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hv_netvsc: Fix unwanted wakeup in netvsc_attach()

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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: 7b2ee50c0c ("hv_netvsc: common detach logic")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Haiyang Zhang 2020-02-21 08:32:18 -08:00 committed by David S. Miller
parent eae7172f81
commit f6f13c125e
2 changed files with 4 additions and 1 deletions
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2
drivers/net/hyperv/netvsc.c
View File

@ -99,7 +99,7 @@ static struct netvsc_device *alloc_net_device(void)
init_waitqueue_head(&net_device->wait_drain); init_waitqueue_head(&net_device->wait_drain);
net_device->destroy = false; net_device->destroy = false;
net_device->tx_disable = false; net_device->tx_disable = true;
net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT; net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT; net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;

3
drivers/net/hyperv/netvsc_drv.c
View File

@ -1068,6 +1068,7 @@ static int netvsc_attach(struct net_device *ndev,
} }
/* In any case device is now ready */ /* In any case device is now ready */
nvdev->tx_disable = false;
netif_device_attach(ndev); netif_device_attach(ndev);
/* Note: enable and attach happen when sub-channels setup */ /* Note: enable and attach happen when sub-channels setup */
@ -2476,6 +2477,8 @@ static int netvsc_probe(struct hv_device *dev,
else else
net->max_mtu = ETH_DATA_LEN; net->max_mtu = ETH_DATA_LEN;
nvdev->tx_disable = false;
ret = register_netdevice(net); ret = register_netdevice(net);
if (ret != 0) { if (ret != 0) {
pr_err("Unable to register netdev.\n"); pr_err("Unable to register netdev.\n");