[PATCH net] hv_netvsc: Fix VF namespace also in netvsc_open

[Haiyang Zhang <haiyangz@microsoft.com>]

The existing code moves VF to the same namespace as the synthetic device
during netvsc_register_vf(). But, if the synthetic device is moved to a
new namespace after the VF registration, the VF won't be moved together.

To make the behavior more consistent, add a namespace check to netvsc_open(),
and move the VF if it is not in the same namespace.

Cc: stable@vger.kernel.org
Fixes: c0a41b887ce6 ("hv_netvsc: move VF to same namespace as netvsc device")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/net/hyperv/netvsc_drv.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 153b97f8ec0d..9caade092524 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -134,6 +134,19 @@ static int netvsc_open(struct net_device *net)
 	}
 
 	if (vf_netdev) {
+		if (!net_eq(dev_net(net), dev_net(vf_netdev))) {
+			ret = dev_change_net_namespace(vf_netdev, dev_net(net),
+						       "eth%d");
+			if (ret)
+				netdev_err(vf_netdev,
+					"Cannot move to same namespace as %s: %d\n",
+					net->name, ret);
+			else
+				netdev_info(vf_netdev,
+					"Moved VF to namespace with: %s\n",
+					net->name);
+		}
+
 		/* Setting synthetic device up transparently sets
 		 * slave as up. If open fails, then slave will be
 		 * still be offline (and not used).
-- 
2.34.1