[PULL,13/28] graph-lock: Add GRAPH_UNLOCKED(_PTR)

Commit Message

Kevin Wolf May 10, 2023, 12:20 p.m. UTC

For some functions, it is part of their interface to be called without
holding the graph lock. Add a new macro to document this.

The macro expands to TSA_EXCLUDES(), which is a relatively weak check
because it passes in cases where the compiler just doesn't know if the
lock is held. Function pointers can't be checked at all. Therefore, its
primary purpose is documentation.

Signed-off-by: Kevin Wolf <[e-mail]>
Reviewed-by: Eric Blake <[e-mail]>
Reviewed-by: Stefan Hajnoczi <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Kevin Wolf <[e-mail]>
---
 include/block/graph-lock.h | 2 ++
 1 file changed, 2 insertions(+)

Patch

diff --git a/include/block/graph-lock.h b/include/block/graph-lock.h
index ac0fef8605..f17d1588e7 100644
--- a/include/block/graph-lock.h
+++ b/include/block/graph-lock.h
@@ -73,6 +73,7 @@  extern BdrvGraphLock graph_lock;
  */
 #define GRAPH_WRLOCK TSA_REQUIRES(graph_lock)
 #define GRAPH_RDLOCK TSA_REQUIRES_SHARED(graph_lock)
+#define GRAPH_UNLOCKED TSA_EXCLUDES(graph_lock)
 
 /*
  * TSA annotations are not part of function types, so checks are defeated when
@@ -83,6 +84,7 @@  extern BdrvGraphLock graph_lock;
  */
 #define GRAPH_RDLOCK_PTR TSA_GUARDED_BY(graph_lock)
 #define GRAPH_WRLOCK_PTR TSA_GUARDED_BY(graph_lock)
+#define GRAPH_UNLOCKED_PTR
 
 /*
  * register_aiocontext: