Re: [PATCH next 1/3] ipvlan: Defer multicast / broadcast processing to a work-queue

Signed-off-by: Mahesh Bandewar <redacted>
---
 drivers/net/ipvlan/ipvlan.h      |   5 ++
 drivers/net/ipvlan/ipvlan_core.c | 134 +++++++++++++++++++++++++--------------
 drivers/net/ipvlan/ipvlan_main.c |   5 ++
 3 files changed, 96 insertions(+), 48 deletions(-)

diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h
index 54549a6223dd..953a97492fab 100644
--- a/drivers/net/ipvlan/ipvlan.h
+++ b/drivers/net/ipvlan/ipvlan.h

@@ -39,6 +39,8 @@
 #define IPVLAN_MAC_FILTER_SIZE	(1 << IPVLAN_MAC_FILTER_BITS)
 #define IPVLAN_MAC_FILTER_MASK	(IPVLAN_MAC_FILTER_SIZE - 1)
 
+#define IPVLAN_QBACKLOG_LIMIT	1000
+
 typedef enum {
 	IPVL_IPV6 = 0,
 	IPVL_ICMPV6,

@@ -93,6 +95,8 @@ struct ipvl_port {
 	struct hlist_head	hlhead[IPVLAN_HASH_SIZE];
 	struct list_head	ipvlans;
 	struct rcu_head		rcu;
+	struct work_struct	wq;
+	struct sk_buff_head	backlog;
 	int			count;
 	u16			mode;
 };

@@ -112,6 +116,7 @@ void ipvlan_set_port_mode(struct ipvl_port *port, u32 nval);
 void ipvlan_init_secret(void);
 unsigned int ipvlan_mac_hash(const unsigned char *addr);
 rx_handler_result_t ipvlan_handle_frame(struct sk_buff **pskb);
+void ipvlan_process_multicast(struct work_struct *work);
 int ipvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev);
 void ipvlan_ht_addr_add(struct ipvl_dev *ipvlan, struct ipvl_addr *addr);
 struct ipvl_addr *ipvlan_find_addr(const struct ipvl_dev *ipvlan,

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index c30b5c300c05..58891666088c 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c

@@ -189,64 +189,85 @@ unsigned int ipvlan_mac_hash(const unsigned char *addr)
 	return hash & IPVLAN_MAC_FILTER_MASK;
 }
 
-static void ipvlan_multicast_frame(struct ipvl_port *port, struct sk_buff *skb,
-				   const struct ipvl_dev *in_dev, bool local)
+void ipvlan_process_multicast(struct work_struct *work)
 {
-	struct ethhdr *eth = eth_hdr(skb);
+	struct ipvl_port *port = container_of(work, struct ipvl_port, wq);
+	struct ethhdr *ethh;
 	struct ipvl_dev *ipvlan;
-	struct sk_buff *nskb;
+	struct sk_buff *skb, *nskb;
+	struct sk_buff_head list;
 	unsigned int len;
 	unsigned int mac_hash;
 	int ret;
+	u8 pkt_type;
+	bool hlocal, dlocal;
 
-	if (skb->protocol == htons(ETH_P_PAUSE))
-		return;
-
-	rcu_read_lock();
-	list_for_each_entry_rcu(ipvlan, &port->ipvlans, pnode) {
-		if (local && (ipvlan == in_dev))
-			continue;
+	__skb_queue_head_init(&list);
 
-		mac_hash = ipvlan_mac_hash(eth->h_dest);
-		if (!test_bit(mac_hash, ipvlan->mac_filters))
-			continue;
+	spin_lock_bh(&port->backlog.lock);
+	skb_queue_splice_tail_init(&port->backlog, &list);
+	spin_unlock_bh(&port->backlog.lock);
 
-		ret = NET_RX_DROP;
-		len = skb->len + ETH_HLEN;
-		nskb = skb_clone(skb, GFP_ATOMIC);
-		if (!nskb)
-			goto mcast_acct;
+	while ((skb = __skb_dequeue(&list)) != NULL) {
+		ethh = eth_hdr(skb);
+		hlocal = ether_addr_equal(ethh->h_source, port->dev->dev_addr);
+		mac_hash = ipvlan_mac_hash(ethh->h_dest);
 
-		if (ether_addr_equal(eth->h_dest, ipvlan->phy_dev->broadcast))
-			nskb->pkt_type = PACKET_BROADCAST;
+		if (ether_addr_equal(ethh->h_dest, port->dev->broadcast))
+			pkt_type = PACKET_BROADCAST;
 		else
-			nskb->pkt_type = PACKET_MULTICAST;
+			pkt_type = PACKET_MULTICAST;
+
+		dlocal = false;
+		rcu_read_lock();
+		list_for_each_entry_rcu(ipvlan, &port->ipvlans, pnode) {
+			if (hlocal && (ipvlan->dev == skb->dev)) {
+				dlocal = true;
+				continue;
+			}
+			if (!test_bit(mac_hash, ipvlan->mac_filters))
+				continue;
+
+			ret = NET_RX_DROP;
+			len = skb->len + ETH_HLEN;
+			nskb = skb_clone(skb, GFP_ATOMIC);
+			if (!nskb)
+				goto acct;
+
+			nskb->pkt_type = pkt_type;
+			nskb->dev = ipvlan->dev;
+			if (hlocal)
+				ret = dev_forward_skb(ipvlan->dev, nskb);
+			else
+				ret = netif_rx(nskb);
+acct:
+			ipvlan_count_rx(ipvlan, len, ret == NET_RX_SUCCESS, true);
+		}
+		rcu_read_unlock();
 
-		nskb->dev = ipvlan->dev;
-		if (local)
-			ret = dev_forward_skb(ipvlan->dev, nskb);
+		if (!dlocal)
+			nskb = skb;
 		else
-			ret = netif_rx(nskb);
-mcast_acct:
-		ipvlan_count_rx(ipvlan, len, ret == NET_RX_SUCCESS, true);
-	}
-	rcu_read_unlock();
+			nskb = skb_clone(skb, GFP_ATOMIC);
 
-	/* Locally generated? ...Forward a copy to the main-device as
-	 * well. On the RX side we'll ignore it (wont give it to any
-	 * of the virtual devices.
-	 */
-	if (local) {
-		nskb = skb_clone(skb, GFP_ATOMIC);
 		if (nskb) {
-			if (ether_addr_equal(eth->h_dest, port->dev->broadcast))
-				nskb->pkt_type = PACKET_BROADCAST;
-			else
-				nskb->pkt_type = PACKET_MULTICAST;
+			/* Always forward a copy to the master device. */
+			if (hlocal) {
+				dev_forward_skb(port->dev, nskb);
+			} else {
+				nskb->dev = port->dev;
+				netif_rx(nskb);
+			}
+		}
 
-			dev_forward_skb(port->dev, nskb);
+		if (dlocal) {
+			/* If the packet originated here, send it out. */
+			skb->dev = port->dev;
+			skb->pkt_type = pkt_type;
+			dev_queue_xmit(skb);
 		}
 	}
+	return;
 }
 
 static int ipvlan_rcv_frame(struct ipvl_addr *addr, struct sk_buff *skb,

@@ -446,6 +467,24 @@ out:
 	return ret;
 }
 
+static void ipvlan_multicast_enqueue(struct ipvl_port *port,
+				     struct sk_buff *skb)
+{
+	if (skb->protocol == htons(ETH_P_PAUSE))
+		return;
+
+	spin_lock(&port->backlog.lock);
+	if (skb_queue_len(&port->backlog) < IPVLAN_QBACKLOG_LIMIT) {
+		__skb_queue_tail(&port->backlog, skb);
+		spin_unlock(&port->backlog.lock);
+	} else {
+		spin_unlock(&port->backlog.lock);
+		atomic_long_inc(&skb->dev->rx_dropped);
+		kfree_skb(skb);
+	}
+	schedule_work(&port->wq);
+}
+
 static int ipvlan_xmit_mode_l3(struct sk_buff *skb, struct net_device *dev)
 {
 	const struct ipvl_dev *ipvlan = netdev_priv(dev);

@@ -493,11 +532,8 @@ static int ipvlan_xmit_mode_l2(struct sk_buff *skb, struct net_device *dev)
 		return dev_forward_skb(ipvlan->phy_dev, skb);
 
 	} else if (is_multicast_ether_addr(eth->h_dest)) {
-		u8 ip_summed = skb->ip_summed;
-
-		skb->ip_summed = CHECKSUM_UNNECESSARY;
-		ipvlan_multicast_frame(ipvlan->port, skb, ipvlan, true);
-		skb->ip_summed = ip_summed;
+		ipvlan_multicast_enqueue(ipvlan->port, skb);
+		return NET_XMIT_SUCCESS;
 	}
 
 	skb->dev = ipvlan->phy_dev;

@@ -581,8 +617,10 @@ static rx_handler_result_t ipvlan_handle_mode_l2(struct sk_buff **pskb,
 	int addr_type;
 
 	if (is_multicast_ether_addr(eth->h_dest)) {
-		if (ipvlan_external_frame(skb, port))
-			ipvlan_multicast_frame(port, skb, NULL, false);
+		if (ipvlan_external_frame(skb, port)) {
+			ipvlan_multicast_enqueue(port, skb);
+			return RX_HANDLER_CONSUMED;
+		}
 	} else {
 		struct ipvl_addr *addr;
 

diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 77b92a0fe557..a16d3017fdc3 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c

@@ -54,6 +54,9 @@ static int ipvlan_port_create(struct net_device *dev)
 	for (idx = 0; idx < IPVLAN_HASH_SIZE; idx++)
 		INIT_HLIST_HEAD(&port->hlhead[idx]);
 
+	skb_queue_head_init(&port->backlog);
+	INIT_WORK(&port->wq, ipvlan_process_multicast);
+
 	err = netdev_rx_handler_register(dev, ipvlan_handle_frame, port);
 	if (err)
 		goto err;

@@ -72,6 +75,8 @@ static void ipvlan_port_destroy(struct net_device *dev)
 
 	dev->priv_flags &= ~IFF_IPVLAN_MASTER;
 	netdev_rx_handler_unregister(dev);
+	cancel_work_sync(&port->wq);
+	__skb_queue_purge(&port->backlog);
 	kfree_rcu(port, rcu);
 }