net: hns3: optimize the tx clean process

Currently HNS3_RING_TX_RING_HEAD_REG register is read to determine
how many tx desc can be cleaned. To avoid the register read operation
in the critical data path, use the valid bit in the tx desc to determine
if a specific tx desc can be cleaned.

The hns3 driver sets valid bit in the tx desc before ringing a doorbell
to the hw, and hw will only clear the valid bit of the tx desc after
corresponding packet is sent out to the wire. And because next_to_use
for tx ring is a changing variable when the driver is filling the tx
desc, so reuse the pull_len for rx ring to record the tx desc that has
notified to the hw, so that hns3_nic_reclaim_desc() can decide how many
tx desc's valid bit need checking when reclaiming tx desc.

And io_err_cnt stat is also removed for it is not used anymore.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 8 deletions

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
index f40738c96cd1..876dc09ac122 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
@@ -344,7 +344,6 @@ enum hns3_pkt_ol4type {
 };
 
 struct ring_stats {
-	u64 io_err_cnt;
 	u64 sw_err_cnt;
 	u64 seg_pkt_cnt;
 	union {
@@ -397,8 +396,10 @@ struct hns3_enet_ring {
 	 * next_to_use
 	 */
 	int next_to_clean;
-
-	u32 pull_len; /* head length for current packet */
+	union {
+		int last_to_use;	/* last idx used by xmit */
+		u32 pull_len;		/* memcpy len for current rx packet */
+	};
 	u32 frag_num;
 	void *va; /* first buffer address for current packet */
 
@@ -513,11 +514,6 @@ static inline int ring_space(struct hns3_enet_ring *ring)
 			(begin - end)) - 1;
 }
 
-static inline int is_ring_empty(struct hns3_enet_ring *ring)
-{
-	return ring->next_to_use == ring->next_to_clean;
-}
-
 static inline u32 hns3_read_reg(void __iomem *base, u32 reg)
 {
 	return readl(base + reg);