Bonding: fix zero address hole bug in arp_ip_target list

upstream commit: 5a31bec014449dc9ca994e4c1dbf2802b7ca458a

Fix a zero address hole bug in the bonding arp_ip_target list
that was causing the bond to ignore ARP replies (bugz 13006).
Instead of just setting the array entry to zero, we now
copy any additional entries down one slot, putting the
zero entry at the end.  With this change we can now have
all the loops that walk the array stop when they hit a zero
since there will be no addresses after it.

Changes are based in part on code fragment provided in kernel:
bugzilla 13006:

	http://bugzilla.kernel.org/show_bug.cgi?id=13006

by Steve Howard <steve@astutenetworks.com>

Signed-off-by: Brian Haley <brian.haley@hp.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

3 files changed, 11 insertions, 10 deletions

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 5ede7473b42..08762750f12 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -1242,7 +1242,7 @@ monitoring is enabled, and vice-versa.
 To add ARP targets:
 # echo +192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target
 # echo +192.168.0.101 > /sys/class/net/bond0/bonding/arp_ip_target
-	NOTE:  up to 10 target addresses may be specified.
+	NOTE:  up to 16 target addresses may be specified.
 
 To remove an ARP target:
 # echo -192.168.0.100 > /sys/class/net/bond0/bonding/arp_ip_target
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 3d76686dcec..87045f8ce4e 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2565,7 +2565,7 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 
 	for (i = 0; (i < BOND_MAX_ARP_TARGETS); i++) {
 		if (!targets[i])
-			continue;
+			break;
 		pr_debug("basa: target %x\n", targets[i]);
 		if (list_empty(&bond->vlan_list)) {
 			pr_debug("basa: empty vlan: arp_send\n");
@@ -2672,7 +2672,6 @@ static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32
 	int i;
 	__be32 *targets = bond->params.arp_targets;
 
-	targets = bond->params.arp_targets;
 	for (i = 0; (i < BOND_MAX_ARP_TARGETS) && targets[i]; i++) {
 		pr_debug("bva: sip %pI4 tip %pI4 t[%d] %pI4 bhti(tip) %d\n",
 			&sip, &tip, i, &targets[i], bond_has_this_ip(bond, tip));
@@ -3294,7 +3293,7 @@ static void bond_info_show_master(struct seq_file *seq)
 
 		for(i = 0; (i < BOND_MAX_ARP_TARGETS) ;i++) {
 			if (!bond->params.arp_targets[i])
-				continue;
+				break;
 			if (printed)
 				seq_printf(seq, ",");
 			seq_printf(seq, " %pI4", &bond->params.arp_targets[i]);
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 18cf4787874..d2873153522 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -684,17 +684,15 @@ static ssize_t bonding_store_arp_targets(struct device *d,
 			goto out;
 		}
 		/* look for an empty slot to put the target in, and check for dupes */
-		for (i = 0; (i < BOND_MAX_ARP_TARGETS); i++) {
+		for (i = 0; (i < BOND_MAX_ARP_TARGETS) && !done; i++) {
 			if (targets[i] == newtarget) { /* duplicate */
 				printk(KERN_ERR DRV_NAME
 				       ": %s: ARP target %pI4 is already present\n",
 				       bond->dev->name, &newtarget);
-				if (done)
-					targets[i] = 0;
 				ret = -EINVAL;
 				goto out;
 			}
-			if (targets[i] == 0 && !done) {
+			if (targets[i] == 0) {
 				printk(KERN_INFO DRV_NAME
 				       ": %s: adding ARP target %pI4.\n",
 				       bond->dev->name, &newtarget);
@@ -720,12 +718,16 @@ static ssize_t bonding_store_arp_targets(struct device *d,
 			goto out;
 		}
 
-		for (i = 0; (i < BOND_MAX_ARP_TARGETS); i++) {
+		for (i = 0; (i < BOND_MAX_ARP_TARGETS) && !done; i++) {
 			if (targets[i] == newtarget) {
+				int j;
 				printk(KERN_INFO DRV_NAME
 				       ": %s: removing ARP target %pI4.\n",
 				       bond->dev->name, &newtarget);
-				targets[i] = 0;
+				for (j = i; (j < (BOND_MAX_ARP_TARGETS-1)) && targets[j+1]; j++)
+					targets[j] = targets[j+1];
+
+				targets[j] = 0;
 				done = 1;
 			}
 		}