Merge branch 'dev-stats-virtio-l2tp_eth'

Eric Dumazet says:

====================
net: use DEV_STATS_xxx() helpers in virtio_net and l2tp_eth

Inspired by another (minor) KCSAN syzbot report.
Both virtio_net and l2tp_eth can use DEV_STATS_xxx() helpers.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macsec.c

@@ -3655,9 +3655,9 @@ static void macsec_get_stats64(struct net_device *dev,
 
 	dev_fetch_sw_netstats(s, dev->tstats);
 
-	s->rx_dropped = atomic_long_read(&dev->stats.__rx_dropped);
-	s->tx_dropped = atomic_long_read(&dev->stats.__tx_dropped);
-	s->rx_errors = atomic_long_read(&dev->stats.__rx_errors);
+	s->rx_dropped = DEV_STATS_READ(dev, rx_dropped);
+	s->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
+	s->rx_errors = DEV_STATS_READ(dev, rx_errors);
 }
 
 static int macsec_get_iflink(const struct net_device *dev)

drivers/net/virtio_net.c

@@ -1258,7 +1258,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
 	if (unlikely(len > GOOD_PACKET_LEN)) {
 		pr_debug("%s: rx error: len %u exceeds max size %d\n",
 			 dev->name, len, GOOD_PACKET_LEN);
-		dev->stats.rx_length_errors++;
+		DEV_STATS_INC(dev, rx_length_errors);
 		goto err;
 	}
 
@@ -1323,7 +1323,7 @@ static void mergeable_buf_free(struct receive_queue *rq, int num_buf,
 		if (unlikely(!buf)) {
 			pr_debug("%s: rx error: %d buffers missing\n",
 				 dev->name, num_buf);
-			dev->stats.rx_length_errors++;
+			DEV_STATS_INC(dev, rx_length_errors);
 			break;
 		}
 		stats->bytes += len;
@@ -1432,7 +1432,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
 			pr_debug("%s: rx error: %d buffers out of %d missing\n",
 				 dev->name, *num_buf,
 				 virtio16_to_cpu(vi->vdev, hdr->num_buffers));
-			dev->stats.rx_length_errors++;
+			DEV_STATS_INC(dev, rx_length_errors);
 			goto err;
 		}
 
@@ -1451,7 +1451,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
 			put_page(page);
 			pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
 				 dev->name, len, (unsigned long)(truesize - room));
-			dev->stats.rx_length_errors++;
+			DEV_STATS_INC(dev, rx_length_errors);
 			goto err;
 		}
 
@@ -1630,7 +1630,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 	if (unlikely(len > truesize - room)) {
 		pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
 			 dev->name, len, (unsigned long)(truesize - room));
-		dev->stats.rx_length_errors++;
+		DEV_STATS_INC(dev, rx_length_errors);
 		goto err_skb;
 	}
 
@@ -1662,7 +1662,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 				 dev->name, num_buf,
 				 virtio16_to_cpu(vi->vdev,
 						 hdr->num_buffers));
-			dev->stats.rx_length_errors++;
+			DEV_STATS_INC(dev, rx_length_errors);
 			goto err_buf;
 		}
 
@@ -1676,7 +1676,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 		if (unlikely(len > truesize - room)) {
 			pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
 				 dev->name, len, (unsigned long)(truesize - room));
-			dev->stats.rx_length_errors++;
+			DEV_STATS_INC(dev, rx_length_errors);
 			goto err_skb;
 		}
 
@@ -1763,7 +1763,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 
 	if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
 		pr_debug("%s: short packet %i\n", dev->name, len);
-		dev->stats.rx_length_errors++;
+		DEV_STATS_INC(dev, rx_length_errors);
 		virtnet_rq_free_unused_buf(rq->vq, buf);
 		return;
 	}
@@ -1803,7 +1803,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 	return;
 
 frame_err:
-	dev->stats.rx_frame_errors++;
+	DEV_STATS_INC(dev, rx_frame_errors);
 	dev_kfree_skb(skb);
 }
 
@@ -2349,12 +2349,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	/* This should not happen! */
 	if (unlikely(err)) {
-		dev->stats.tx_fifo_errors++;
+		DEV_STATS_INC(dev, tx_fifo_errors);
 		if (net_ratelimit())
 			dev_warn(&dev->dev,
 				 "Unexpected TXQ (%d) queue failure: %d\n",
 				 qnum, err);
-		dev->stats.tx_dropped++;
+		DEV_STATS_INC(dev, tx_dropped);
 		dev_kfree_skb_any(skb);
 		return NETDEV_TX_OK;
 	}
@@ -2573,10 +2573,10 @@ static void virtnet_stats(struct net_device *dev,
 		tot->tx_errors  += terrors;
 	}
 
-	tot->tx_dropped = dev->stats.tx_dropped;
-	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
-	tot->rx_length_errors = dev->stats.rx_length_errors;
-	tot->rx_frame_errors = dev->stats.rx_frame_errors;
+	tot->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
+	tot->tx_fifo_errors = DEV_STATS_READ(dev, tx_fifo_errors);
+	tot->rx_length_errors = DEV_STATS_READ(dev, rx_length_errors);
+	tot->rx_frame_errors = DEV_STATS_READ(dev, rx_frame_errors);
 }
 
 static void virtnet_ack_link_announce(struct virtnet_info *vi)

include/linux/netdevice.h

@@ -5236,5 +5236,6 @@ extern struct net_device *blackhole_netdev;
 #define DEV_STATS_INC(DEV, FIELD) atomic_long_inc(&(DEV)->stats.__##FIELD)
 #define DEV_STATS_ADD(DEV, FIELD, VAL) 	\
 		atomic_long_add((VAL), &(DEV)->stats.__##FIELD)
+#define DEV_STATS_READ(DEV, FIELD) atomic_long_read(&(DEV)->stats.__##FIELD)
 
 #endif	/* _LINUX_NETDEVICE_H */

net/l2tp/l2tp_eth.c

@@ -37,12 +37,6 @@
 /* via netdev_priv() */
 struct l2tp_eth {
 	struct l2tp_session	*session;
-	atomic_long_t		tx_bytes;
-	atomic_long_t		tx_packets;
-	atomic_long_t		tx_dropped;
-	atomic_long_t		rx_bytes;
-	atomic_long_t		rx_packets;
-	atomic_long_t		rx_errors;
 };
 
 /* via l2tp_session_priv() */
@@ -79,10 +73,10 @@ static netdev_tx_t l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev
 	int ret = l2tp_xmit_skb(session, skb);
 
 	if (likely(ret == NET_XMIT_SUCCESS)) {
-		atomic_long_add(len, &priv->tx_bytes);
-		atomic_long_inc(&priv->tx_packets);
+		DEV_STATS_ADD(dev, tx_bytes, len);
+		DEV_STATS_INC(dev, tx_packets);
 	} else {
-		atomic_long_inc(&priv->tx_dropped);
+		DEV_STATS_INC(dev, tx_dropped);
 	}
 	return NETDEV_TX_OK;
 }
@@ -90,14 +84,12 @@ static netdev_tx_t l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev
 static void l2tp_eth_get_stats64(struct net_device *dev,
 				 struct rtnl_link_stats64 *stats)
 {
-	struct l2tp_eth *priv = netdev_priv(dev);
-
-	stats->tx_bytes   = (unsigned long)atomic_long_read(&priv->tx_bytes);
-	stats->tx_packets = (unsigned long)atomic_long_read(&priv->tx_packets);
-	stats->tx_dropped = (unsigned long)atomic_long_read(&priv->tx_dropped);
-	stats->rx_bytes   = (unsigned long)atomic_long_read(&priv->rx_bytes);
-	stats->rx_packets = (unsigned long)atomic_long_read(&priv->rx_packets);
-	stats->rx_errors  = (unsigned long)atomic_long_read(&priv->rx_errors);
+	stats->tx_bytes   = DEV_STATS_READ(dev, tx_bytes);
+	stats->tx_packets = DEV_STATS_READ(dev, tx_packets);
+	stats->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
+	stats->rx_bytes   = DEV_STATS_READ(dev, rx_bytes);
+	stats->rx_packets = DEV_STATS_READ(dev, rx_packets);
+	stats->rx_errors  = DEV_STATS_READ(dev, rx_errors);
 }
 
 static const struct net_device_ops l2tp_eth_netdev_ops = {
@@ -126,7 +118,6 @@ static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb,
 {
 	struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
 	struct net_device *dev;
-	struct l2tp_eth *priv;
 
 	if (!pskb_may_pull(skb, ETH_HLEN))
 		goto error;
@@ -144,12 +135,11 @@ static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb,
 	if (!dev)
 		goto error_rcu;
 
-	priv = netdev_priv(dev);
 	if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
-		atomic_long_inc(&priv->rx_packets);
-		atomic_long_add(data_len, &priv->rx_bytes);
+		DEV_STATS_INC(dev, rx_packets);
+		DEV_STATS_ADD(dev, rx_bytes, data_len);
 	} else {
-		atomic_long_inc(&priv->rx_errors);
+		DEV_STATS_INC(dev, rx_errors);
 	}
 	rcu_read_unlock();