If I understand correctly, bnx2x_reload_if_running() failure does not
mean exactly that features change failed. It means that device failed
to initialize, possibly because of other (transient?) conditions. So
unless reverting features change and retrying the initialization is
known to allow the device to be brought back, 

In a general case u can't be sure which (if at all) features change caused
the failure. So, u should return the configuration to the last known "good" one.

there's no difference
whether old or new dev->features value is kept and which set is
reported by ethtool.

Well, I disagree with u on this one - I think that if the state change operation
(of any object, in our case it's a netdev) fails, the current state should remain unchanged.

Thanks,
vlad

Best Regards,
Michał Mirosław