Larry Pezzaglia - Nice. That's probably similar to what needs to be done in the next release of Mellanox OFED.
Thomas Graf, the original author of the Red Hat patch that adds __pskb_copy to the EL6 kernel in 358.10.1, mentioned in private email a few minutes ago that it's been added on purpose (eg not a bug in EL6).
So, Mellanox's compat module will need to work around it, probably like you've done.