[PATCH net-next] net-next/hinic: Fix a case of Tx Queue is Stopped forever
From: Aviad Krawczyk <hidden>
Date: 2017-09-26 18:12:34
Fix the following scenario: 1. tx_free_poll is running on cpu X 2. xmit function is running on cpu Y and fails to get sq wqe 3. tx_free_poll frees wqes on cpu X and checks the queue is not stopped 4. xmit function stops the queue after failed to get sq wqe 5. The queue is stopped forever Signed-off-by: Aviad Krawczyk <redacted> --- drivers/net/ethernet/huawei/hinic/hinic_tx.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/huawei/hinic/hinic_tx.c b/drivers/net/ethernet/huawei/hinic/hinic_tx.c
index abe3e38..9128858 100644
--- a/drivers/net/ethernet/huawei/hinic/hinic_tx.c
+++ b/drivers/net/ethernet/huawei/hinic/hinic_tx.c@@ -212,10 +212,19 @@ netdev_tx_t hinic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) sq_wqe = hinic_sq_get_wqe(txq->sq, wqe_size, &prod_idx); if (!sq_wqe) { - tx_unmap_skb(nic_dev, skb, txq->sges); - netif_stop_subqueue(netdev, qp->q_id); + /* Check for the case free_tx_poll is called in another cpu + * and we stopped the subqueue after free_tx_poll check. + */ + sq_wqe = hinic_sq_get_wqe(txq->sq, wqe_size, &prod_idx); + if (sq_wqe) { + netif_wake_subqueue(nic_dev->netdev, qp->q_id); + goto process_sq_wqe; + } + + tx_unmap_skb(nic_dev, skb, txq->sges); + u64_stats_update_begin(&txq->txq_stats.syncp); txq->txq_stats.tx_busy++; u64_stats_update_end(&txq->txq_stats.syncp);
@@ -223,6 +232,7 @@ netdev_tx_t hinic_xmit_frame(struct sk_buff *skb, struct net_device *netdev) goto flush_skbs; } +process_sq_wqe: hinic_sq_prepare_wqe(txq->sq, prod_idx, sq_wqe, txq->sges, nr_sges); hinic_sq_write_wqe(txq->sq, prod_idx, sq_wqe, skb, wqe_size);
--
1.9.1