[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>

/*
 * 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
	17	/*
	18	* This is the control structure for tasks blocked on a rt_mutex,
	19	* which is allocated on the kernel stack on of the blocked task.
	20	*
fb00aca4 PZ	21	* @tree_entry: pi node to enqueue into the mutex waiters tree
fb00aca4 PZ	22	* @pi_tree_entry: pi node to enqueue into the mutex owner waiters tree
23f78d4a IM	23	* @task: task reference to the blocked task
	24	*/
	25	struct rt_mutex_waiter {
fb00aca4 PZ	26	struct rb_node tree_entry;
fb00aca4 PZ	27	struct rb_node pi_tree_entry;
23f78d4a IM	28	struct task_struct *task;
	29	struct rt_mutex *lock;
	30	#ifdef CONFIG_DEBUG_RT_MUTEXES
	31	unsigned long ip;
48d13e48	32	struct pid *deadlock_task_pid;
23f78d4a IM	33	struct rt_mutex *deadlock_lock;
23f78d4a IM	34	#endif
2d3d891d	35	int prio;
23f78d4a IM	36	};
	37
	38	/*
fb00aca4	39	* Various helpers to access the waiters-tree:
23f78d4a IM	40	*/
	41	static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
	42	{
fb00aca4	43	return !RB_EMPTY_ROOT(&lock->waiters);
23f78d4a IM	44	}
	45
	46	static inline struct rt_mutex_waiter *
	47	rt_mutex_top_waiter(struct rt_mutex *lock)
	48	{
	49	struct rt_mutex_waiter *w;
	50
fb00aca4 PZ	51	w = rb_entry(lock->waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	52	tree_entry);
23f78d4a IM	53	BUG_ON(w->lock != lock);
	54
	55	return w;
	56	}
	57
	58	static inline int task_has_pi_waiters(struct task_struct *p)
	59	{
fb00aca4	60	return !RB_EMPTY_ROOT(&p->pi_waiters);
23f78d4a IM	61	}
	62
	63	static inline struct rt_mutex_waiter *
	64	task_top_pi_waiter(struct task_struct *p)
	65	{
fb00aca4 PZ	66	return rb_entry(p->pi_waiters_leftmost, struct rt_mutex_waiter,
fb00aca4 PZ	67	pi_tree_entry);
23f78d4a IM	68	}
	69
	70	/*
	71	* lock->owner state tracking:
	72	*/
8161239a LJ	73	#define RT_MUTEX_HAS_WAITERS 1UL
8161239a LJ	74	#define RT_MUTEX_OWNER_MASKALL 1UL
23f78d4a IM	75
	76	static inline struct task_struct rt_mutex_owner(struct rt_mutex lock)
	77	{
	78	return (struct task_struct *)
	79	((unsigned long)lock->owner & ~RT_MUTEX_OWNER_MASKALL);
	80	}
	81
8930ed80 TG	82	/*
	83	* Constants for rt mutex functions which have a selectable deadlock
	84	* detection.
	85	*
	86	* RT_MUTEX_MIN_CHAINWALK: Stops the lock chain walk when there are
	87	* no further PI adjustments to be made.
	88	*
	89	* RT_MUTEX_FULL_CHAINWALK: Invoke deadlock detection with a full
	90	* walk of the lock chain.
	91	*/
	92	enum rtmutex_chainwalk {
	93	RT_MUTEX_MIN_CHAINWALK,
	94	RT_MUTEX_FULL_CHAINWALK,
	95	};
	96
c87e2837 IM	97	/*
	98	* PI-futex support (proxy locking functions, etc.):
	99	*/
	100	extern struct task_struct rt_mutex_next_owner(struct rt_mutex lock);
	101	extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
	102	struct task_struct *proxy_owner);
	103	extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
	104	struct task_struct *proxy_owner);
8dac456a DH	105	extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
8dac456a DH	106	struct rt_mutex_waiter *waiter,
c051b21f	107	struct task_struct *task);
8dac456a DH	108	extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
8dac456a DH	109	struct hrtimer_sleeper *to,
c051b21f TG	110	struct rt_mutex_waiter *waiter);
c051b21f TG	111	extern int rt_mutex_timed_futex_lock(struct rt_mutex l, struct hrtimer_sleeper to);
802ab58d SAS	112	extern bool rt_mutex_futex_unlock(struct rt_mutex *lock,
	113	struct wake_q_head *wqh);
	114	extern void rt_mutex_adjust_prio(struct task_struct *task);
36cf3b5c TG	115
	116	#ifdef CONFIG_DEBUG_RT_MUTEXES
	117	# include "rtmutex-debug.h"
	118	#else
	119	# include "rtmutex.h"
	120	#endif
	121
23f78d4a	122	#endif