[linux-2.6-block.git] / kernel / locking / rtmutex_common.h

/*
 * RT Mutexes: blocking mutual exclusion locks with PI support
 *
 * started by Ingo Molnar and Thomas Gleixner:
 *
 *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
 *
 * This file contains the private data structure and API definitions.
 */

#ifndef __KERNEL_RTMUTEX_COMMON_H
#define __KERNEL_RTMUTEX_COMMON_H

#include <linux/rtmutex.h>

/*
 * The rtmutex in kernel tester is independent of rtmutex debugging. We
 * call schedule_rt_mutex_test() instead of schedule() for the tasks which
 * belong to the tester. That way we can delay the wakeup path of those
 * threads to provoke lock stealing and testing of  complex boosting scenarios.
 */
#ifdef CONFIG_RT_MUTEX_TESTER

extern void schedule_rt_mutex_test(struct rt_mutex *lock);

#define schedule_rt_mutex(_lock)				\
  do {								\
	if (!(current->flags & PF_MUTEX_TESTER))		\
		schedule();					\
	else							\
		schedule_rt_mutex_test(_lock);			\
  } while (0)

#else
# define schedule_rt_mutex(_lock)			schedule()
#endif

/*
 * This is the control structure for tasks blocked on a rt_mutex,
 * which is allocated on the kernel stack on of the blocked task.
 *
 * @tree_entry:		pi node to enqueue into the mutex waiters tree
 * @pi_tree_entry:	pi node to enqueue into the mutex owner waiters tree
 * @task:		task reference to the blocked task
 */
struct rt_mutex_waiter {
	struct rb_node          tree_entry;
	struct rb_node          pi_tree_entry;
	struct task_struct	*task;
	struct rt_mutex		*lock;
#ifdef CONFIG_DEBUG_RT_MUTEXES
	unsigned long		ip;
	struct pid		*deadlock_task_pid;
	struct rt_mutex		*deadlock_lock;
#endif
	int prio;
};

/*
 * Various helpers to access the waiters-tree:
 */
static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
{
	return !RB_EMPTY_ROOT(&lock->waiters);
}

static inline struct rt_mutex_waiter *
rt_mutex_top_waiter(struct rt_mutex *lock)
{
	struct rt_mutex_waiter *w;

	w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
		     tree_entry);
	BUG_ON(w->lock != lock);

	return w;
}

static inline int task_has_pi_waiters(struct task_struct *p)
{
	return !RB_EMPTY_ROOT(&p->pi_waiters);
}

static inline struct rt_mutex_waiter *
task_top_pi_waiter(struct task_struct *p)
{
	return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
			pi_tree_entry);
}

/*
 * lock->owner state tracking:
 */
#define RT_MUTEX_HAS_WAITERS	1UL
#define RT_MUTEX_OWNER_MASKALL	1UL

static inline struct task_struct *rt_mutex_owner(struct rt_mutex *lock)
{
	return (struct task_struct *)
		((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
}

/*
 * Constants for rt mutex functions which have a selectable deadlock
 * detection.
 *
 * RT_MUTEX_MIN_CHAINWALK:	Stops the lock chain walk when there are
 *				no further PI adjustments to be made.
 *
 * RT_MUTEX_FULL_CHAINWALK:	Invoke deadlock detection with a full
 *				walk of the lock chain.
 */
enum rtmutex_chainwalk {
	RT_MUTEX_MIN_CHAINWALK,
	RT_MUTEX_FULL_CHAINWALK,
};

/*
 * PI-futex support (proxy locking functions, etc.):
 */
extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
				       struct task_struct *proxy_owner);
extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
				  struct task_struct *proxy_owner);
extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
				     struct rt_mutex_waiter *waiter,
				     struct task_struct *task);
extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
				      struct hrtimer_sleeper *to,
				      struct rt_mutex_waiter *waiter);
extern int rt_mutex_timed_futex_lock(struct rt_mutex *l, struct hrtimer_sleeper *to);
extern bool rt_mutex_futex_unlock(struct rt_mutex *lock,
				  struct wake_q_head *wqh);
extern void rt_mutex_adjust_prio(struct task_struct *task);

#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
#else
# include "rtmutex.h"
#endif

#endif
Commit	Line	Data
23f78d4a IM	1	/*
	2	* RT Mutexes: blocking mutual exclusion locks with PI support
	3	*
	4	* started by Ingo Molnar and Thomas Gleixner:
	5	*
	6	* Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
	7	* Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
	8	*
	9	* This file contains the private data structure and API definitions.
	10	*/
	11
	12	#ifndef __KERNEL_RTMUTEX_COMMON_H
	13	#define __KERNEL_RTMUTEX_COMMON_H
	14
	15	#include <linux/rtmutex.h>
	16
61a87122 TG	17	/*
	18	* The rtmutex in kernel tester is independent of rtmutex debugging. We
	19	* call schedule_rt_mutex_test() instead of schedule() for the tasks which
	20	* belong to the tester. That way we can delay the wakeup path of those
	21	* threads to provoke lock stealing and testing of complex boosting scenarios.
	22	*/
	23	#ifdef CONFIG_RT_MUTEX_TESTER
	24
	25	extern void schedule_rt_mutex_test(struct rt_mutex *lock);
	26
	27	#define schedule_rt_mutex(_lock) \
	28	do { \
	29	if (!(current->flags & PF_MUTEX_TESTER)) \
	30	schedule(); \
	31	else \
	32	schedule_rt_mutex_test(_lock); \
	33	} while (0)
	34
	35	#else
	36	# define schedule_rt_mutex(_lock) schedule()
	37	#endif
	38
23f78d4a IM	39	/*
	40	* This is the control structure for tasks blocked on a rt_mutex,
	41	* which is allocated on the kernel stack on of the blocked task.
	42	*
fb00aca4 PZ	43	* @tree_entry: pi node to enqueue into the mutex waiters tree
fb00aca4 PZ	44	* @pi_tree_entry: pi node to enqueue into the mutex owner waiters tree
23f78d4a IM	45	* @task: task reference to the blocked task
	46	*/
	47	struct rt_mutex_waiter {
fb00aca4 PZ	48	struct rb_node tree_entry;
fb00aca4 PZ	49	struct rb_node pi_tree_entry;
23f78d4a IM	50	struct task_struct *task;
	51	struct rt_mutex *lock;
	52	#ifdef CONFIG_DEBUG_RT_MUTEXES
	53	unsigned long ip;
48d13e48	54	struct pid *deadlock_task_pid;
23f78d4a IM	55	struct rt_mutex *deadlock_lock;
23f78d4a IM	56	#endif
2d3d891d	57	int prio;
23f78d4a IM	58	};
	59
	60	/*
fb00aca4	61	* Various helpers to access the waiters-tree:
23f78d4a IM	62	*/
	63	static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
	64	{
fb00aca4	65	return !RB_EMPTY_ROOT(&lock->waiters);
23f78d4a IM	66	}
	67
	68	static inline struct rt_mutex_waiter *
	69	rt_mutex_top_waiter(struct rt_mutex *lock)
	70	{
	71	struct rt_mutex_waiter *w;
	72
fb00aca4 PZ	73	w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	74	tree_entry);
23f78d4a IM	75	BUG_ON(w->lock != lock);
	76
	77	return w;
	78	}
	79
	80	static inline int task_has_pi_waiters(struct task_struct *p)
	81	{
fb00aca4	82	return !RB_EMPTY_ROOT(&p->pi_waiters);
23f78d4a IM	83	}
	84
	85	static inline struct rt_mutex_waiter *
	86	task_top_pi_waiter(struct task_struct *p)
	87	{
fb00aca4 PZ	88	return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	89	pi_tree_entry);
23f78d4a IM	90	}
	91
	92	/*
	93	* lock->owner state tracking:
	94	*/
8161239a LJ	95	#define RT_MUTEX_HAS_WAITERS 1UL
8161239a LJ	96	#define RT_MUTEX_OWNER_MASKALL 1UL
23f78d4a IM	97
	98	static inline struct task_struct rt_mutex_owner(struct rt_mutex lock)
	99	{
	100	return (struct task_struct *)
	101	((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
	102	}
	103
8930ed80 TG	104	/*
	105	* Constants for rt mutex functions which have a selectable deadlock
	106	* detection.
	107	*
	108	* RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
	109	* no further PI adjustments to be made.
	110	*
	111	* RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
	112	* walk of the lock chain.
	113	*/
	114	enum rtmutex_chainwalk {
	115	RT_MUTEX_MIN_CHAINWALK,
	116	RT_MUTEX_FULL_CHAINWALK,
	117	};
	118
c87e2837 IM	119	/*
	120	* PI-futex support (proxy locking functions, etc.):
	121	*/
	122	extern struct task_struct rt_mutex_next_owner(struct rt_mutex lock);
	123	extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
	124	struct task_struct *proxy_owner);
	125	extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
	126	struct task_struct *proxy_owner);
8dac456a DH	127	extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
8dac456a DH	128	struct rt_mutex_waiter *waiter,
c051b21f	129	struct task_struct *task);
8dac456a DH	130	extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
8dac456a DH	131	struct hrtimer_sleeper *to,
c051b21f TG	132	struct rt_mutex_waiter *waiter);
c051b21f TG	133	extern int rt_mutex_timed_futex_lock(struct rt_mutex l, struct hrtimer_sleeper to);
802ab58d SAS	134	extern bool rt_mutex_futex_unlock(struct rt_mutex *lock,
	135	struct wake_q_head *wqh);
	136	extern void rt_mutex_adjust_prio(struct task_struct *task);
36cf3b5c TG	137
	138	#ifdef CONFIG_DEBUG_RT_MUTEXES
	139	# include "rtmutex-debug.h"
	140	#else
	141	# include "rtmutex.h"
	142	#endif
	143
23f78d4a	144	#endif