| Message ID | 1582302738-24352-1-git-send-email-haiyangz@microsoft.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] hv_netvsc: Fix unwanted wakeup in netvsc_attach() | expand |
From: Haiyang Zhang <haiyangz@microsoft.com> Date: Fri, 21 Feb 2020 08:32:18 -0800 > When netvsc_attach() is called by operations like changing MTU, etc., > an extra wakeup may happen while netvsc_attach() calling > rndis_filter_device_add() which sends rndis messages when queue is > stopped in netvsc_detach(). The completion message will wake up queue 0. > > We can reproduce the issue by changing MTU etc., then the wake_queue > counter from "ethtool -S" will increase beyond stop_queue counter: > stop_queue: 0 > wake_queue: 1 > The issue causes queue wake up, and counter increment, no other ill > effects in current code. So we didn't see any network problem for now. > > To fix this, initialize tx_disable to true, and set it to false when > the NIC is ready to be attached or registered. > > Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic") > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Applied, thank you.
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index ae3f308..1b320bc 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -99,7 +99,7 @@ static struct netvsc_device *alloc_net_device(void) init_waitqueue_head(&net_device->wait_drain); net_device->destroy = false; - net_device->tx_disable = false; + net_device->tx_disable = true; net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT; net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT; diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 65e12cb..2c0a24c 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -1068,6 +1068,7 @@ static int netvsc_attach(struct net_device *ndev, } /* In any case device is now ready */ + nvdev->tx_disable = false; netif_device_attach(ndev); /* Note: enable and attach happen when sub-channels setup */ @@ -2476,6 +2477,8 @@ static int netvsc_probe(struct hv_device *dev, else net->max_mtu = ETH_DATA_LEN; + nvdev->tx_disable = false; + ret = register_netdevice(net); if (ret != 0) { pr_err("Unable to register netdev.\n");
When netvsc_attach() is called by operations like changing MTU, etc., an extra wakeup may happen while netvsc_attach() calling rndis_filter_device_add() which sends rndis messages when queue is stopped in netvsc_detach(). The completion message will wake up queue 0. We can reproduce the issue by changing MTU etc., then the wake_queue counter from "ethtool -S" will increase beyond stop_queue counter: stop_queue: 0 wake_queue: 1 The issue causes queue wake up, and counter increment, no other ill effects in current code. So we didn't see any network problem for now. To fix this, initialize tx_disable to true, and set it to false when the NIC is ready to be attached or registered. Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic") Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> --- drivers/net/hyperv/netvsc.c | 2 +- drivers/net/hyperv/netvsc_drv.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-)