From fb6e510b9ae45b9b984b4646b4be6b9d7a2bbf7c Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Date: Tue, 15 Sep 2009 14:36:55 -0400
Subject: [PATCH] urcu qsbr: add DEBUG_RCU self check

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
---
 Makefile.build.inc | 13 ++++++++++---
 README             |  2 ++
 urcu-qsbr.h        |  8 ++++++++
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/Makefile.build.inc b/Makefile.build.inc
index fc4c471..56c7705 100644
--- a/Makefile.build.inc
+++ b/Makefile.build.inc
@@ -1,7 +1,14 @@
 
-CFLAGS=-Wall -O2 -g -I.
-#debug
-#CFLAGS=-Wall -g
+CFLAGS=-Wall -I.
+
+#optimized
+CFLAGS+=-O2
+
+#debug information
+CFLAGS+=-g
+
+#RCU debug (slower, with error-checks)
+#CFLAGS+=-DDEBUG_RCU
 
 LDFLAGS=-lpthread
 
diff --git a/README b/README
index 0ec723d..f9af1eb 100644
--- a/README
+++ b/README
@@ -53,6 +53,8 @@ Usage of DEBUG_RCU
 
 	DEBUG_RCU is used to add internal debugging self-checks to the
 	RCU library. This define adds a performance penality when enabled.
+	Can be enabled by uncommenting the corresponding line in
+	Makefile.build.inc.
 
 Usage of DEBUG_YIELD
 
diff --git a/urcu-qsbr.h b/urcu-qsbr.h
index f5392a3..448074d 100644
--- a/urcu-qsbr.h
+++ b/urcu-qsbr.h
@@ -31,6 +31,7 @@
 
 #include <stdlib.h>
 #include <pthread.h>
+#include <assert.h>
 
 #include <compiler.h>
 #include <arch.h>
@@ -108,6 +109,12 @@
  */
 #define KICK_READER_LOOPS 10000
 
+#ifdef DEBUG_RCU
+#define rcu_assert(args...)	assert(args)
+#else
+#define rcu_assert(args...)
+#endif
+
 #ifdef DEBUG_YIELD
 #include <sched.h>
 #include <time.h>
@@ -180,6 +187,7 @@ static inline int rcu_gp_ongoing(long *value)
 
 static inline void _rcu_read_lock(void)
 {
+	rcu_assert(rcu_reader_qs_gp & 1);
 }
 
 static inline void _rcu_read_unlock(void)
-- 
2.34.1