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Re: [libvirt] [PATCH] qemu_conf: Properly mark driver->config as self-locking APIs



On Tue, Jul 16, 2013 at 08:25:25PM +0200, Michal Privoznik wrote:
> Since a9e97e0c we don't require driver->config, or
> virQEMUDriverGetConfig() to be called with locked QEMU driver. In fact,
> calling it with the driver locked would cause deadlock. Hence, the
> annotation to the struct field is not right.
> ---
>  src/qemu/qemu_conf.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
> index 8229cfc..fd5cc57 100644
> --- a/src/qemu/qemu_conf.h
> +++ b/src/qemu/qemu_conf.h
> @@ -160,8 +160,7 @@ struct _virQEMUDriverConfig {
>  struct _virQEMUDriver {
>      virMutex lock;
>  
> -    /* Require lock to get reference on 'config',
> -     * then lockless thereafter */
> +    /* Immutable pointer, self-locking APIs */
>      virQEMUDriverConfigPtr config;

Actually, it is  'immutable pointer, immutable+lockless data', since
we don't require any locks to be held in order to access fields in
the config object.

Regards,
Daniel
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