Re: [Qemu-devel] [PULL 27/28] migration: protect migration_bitmap

[Paolo Bonzini]

On 09/07/2015 10:14, Wen Congyang wrote:
> >      flush_compressed_data(f);
> >      ram_control_after_iterate(f, RAM_CONTROL_FINISH);
> > -    migration_end();
> > -
> >      rcu_read_unlock();
> > +
> > +    migration_end();
> >      qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
>
> Yes, this patch can work. But if the caller hold the rcu read lock in
> the future, we may need to fix it again. I think it is better to use
> call_rcu().

Why?  Just document that migration_end must be called outside an RCU
read-side critical section.  It's not a heavy limitation.

Paolo