1 files changed, 67 insertions, 25 deletions

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 3bc5ca40c9fb..7efc753e4d9d 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -522,10 +522,10 @@ static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
 	if (!clone)
 		return;
 
-	DSA_SKB_CB(skb)->clone = clone;
-
-	if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type))
+	if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type)) {
+		DSA_SKB_CB(skb)->clone = clone;
 		return;
+	}
 
 	kfree_skb(clone);
 }
@@ -548,17 +548,36 @@ netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(dsa_enqueue_skb);
 
+static int dsa_realloc_skb(struct sk_buff *skb, struct net_device *dev)
+{
+	int needed_headroom = dev->needed_headroom;
+	int needed_tailroom = dev->needed_tailroom;
+
+	/* For tail taggers, we need to pad short frames ourselves, to ensure
+	 * that the tail tag does not fail at its role of being at the end of
+	 * the packet, once the master interface pads the frame. Account for
+	 * that pad length here, and pad later.
+	 */
+	if (unlikely(needed_tailroom && skb->len < ETH_ZLEN))
+		needed_tailroom += ETH_ZLEN - skb->len;
+	/* skb_headroom() returns unsigned int... */
+	needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0);
+	needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0);
+
+	if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb)))
+		/* No reallocation needed, yay! */
+		return 0;
+
+	return pskb_expand_head(skb, needed_headroom, needed_tailroom,
+				GFP_ATOMIC);
+}
+
 static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
-	struct pcpu_sw_netstats *s;
 	struct sk_buff *nskb;
 
-	s = this_cpu_ptr(p->stats64);
-	u64_stats_update_begin(&s->syncp);
-	s->tx_packets++;
-	s->tx_bytes += skb->len;
-	u64_stats_update_end(&s->syncp);
+	dev_sw_netstats_tx_add(dev, 1, skb->len);
 
 	DSA_SKB_CB(skb)->clone = NULL;
 
@@ -567,6 +586,17 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 	 */
 	dsa_skb_tx_timestamp(p, skb);
 
+	if (dsa_realloc_skb(skb, dev)) {
+		dev_kfree_skb_any(skb);
+		return NETDEV_TX_OK;
+	}
+
+	/* needed_tailroom should still be 'warm' in the cache line from
+	 * dsa_realloc_skb(), which has also ensured that padding is safe.
+	 */
+	if (dev->needed_tailroom)
+		eth_skb_pad(skb);
+
 	/* Transmit function may have to reallocate the original SKB,
 	 * in which case it must have freed it. Only free it here on error.
 	 */
@@ -679,7 +709,6 @@ static void dsa_slave_get_ethtool_stats(struct net_device *dev,
 					uint64_t *data)
 {
 	struct dsa_port *dp = dsa_slave_to_port(dev);
-	struct dsa_slave_priv *p = netdev_priv(dev);
 	struct dsa_switch *ds = dp->ds;
 	struct pcpu_sw_netstats *s;
 	unsigned int start;
@@ -688,7 +717,7 @@ static void dsa_slave_get_ethtool_stats(struct net_device *dev,
 	for_each_possible_cpu(i) {
 		u64 tx_packets, tx_bytes, rx_packets, rx_bytes;
 
-		s = per_cpu_ptr(p->stats64, i);
+		s = per_cpu_ptr(dev->tstats, i);
 		do {
 			start = u64_stats_fetch_begin_irq(&s->syncp);
 			tx_packets = s->tx_packets;
@@ -1217,15 +1246,6 @@ static int dsa_slave_setup_tc(struct net_device *dev, enum tc_setup_type type,
 	return ds->ops->port_setup_tc(ds, dp->index, type, type_data);
 }
 
-static void dsa_slave_get_stats64(struct net_device *dev,
-				  struct rtnl_link_stats64 *stats)
-{
-	struct dsa_slave_priv *p = netdev_priv(dev);
-
-	netdev_stats_to_stats64(stats, &dev->stats);
-	dev_fetch_sw_netstats(stats, p->stats64);
-}
-
 static int dsa_slave_get_rxnfc(struct net_device *dev,
 			       struct ethtool_rxnfc *nfc, u32 *rule_locs)
 {
@@ -1601,7 +1621,7 @@ static const struct net_device_ops dsa_slave_netdev_ops = {
 #endif
 	.ndo_get_phys_port_name	= dsa_slave_get_phys_port_name,
 	.ndo_setup_tc		= dsa_slave_setup_tc,
-	.ndo_get_stats64	= dsa_slave_get_stats64,
+	.ndo_get_stats64	= dev_get_tstats64,
 	.ndo_get_port_parent_id	= dsa_slave_get_port_parent_id,
 	.ndo_vlan_rx_add_vid	= dsa_slave_vlan_rx_add_vid,
 	.ndo_vlan_rx_kill_vid	= dsa_slave_vlan_rx_kill_vid,
@@ -1791,6 +1811,16 @@ int dsa_slave_create(struct dsa_port *port)
 	slave_dev->netdev_ops = &dsa_slave_netdev_ops;
 	if (ds->ops->port_max_mtu)
 		slave_dev->max_mtu = ds->ops->port_max_mtu(ds, port->index);
+	if (cpu_dp->tag_ops->tail_tag)
+		slave_dev->needed_tailroom = cpu_dp->tag_ops->overhead;
+	else
+		slave_dev->needed_headroom = cpu_dp->tag_ops->overhead;
+	/* Try to save one extra realloc later in the TX path (in the master)
+	 * by also inheriting the master's needed headroom and tailroom.
+	 * The 8021q driver also does this.
+	 */
+	slave_dev->needed_headroom += master->needed_headroom;
+	slave_dev->needed_tailroom += master->needed_tailroom;
 	SET_NETDEV_DEVTYPE(slave_dev, &dsa_type);
 
 	netdev_for_each_tx_queue(slave_dev, dsa_slave_set_lockdep_class_one,
@@ -1801,8 +1831,8 @@ int dsa_slave_create(struct dsa_port *port)
 	slave_dev->vlan_features = master->vlan_features;
 
 	p = netdev_priv(slave_dev);
-	p->stats64 = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!p->stats64) {
+	slave_dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+	if (!slave_dev->tstats) {
 		free_netdev(slave_dev);
 		return -ENOMEM;
 	}
@@ -1864,7 +1894,7 @@ out_phy:
 out_gcells:
 	gro_cells_destroy(&p->gcells);
 out_free:
-	free_percpu(p->stats64);
+	free_percpu(slave_dev->tstats);
 	free_netdev(slave_dev);
 	port->slave = NULL;
 	return ret;
@@ -1886,7 +1916,7 @@ void dsa_slave_destroy(struct net_device *slave_dev)
 	dsa_slave_notify(slave_dev, DSA_PORT_UNREGISTER);
 	phylink_destroy(dp->pl);
 	gro_cells_destroy(&p->gcells);
-	free_percpu(p->stats64);
+	free_percpu(slave_dev->tstats);
 	free_netdev(slave_dev);
 }
 
@@ -1987,10 +2017,22 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
 	switch (event) {
 	case NETDEV_PRECHANGEUPPER: {
 		struct netdev_notifier_changeupper_info *info = ptr;
+		struct dsa_switch *ds;
+		struct dsa_port *dp;
+		int err;
 
 		if (!dsa_slave_dev_check(dev))
 			return dsa_prevent_bridging_8021q_upper(dev, ptr);
 
+		dp = dsa_slave_to_port(dev);
+		ds = dp->ds;
+
+		if (ds->ops->port_prechangeupper) {
+			err = ds->ops->port_prechangeupper(ds, dp->index, info);
+			if (err)
+				return notifier_from_errno(err);
+		}
+
 		if (is_vlan_dev(info->upper_dev))
 			return dsa_slave_check_8021q_upper(dev, ptr);
 		break;