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net: hns3: fix for TX queue not restarted problem

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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: 76ad4f0ee7 ("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>
This commit is contained in:
Yunsheng Lin 2019-12-05 10:12:27 +08:00 committed by David S. Miller
parent aacf6578ef
commit 2a597eff24
1 changed files with 21 additions and 12 deletions
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33
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
View File

@ -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 @@ 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 +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.