On Fri, May 29, 2020 at 02:00:47AM +0530, Kirti Wankhede wrote:
> + * The sequence to be followed while in pre-copy state and stop-and-copy state
> + * is as follows:
> + * a. Read pending_bytes, indicating the start of a new iteration to get device
> + *    data. Repeated read on pending_bytes at this stage should have no side
> + *    effects.
> + *    If pending_bytes == 0, the user application should not iterate to get data
> + *    for that device.

What if the device doesn't have any data yet but might have some later?
This seems to say that if pending_bytes reads 0 the first time then this
device doesn't support pre-copy at all.