[libvirt] [PATCH] qemu_conf: Properly mark driver->config as self-locking APIs
Daniel P. Berrange
berrange at redhat.com
Wed Jul 17 09:46:03 UTC 2013
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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