From 2a597eff2437d21841a1e87ffa536ab69dbffdcf Mon Sep 17 00:00:00 2001 From: Yunsheng Lin Date: Thu, 5 Dec 2019 10:12:27 +0800 Subject: net: hns3: fix for TX queue not restarted problem 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 Signed-off-by: Huazhong Tan Signed-off-by: David S. Miller --- drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 33 ++++++++++++++++--------- 1 file changed, 21 insertions(+), 12 deletions(-) (limited to 'drivers/net/ethernet') diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c index ba0536802b13..e2730319bd43 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c @@ -1287,8 +1287,10 @@ static bool hns3_skb_need_linearized(struct sk_buff *skb, unsigned int *bd_size, } static int hns3_nic_maybe_stop_tx(struct hns3_enet_ring *ring, + 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; unsigned int bd_num; @@ -1320,10 +1322,23 @@ 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 +1415,13 @@ 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(ring, 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 +1472,6 @@ fill_err: 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 +2528,7 @@ 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. -- cgit v1.2.3-59-g8ed1b