2020-09-09 04:09:30

by Dexuan Cui

Subject: [PATCH net 1/2] hv_netvsc: Switch the data path at the right time during hibernation

When netvsc_resume() is called, the mlx5 VF NIC has not been resumed yet,
so in the future the host might sliently fail the call netvsc_vf_changed()
-> netvsc_switch_datapath() there, even if the call works now.

Call netvsc_vf_changed() in the NETDEV_CHANGE event handler: at that time
the mlx5 VF NIC has been resumed.

Fixes: 19162fd4063a ("hv_netvsc: Fix hibernation for mlx5 VF driver")
Signed-off-by: Dexuan Cui <[email protected]>
---
drivers/net/hyperv/netvsc_drv.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 81c5c70b616a..4a25886e2346 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2619,7 +2619,6 @@ static int netvsc_resume(struct hv_device *dev)
struct net_device *net = hv_get_drvdata(dev);
struct net_device_context *net_device_ctx;
struct netvsc_device_info *device_info;
- struct net_device *vf_netdev;
int ret;

rtnl_lock();
@@ -2632,15 +2631,6 @@ static int netvsc_resume(struct hv_device *dev)
netvsc_devinfo_put(device_info);
net_device_ctx->saved_netvsc_dev_info = NULL;

- /* A NIC driver (e.g. mlx5) may keep the VF network interface across
- * hibernation, but here the data path is implicitly switched to the
- * netvsc NIC since the vmbus channel is closed and re-opened, so
- * netvsc_vf_changed() must be used to switch the data path to the VF.
- */
- vf_netdev = rtnl_dereference(net_device_ctx->vf_netdev);
- if (vf_netdev && netvsc_vf_changed(vf_netdev) != NOTIFY_OK)
- ret = -EINVAL;
-
rtnl_unlock();

return ret;
@@ -2701,6 +2691,7 @@ static int netvsc_netdev_event(struct notifier_block *this,
return netvsc_unregister_vf(event_dev);
case NETDEV_UP:
case NETDEV_DOWN:
+ case NETDEV_CHANGE:
return netvsc_vf_changed(event_dev);
default:
return NOTIFY_DONE;
--
2.19.1

2020-09-10 20:00:05

by David Miller

Subject: Re: [PATCH net 1/2] hv_netvsc: Switch the data path at the right time during hibernation

From: Dexuan Cui <[email protected]>
Date: Tue, 8 Sep 2020 21:07:32 -0700

> When netvsc_resume() is called, the mlx5 VF NIC has not been resumed yet,
> so in the future the host might sliently fail the call netvsc_vf_changed()
> -> netvsc_switch_datapath() there, even if the call works now.
>
> Call netvsc_vf_changed() in the NETDEV_CHANGE event handler: at that time
> the mlx5 VF NIC has been resumed.
>
> Fixes: 19162fd4063a ("hv_netvsc: Fix hibernation for mlx5 VF driver")
> Signed-off-by: Dexuan Cui <[email protected]>

Applied.