net: hns3: optimize the barrier using when cleaning tx BD

driver inclusion
category: bugfix
bugzilla: NA
CVE: NA

Currently, a barrier is used when cleaning each tx BD, which may
cause performance degradation.

This patch optimize it to use one barrier when cleaning tx BD
each round.

Feature or Bugfix:Bugfix
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Reviewed-by: Nlipeng <lipeng321@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

@@ -2287,12 +2287,13 @@ static void hns3_reuse_buffer(struct hns3_enet_ring *ring, int i)
 	ring->desc[i].rx.bd_base_info = 0;
 }
 
-static void hns3_nic_reclaim_one_desc(struct hns3_enet_ring *ring, int *bytes,
-				      int *pkts)
+static void hns3_nic_reclaim_desc(struct hns3_enet_ring *ring, int head,
+				  int *bytes, int *pkts)
 {
 	int ntc = ring->next_to_clean;
 	struct hns3_desc_cb *desc_cb;
 
+	while (head != ntc) {
 		desc_cb = &ring->desc_cb[ntc];
 		(*pkts) += (desc_cb->type == DESC_TYPE_SKB);
 		(*bytes) += desc_cb->length;
@@ -2302,6 +2303,10 @@ static void hns3_nic_reclaim_one_desc(struct hns3_enet_ring *ring, int *bytes,
 		if (++ntc == ring->desc_num)
 			ntc = 0;
 
+		/* Issue prefetch for next Tx descriptor */
+		prefetch(&ring->desc_cb[ntc]);
+	}
+
 	/* This smp_store_release() pairs with smp_load_acquire() in
 	 * ring_space called by hns3_nic_net_xmit.
 	 */
@@ -2345,11 +2350,7 @@ void hns3_clean_tx_ring(struct hns3_enet_ring *ring)
 
 	bytes = 0;
 	pkts = 0;
-	while (head != ring->next_to_clean) {
-		hns3_nic_reclaim_one_desc(ring, &bytes, &pkts);
-		/* Issue prefetch for next Tx descriptor */
-		prefetch(&ring->desc_cb[ring->next_to_clean]);
-	}
+	hns3_nic_reclaim_desc(ring, head, &bytes, &pkts);
 
 	ring->tqp_vector->tx_group.total_bytes += bytes;
 	ring->tqp_vector->tx_group.total_packets += pkts;