see thread: http://marc.info/?t=131235399700001&r=1&w=2
The last e-mail of the thread and current content of kernel.org doesn't look like final decision.
from http://marc.info/?l=linux-netdev&m=131240208813146&w=2 "The ifenslave.c in mainline is pretty much just a legacy for backwards compatibility; it has not had a bug fix since 2005 (a few typo repairs since then), and no major functional changes since before the git era." Bonding should be configured via sysfs, with initscripts or etcnet.