Drivers: hv: vmbus: don't send CHANNELMSG_UNLOAD on pre-Win2012R2 hosts

Pre-Win2012R2 hosts don't properly handle CHANNELMSG_UNLOAD and
wait_for_completion() hangs. Avoid sending such request on old hosts.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 4506a66236181abe932f4c0358db6ef9a6bf61b3..00ba3f36f193795ba09bce7c97091229e5b2b530 100644 (file)
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -469,6 +469,10 @@ void vmbus_initiate_unload(void)
 {
        struct vmbus_channel_message_header hdr;
 
+       /* Pre-Win2012R2 hosts don't support reconnect */
+       if (vmbus_proto_version < VERSION_WIN8_1)
+               return;
+
        init_completion(&vmbus_connection.unload_event);
        memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
        hdr.msgtype = CHANNELMSG_UNLOAD;