[PATCH net 1/3] net: hns3: fix for TX queue not restarted problem
From: Huazhong Tan <hidden>
Date: 2019-12-03 03:08:56
Also in:
lkml
Subsystem:
hisilicon network subsystem 3 driver (hns3), hisilicon network subsystem driver, networking drivers, the rest · Maintainers:
Jian Shen, Jijie Shao, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Yunsheng Lin <redacted>
There is timing window between ring_space checking and
netif_stop_subqueue when transmiting a SKB, and the TX BD
cleaning may be executed during the time window, which may
caused TX queue not restarted problem.
This patch fixes it by rechecking the ring_space after
netif_stop_subqueue to make sure TX queue is restarted.
Also, the ring->next_to_clean is updated even when pkts is
zero, because all the TX BD cleaned may be non-SKB, so it
needs to check if TX queue need to be restarted.
Fixes: 76ad4f0ee747 ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: Yunsheng Lin <redacted>
Signed-off-by: Huazhong Tan <redacted>
---
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 36 ++++++++++++++++---------
1 file changed, 23 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index ba05368..b2bb8e2 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c@@ -1286,13 +1286,16 @@ static bool hns3_skb_need_linearized(struct sk_buff *skb, unsigned int *bd_size, return false; } -static int hns3_nic_maybe_stop_tx(struct hns3_enet_ring *ring, +static int hns3_nic_maybe_stop_tx(struct net_device *netdev, struct sk_buff **out_skb) { + struct hns3_nic_priv *priv = netdev_priv(netdev); unsigned int bd_size[HNS3_MAX_TSO_BD_NUM + 1U]; struct sk_buff *skb = *out_skb; + struct hns3_enet_ring *ring; unsigned int bd_num; + ring = &priv->ring[skb->queue_mapping]; bd_num = hns3_tx_bd_num(skb, bd_size); if (unlikely(bd_num > HNS3_MAX_NON_TSO_BD_NUM)) { struct sk_buff *new_skb;
@@ -1320,10 +1323,23 @@ static int hns3_nic_maybe_stop_tx(struct hns3_enet_ring *ring, } out: - if (unlikely(ring_space(ring) < bd_num)) - return -EBUSY; + if (likely(ring_space(ring) >= bd_num)) + return bd_num; - return bd_num; + netif_stop_subqueue(netdev, ring->queue_index); + smp_mb(); /* Memory barrier before checking ring_space */ + + /* Start queue in case hns3_clean_tx_ring has just made room + * available and has not seen the queue stopped state performed + * by netif_stop_subqueue above. + */ + if (ring_space(ring) >= bd_num && netif_carrier_ok(netdev) && + !test_bit(HNS3_NIC_STATE_DOWN, &priv->state)) { + netif_start_subqueue(netdev, ring->queue_index); + return bd_num; + } + + return -EBUSY; } static void hns3_clear_desc(struct hns3_enet_ring *ring, int next_to_use_orig)
@@ -1400,13 +1416,13 @@ netdev_tx_t hns3_nic_net_xmit(struct sk_buff *skb, struct net_device *netdev) /* Prefetch the data used later */ prefetch(skb->data); - ret = hns3_nic_maybe_stop_tx(ring, &skb); + ret = hns3_nic_maybe_stop_tx(netdev, &skb); if (unlikely(ret <= 0)) { if (ret == -EBUSY) { u64_stats_update_begin(&ring->syncp); ring->stats.tx_busy++; u64_stats_update_end(&ring->syncp); - goto out_net_tx_busy; + return NETDEV_TX_BUSY; } else if (ret == -ENOMEM) { u64_stats_update_begin(&ring->syncp); ring->stats.sw_err_cnt++;
@@ -1457,12 +1473,6 @@ netdev_tx_t hns3_nic_net_xmit(struct sk_buff *skb, struct net_device *netdev) out_err_tx_ok: dev_kfree_skb_any(skb); return NETDEV_TX_OK; - -out_net_tx_busy: - netif_stop_subqueue(netdev, ring->queue_index); - smp_mb(); /* Commit all data before submit */ - - return NETDEV_TX_BUSY; } static int hns3_nic_net_set_mac_address(struct net_device *netdev, void *p)
@@ -2519,7 +2529,7 @@ void hns3_clean_tx_ring(struct hns3_enet_ring *ring) dev_queue = netdev_get_tx_queue(netdev, ring->tqp->tqp_index); netdev_tx_completed_queue(dev_queue, pkts, bytes); - if (unlikely(pkts && netif_carrier_ok(netdev) && + if (unlikely(netif_carrier_ok(netdev) && ring_space(ring) > HNS3_MAX_TSO_BD_NUM)) { /* Make sure that anybody stopping the queue after this * sees the new next_to_clean.
--
2.7.4