Re: [PATCH v2 2/7] Implement drain_call_rcu and use it in hmp_device_del

[Markus Armbruster]

Maxim Levitsky <mlevitsk@redhat.com> writes:

> This allows to preserve the semantics of hmp_device_del,
> that the device is deleted immediatly which was changed by previos
> patch that delayed this to RCU callback
>
> Suggested-by: Stefan Hajnoczi <stefanha@gmail.com>
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>  include/qemu/rcu.h |  1 +
>  qdev-monitor.c     |  3 +++
>  util/rcu.c         | 33 +++++++++++++++++++++++++++++++++
>  3 files changed, 37 insertions(+)
>
> diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h
> index 570aa603eb..0e375ebe13 100644
> --- a/include/qemu/rcu.h
> +++ b/include/qemu/rcu.h
> @@ -133,6 +133,7 @@ struct rcu_head {
>  };
>  
>  extern void call_rcu1(struct rcu_head *head, RCUCBFunc *func);
> +extern void drain_call_rcu(void);
>  
>  /* The operands of the minus operator must have the same type,
>   * which must be the one that we specify in the cast.
> diff --git a/qdev-monitor.c b/qdev-monitor.c
> index 56cee1483f..70877840a2 100644
> --- a/qdev-monitor.c
> +++ b/qdev-monitor.c
> @@ -812,6 +812,8 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, 
> Error **errp)
>          return;
>      }
>      dev = qdev_device_add(opts, &local_err);
> +    drain_call_rcu();
> +
>      if (!dev) {
>          error_propagate(errp, local_err);
>          qemu_opts_del(opts);
> @@ -904,6 +906,7 @@ void qmp_device_del(const char *id, Error **errp)
>          }
>  
>          qdev_unplug(dev, errp);
> +        drain_call_rcu();
>      }
>  }
>  

Subject claims "in hmp_device_del", code has it in qmp_device_add() and
qmp_device_del().  Please advise.

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