Commit 2a597eff authored by Yunsheng Lin's avatar Yunsheng Lin Committed by David S. Miller
Browse files

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: 76ad4f0e ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: default avatarYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: default avatarHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aacf6578

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

+21 −12
Original line number Diff line number Diff line
@@ -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;
@@ -1320,12 +1322,25 @@ 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;



	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)

{

	struct device *dev = ring_to_dev(ring);
@@ -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.

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