From 93aa4792c3908eac87ddd368ee0fe0564148232b Mon Sep 17 00:00:00 2001 From: Haiyang Zhang Date: Tue, 30 Apr 2019 19:29:07 +0000 Subject: hv_netvsc: fix race that may miss tx queue wakeup When the ring buffer is almost full due to RX completion messages, a TX packet may reach the "low watermark" and cause the queue stopped. If the TX completion arrives earlier than queue stopping, the wakeup may be missed. This patch moves the check for the last pending packet to cover both EAGAIN and success cases, so the queue will be reliably waked up when necessary. Reported-and-tested-by: Stephan Klein Signed-off-by: Haiyang Zhang Signed-off-by: David S. Miller --- drivers/net/hyperv/netvsc.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'drivers/net/hyperv/netvsc.c') diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index e0dce373cdd9..3d4a166a49d5 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -875,12 +875,6 @@ static inline int netvsc_send_pkt( } else if (ret == -EAGAIN) { netif_tx_stop_queue(txq); ndev_ctx->eth_stats.stop_queue++; - if (atomic_read(&nvchan->queue_sends) < 1 && - !net_device->tx_disable) { - netif_tx_wake_queue(txq); - ndev_ctx->eth_stats.wake_queue++; - ret = -ENOSPC; - } } else { netdev_err(ndev, "Unable to send packet pages %u len %u, ret %d\n", @@ -888,6 +882,15 @@ static inline int netvsc_send_pkt( ret); } + if (netif_tx_queue_stopped(txq) && + atomic_read(&nvchan->queue_sends) < 1 && + !net_device->tx_disable) { + netif_tx_wake_queue(txq); + ndev_ctx->eth_stats.wake_queue++; + if (ret == -EAGAIN) + ret = -ENOSPC; + } + return ret; } -- cgit v1.2.3