bonding: Rework / fix multiple gratuitous ARP support

	Support for sending multiple gratuitous ARPs during failovers
was added by commit:

commit 7893b24
Author: Moni Shoua <[email protected]>
Date:   Sat May 17 21:10:12 2008 -0700

    bonding: Send more than one gratuitous ARP when slave takes over

	This change modifies that support to remove duplicated code,
add support for ARP monitor (the original only supported miimon), clear
the grat ARP counter in bond_close (lest a later "ifconfig up" immediately
start spewing ARPs), and add documentation for the module parameter.

	Also updated driver version to 3.3.0.

Signed-off-by: Jay Vosburgh <[email protected]>
Signed-off-by: Jeff Garzik <[email protected]>

Author: Jay Vosburgh

Documentation/networking/bonding.txt

@@ -539,6 +539,17 @@ mode
 		swapped with the new curr_active_slave that was
 		chosen.
 
+num_grat_arp
+
+	Specifies the number of gratuitous ARPs to be issued after a
+	failover event.  One gratuitous ARP is issued immediately after
+	the failover, subsequent ARPs are sent at a rate of one per link
+	monitor interval (arp_interval or miimon, whichever is active).
+
+	The valid range is 0 - 255; the default value is 1.  This option
+	affects only the active-backup mode.  This option was added for
+	bonding version 3.3.0.
+
 primary
 
 	A string (eth0, eth2, etc) specifying which slave is the

drivers/net/bonding/bond_main.c

@@ -1195,14 +1195,7 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
 						      old_active);
 
 			bond->send_grat_arp = bond->params.num_grat_arp;
-			if (!test_bit(__LINK_STATE_LINKWATCH_PENDING,
-					&bond->curr_active_slave->dev->state)) {
-				bond_send_gratuitous_arp(bond);
-				bond->send_grat_arp--;
-			} else {
-				dprintk("delaying gratuitous arp on %s\n",
-					bond->curr_active_slave->dev->name);
-			}
+			bond_send_gratuitous_arp(bond);
 
 			write_unlock_bh(&bond->curr_slave_lock);
 			read_unlock(&bond->lock);
@@ -2241,17 +2234,6 @@ static int __bond_mii_monitor(struct bonding *bond, int have_locks)
 	 * program could monitor the link itself if needed.
 	 */
 
-	if (bond->send_grat_arp) {
-		if (bond->curr_active_slave && test_bit(__LINK_STATE_LINKWATCH_PENDING,
-				&bond->curr_active_slave->dev->state))
-			dprintk("Needs to send gratuitous arp but not yet\n");
-		else {
-			dprintk("sending delayed gratuitous arp on on %s\n",
-				bond->curr_active_slave->dev->name);
-			bond_send_gratuitous_arp(bond);
-			bond->send_grat_arp--;
-		}
-	}
 	read_lock(&bond->curr_slave_lock);
 	oldcurrent = bond->curr_active_slave;
 	read_unlock(&bond->curr_slave_lock);
@@ -2492,6 +2474,13 @@ void bond_mii_monitor(struct work_struct *work)
 		read_unlock(&bond->lock);
 		return;
 	}
+
+	if (bond->send_grat_arp) {
+		read_lock(&bond->curr_slave_lock);
+		bond_send_gratuitous_arp(bond);
+		read_unlock(&bond->curr_slave_lock);
+	}
+
 	if (__bond_mii_monitor(bond, 0)) {
 		read_unlock(&bond->lock);
 		rtnl_lock();
@@ -2657,6 +2646,8 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 /*
  * Kick out a gratuitous ARP for an IP on the bonding master plus one
  * for each VLAN above us.
+ *
+ * Caller must hold curr_slave_lock for read or better
  */
 static void bond_send_gratuitous_arp(struct bonding *bond)
 {
@@ -2666,9 +2657,13 @@ static void bond_send_gratuitous_arp(struct bonding *bond)
 
 	dprintk("bond_send_grat_arp: bond %s slave %s\n", bond->dev->name,
 				slave ? slave->dev->name : "NULL");
-	if (!slave)
+
+	if (!slave || !bond->send_grat_arp ||
+	    test_bit(__LINK_STATE_LINKWATCH_PENDING, &slave->dev->state))
 		return;
 
+	bond->send_grat_arp--;
+
 	if (bond->master_ip) {
 		bond_arp_send(slave->dev, ARPOP_REPLY, bond->master_ip,
 				bond->master_ip, 0);
@@ -3172,6 +3167,12 @@ void bond_activebackup_arp_mon(struct work_struct *work)
 	if (bond->slave_cnt == 0)
 		goto re_arm;
 
+	if (bond->send_grat_arp) {
+		read_lock(&bond->curr_slave_lock);
+		bond_send_gratuitous_arp(bond);
+		read_unlock(&bond->curr_slave_lock);
+	}
+
 	if (bond_ab_arp_inspect(bond, delta_in_ticks)) {
 		read_unlock(&bond->lock);
 		rtnl_lock();
@@ -3846,6 +3847,7 @@ static int bond_close(struct net_device *bond_dev)
 
 	write_lock_bh(&bond->lock);
 
+	bond->send_grat_arp = 0;
 
 	/* signal timers not to re-arm */
 	bond->kill_timers = 1;

drivers/net/bonding/bonding.h

@@ -22,8 +22,8 @@
 #include "bond_3ad.h"
 #include "bond_alb.h"
 
-#define DRV_VERSION	"3.2.5"
-#define DRV_RELDATE	"March 21, 2008"
+#define DRV_VERSION	"3.3.0"
+#define DRV_RELDATE	"June 10, 2008"
 #define DRV_NAME	"bonding"
 #define DRV_DESCRIPTION	"Ethernet Channel Bonding Driver"