Implement sleepable RCU mechanism using shared exclusive locks.

MFC after:	1 week
Sponsored by:	Mellanox Technologies

1 files changed, 72 insertions, 0 deletions

diff --git a/sys/compat/linuxkpi/common/include/linux/srcu.h b/sys/compat/linuxkpi/common/include/linux/srcu.h
new file mode 100644
index 0000000..c20215b
--- /dev/null
+++ b/sys/compat/linuxkpi/common/include/linux/srcu.h
@@ -0,0 +1,72 @@
+/*-
+ * Copyright (c) 2015 Mellanox Technologies, Ltd.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice unmodified, this list of conditions, and the following
+ *    disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+#ifndef	_LINUX_SRCU_H_
+#define	_LINUX_SRCU_H_
+
+#include <sys/param.h>
+#include <sys/lock.h>
+#include <sys/sx.h>
+
+struct srcu_struct {
+	struct sx sx;
+};
+
+static inline int
+init_srcu_struct(struct srcu_struct *srcu)
+{
+	sx_init(&srcu->sx, "SleepableRCU");
+	return (0);
+}
+
+static inline void
+cleanup_srcu_struct(struct srcu_struct *srcu)
+{
+	sx_destroy(&srcu->sx);
+}
+
+static inline int
+srcu_read_lock(struct srcu_struct *srcu)
+{
+	sx_slock(&srcu->sx);
+	return (0);
+}
+
+static inline void
+srcu_read_unlock(struct srcu_struct *srcu, int key)
+{
+	sx_sunlock(&srcu->sx);
+}
+
+static inline void
+synchronize_srcu(struct srcu_struct *srcu)
+{
+	sx_xlock(&srcu->sx);
+	sx_xunlock(&srcu->sx);
+}
+
+#endif					/* _LINUX_SRCU_H_ */