This patch is a workaround for the issue at the level of the ixgbe driver code. The problem can actually be fixed at the level of DPDK instead. Furthermore, this patch circumvents the problem by moving the check that determines if the link status needs to be read (which always fails because get_link_status is not set before the ixgbe_check_mac_link_vf function is called) into a portion of the code that is skipped in most cases. I believe that this patch should be superseded by the following patch:
http://dpdk.org/dev/patchwork/patch/2104/
