[Regression] Bonding no longer support tun-interfaces

["Jörn Engel" <joern@purestorage.com>]

This has been reported (and ignored) before:
http://lkml.iu.edu/hypermail/linux/kernel/1407.2/03790.html
https://bugzilla.kernel.org/show_bug.cgi?id=89161

Regression was introduced by:

commit 00503b6f702e (refs/bisect/bad)
Author: dingtianhong <dingtianhong@huawei.com>
Date:   Sat Jan 25 13:00:29 2014 +0800

    bonding: fail_over_mac should only affect AB mode at enslave and removal processing
    
    According to bonding.txt, the fail_over_ma should only affect active-backup mode,
    but I found that the fail_over_mac could be set to active or follow in all
    modes, this will cause new slave could not be set to bond's MAC address at
    enslave processing and restore its own MAC address at removal processing.
    
    The correct way to fix the problem is that we should not add restrictions when
    setting options, just need to modify the bond enslave and removal processing
    to check the mode in addition to fail_over_mac when setting a slave's MAC during
    enslavement. The change active slave processing already only calls the fail_over_mac
    function when in active-backup mode.
    
    Thanks for Jay's suggestion.
    
    The patch also modify the pr_warning() to pr_warn().
    
    Cc: Jay Vosburgh <fubar@us.ibm.com>
    Cc: Veaceslav Falico <vfalico@redhat.com>
    Cc: Andy Gospodarek <andy@greyhouse.net>
    Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Since I never needed bonding or tun-interfaces before, I come late to
the party.  Some 6k lines have changed in the bonding driver since the
regression got in two years ago.  So a simple revert is unlikely to lead
to happiness.

But I absolutely need that functionality and would rather run a 3.13
kernel than live with the regression.  dingtianhong, any suggestions?

J�rn

--
It is a clich� that most clich�s are true, but then, like most clich�s,
that clich� is untrue.
-- Stephen Fry