buffer space. This is a combined backport of the following commits from
net-next-2.6:
0e3125c755445664f00ad036e4fc2cd32fd52877
bbce5a59e4e0e6e1dbc85492caaf310ff6611309
0af55bb58f8fa7865004ac48d16affe125ac1b7f
920b8d913bd3d963d5c88bca160a272b71e0c95a
Resolves: bz637619