lock: use rwlock by default (#232)

lock: use rwlock by default

src/lock/lock.c

@@ -1,10 +1,9 @@
 /**
- * @file lock/lock.c  Pthread mutex locking
+ * @file lock.c  Pthread read/write locking
  *
  * Copyright (C) 2010 Creytiv.com
  */
-#define _DEFAULT_SOURCE 1
-#define __USE_UNIX98 1
+#define _GNU_SOURCE 1
 #include <pthread.h>
 #include <re_types.h>
 #include <re_mem.h>
@@ -16,39 +15,26 @@
 #include <re_dbg.h>
 
 
-#ifndef RELEASE
-#define LOCK_DEBUG 0
-#endif
-
-
-/** Defines a lock */
 struct lock {
-	pthread_mutex_t m;
+	pthread_rwlock_t lock;
 };
 
 
 static void lock_destructor(void *data)
 {
 	struct lock *l = data;
 
-	int err = pthread_mutex_destroy(&l->m);
+	int err = pthread_rwlock_destroy(&l->lock);
 	if (err) {
-		DEBUG_WARNING("pthread_mutex_destroy: %m\n", err);
+		DEBUG_WARNING("pthread_rwlock_destroy: %m\n", err);
 	}
 }
 
 
-/**
- * Allocate a new lock
- *
- * @param lp Pointer to allocated lock object
- *
- * @return 0 if success, otherwise errorcode
- */
 int lock_alloc(struct lock **lp)
 {
-	pthread_mutexattr_t attr;
 	struct lock *l;
+	int err;
 
 	if (!lp)
 		return EINVAL;
@@ -57,85 +43,71 @@ int lock_alloc(struct lock **lp)
 	if (!l)
 		return ENOMEM;
 
-	(void)pthread_mutex_init(&l->m, NULL);
-
-	pthread_mutexattr_init(&attr);
-
-#if LOCK_DEBUG
-	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK);
-	DEBUG_NOTICE("init debug lock\n");
-#else
-	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
-#endif
-	pthread_mutex_init(&l->m, &attr);
+	err = pthread_rwlock_init(&l->lock, NULL);
+	if (err)
+		goto out;
 
 	*lp = l;
-	return 0;
+
+ out:
+	if (err)
+		mem_deref(l);
+	return err;
 }
 
 
-/**
- * Get the lock for reading
- *
- * @param l Lock object
- */
 void lock_read_get(struct lock *l)
 {
-	const int err = pthread_mutex_lock(&l->m);
+	int err;
+
+	if (!l)
+		return;
+
+	err = pthread_rwlock_rdlock(&l->lock);
 	if (err) {
 		DEBUG_WARNING("lock_read_get: %m\n", err);
 	}
 }
 
 
-/**
- * Get the lock for writing
- *
- * @param l Lock object
- */
 void lock_write_get(struct lock *l)
 {
-	const int err = pthread_mutex_lock(&l->m);
+	int err;
+
+	if (!l)
+		return;
+
+	err = pthread_rwlock_wrlock(&l->lock);
 	if (err) {
 		DEBUG_WARNING("lock_write_get: %m\n", err);
 	}
 }
 
 
-/**
- * Attempt to get a lock for reading
- *
- * @param l Lock object
- *
- * @return 0 if success, otherwise errorcode
- */
 int lock_read_try(struct lock *l)
 {
-	return pthread_mutex_trylock(&l->m);
+	if (!l)
+		return EINVAL;
+	return pthread_rwlock_tryrdlock(&l->lock);
 }
 
 
-/**
- * Attempt to get a lock for writing
- *
- * @param l Lock object
- *
- * @return 0 if success, otherwise errorcode
- */
 int lock_write_try(struct lock *l)
 {
-	return pthread_mutex_trylock(&l->m);
+	if (!l)
+		return EINVAL;
+	return pthread_rwlock_trywrlock(&l->lock);
 }
 
 
-/**
- * Release a lock
- *
- * @param l Lock object
- */
 void lock_rel(struct lock *l)
 {
-	const int err = pthread_mutex_unlock(&l->m);
+	int err;
+
+	if (!l)
+		return;
+
+	err = pthread_rwlock_unlock(&l->lock);
 	if (err) {
 		DEBUG_WARNING("lock_rel: %m\n", err);
 	}

src/lock/mod.mk

@@ -4,9 +4,7 @@
 # Copyright (C) 2010 Creytiv.com
 #
 
-ifdef HAVE_PTHREAD_RWLOCK
-SRCS	+= lock/rwlock.c
-else ifdef HAVE_PTHREAD
+ifdef HAVE_PTHREAD
 SRCS	+= lock/lock.c
 else ifeq ($(OS),win32)
 SRCS	+= lock/win32/lock.c