Bonding device forbids slave device of different types under the same
master.

However, it is possible for a bonding master to change type during its
lifetime.  This can be either from ARPHRD_ETHER to ARPHRD_INFINIBAND
or the other way arround.  The change of type requires device level
multicast address cleanup because device level multicast addresses
depend on the device type.

The patch adds a call to dev_close() before the bonding master changes
type and dev_open() just after that.

In the example below I enslaved an IPoIB device (ib0) under
bond0. Since each bonding master starts as device of type ARPHRD_ETHER
by default, a change of type occurs when ib0 is enslaved.

This is how /proc/net/dev_mcast looks like without the patch

5    bond0           1     0     00ffffffff12601bffff000000000001ff96ca05
5    bond0           1     0     01005e000116
5    bond0           1     0     01005e7ffffd
5    bond0           1     0     01005e000001
5    bond0           1     0     333300000001
6    ib0             1     0     00ffffffff12601bffff000000000001ff96ca05
6    ib0             1     0     333300000001
6    ib0             1     0     01005e000001
6    ib0             1     0     01005e7ffffd
6    ib0             1     0     01005e000116
6    ib0             1     0     00ffffffff12401bffff00000000000000000001
6    ib0             1     0     00ffffffff12601bffff00000000000000000001

and this is how it looks like after the patch.

5    bond0           1     0     00ffffffff12601bffff000000000001ff96ca05
5    bond0           1     0     00ffffffff12601bffff00000000000000000001
5    bond0           1     0     00ffffffff12401bffff0000000000000ffffffd
5    bond0           1     0     00ffffffff12401bffff00000000000000000116
5    bond0           1     0     00ffffffff12401bffff00000000000000000001
6    ib0             1     0     00ffffffff12601bffff000000000001ff96ca05
6    ib0             1     0     00ffffffff12401bffff00000000000000000116
6    ib0             1     0     00ffffffff12401bffff0000000000000ffffffd
6    ib0             2     0     00ffffffff12401bffff00000000000000000001
6    ib0             2     0     00ffffffff12601bffff00000000000000000001

Signed-off-by: Moni Shoua <monis@voltaire.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>