Drivers: hv: vmbus: Fix a bug in vmbus_establish_gpadl()

Correctly compute the local (gpadl) handle.
I would like to thank Michael Brown <mcb30@ipxe.org> for seeing this bug.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reported-by: NMichael Brown <mcb30@ipxe.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/channel.c

@@ -366,8 +366,8 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 	unsigned long flags;
 	int ret = 0;
 
-	next_gpadl_handle = atomic_read(&vmbus_connection.next_gpadl_handle);
-	atomic_inc(&vmbus_connection.next_gpadl_handle);
+	next_gpadl_handle =
+		(atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 
 	ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
 	if (ret)