1 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index ec2fc5b32646..411969cb5243 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -40,6 +40,7 @@
 #include <linux/cpumask.h>
 #include <linux/seqlock.h>
 #include <linux/lockdep.h>
+#include <linux/completion.h>
 
 /**
  * struct rcu_head - callback structure for use with RCU
@@ -168,6 +169,27 @@ struct rcu_head {
                 (p) = (v); \
         })
 
+/* Infrastructure to implement the synchronize_() primitives. */
+
+struct rcu_synchronize {
+        struct rcu_head head;
+        struct completion completion;
+};
+
+extern void wakeme_after_rcu(struct rcu_head  *head);
+
+#define synchronize_rcu_xxx(name, func) \
+void name(void) \
+{ \
+        struct rcu_synchronize rcu; \
+        \
+        init_completion(&rcu.completion); \
+        /* Will wake me after RCU finished. */ \
+        func(&rcu.head, wakeme_after_rcu); \
+        /* Wait for it. */ \
+        wait_for_completion(&rcu.completion); \
+}
+
 /**
  * synchronize_sched - block until all CPUs have exited any non-preemptive
  * kernel code sequences.