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-rw-r--r--include/linux/rcupdate.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 75a2eded7aa2..185dd9736863 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -383,6 +383,24 @@ do { \
} while (0)
/**
+ * rcu_replace_pointer() - replace an RCU pointer, returning its old value
+ * @rcu_ptr: RCU pointer, whose old value is returned
+ * @ptr: regular pointer
+ * @c: the lockdep conditions under which the dereference will take place
+ *
+ * Perform a replacement, where @rcu_ptr is an RCU-annotated
+ * pointer and @c is the lockdep argument that is passed to the
+ * rcu_dereference_protected() call used to read that pointer. The old
+ * value of @rcu_ptr is returned, and @rcu_ptr is set to @ptr.
+ */
+#define rcu_replace_pointer(rcu_ptr, ptr, c) \
+({ \
+ typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c)); \
+ rcu_assign_pointer((rcu_ptr), (ptr)); \
+ __tmp; \
+})
+
+/**
* rcu_swap_protected() - swap an RCU and a regular pointer
* @rcu_ptr: RCU pointer
* @ptr: regular pointer