vPMD tx does not set sw_ring's mbuf to NULL after free.
Therefore, in cases where the vector transmit function is in
use, we must use the appropriate index and threshold values
for the queue to only free the unreleased mbufs
Fixes: b4669bb95038 ("i40e: add vector Tx")
Cc: stable@dpdk.org
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
24853544c8