kern/rcu: new module

This module implements preemptible RCU.

1 files changed, 61 insertions, 0 deletions

diff --git a/kern/rcu_i.h b/kern/rcu_i.h
new file mode 100644
index 00000000..6be933db
--- /dev/null
+++ b/kern/rcu_i.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2018 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _KERN_RCU_I_H
+#define _KERN_RCU_I_H
+
+#include <assert.h>
+#include <stdbool.h>
+
+#include <kern/macros.h>
+#include <kern/rcu_types.h>
+#include <kern/thread.h>
+
+void rcu_reader_leave(struct rcu_reader *reader);
+
+static inline bool
+rcu_reader_in_cs(const struct rcu_reader *reader)
+{
+    return reader->level != 0;
+}
+
+static inline bool
+rcu_reader_linked(const struct rcu_reader *reader)
+{
+    assert(reader == thread_rcu_reader(thread_self()));
+    return reader->linked;
+}
+
+static inline void
+rcu_reader_inc(struct rcu_reader *reader)
+{
+    reader->level++;
+    assert(reader->level != 0);
+}
+
+static inline void
+rcu_reader_dec(struct rcu_reader *reader)
+{
+    assert(reader->level != 0);
+    reader->level--;
+
+    if (unlikely(!rcu_reader_in_cs(reader) && rcu_reader_linked(reader))) {
+        rcu_reader_leave(reader);
+    }
+}
+
+#endif /* _KERN_RCU_I_H */