hv_netvsc: change GPAD teardown order on older versions

[ Commit 0ef58b0a05c127762f975c3dfe8b922e4aa87a29 upstream. ]

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: 0cf737808ae7 ("hv_netvsc: netvsc_teardown_gpadl() split")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 03328a60377eb504d4f320c5f22041c506c6bee9..3f3c6489ade209931fe0563c30bb4e25009a913d 100644 (file)
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -570,10 +570,15 @@ 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);