haiku/headers/private/kernel/lock.h
Axel Dörfler 78b32dd026 * The rw_lock is now able to nest read/write locks when you have a write lock.
It follows the semantics of the BFS R/W lock, though, that is, if you unlock
  your write lock before the read locks, the read locks effectively become
  write locks, too.
* Added a mutex_transfer_lock() function that will allow you to unlock a mutex
  in a different thread than the one which locked it (only matters if KDEBUG
  is enabled, though).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26316 a95241bf-73f2-0310-859d-f6bbb57e9c96
2008-07-08 07:56:49 +00:00

179 lines
4.1 KiB
C

/*
* Copyright 2008, Ingo Weinhold, ingo_weinhold@gmx.de.
* Copyright 2002-2008, Axel Dörfler, axeld@pinc-software.de.
* Distributed under the terms of the MIT License.
*
* Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
* Distributed under the terms of the NewOS License.
*/
#ifndef _KERNEL_LOCK_H
#define _KERNEL_LOCK_H
#include <OS.h>
#include <debug.h>
struct mutex_waiter;
typedef struct mutex {
const char* name;
struct mutex_waiter* waiters;
#ifdef KDEBUG
thread_id holder;
#else
int32 count;
#endif
uint8 flags;
} mutex;
#define MUTEX_FLAG_CLONE_NAME 0x1
typedef struct recursive_lock {
mutex lock;
#ifndef KDEBUG
thread_id holder;
#endif
int recursion;
} recursive_lock;
struct rw_lock_waiter;
typedef struct rw_lock {
const char* name;
struct rw_lock_waiter* waiters;
thread_id holder;
int32 reader_count;
int32 writer_count;
int32 owner_count;
uint32 flags;
} rw_lock;
#define RW_LOCK_FLAG_CLONE_NAME 0x1
#if 0 && KDEBUG // XXX disable this for now, it causes problems when including thread.h here
# include <thread.h>
#define ASSERT_LOCKED_RECURSIVE(r) { ASSERT(thread_get_current_thread_id() == (r)->holder); }
#define ASSERT_LOCKED_MUTEX(m) { ASSERT(thread_get_current_thread_id() == (m)->holder); }
#else
#define ASSERT_LOCKED_RECURSIVE(r)
#define ASSERT_LOCKED_MUTEX(m)
#endif
// static initializers
#ifdef KDEBUG
# define MUTEX_INITIALIZER(name) { name, NULL, -1, 0 }
# define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), 0 }
#else
# define MUTEX_INITIALIZER(name) { name, NULL, 0, 0 }
# define RECURSIVE_LOCK_INITIALIZER(name) { MUTEX_INITIALIZER(name), -1, 0 }
#endif
#define RW_LOCK_INITIALIZER(name) { name, NULL, -1, 0, 0, 0 }
#ifdef __cplusplus
extern "C" {
#endif
extern void recursive_lock_init(recursive_lock *lock, const char *name);
// name is *not* cloned nor freed in recursive_lock_destroy()
extern void recursive_lock_init_etc(recursive_lock *lock, const char *name,
uint32 flags);
extern void recursive_lock_destroy(recursive_lock *lock);
extern status_t recursive_lock_lock(recursive_lock *lock);
extern status_t recursive_lock_trylock(recursive_lock *lock);
extern void recursive_lock_unlock(recursive_lock *lock);
extern int32 recursive_lock_get_recursion(recursive_lock *lock);
extern void rw_lock_init(rw_lock* lock, const char* name);
// name is *not* cloned nor freed in rw_lock_destroy()
extern void rw_lock_init_etc(rw_lock* lock, const char* name, uint32 flags);
extern void rw_lock_destroy(rw_lock* lock);
extern status_t rw_lock_read_lock(rw_lock* lock);
extern status_t rw_lock_read_unlock(rw_lock* lock);
extern status_t rw_lock_write_lock(rw_lock* lock);
extern status_t rw_lock_write_unlock(rw_lock* lock);
extern void mutex_init(mutex* lock, const char* name);
// name is *not* cloned nor freed in mutex_destroy()
extern void mutex_init_etc(mutex* lock, const char* name, uint32 flags);
extern void mutex_destroy(mutex* lock);
// implementation private:
extern status_t _mutex_lock(mutex* lock, bool threadsLocked);
extern void _mutex_unlock(mutex* lock);
extern status_t _mutex_trylock(mutex* lock);
static inline status_t
mutex_lock(mutex* lock)
{
#ifdef KDEBUG
return _mutex_lock(lock, false);
#else
if (atomic_add(&lock->count, -1) < 0)
return _mutex_lock(lock, false);
return B_OK;
#endif
}
static inline status_t
mutex_lock_threads_locked(mutex* lock)
{
#ifdef KDEBUG
return _mutex_lock(lock, true);
#else
if (atomic_add(&lock->count, -1) < 0)
return _mutex_lock(lock, true);
return B_OK;
#endif
}
static inline status_t
mutex_trylock(mutex* lock)
{
#ifdef KDEBUG
return _mutex_trylock(lock);
#else
if (atomic_test_and_set(&lock->count, -1, 0) != 0)
return B_WOULD_BLOCK;
return B_OK;
#endif
}
static inline void
mutex_unlock(mutex* lock)
{
#ifdef KDEBUG
_mutex_unlock(lock);
#else
if (atomic_add(&lock->count, 1) < -1)
_mutex_unlock(lock);
#endif
}
static inline void
mutex_transfer_lock(mutex* lock, thread_id thread)
{
#ifdef KDEBUG
lock->holder = thread;
#endif
}
extern void lock_debug_init();
#ifdef __cplusplus
}
#endif
#endif /* _KERNEL_LOCK_H */