hv_netvsc: Fix a network regression after ifdown/ifup

Recently people reported the NIC stops working after
"ifdown eth0; ifup eth0". It turns out in this case the TX queues are not
enabled, after the refactoring of the common detach logic: when the NIC
has sub-channels, usually we enable all the TX queues after all
sub-channels are set up: see rndis_set_subchannel() ->
netif_device_attach(), but in the case of "ifdown eth0; ifup eth0" where
the number of channels doesn't change, we also must make sure the TX queues
are enabled. The patch fixes the regression.

Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name hv_netvsc-Fix-a-network-regression-after-ifdown-ifup.patch

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 2a7752c113df91139e9a676b18a02b902fd15ab1..adbfa82b76e9e617ca0ebd418e9b5aaa2939a129 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -126,8 +126,10 @@ static int netvsc_open(struct net_device *net)
        }
 
        rdev = nvdev->extension;
-       if (!rdev->link_state)
+       if (!rdev->link_state) {
                netif_carrier_on(net);
+               netif_tx_wake_all_queues(net);
+       }
 
        if (vf_netdev) {
                /* Setting synthetic device up transparently sets