bonding: Add "follow" option to fail_over_mac

	Add a "follow" selection for fail_over_mac.  This option
causes the MAC address to move from slave to slave as the active
slave changes.  This is in addition to the existing fail_over_mac option
that causes the bond's MAC address to change during failover.

	This new option is useful for devices that cannot tolerate
multiple ports using the same MAC address simultaneously, either
because it confuses them or incurs a performance penalty (as is the
case with some LPAR-aware multiport devices).  Because the MAC of the
bond itself does not change, the "follow" option is slightly more
reliable during failover and doesn't change the MAC of the bond during
operation.

	This patch requires a previous ARP monitor change to properly
handle RTNL during failovers.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 8766b1213690..89fd9963db7a 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -248,6 +248,10 @@ static inline struct bonding *bond_get_bond_by_slave(struct slave *slave)
         return (struct bonding *)slave->dev->master->priv;
 }
 
+#define BOND_FOM_NONE                   0
+#define BOND_FOM_ACTIVE                 1
+#define BOND_FOM_FOLLOW                 2
+
 #define BOND_ARP_VALIDATE_NONE          0
 #define BOND_ARP_VALIDATE_ACTIVE        (1 << BOND_STATE_ACTIVE)
 #define BOND_ARP_VALIDATE_BACKUP        (1 << BOND_STATE_BACKUP)