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-rw-r--r--include/linux/lockdep.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index d36619ead3ba..00e46376e28f 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -157,6 +157,24 @@ struct lockdep_map {
#endif
};
+static inline void lockdep_copy_map(struct lockdep_map *to,
+ struct lockdep_map *from)
+{
+ int i;
+
+ *to = *from;
+ /*
+ * Since the class cache can be modified concurrently we could observe
+ * half pointers (64bit arch using 32bit copy insns). Therefore clear
+ * the caches and take the performance hit.
+ *
+ * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
+ * that relies on cache abuse.
+ */
+ for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
+ to->class_cache[i] = NULL;
+}
+
/*
* Every lock has a list of other locks that were taken after it.
* We only grow the list, never remove from it: