Subject: Re: [PATCH v3] bonding: don't increase rx_dropped after processing LACPDUs

From: Jiri Bohac <[email-masked]>
Date: Fri, 4 May 2012 15:28:24 +0200

On Fri, May 04, 2012 at 03:04:56PM +0200, Eric Dumazet wrote:
> On Fri, 2012-05-04 at 14:19 +0200, Jiri Bohac wrote:
> >  		if (likely(nskb)) {
> > -			recv_probe(nskb, bond, slave);
> > +			ret = recv_probe(nskb, bond, slave);
> >  			dev_kfree_skb(nskb);
> > +			if (ret == RX_HANDLER_CONSUMED) {
> > +				kfree_skb(skb);
> 
> consume_skb(skb) to not fool drop_monitor/dropwatch ?

Thanks, fixed below:

Since commit 3aba891d, bonding processes LACP frames (802.3ad
mode) with bond_handle_frame(). Currently a copy of the skb is
made and the original is left to be processed by other
rx_handlers and the rest of the network stack by returning
RX_HANDLER_ANOTHER.  As there is no protocol handler for
PKT_TYPE_LACPDU, the frame is dropped and dev->rx_dropped
increased.

Fix this by making bond_handle_frame() return RX_HANDLER_CONSUMED
if bonding has processed the LACP frame.

Signed-off-by: Jiri Bohac <[email-masked]>

diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -2173,9 +2173,10 @@ re_arm:
  * received frames (loopback). Since only the payload is given to this
  * function, it check for loopback.
  */
-static void bond_3ad_rx_indication(struct lacpdu *lacpdu, struct slave *slave, u16 length)
+static int bond_3ad_rx_indication(struct lacpdu *lacpdu, struct slave *slave, u16 length)
 {
 	struct port *port;
+	int ret = RX_HANDLER_ANOTHER;
 
 	if (length >= sizeof(struct lacpdu)) {
 
@@ -2184,11 +2185,12 @@ static void bond_3ad_rx_indication(struct lacpdu *lacpdu, struct slave *slave, u
 		if (!port->slave) {
 			pr_warning("%s: Warning: port of slave %s is uninitialized\n",
 				   slave->dev->name, slave->dev->master->name);
-			return;
+			return ret;
 		}
 
 		switch (lacpdu->subtype) {
 		case AD_TYPE_LACPDU:
+			ret = RX_HANDLER_CONSUMED;
 			pr_debug("Received LACPDU on port %d\n",
 				 port->actor_port_number);
 			/* Protect against concurrent state machines */
@@ -2198,6 +2200,7 @@ static void bond_3ad_rx_indication(struct lacpdu *lacpdu, struct slave *slave, u
 			break;
 
 		case AD_TYPE_MARKER:
+			ret = RX_HANDLER_CONSUMED;
 			// No need to convert fields to Little Endian since we don't use the marker's fields.
 
 			switch (((struct bond_marker *)lacpdu)->tlv_type) {
@@ -2219,6 +2222,7 @@ static void bond_3ad_rx_indication(struct lacpdu *lacpdu, struct slave *slave, u
 			}
 		}
 	}
+	return ret;
 }
 
 /**
@@ -2456,18 +2460,20 @@ out:
 	return NETDEV_TX_OK;
 }
 
-void bond_3ad_lacpdu_recv(struct sk_buff *skb, struct bonding *bond,
+int bond_3ad_lacpdu_recv(struct sk_buff *skb, struct bonding *bond,
 			  struct slave *slave)
 {
+	int ret = RX_HANDLER_ANOTHER;
 	if (skb->protocol != PKT_TYPE_LACPDU)
-		return;
+		return ret;
 
 	if (!pskb_may_pull(skb, sizeof(struct lacpdu)))
-		return;
+		return ret;
 
 	read_lock(&bond->lock);
-	bond_3ad_rx_indication((struct lacpdu *) skb->data, slave, skb->len);
+	ret = bond_3ad_rx_indication((struct lacpdu *) skb->data, slave, skb->len);
 	read_unlock(&bond->lock);
+	return ret;
 }
 
 /*
diff --git a/drivers/net/bonding/bond_3ad.h b/drivers/net/bonding/bond_3ad.h
index 235b2cc..5ee7e3c 100644
--- a/drivers/net/bonding/bond_3ad.h
+++ b/drivers/net/bonding/bond_3ad.h
@@ -274,7 +274,7 @@ void bond_3ad_adapter_duplex_changed(struct slave *slave);
 void bond_3ad_handle_link_change(struct slave *slave, char link);
 int  bond_3ad_get_active_agg_info(struct bonding *bond, struct ad_info *ad_info);
 int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev);
-void bond_3ad_lacpdu_recv(struct sk_buff *skb, struct bonding *bond,
+int bond_3ad_lacpdu_recv(struct sk_buff *skb, struct bonding *bond,
 			  struct slave *slave);
 int bond_3ad_set_carrier(struct bonding *bond);
 void bond_3ad_update_lacp_rate(struct bonding *bond);
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 62d2409..0a0f4a6 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1444,8 +1444,9 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
 	struct sk_buff *skb = *pskb;
 	struct slave *slave;
 	struct bonding *bond;
-	void (*recv_probe)(struct sk_buff *, struct bonding *,
+	int (*recv_probe)(struct sk_buff *, struct bonding *,
 				struct slave *);
+	int ret = RX_HANDLER_ANOTHER;
 
 	skb = skb_share_check(skb, GFP_ATOMIC);
 	if (unlikely(!skb))
@@ -1464,8 +1465,12 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
 		struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
 
 		if (likely(nskb)) {
-			recv_probe(nskb, bond, slave);
+			ret = recv_probe(nskb, bond, slave);
 			dev_kfree_skb(nskb);
+			if (ret == RX_HANDLER_CONSUMED) {
+				consume_skb(skb);
+				return ret;
+			}
 		}
 	}
 
@@ -1487,7 +1492,7 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
 		memcpy(eth_hdr(skb)->h_dest, bond->dev->dev_addr, ETH_ALEN);
 	}
 
-	return RX_HANDLER_ANOTHER;
+	return ret;
 }
 
 /* enslave device <slave> to bond device <master> */
@@ -2723,7 +2728,7 @@ static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32
 	}
 }
 
-static void bond_arp_rcv(struct sk_buff *skb, struct bonding *bond,
+static int bond_arp_rcv(struct sk_buff *skb, struct bonding *bond,
 			 struct slave *slave)
 {
 	struct arphdr *arp;
@@ -2731,7 +2736,7 @@ static void bond_arp_rcv(struct sk_buff *skb, struct bonding *bond,
 	__be32 sip, tip;
 
 	if (skb->protocol != __cpu_to_be16(ETH_P_ARP))
-		return;
+		return RX_HANDLER_ANOTHER;
 
 	read_lock(&bond->lock);
 
@@ -2776,6 +2781,7 @@ static void bond_arp_rcv(struct sk_buff *skb, struct bonding *bond,
 
 out_unlock:
 	read_unlock(&bond->lock);
+	return RX_HANDLER_ANOTHER;
 }
 
 /*
-- 
Jiri Bohac <[email-masked]>
SUSE Labs, SUSE CZ

-- 
Jiri Bohac <[email-masked]>
SUSE Labs, SUSE CZ