net/bonding: Optionally allow ethernet slaves to keep own MAC

	Update the "don't change MAC of slaves" functionality added in
previous changes to be a generic option, rather than something tied to
IB devices, as it's occasionally useful for regular ethernet devices as
well.

	Adds "fail_over_mac" option (which is automatically enabled for IB
slaves), applicable only to active-backup mode.

	Includes documentation update.

	Updates bonding driver version to 3.2.0.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

4 files changed, 121 insertions, 24 deletions

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index 1da566630831..11340625e363 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -281,6 +281,39 @@ downdelay
         will be rounded down to the nearest multiple.  The default
         value is 0.
 
+fail_over_mac
+
+        Specifies whether active-backup mode should set all slaves to
+        the same MAC address (the traditional behavior), or, when
+        enabled, change the bond's MAC address when changing the
+        active interface (i.e., fail over the MAC address itself).
+
+        Fail over MAC is useful for devices that cannot ever alter
+        their MAC address, or for devices that refuse incoming
+        broadcasts with their own source MAC (which interferes with
+        the ARP monitor).
+
+        The down side of fail over MAC is that every device on the
+        network must be updated via gratuitous ARP, vs. just updating
+        a switch or set of switches (which often takes place for any
+        traffic, not just ARP traffic, if the switch snoops incoming
+        traffic to update its tables) for the traditional method.  If
+        the gratuitous ARP is lost, communication may be disrupted.
+
+        When fail over MAC is used in conjuction with the mii monitor,
+        devices which assert link up prior to being able to actually
+        transmit and receive are particularly susecptible to loss of
+        the gratuitous ARP, and an appropriate updelay setting may be
+        required.
+
+        A value of 0 disables fail over MAC, and is the default.  A
+        value of 1 enables fail over MAC.  This option is enabled
+        automatically if the first slave added cannot change its MAC
+        address.  This option may be modified via sysfs only when no
+        slaves are present in the bond.
+
+        This option was added in bonding version 3.2.0.
+
 lacp_rate
 
         Option specifying the rate in which we'll ask our link partner
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 0e198dd87c20..db80f243dd37 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -98,6 +98,7 @@ static char *xmit_hash_policy = NULL;
 static int arp_interval = BOND_LINK_ARP_INTERV;
 static char *arp_ip_target[BOND_MAX_ARP_TARGETS] = { NULL, };
 static char *arp_validate = NULL;
+static int fail_over_mac = 0;
 struct bond_params bonding_defaults;
 
 module_param(max_bonds, int, 0);
@@ -131,6 +132,8 @@ module_param_array(arp_ip_target, charp, NULL, 0);
 MODULE_PARM_DESC(arp_ip_target, "arp targets in n.n.n.n form");
 module_param(arp_validate, charp, 0);
 MODULE_PARM_DESC(arp_validate, "validate src/dst of ARP probes: none (default), active, backup or all");
+module_param(fail_over_mac, int, 0);
+MODULE_PARM_DESC(fail_over_mac, "For active-backup, do not set all slaves to the same MAC.  0 of off (default), 1 for on.");
 
 /*----------------------------- Global variables ----------------------------*/
 
@@ -1100,7 +1103,7 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
                 /* when bonding does not set the slave MAC address, the bond MAC
                  * address is the one of the active slave.
                  */
-                if (new_active && !bond->do_set_mac_addr)
+                if (new_active && bond->params.fail_over_mac)
                         memcpy(bond->dev->dev_addr,  new_active->dev->dev_addr,
                                 new_active->dev->addr_len);
                 if (bond->curr_active_slave &&
@@ -1367,16 +1370,16 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
         if (slave_dev->set_mac_address == NULL) {
                 if (bond->slave_cnt == 0) {
                         printk(KERN_WARNING DRV_NAME
-                                ": %s: Warning: The first slave device you "
-                                "specified does not support setting the MAC "
-                                "address. This bond MAC address would be that "
-                                "of the active slave.\n", bond_dev->name);
-                        bond->do_set_mac_addr = 0;
-                } else if (bond->do_set_mac_addr) {
+                               ": %s: Warning: The first slave device "
+                               "specified does not support setting the MAC "
+                               "address. Enabling the fail_over_mac option.",
+                               bond_dev->name);
+                        bond->params.fail_over_mac = 1;
+                } else if (!bond->params.fail_over_mac) {
                         printk(KERN_ERR DRV_NAME
-                                ": %s: Error: The slave device you specified "
-                                "does not support setting the MAC addres,."
-                                "but this bond uses this practice. \n"
+                                ": %s: Error: The slave device specified "
+                                "does not support setting the MAC address, "
+                                "but fail_over_mac is not enabled.\n"
                                 , bond_dev->name);
                         res = -EOPNOTSUPP;
                         goto err_undo_flags;
@@ -1401,7 +1404,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
          */
         memcpy(new_slave->perm_hwaddr, slave_dev->dev_addr, ETH_ALEN);
 
-        if (bond->do_set_mac_addr) {
+        if (!bond->params.fail_over_mac) {
                 /*
                  * Set slave to master's mac address.  The application already
                  * set the master's mac address to that of the first slave
@@ -1637,7 +1640,7 @@ err_close:
         dev_close(slave_dev);
 
 err_restore_mac:
-        if (bond->do_set_mac_addr) {
+        if (!bond->params.fail_over_mac) {
                 memcpy(addr.sa_data, new_slave->perm_hwaddr, ETH_ALEN);
                 addr.sa_family = slave_dev->type;
                 dev_set_mac_address(slave_dev, &addr);
@@ -1814,7 +1817,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
         /* close slave before restoring its mac address */
         dev_close(slave_dev);
 
-        if (bond->do_set_mac_addr) {
+        if (!bond->params.fail_over_mac) {
                 /* restore original ("permanent") mac address */
                 memcpy(addr.sa_data, slave->perm_hwaddr, ETH_ALEN);
                 addr.sa_family = slave_dev->type;
@@ -1935,7 +1938,7 @@ static int bond_release_all(struct net_device *bond_dev)
                 /* close slave before restoring its mac address */
                 dev_close(slave_dev);
 
-                if (bond->do_set_mac_addr) {
+                if (!bond->params.fail_over_mac) {
                         /* restore original ("permanent") mac address*/
                         memcpy(addr.sa_data, slave->perm_hwaddr, ETH_ALEN);
                         addr.sa_family = slave_dev->type;
@@ -3060,9 +3063,15 @@ static void bond_info_show_master(struct seq_file *seq)
         curr = bond->curr_active_slave;
         read_unlock(&bond->curr_slave_lock);
 
-        seq_printf(seq, "Bonding Mode: %s\n",
+        seq_printf(seq, "Bonding Mode: %s",
                    bond_mode_name(bond->params.mode));
 
+        if (bond->params.mode == BOND_MODE_ACTIVEBACKUP &&
+            bond->params.fail_over_mac)
+                seq_printf(seq, " (fail_over_mac)");
+
+        seq_printf(seq, "\n");
+
         if (bond->params.mode == BOND_MODE_XOR ||
                 bond->params.mode == BOND_MODE_8023AD) {
                 seq_printf(seq, "Transmit Hash Policy: %s (%d)\n",
@@ -3994,8 +4003,12 @@ static int bond_set_mac_address(struct net_device *bond_dev, void *addr)
 
         dprintk("bond=%p, name=%s\n", bond, (bond_dev ? bond_dev->name : "None"));
 
-        if (!bond->do_set_mac_addr)
-                return -EOPNOTSUPP;
+        /*
+         * If fail_over_mac is enabled, do nothing and return success.
+         * Returning an error causes ifenslave to fail.
+         */
+        if (bond->params.fail_over_mac)
+                return 0;
 
         if (!is_valid_ether_addr(sa->sa_data)) {
                 return -EADDRNOTAVAIL;
@@ -4384,10 +4397,6 @@ static int bond_init(struct net_device *bond_dev, struct bond_params *params)
 #ifdef CONFIG_PROC_FS
         bond_create_proc_entry(bond);
 #endif
-
-        /* set do_set_mac_addr to true on startup */
-        bond->do_set_mac_addr = 1;
-
         list_add_tail(&bond->bond_list, &bond_dev_list);
 
         return 0;
@@ -4721,6 +4730,11 @@ static int bond_check_params(struct bond_params *params)
                 primary = NULL;
         }
 
+        if (fail_over_mac && (bond_mode != BOND_MODE_ACTIVEBACKUP))
+                printk(KERN_WARNING DRV_NAME
+                       ": Warning: fail_over_mac only affects "
+                       "active-backup mode.\n");
+
         /* fill params struct with the proper values */
         params->mode = bond_mode;
         params->xmit_policy = xmit_hashtype;
@@ -4732,6 +4746,7 @@ static int bond_check_params(struct bond_params *params)
         params->use_carrier = use_carrier;
         params->lacp_fast = lacp_fast;
         params->primary[0] = 0;
+        params->fail_over_mac = fail_over_mac;
 
         if (primary) {
                 strncpy(params->primary, primary, IFNAMSIZ);
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index b5d2a13fe627..80c0c8c415ed 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -568,6 +568,54 @@ static ssize_t bonding_store_arp_validate(struct device *d,
 static DEVICE_ATTR(arp_validate, S_IRUGO | S_IWUSR, bonding_show_arp_validate, bonding_store_arp_validate);
 
 /*
+ * Show and store fail_over_mac.  User only allowed to change the
+ * value when there are no slaves.
+ */
+static ssize_t bonding_show_fail_over_mac(struct device *d, struct device_attribute *attr, char *buf)
+{
+        struct bonding *bond = to_bond(d);
+
+        return sprintf(buf, "%d\n", bond->params.fail_over_mac) + 1;
+}
+
+static ssize_t bonding_store_fail_over_mac(struct device *d, struct device_attribute *attr, const char *buf, size_t count)
+{
+        int new_value;
+        int ret = count;
+        struct bonding *bond = to_bond(d);
+
+        if (bond->slave_cnt != 0) {
+                printk(KERN_ERR DRV_NAME
+                       ": %s: Can't alter fail_over_mac with slaves in bond.\n",
+                       bond->dev->name);
+                ret = -EPERM;
+                goto out;
+        }
+
+        if (sscanf(buf, "%d", &new_value) != 1) {
+                printk(KERN_ERR DRV_NAME
+                       ": %s: no fail_over_mac value specified.\n",
+                       bond->dev->name);
+                ret = -EINVAL;
+                goto out;
+        }
+
+        if ((new_value == 0) || (new_value == 1)) {
+                bond->params.fail_over_mac = new_value;
+                printk(KERN_INFO DRV_NAME ": %s: Setting fail_over_mac to %d.\n",
+                       bond->dev->name, new_value);
+        } else {
+                printk(KERN_INFO DRV_NAME
+                       ": %s: Ignoring invalid fail_over_mac value %d.\n",
+                       bond->dev->name, new_value);
+        }
+out:
+        return ret;
+}
+
+static DEVICE_ATTR(fail_over_mac, S_IRUGO | S_IWUSR, bonding_show_fail_over_mac, bonding_store_fail_over_mac);
+
+/*
  * Show and set the arp timer interval.  There are two tricky bits
  * here.  First, if ARP monitoring is activated, then we must disable
  * MII monitoring.  Second, if the ARP timer isn't running, we must
@@ -1388,6 +1436,7 @@ static DEVICE_ATTR(ad_partner_mac, S_IRUGO, bonding_show_ad_partner_mac, NULL);
 static struct attribute *per_bond_attrs[] = {
         &dev_attr_slaves.attr,
         &dev_attr_mode.attr,
+        &dev_attr_fail_over_mac.attr,
         &dev_attr_arp_validate.attr,
         &dev_attr_arp_interval.attr,
         &dev_attr_arp_ip_target.attr,
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 85e579b0d6f4..a8bbd563265c 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -22,8 +22,8 @@
 #include "bond_3ad.h"
 #include "bond_alb.h"
 
-#define DRV_VERSION     "3.1.3"
-#define DRV_RELDATE     "June 13, 2007"
+#define DRV_VERSION     "3.2.0"
+#define DRV_RELDATE     "September 13, 2007"
 #define DRV_NAME        "bonding"
 #define DRV_DESCRIPTION "Ethernet Channel Bonding Driver"
 
@@ -128,6 +128,7 @@ struct bond_params {
         int arp_interval;
         int arp_validate;
         int use_carrier;
+        int fail_over_mac;
         int updelay;
         int downdelay;
         int lacp_fast;
@@ -186,7 +187,6 @@ struct bonding {
         struct   timer_list mii_timer;
         struct   timer_list arp_timer;
         s8       kill_timers;
-        s8       do_set_mac_addr;
         s8       send_grat_arp;
         s8       setup_by_slave;
         struct   net_device_stats stats;