Re: [PATCH v3 2/7] migration: Implement switchover ack logic

[Peter Xu]

On Thu, May 25, 2023 at 12:51:46PM +0300, Avihai Horon wrote:
> However, there is one issue -- we can't send the ACK up here [1], as at that
> point the return path has not been created yet.
> A possible solution is to check for mis->switchover_ack_pending_num == 0
> when we create the return path and send the ACK there.
> It's not as clean as checking the number of users and ACKing here in the
> same place, but it works.
> 
> Do you think it's OK? or do you have another idea?

Good point. It looks fine to me as we create the return path mostly at the
very early stage right after the migration headers.

Let's just add a comment describing the ordering fact?  IMHO it's about
switchover_ack_pending_num won't be used before setup of the return path
due to current wire protocol (we create return path before sending mostly
anything else), so setup it there is fine.

-- 
Peter Xu