net/bonding: Handlle wrong assumptions that slave is always an Ethernet device

bonding sometimes uses Ethernet constants (such as MTU and address length) which
are not good when it enslaves non Ethernet devices (such as InfiniBand).

Signed-off-by: Moni Shoua <monis at voltaire.com>
Acked-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index ca4e429f9ec2..583c568e1764 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -260,6 +260,7 @@ static ssize_t bonding_store_slaves(struct device *d,
         char command[IFNAMSIZ + 1] = { 0, };
         char *ifname;
         int i, res, found, ret = count;
+        u32 original_mtu;
         struct slave *slave;
         struct net_device *dev = NULL;
         struct bonding *bond = to_bond(d);
@@ -325,6 +326,7 @@ static ssize_t bonding_store_slaves(struct device *d,
                 }
 
                 /* Set the slave's MTU to match the bond */
+                original_mtu = dev->mtu;
                 if (dev->mtu != bond->dev->mtu) {
                         if (dev->change_mtu) {
                                 res = dev->change_mtu(dev,
@@ -339,6 +341,9 @@ static ssize_t bonding_store_slaves(struct device *d,
                 }
                 rtnl_lock();
                 res = bond_enslave(bond->dev, dev);
+                bond_for_each_slave(bond, slave, i)
+                        if (strnicmp(slave->dev->name, ifname, IFNAMSIZ) == 0)
+                                slave->original_mtu = original_mtu;
                 rtnl_unlock();
                 if (res) {
                         ret = res;
@@ -351,6 +356,7 @@ static ssize_t bonding_store_slaves(struct device *d,
                 bond_for_each_slave(bond, slave, i)
                         if (strnicmp(slave->dev->name, ifname, IFNAMSIZ) == 0) {
                                 dev = slave->dev;
+                                original_mtu = slave->original_mtu;
                                 break;
                         }
                 if (dev) {
@@ -365,9 +371,9 @@ static ssize_t bonding_store_slaves(struct device *d,
                         }
                         /* set the slave MTU to the default */
                         if (dev->change_mtu) {
-                                dev->change_mtu(dev, 1500);
+                                dev->change_mtu(dev, original_mtu);
                         } else {
-                                dev->mtu = 1500;
+                                dev->mtu = original_mtu;
                         }
                 }
                 else {