Move c_src dirs back to toplevel

We just wanted c sourcefiles out of the top level, not c source
directories.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 48 insertions, 0 deletions

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
new file mode 100644
index 00000000..f5260270
--- /dev/null
+++ b/include/linux/rcupdate.h
@@ -0,0 +1,48 @@
+#ifndef __TOOLS_LINUX_RCUPDATE_H
+#define __TOOLS_LINUX_RCUPDATE_H
+
+#include <urcu.h>
+#include <linux/compiler.h>
+
+#define ULONG_CMP_GE(a, b)      (ULONG_MAX / 2 >= (a) - (b))
+
+#define rcu_dereference_check(p, c)	rcu_dereference(p)
+#define rcu_dereference_raw(p)		rcu_dereference(p)
+#define rcu_dereference_protected(p, c)	rcu_dereference(p)
+#define rcu_access_pointer(p)		READ_ONCE(p)
+
+#define kfree_rcu(ptr, rcu_head)	kfree(ptr) /* XXX */
+#define kfree_rcu_mightsleep(ptr)	kfree(ptr) /* XXX */
+#define kvfree_rcu_mightsleep(ptr)	kfree(ptr) /* XXX */
+
+#define RCU_INIT_POINTER(p, v)		WRITE_ONCE(p, v)
+
+/* Has the specified rcu_head structure been handed to call_rcu()? */
+
+/**
+ * rcu_head_init - Initialize rcu_head for rcu_head_after_call_rcu()
+ * @rhp: The rcu_head structure to initialize.
+ *
+ * If you intend to invoke rcu_head_after_call_rcu() to test whether a
+ * given rcu_head structure has already been passed to call_rcu(), then
+ * you must also invoke this rcu_head_init() function on it just after
+ * allocating that structure.  Calls to this function must not race with
+ * calls to call_rcu(), rcu_head_after_call_rcu(), or callback invocation.
+ */
+static inline void rcu_head_init(struct rcu_head *rhp)
+{
+	rhp->func = (void *)~0L;
+}
+
+static inline bool
+rcu_head_after_call_rcu(struct rcu_head *rhp,
+			void (*f)(struct rcu_head *head))
+{
+	void (*func)(struct rcu_head *head) = READ_ONCE(rhp->func);
+
+	if (func == f)
+		return true;
+	return false;
+}
+
+#endif /* __TOOLS_LINUX_RCUPDATE_H */