From 8b4e954ca8cf671c25e6df1d675caa34b64f7678 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 21 Mar 2013 10:05:07 -0600
Subject: [PATCH] mutex: add magic checks

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 mutex.c | 15 +++++++++++++++
 mutex.h |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/mutex.c b/mutex.c
index 332e9f9e..af5e5011 100644
--- a/mutex.c
+++ b/mutex.c
@@ -7,6 +7,7 @@
 #include <errno.h>
 #include <pthread.h>
 #include <sys/mman.h>
+#include <assert.h>
 
 #include "fio.h"
 #include "log.h"
@@ -19,6 +20,7 @@
 
 void fio_mutex_remove(struct fio_mutex *mutex)
 {
+	assert(mutex->magic = FIO_MUTEX_MAGIC);
 	pthread_cond_destroy(&mutex->cond);
 	munmap((void *) mutex, sizeof(*mutex));
 }
@@ -40,6 +42,7 @@ struct fio_mutex *fio_mutex_init(int value)
 	}
 
 	mutex->value = value;
+	mutex->magic = FIO_MUTEX_MAGIC;
 
 	ret = pthread_mutexattr_init(&attr);
 	if (ret) {
@@ -92,6 +95,8 @@ int fio_mutex_down_timeout(struct fio_mutex *mutex, unsigned int seconds)
 	struct timespec t;
 	int ret = 0;
 
+	assert(mutex->magic = FIO_MUTEX_MAGIC);
+
 	gettimeofday(&tv_s, NULL);
 	t.tv_sec = tv_s.tv_sec + seconds;
 	t.tv_nsec = tv_s.tv_usec * 1000;
@@ -122,6 +127,8 @@ int fio_mutex_down_timeout(struct fio_mutex *mutex, unsigned int seconds)
 
 void fio_mutex_down(struct fio_mutex *mutex)
 {
+	assert(mutex->magic = FIO_MUTEX_MAGIC);
+
 	pthread_mutex_lock(&mutex->lock);
 
 	while (!mutex->value) {
@@ -136,6 +143,8 @@ void fio_mutex_down(struct fio_mutex *mutex)
 
 void fio_mutex_up(struct fio_mutex *mutex)
 {
+	assert(mutex->magic = FIO_MUTEX_MAGIC);
+
 	pthread_mutex_lock(&mutex->lock);
 	read_barrier();
 	if (!mutex->value && mutex->waiters)
@@ -146,21 +155,25 @@ void fio_mutex_up(struct fio_mutex *mutex)
 
 void fio_rwlock_write(struct fio_rwlock *lock)
 {
+	assert(lock->magic = FIO_RWLOCK_MAGIC);
 	pthread_rwlock_wrlock(&lock->lock);
 }
 
 void fio_rwlock_read(struct fio_rwlock *lock)
 {
+	assert(lock->magic = FIO_RWLOCK_MAGIC);
 	pthread_rwlock_rdlock(&lock->lock);
 }
 
 void fio_rwlock_unlock(struct fio_rwlock *lock)
 {
+	assert(lock->magic = FIO_RWLOCK_MAGIC);
 	pthread_rwlock_unlock(&lock->lock);
 }
 
 void fio_rwlock_remove(struct fio_rwlock *lock)
 {
+	assert(lock->magic = FIO_RWLOCK_MAGIC);
 	munmap((void *) lock, sizeof(*lock));
 }
 
@@ -178,6 +191,8 @@ struct fio_rwlock *fio_rwlock_init(void)
 		goto err;
 	}
 
+	lock->magic = FIO_RWLOCK_MAGIC;
+
 	ret = pthread_rwlock_init(&lock->lock, NULL);
 	if (ret) {
 		log_err("pthread_rwlock_init: %s\n", strerror(ret));
diff --git a/mutex.h b/mutex.h
index 49a66e36..4f3486df 100644
--- a/mutex.h
+++ b/mutex.h
@@ -3,15 +3,20 @@
 
 #include <pthread.h>
 
+#define FIO_MUTEX_MAGIC		0x4d555445U
+#define FIO_RWLOCK_MAGIC	0x52574c4fU
+
 struct fio_mutex {
 	pthread_mutex_t lock;
 	pthread_cond_t cond;
 	int value;
 	int waiters;
+	int magic;
 };
 
 struct fio_rwlock {
 	pthread_rwlock_t lock;
+	int magic;
 };
 
 enum {
-- 
2.25.1