);

@@ -1078,22 +1081,32 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Drop if the filter does not like it.
 	 * This is a noop if the filter is disabled.
 	 * Filter can be enabled only for the TAP devices. */
-	if (!check_filter(&tun->txflt, skb))
+	if (!check_filter(&tun->txflt, skb)) {
+		drop_reason = SKB_DROP_REASON_DEV_FILTER;
 		goto drop;
+	}
 
 	if (tfile->socket.sk->sk_filter &&
-	    sk_filter(tfile->socket.sk, skb))
+	    sk_filter(tfile->socket.sk, skb)) {
+		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
 		goto drop;
+	}
 
 	len = run_ebpf_filter(tun, skb, len);
-	if (len == 0)
+	if (len == 0) {
+		drop_reason = SKB_DROP_REASON_BPF_FILTER;