[PATCH v3] net/i40e: reduce redundant reset operation

[Feifei Wang]

For free buffer operation in i40e vector path, it is unnecessary to
store 'NULL' into txep.mbuf. This is because when putting mbuf into Tx
queue, tx_tail is the sentinel. And when doing tx_free, tx_next_dd is
the sentinel. In all processes, mbuf==NULL is not a condition in check.
Thus reset of mbuf is unnecessary and can be omitted.

Signed-off-by: Feifei Wang <feifei.wang2 at arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
---

v2: remove the change for scalar path due to scalar path needs to check
whether the mbuf is 'NULL' to release and clean up (Haiyue)

v3: add comments to remind reset mbuf is unnecessary here (Qi Zhang)

 drivers/net/i40e/i40e_rxtx_vec_common.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/i40e/i40e_rxtx_vec_common.h b/drivers/net/i40e/i40e_rxtx_vec_common.h
index f9a7f46550..959832ed6a 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_common.h
+++ b/drivers/net/i40e/i40e_rxtx_vec_common.h
@@ -103,7 +103,7 @@ i40e_tx_free_bufs(struct i40e_tx_queue *txq)
 	if (txq->offloads & RTE_ETH_TX_OFFLOAD_MBUF_FAST_FREE) {
 		for (i = 0; i < n; i++) {
 			free[i] = txep[i].mbuf;
-			txep[i].mbuf = NULL;
+			/* no need to reset txep[i].mbuf in vector path */
 		}
 		rte_mempool_put_bulk(free[0]->pool, (void **)free, n);
 		goto done;
-- 
2.25.1