From dcad4d19497876da833714a644c36e2ad1a9d72d Mon Sep 17 00:00:00 2001
From: Sepherosa Ziehau <sephe@dragonflybsd.org>
Date: Sun, 28 Dec 2008 11:24:30 +0800
Subject: [PATCH] Put last_td accessing back into INVARIANTS

---
 sys/kern/lwkt_serialize.c | 25 ++++++++++++++++++-------
 sys/sys/serialize.h       |  8 ++++++++
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/sys/kern/lwkt_serialize.c b/sys/kern/lwkt_serialize.c
index f63e1bb77d..7b972e3d36 100644
--- a/sys/kern/lwkt_serialize.c
+++ b/sys/kern/lwkt_serialize.c
@@ -122,8 +122,9 @@ void
 lwkt_serialize_init(lwkt_serialize_t s)
 {
     atomic_intr_init(&s->interlock);
+#ifdef INVARIANTS
     s->last_td = (void *)-4;
-
+#endif
     s->sleep_cnt = 0;
     s->tryfail_cnt = 0;
     s->enter_cnt = 0;
@@ -145,8 +146,9 @@ lwkt_serialize_adaptive_enter(lwkt_serialize_t s)
     logslz(enter_beg, s);
     atomic_intr_cond_enter(&s->interlock, lwkt_serialize_adaptive_sleep, &bo);
     logslz(enter_end, s);
-
+#ifdef INVARIANTS
     s->last_td = curthread;
+#endif
 #ifdef PROFILE_SERIALIZER
     s->enter_cnt++;
 #endif
@@ -161,8 +163,9 @@ lwkt_serialize_enter(lwkt_serialize_t s)
     logslz(enter_beg, s);
     atomic_intr_cond_enter(&s->interlock, lwkt_serialize_sleep, s);
     logslz(enter_end, s);
-
+#ifdef INVARIANTS
     s->last_td = curthread;
+#endif
 #ifdef PROFILE_SERIALIZER
     s->enter_cnt++;
 #endif
@@ -183,7 +186,9 @@ lwkt_serialize_try(lwkt_serialize_t s)
 #endif
     logslz(try, s);
     if ((error = atomic_intr_cond_try(&s->interlock)) == 0) {
+#ifdef INVARIANTS
 	s->last_td = curthread;
+#endif
 	logslz(tryok, s);
 	return(1);
     }
@@ -198,8 +203,9 @@ void
 lwkt_serialize_exit(lwkt_serialize_t s)
 {
     ASSERT_SERIALIZED(s);
+#ifdef INVARIANTS
     s->last_td = (void *)-2;
-
+#endif
     logslz(exit_beg, s);
     atomic_intr_cond_exit(&s->interlock, lwkt_serialize_wakeup, s);
     logslz(exit_end, s);
@@ -233,8 +239,9 @@ lwkt_serialize_handler_call(lwkt_serialize_t s, void (*func)(void *, void *),
 	logslz(enter_beg, s);
 	atomic_intr_cond_enter(&s->interlock, lwkt_serialize_sleep, s);
 	logslz(enter_end, s);
-
+#ifdef INVARIANTS
 	s->last_td = curthread;
+#endif
 #ifdef PROFILE_SERIALIZER
 	s->enter_cnt++;
 #endif
@@ -242,8 +249,9 @@ lwkt_serialize_handler_call(lwkt_serialize_t s, void (*func)(void *, void *),
 	    func(arg, frame);
 
 	ASSERT_SERIALIZED(s);
+#ifdef INVARIANTS
 	s->last_td = (void *)-2;
-
+#endif
 	logslz(exit_beg, s);
 	atomic_intr_cond_exit(&s->interlock, lwkt_serialize_wakeup, s);
 	logslz(exit_end, s);
@@ -268,14 +276,17 @@ lwkt_serialize_handler_try(lwkt_serialize_t s, void (*func)(void *, void *),
 #endif
 	logslz(try, s);
 	if (atomic_intr_cond_try(&s->interlock) == 0) {
+#ifdef INVARIANTS
 	    s->last_td = curthread;
+#endif
 	    logslz(tryok, s);
 
 	    func(arg, frame);
 
 	    ASSERT_SERIALIZED(s);
+#ifdef INVARIANTS
 	    s->last_td = (void *)-2;
-
+#endif
 	    logslz(exit_beg, s);
 	    atomic_intr_cond_exit(&s->interlock, lwkt_serialize_wakeup, s);
 	    logslz(exit_end, s);
diff --git a/sys/sys/serialize.h b/sys/sys/serialize.h
index b54ba100bb..88c0dc2c24 100644
--- a/sys/sys/serialize.h
+++ b/sys/sys/serialize.h
@@ -29,10 +29,18 @@ struct lwkt_serialize {
     unsigned int	try_cnt;
 };
 
+#ifdef INVARIANTS
+
+/*
+ * Note that last_td is only maintained when INVARIANTS is turned on,
+ * so this check is only useful as part of a [K]KASSERT.
+ */
 #define IS_SERIALIZED(ss)		((ss)->last_td == curthread)
 #define ASSERT_SERIALIZED(ss)		KKASSERT(IS_SERIALIZED((ss)))
 #define ASSERT_NOT_SERIALIZED(ss)	KKASSERT(!IS_SERIALIZED((ss)))
 
+#endif	/* INVARIANTS */
+
 typedef struct lwkt_serialize *lwkt_serialize_t;
 
 void lwkt_serialize_init(lwkt_serialize_t);
-- 
2.41.0