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authorYunsheng Lin <linyunsheng@huawei.com>2019-12-05 10:12:27 +0800
committerDavid S. Miller <davem@davemloft.net>2019-12-05 14:42:43 -0800
commit2a597eff2437d21841a1e87ffa536ab69dbffdcf (patch)
tree77f525bc175fc602837123c0c416de117eb16d36
parentaacf6578ef7704d8df252bbc146b1a35ca131248 (diff)
downloadlinux-2a597eff2437d21841a1e87ffa536ab69dbffdcf.tar.bz2
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 <linyunsheng@huawei.com> Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ethernet/hisilicon/hns3/hns3_enet.c33
1 files changed, 21 insertions, 12 deletions
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.