Similar to the implementation in lockable.h, implement macros to automatically take and release the rdlock. Create the empty GraphLockable struct only to use it as a type for G_DEFINE_AUTOPTR_CLEANUP_FUNC.
Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com> --- include/block/graph-lock.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h index 9430707dca..0d886a9ca3 100644 --- a/include/block/graph-lock.h +++ b/include/block/graph-lock.h @@ -141,5 +141,40 @@ void assert_bdrv_graph_readable(void); */ void assert_bdrv_graph_writable(void); +typedef struct GraphLockable { } GraphLockable; + +/* + * In C, compound literals have the lifetime of an automatic variable. + * In C++ it would be different, but then C++ wouldn't need QemuLockable + * either... + */ +#define GML_OBJ_() (&(GraphLockable) { }) + +static inline GraphLockable *graph_lockable_auto_lock(GraphLockable *x) +{ + bdrv_graph_co_rdlock(); + return x; +} + +static inline void graph_lockable_auto_unlock(GraphLockable *x) +{ + bdrv_graph_co_rdunlock(); +} + +G_DEFINE_AUTOPTR_CLEANUP_FUNC(GraphLockable, graph_lockable_auto_unlock) + +#define WITH_GRAPH_RDLOCK_GUARD_(var) \ + for (g_autoptr(GraphLockable) var = graph_lockable_auto_lock(GML_OBJ_()); \ + var; \ + graph_lockable_auto_unlock(var), var = NULL) + +#define WITH_GRAPH_RDLOCK_GUARD() \ + WITH_GRAPH_RDLOCK_GUARD_(glue(graph_lockable_auto, __COUNTER__)) + +#define GRAPH_RDLOCK_GUARD(x) \ + g_autoptr(GraphLockable) \ + glue(graph_lockable_auto, __COUNTER__) G_GNUC_UNUSED = \ + graph_lockable_auto_lock(GML_OBJ_()) + #endif /* GRAPH_LOCK_H */ -- 2.31.1