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Subject[PATCH net v2] hv_netvsc: Fix hibernation for mlx5 VF driver
mlx5_suspend()/resume() keep the network interface, so during hibernation
netvsc_unregister_vf() and netvsc_register_vf() are not called, and hence
netvsc_resume() should call netvsc_vf_changed() to switch the data path
back to the VF after hibernation. Note: after we close and re-open the
vmbus channel of the netvsc NIC in netvsc_suspend() and netvsc_resume(),
the data path is implicitly switched to the netvsc NIC. Similarly,
netvsc_suspend() should not call netvsc_unregister_vf(), otherwise the VF
can no longer be used after hibernation.

For mlx4, since the VF network interafce is explicitly destroyed and
re-created during hibernation (see mlx4_suspend()/resume()), hv_netvsc
already explicitly switches the data path from and to the VF automatically
via netvsc_register_vf() and netvsc_unregister_vf(), so mlx4 doesn't need
this fix. Note: mlx4 can still work with the fix because in
netvsc_suspend()/resume() ndev_ctx->vf_netdev is NULL for mlx4.

Fixes: 0efeea5fb153 ("hv_netvsc: Add the support of hibernation")
Signed-off-by: Dexuan Cui <>

Changes in v2 (Thanks Jakub Kicinski <>):
Added coments in the changelog and the code about the implicit
data path switching to the netvsc when we close/re-open the vmbus
Used reverse xmas order ordering in netvsc_remove().

drivers/net/hyperv/netvsc_drv.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 64b0a74c1523..81c5c70b616a 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2587,8 +2587,8 @@ static int netvsc_remove(struct hv_device *dev)
static int netvsc_suspend(struct hv_device *dev)
struct net_device_context *ndev_ctx;
- struct net_device *vf_netdev, *net;
struct netvsc_device *nvdev;
+ struct net_device *net;
int ret;

net = hv_get_drvdata(dev);
@@ -2604,10 +2604,6 @@ static int netvsc_suspend(struct hv_device *dev)
goto out;

- vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
- if (vf_netdev)
- netvsc_unregister_vf(vf_netdev);
/* Save the current config info */
ndev_ctx->saved_netvsc_dev_info = netvsc_devinfo_get(nvdev);

@@ -2623,6 +2619,7 @@ 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;

@@ -2635,6 +2632,15 @@ static int netvsc_resume(struct hv_device *dev)
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;

return ret;
 \ /
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