hv_netvsc: change GPAD teardown order on older versions

On older versions of Windows, the host ignores messages after
vmbus channel is closed.

Workaround this by doing what Windows does and send the teardown
before close on older versions of NVSP protocol.

Reported-by: Mohammed Gamal <mgamal@redhat.com>
Fixes: 30a734dfed91 ("hv_netvsc: netvsc_teardown_gpadl() split")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 12c044baf1af7849bee079449635f982260929ab..37b0a30d6b034666eb1f486cb38371cc78f448f1 100644 (file)
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -571,10 +571,15 @@ void netvsc_device_remove(struct hv_device *device)
         */
        netdev_dbg(ndev, "net device safe to remove\n");
 
+       /* older versions require that buffer be revoked before close */
+       if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_4)
+               netvsc_teardown_gpadl(device, net_device);
+
        /* Now, we can close the channel safely */
        vmbus_close(device->channel);
 
-       netvsc_teardown_gpadl(device, net_device);
+       if (net_device->nvsp_version >= NVSP_PROTOCOL_VERSION_4)
+               netvsc_teardown_gpadl(device, net_device);
 
        /* Release all resources */
        free_netvsc_device_rcu(net_device);