lockdep: add might_lock() / might_lock_read()
useful to establish a lock dependency in case the actual dependency is
rare or hard to trigger.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 331e5f1..0aa657a 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -480,4 +480,22 @@
# define lock_map_release(l) do { } while (0)
#endif
+#ifdef CONFIG_PROVE_LOCKING
+# define might_lock(lock) \
+do { \
+ typecheck(struct lockdep_map *, &(lock)->dep_map); \
+ lock_acquire(&(lock)->dep_map, 0, 0, 0, 2, NULL, _THIS_IP_); \
+ lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
+} while (0)
+# define might_lock_read(lock) \
+do { \
+ typecheck(struct lockdep_map *, &(lock)->dep_map); \
+ lock_acquire(&(lock)->dep_map, 0, 0, 1, 2, NULL, _THIS_IP_); \
+ lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
+} while (0)
+#else
+# define might_lock(lock) do { } while (0)
+# define might_lock_read(lock) do { } while (0)
+#endif
+
#endif /* __LINUX_LOCKDEP_H */