vlan: adopt u64_stats_t

As explained in commit 316580b6 ("u64_stats: provide u64_stats_t type")
we should use u64_stats_t and related accessors to avoid load/store tearing.

Add READ_ONCE() when reading rx_errors & tx_dropped.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/macvlan.c

@@ -575,8 +575,8 @@ static netdev_tx_t macvlan_start_xmit(struct sk_buff *skb,
 
 		pcpu_stats = this_cpu_ptr(vlan->pcpu_stats);
 		u64_stats_update_begin(&pcpu_stats->syncp);
-		pcpu_stats->tx_packets++;
-		pcpu_stats->tx_bytes += len;
+		u64_stats_inc(&pcpu_stats->tx_packets);
+		u64_stats_add(&pcpu_stats->tx_bytes, len);
 		u64_stats_update_end(&pcpu_stats->syncp);
 	} else {
 		this_cpu_inc(vlan->pcpu_stats->tx_dropped);
@@ -949,11 +949,11 @@ static void macvlan_dev_get_stats64(struct net_device *dev,
 			p = per_cpu_ptr(vlan->pcpu_stats, i);
 			do {
 				start = u64_stats_fetch_begin_irq(&p->syncp);
-				rx_packets	= p->rx_packets;
-				rx_bytes	= p->rx_bytes;
-				rx_multicast	= p->rx_multicast;
-				tx_packets	= p->tx_packets;
-				tx_bytes	= p->tx_bytes;
+				rx_packets	= u64_stats_read(&p->rx_packets);
+				rx_bytes	= u64_stats_read(&p->rx_bytes);
+				rx_multicast	= u64_stats_read(&p->rx_multicast);
+				tx_packets	= u64_stats_read(&p->tx_packets);
+				tx_bytes	= u64_stats_read(&p->tx_bytes);
 			} while (u64_stats_fetch_retry_irq(&p->syncp, start));
 
 			stats->rx_packets	+= rx_packets;
@@ -964,8 +964,8 @@ static void macvlan_dev_get_stats64(struct net_device *dev,
 			/* rx_errors & tx_dropped are u32, updated
 			 * without syncp protection.
 			 */
-			rx_errors	+= p->rx_errors;
-			tx_dropped	+= p->tx_dropped;
+			rx_errors	+= READ_ONCE(p->rx_errors);
+			tx_dropped	+= READ_ONCE(p->tx_dropped);
 		}
 		stats->rx_errors	= rx_errors;
 		stats->rx_dropped	= rx_errors;

include/linux/if_macvlan.h

@@ -46,10 +46,10 @@ static inline void macvlan_count_rx(const struct macvlan_dev *vlan,
 
 		pcpu_stats = get_cpu_ptr(vlan->pcpu_stats);
 		u64_stats_update_begin(&pcpu_stats->syncp);
-		pcpu_stats->rx_packets++;
-		pcpu_stats->rx_bytes += len;
+		u64_stats_inc(&pcpu_stats->rx_packets);
+		u64_stats_add(&pcpu_stats->rx_bytes, len);
 		if (multicast)
-			pcpu_stats->rx_multicast++;
+			u64_stats_inc(&pcpu_stats->rx_multicast);
 		u64_stats_update_end(&pcpu_stats->syncp);
 		put_cpu_ptr(vlan->pcpu_stats);
 	} else {

include/linux/if_vlan.h

@@ -118,11 +118,11 @@ static inline void vlan_drop_rx_stag_filter_info(struct net_device *dev)
  *	@tx_dropped: number of tx drops
  */
 struct vlan_pcpu_stats {
-	u64			rx_packets;
-	u64			rx_bytes;
-	u64			rx_multicast;
-	u64			tx_packets;
-	u64			tx_bytes;
+	u64_stats_t		rx_packets;
+	u64_stats_t		rx_bytes;
+	u64_stats_t		rx_multicast;
+	u64_stats_t		tx_packets;
+	u64_stats_t		tx_bytes;
 	struct u64_stats_sync	syncp;
 	u32			rx_errors;
 	u32			tx_dropped;

net/8021q/vlan_core.c

@@ -63,10 +63,10 @@ bool vlan_do_receive(struct sk_buff **skbp)
 	rx_stats = this_cpu_ptr(vlan_dev_priv(vlan_dev)->vlan_pcpu_stats);
 
 	u64_stats_update_begin(&rx_stats->syncp);
-	rx_stats->rx_packets++;
-	rx_stats->rx_bytes += skb->len;
+	u64_stats_inc(&rx_stats->rx_packets);
+	u64_stats_add(&rx_stats->rx_bytes, skb->len);
 	if (skb->pkt_type == PACKET_MULTICAST)
-		rx_stats->rx_multicast++;
+		u64_stats_inc(&rx_stats->rx_multicast);
 	u64_stats_update_end(&rx_stats->syncp);
 
 	return true;

net/8021q/vlan_dev.c

@@ -128,8 +128,8 @@ static netdev_tx_t vlan_dev_hard_start_xmit(struct sk_buff *skb,
 
 		stats = this_cpu_ptr(vlan->vlan_pcpu_stats);
 		u64_stats_update_begin(&stats->syncp);
-		stats->tx_packets++;
-		stats->tx_bytes += len;
+		u64_stats_inc(&stats->tx_packets);
+		u64_stats_add(&stats->tx_bytes, len);
 		u64_stats_update_end(&stats->syncp);
 	} else {
 		this_cpu_inc(vlan->vlan_pcpu_stats->tx_dropped);
@@ -713,11 +713,11 @@ static void vlan_dev_get_stats64(struct net_device *dev,
 		p = per_cpu_ptr(vlan_dev_priv(dev)->vlan_pcpu_stats, i);
 		do {
 			start = u64_stats_fetch_begin_irq(&p->syncp);
-			rxpackets	= p->rx_packets;
-			rxbytes		= p->rx_bytes;
-			rxmulticast	= p->rx_multicast;
-			txpackets	= p->tx_packets;
-			txbytes		= p->tx_bytes;
+			rxpackets	= u64_stats_read(&p->rx_packets);
+			rxbytes		= u64_stats_read(&p->rx_bytes);
+			rxmulticast	= u64_stats_read(&p->rx_multicast);
+			txpackets	= u64_stats_read(&p->tx_packets);
+			txbytes		= u64_stats_read(&p->tx_bytes);
 		} while (u64_stats_fetch_retry_irq(&p->syncp, start));
 
 		stats->rx_packets	+= rxpackets;
@@ -726,8 +726,8 @@ static void vlan_dev_get_stats64(struct net_device *dev,
 		stats->tx_packets	+= txpackets;
 		stats->tx_bytes		+= txbytes;
 		/* rx_errors & tx_dropped are u32 */
-		rx_errors	+= p->rx_errors;
-		tx_dropped	+= p->tx_dropped;
+		rx_errors	+= READ_ONCE(p->rx_errors);
+		tx_dropped	+= READ_ONCE(p->tx_dropped);
 	}
 	stats->rx_errors  = rx_errors;
 	stats->tx_dropped = tx_dropped;