[v2] hv_netvsc: Fix a network regression after ifdown/ifup

Message ID KL1P15301MB00062D55F01921B958359A55BF650@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM
State Accepted
Delegated to: David Miller
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Series
  • [v2] hv_netvsc: Fix a network regression after ifdown/ifup
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Commit Message

Dexuan Cui June 6, 2018, 9:32 p.m.
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: stable@vger.kernel.org
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
---

Changes since v1:
Removed the check and the comment from the code [Stephen Hemminger]

 drivers/net/hyperv/netvsc_drv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

David Miller June 7, 2018, 8:24 p.m. | #1
From: Dexuan Cui <decui@microsoft.com>
Date: Wed, 6 Jun 2018 21:32:51 +0000

> 
> 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>

Applied and queued up for -stable.

Patch

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index da07ccd..eb8dccd 100644
--- 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