Not only does this make it atomic when moving commands from the waiting_for_response_list to the command_list if the descriptor is full, it will also make the entire process of submitting a packet the packet transmission logic atomic. Signed-off-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>